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nzjetboating.com Forums => Projects => Topic started by: Jimmy Jet on June 12, 2018, 20:10:58 PM

Title: New Perron Mitchell hull
Post by: Jimmy Jet on June 12, 2018, 20:10:58 PM
Howzit Team,
Here's a peak at the new hull I have on the way. Built by Perron Mitchell (Mitchell Machines) near Tauranga.
4.45mtr.
Lexus and 2 stage Colorado going in it.
Hopefully will remember to keep posting updates.
Title: Re: New Perron Mitchell hull
Post by: steelo on June 12, 2018, 22:31:08 PM
Niiiice JJ. Good luck with the build and don't forget the pics
Title: Re: New Perron Mitchell hull
Post by: rockstars on June 13, 2018, 06:50:22 AM
Great looking boat,
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on June 21, 2018, 22:19:48 PM
Will slowly update with a few pics as I remember. A lot of my files are too big.
Started the underfloor HX tonight.
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on June 22, 2018, 08:05:53 AM
Thats a cunning little trick for drilling a hole in a bend.
Keep the pictures coming.

You may have to install "photo & picture resizer" app, it's quick and easy to use.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on June 22, 2018, 20:08:51 PM
 Steering hub. Started life as a damaged hydraulic actuator boss. I machined off all the unwanted excess and bored it out to take a couple of sealed bearings. I haven't countersunk the mount holes yet.
Title: Re: New Perron Mitchell hull
Post by: steelo on June 22, 2018, 20:53:11 PM
That's what we like to see JJ. Lots of pics of every aspect of the build. Good luck and regards from oz
Title: Re: New Perron Mitchell hull
Post by: PM on June 23, 2018, 18:55:01 PM
Steering hub. Started life as a damaged hydraulic actuator boss. I machined off all the unwanted excess and bored it out to take a couple of sealed bearings. I haven't countersunk the mount holes yet.

Counter-bore them instead
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on July 18, 2018, 20:08:04 PM
Whipped up one half of the underfloor heat exchanger tonight. I've done a fair bit of tig welding before but copper is next level in terms of heat control. Guess that's why it makes good heat exchanger material.
Title: Re: New Perron Mitchell hull
Post by: steelo on July 18, 2018, 21:52:15 PM
Tigging is pretty high tech. Don't you just sweat the pipes or braze them together with solder.
Title: Re: New Perron Mitchell hull
Post by: mohawk on July 18, 2018, 22:10:37 PM
Tigging copper is pretty easy steelo , even i can do it.
 
Title: Re: New Perron Mitchell hull
Post by: steelo on July 18, 2018, 22:12:37 PM
Thanks Mohawk. I didn't know that. (not that I've ever done it) I've only watched a lot of plumbers. Cheers S
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on July 18, 2018, 22:16:22 PM
Tigging is pretty high tech. Don't you just sweat the pipes or braze them together with solder.
Yes normally it's soldered or brazed but I couldn't remember which Flux to use and we had no filler wire. There was plenty of oxygen free copper heavy multi core cable around so I split that and used it as filler wire.
Tig is not really that high tech, it's electric gas welding really. On DC anyway.
Title: Re: New Perron Mitchell hull
Post by: mohawk on July 18, 2018, 22:32:41 PM
i just stripped some random copper cable for filler wire and found it pretty easy .. I Had too do tiny runs too stop blowing thru cause im pretty useless , but jeff did some fittings for me and he was a bit better at it  ;D
Title: Re: New Perron Mitchell hull
Post by: steelo on July 18, 2018, 22:47:02 PM
That'd be an understatement. Jeff could tig two sheets of paper together using navel lint as a filler
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 15, 2018, 20:27:17 PM
Sorry about lack of updates. Our workshop burnt to the ground last week so I'm really thin on gear for a while and lost a few pieces out of the Colorado and off the Lexus. On the bright side Perron is going really well on the hull.
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on August 15, 2018, 21:03:08 PM
Mate! That's not great. Hope things go a bit smoother from now on
Title: Re: New Perron Mitchell hull
Post by: Matthewf/Norbert/TuiDog on August 15, 2018, 23:24:37 PM
ouch.. keep on keeping on!
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on October 23, 2018, 20:29:09 PM
Been a slow process since the workshop burnt down but very happy with the product Perron has produced. Not my trailer its on. Budget can't do it. This time....
Title: Re: New Perron Mitchell hull
Post by: rockstars on October 23, 2018, 20:59:39 PM
Very nice looking boat and trailer, keep the updates comming.
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on October 23, 2018, 21:12:14 PM
Nice looking boat! What length?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on October 23, 2018, 22:20:53 PM
The hull is 4.6m. 12deg at the transom variable to 15 at the front. Will confirm beam. Setting up as a 4 seat boat. Keeps a little weight out and leaves some floor space either side of the rear seat for bits n pieces.
Title: Re: New Perron Mitchell hull
Post by: luckxb on November 15, 2018, 01:53:58 AM
The hull is 4.6m. 12deg at the transom variable to 15 at the front. Will confirm beam. Setting up as a 4 seat boat. Keeps a little weight out and leaves some floor space either side of the rear seat for bits n pieces.

Nice boat! Where to buy the DXF or  CAD ?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on December 14, 2018, 10:44:18 AM
Picked up the hull from Michell Machines 2 nights ago. Really happy with build quality and the lines. Time to get into it.
Title: Re: New Perron Mitchell hull
Post by: silvafox on December 14, 2018, 12:03:16 PM
chine line looks pretty interesting at the front how it stops back quite a way front the tip of the bow sheets, can we have a better pic?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on December 14, 2018, 12:28:32 PM
Yep its a point of difference not usually seen in many Kiwi boats. The builder spent
time in the Pacific Northwest of the States building boats so a few ideas have migrated over. Will update again when I get more pics.
 
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 02, 2019, 09:01:19 AM
Slowly getting things done. Just need to mount steering hub and the wheel and the steering will be complete once I splice up the dyneema.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 02, 2019, 09:04:48 AM
Common shaft for steering and reverse. Spherical bearing top and bottom.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 02, 2019, 14:47:41 PM
Be sure too stretch crap out of the Dyneema (if you didnt already know too )
What was the beam at the chine ?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 02, 2019, 16:48:37 PM
Yep copy on pre-stretch. I had read that on one of your posts I think Mohawk. Will come back to you on chine beam.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 02, 2019, 18:32:23 PM
Can ya post some more pics of how he has mounted the pump... Has the grill been sleeved into the hull at the front or bolted ?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 02, 2019, 20:31:31 PM
Correct the grill is sleeved in with 3 bolts at the back. I'll put a pic up next time I can get an undershot. The boat is in at work stored on top of a container and I use the gantry to get it down when doing a big run of stuff.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 02, 2019, 20:47:35 PM
Best way too do a colorado IMO  b>
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 02, 2019, 21:24:07 PM
Yeah hes done a nice job of it. I'll build the trailer so the grill can be pulled if needed without sliding the boat back.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 08:26:15 AM
Sorry for the lack of updates, things are progressing....slowly. A few pics attached.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 08:29:32 AM
Painted the unit in industrial 2 pak. Tough as nails. By fluke its an exact colour match with the sealant I used.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 08:33:57 AM
Using bellows isnt the prettiest but the cover hides them.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 08:36:25 AM
A lot of the fasteners you see are temporary galv while sealant was setting. Nothing is locked up in these photos.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 09:15:19 AM
Some of the new parts I machined up/refurbished for the unit.Carbon seal face holder. Bearing housing seal holder. Torquing up the main bearing before install into the housing.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 09:26:00 AM
Engine parts. Flywheel prior to ring gear being shrunk on and machined to suit driveshaft flange. Alternator belt tensioner. Will be lightened once I know if I have enough adjustment, waiting on the belt.
Title: Re: New Perron Mitchell hull
Post by: mohawk on August 17, 2019, 10:59:48 AM
Nice job on the front bearing gussets , Thin castings in that area is the only thing that lets the colorado down ....
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 11:14:32 AM
I didn't do those, and they are definitely  cast into the housing. Not sure if it is the very last of the Colorados. I've only seen one other with them. Does anyone have further knowledge on this?
Title: Re: New Perron Mitchell hull
Post by: daveb on August 17, 2019, 13:18:56 PM
That intake you have is a factory race intake, strengthened up around the bearing mount.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on August 17, 2019, 14:39:45 PM
Thanks. Makes sense, I was told it was a sprint unit when I got it 20+ years ago. Thats why the std steering has been modified as well.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on September 02, 2019, 09:53:13 AM
Got the front engine mounts started. Still have to bore the lightening holes.
Perron's accuracy is excellent, once the engine was aligned with the unit I made templates for the port side. When transferred to the stb the parts were virtually identical.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on September 10, 2019, 13:56:46 PM
Got rear mount in place and tacked up. Front mounts drilled out. Will get them off to the platers tomorrow I hope. Interesting on the lexus that the front mounts bear most the weight, its nearly balanced.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on September 10, 2019, 20:20:31 PM
Rear mount. Will drill the bolt down holes tomorrow and get off for plating.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on September 28, 2019, 08:13:43 AM
Mounts plated and installed. I've ditched as much excess crap off the Lexus as I can. Still a few bolts to go in. Filter relocation kit is from Venom Automotive in Oz. Very nice quality.
Title: Re: New Perron Mitchell hull
Post by: wad26 on September 30, 2019, 16:26:13 PM
How much was the filter relocation kit? I got mine off Aliexpress for around $100 including hoses and fittings. Quality was terrible though and required some time in the milling machine...
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on September 30, 2019, 17:12:39 PM
It was $175 Australian for the block plate, filter holder and AN fittings. All cnc'd. Can't fault the quality.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on December 03, 2019, 18:10:54 PM
Been slow on updates but still chipping away. I made a small header tank. Have got the trailer frame and slides well underway and the exhaust system started. I went for logs in the end for various reasons and have managed to get the muffler tucked up and out of the way right up the back. Gives heaps of access to the steering gear and driveshaft. Jacketing the main outlets is time consuming but going not too bad. Not as sharp on tube as I used to be but you need to be doing it a bit more than I do.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on December 03, 2019, 18:14:15 PM
Sorry on photo quality, I think I resized a bit small.
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on December 03, 2019, 21:37:40 PM
Good work b>
Using small file size photos and poor lighting is a trick Mohawk and me have been using to hide yucky welds for years..... he has to do it more often than me  ;)
Title: Re: New Perron Mitchell hull
Post by: mohawk on December 04, 2019, 09:23:19 AM
Good work b>
Using small file size photos and poor lighting is a trick Mohawk and me have been using to hide yucky welds for years..... he has to do it more often than me  ;)
Not just welds either
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on December 04, 2019, 09:32:03 AM
I've shrunk the ring gear and welded it onto the flywheel. I lost the original starter in the workshop fire so went with a Roadrunner for not much more. Plenty of grunt and has bearings instead of bushes. The supplier is local so its good to support him.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on December 04, 2019, 15:34:14 PM
Skiddy stuff. I added a 3mm Bisalloy skid plate a while back. Took a lot of templating with the compound curve at the bow to get right but pretty pleased with how it came up. Purely there to help the boat slide, not as impact protection.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 27, 2020, 11:09:36 AM
Hi guys, time for a quick update. I've pretty much sorted the exhaust system, just need to tap the boss for the 02 sensor. HX is completed and mounted just needs hosing up but being in the same boat as most of you I can't buy any parts...the other bummer is that I can be in at work (we are an essential business) but only there for hours of WORK so no staying on to do jetboat bits.
Title: Re: New Perron Mitchell hull
Post by: Swift12 on March 27, 2020, 13:23:33 PM
hey jimmy. im not being a smart ass but how does water left in the exhaust not get back into the motor with the exhaust setup? im intrigued as to how it works...
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 27, 2020, 14:02:25 PM
All good not taken that way. A more recent photo of the exhaust with the outlet included. Inside the main tube off each major 'log' is a 90deg bend so the pulses are facing each other. They are positioned at the highest point in the tube. The pipes off each bank are fully jacketed and dump into the main cross tube at the lowest point. Its more or less just a common riser.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 27, 2020, 14:08:48 PM
Another solidworks drawing attached.
Title: Re: New Perron Mitchell hull
Post by: Swift12 on March 27, 2020, 20:16:26 PM
ah right I see....nice one....so the water left in the main balance tube just runs nicely out the outlet...cheers..g
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 27, 2020, 20:27:10 PM
Yes thats the theory. I can't find the figures on how much water it would need to backfill before getting into the bends but it was a lot, and it would need the flapper to be jammed shut at that.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 27, 2020, 20:32:23 PM
Arent lexuses prone too back sucking water ?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 27, 2020, 21:32:57 PM
Not sure but its got quite a lift if its going to do it. I've got more rise than any off the shelf riser.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 27, 2020, 21:41:56 PM
your cooling water , not water from outside  ...
Its all down hill from the ballance pipe and you run the risk of sucking water back from inside the ballance pipe possibly ..
Ive just had much the same issue , I had water entering at the top of my riser and not far enough down stream too keep it out of the engine at idle and shutdown.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 27, 2020, 22:13:50 PM
I totally understand your concern and appreciate it for sure. Is it not pretty much the same set up as the attached photo on Karls boat, just my collector/balance pipe is placed further back? I'm sure Jeff B has also done similar mufflers as well I just can't find the photo, as thats pretty much where I got the idea.
Title: Re: New Perron Mitchell hull
Post by: Jeff B on March 27, 2020, 22:32:59 PM
Will be fine.
The balance pipe will have to half fill up with water before it feeds back down to engine. And the cooling water only flows when engine is running.
You might get a bit of vapour mist at idle.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 27, 2020, 22:59:27 PM
Its usually at idle or when you stop , or if you have issues with idle...
Should be fine if jeff says so ( havent seen water in any of his motors lately )  b>
 its the bends at the top that make me wonder ..
https://www.youtube.com/watch?v=dWF8xK2gzH8
Title: Re: New Perron Mitchell hull
Post by: Warwick Marflitt on March 27, 2020, 23:25:54 PM
Jimmy
      Your builds looking awesome. Fabrication and set up looks trick...... Copper heat exchanger fits in well. Good to see its insulated from the hull. Knowing what I know about Boats Electricity and Galvanic corrosion. I would have made it out of alloy not copper.
Have a read over this post from another forum.... It will allow you some insight into what can go wrong...

https://www.boatdesign.net/threads/corrosion-copper-and-aluminum.37891/

Maybe paint the copper outside with some of that good paint you used on the jet unit and with the correct % of antifreeze mix in the coolant you wont have to worry.... Some will disagree with me. I have no issue with that.... Each too his informed own....
For an in depth read you could waste some valuable time reading this PDF On "Corrosion Zincs and Bonding"  by Editor & Publisher:   Michael Kasten from the "Metal boat Quarterly" Published by "The Metal Boat Society"

http://www.kastenmarine.com/_pdf/mbqCref.pdf

Keep up the fantastic build. Its a great looking hull.....Keep chipping away at it
   
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 07:41:29 AM
Thanks Warwick. Yes I did consider alloy but preferred the extra cooling capacity of the copper. The mounts are plastic hydraulic hose clamps. I too share your concerns about copper and aluminum, have had several alloy eggbeater ocean boats and have seen first hand damage from dissimilar metals. Even copper wire shards sitting in the hull after wiring can be an issue particularly when salt water is in play. I don't have any intention of using this boat in salt. Yes I'll def be using anti-freeze.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 08:02:49 AM
Mohawk, suggestions on a better way to do it maybe or a drawing? Of course I don't want to get water back so will redesign it if needed BUT I have more or less copied others designs on here and gotten advice on the forum from some switched on guys. I think maybe a saving grace when at idle is the length of the run up to the balance pipe, anything coming back should run into a pulse and get pushed back out. Do you think running a bit higher idle would be a good idea? Turning the motor off sounds like it could be my biggest worry. Is the Lexus worse that others with overlap/suckback?
I'm not too proud to make it again but happy with Jeffs endorsement. The worst bit is I wont know until I use it.....
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 08:23:12 AM
I may add a second outlet yet which should help keep water out of the balance pipe also. I'm sure I read that some have put pcv valves in the system as well to help break vacuum. Thoughts?
Title: Re: New Perron Mitchell hull
Post by: Allen M on March 28, 2020, 09:45:04 AM
Its usually at idle or when you stop , or if you have issues with idle...
Should be fine if jeff says so ( havent seen water in any of his motors lately )  b>
 its the bends at the top that make me wonder ..
https://www.youtube.com/watch?v=dWF8xK2gzH8
I?m with Jeff on the one.
The bends at the top are dry inside unlike the attached YouTube clip where the cooling water is being injected into the main tube.
The bends help seperate the cooling water in the balance tube.
You may get a small amount of vapour sucked back down the main tube on shutdown.
When you trailer your boat give the throttle a small blip once the Jetunit is clear of the water to clear any vapour. B))T
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 28, 2020, 11:09:11 AM
Some engines are worse than others ..
I had a hard time ballancing carbs on my honda ( cause i was looking at the 4 guages back too front  l-l )
For 20 min it was stumbling and stalling and coughing and once i had it sorted the oil was all milky..
Was so clean you couldnt see it on the did stick an hour earlyer , and had been for 5 months.

I had always had lots of white puss in the rocker covers though  that would clear on an hour long run but return quickly when doing short test runs or fishing ( 20 min trips )
I had the water entering at the top of the riser 50mm down stream of the bend and thought it would be enough , but after moving it 200mm further down the rocker cover is spotless now.

If your like jeff and allan , and seldom do alot of short runs its probly no big deal , but the bends are horizontal , then turn down and id be affraid the exhaust pulse may shoot water into them ?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 11:24:14 AM
Don't get me wrong Mohawk, I'm hearing you and concerned about it now. It def might not be ideal and it could be fine. It might be a case of run it and shut down then crack the flanges at the end of logs and look for evidence of moisture. It would pain me to do it again as there was a shitload of time in it but I will if its proving no good. Bad case, milky oil. Worst case hydraulic....
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 28, 2020, 11:34:19 AM
Leave it as the experts have said if you want ...
But heres a list of thing i noticed from 7 months of using the every second weekend .

Idling on the hose with bugger all water running you could clearly notice the idle stumble and drop .

White puss would build up under the rocker cover ( but burn off on a long run )

oil in the sump stayed spotless most of the time.

After stopping on long and short runs , restarts were instant but rough as gutts for a second or two.

I moved the water down stream twice , each time starts and puss got better ..


Note , the header and exhaust system were identical too what i had on the M18a for 5 years without issue.

Not trying too bum you out , and the symtems arent going too hurt the motor so dont change what aint broke , I also take expert advice with a pinch of salt ( usually theyre trying too sell you something  :P )
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 11:46:30 AM
Its not bumming me out at all, if we all get good information for better design then the forum is working.
How do injected headers get on with it? The type that have water injected an inch from the exhaust port? Surely they are a recipe for disaster?
Can you draw what you think would work better. Would be most appreciated.
Cheers.
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on March 28, 2020, 11:51:15 AM
Jimmy as we all know, we often worry about things that never eventuate.
 
My advice would be to forget about it and stop worrying. It looks like you have put a lot of work into it and made a nice job.
Once you have run it and shut it down a few times pull the plugs and see what you find... moisture on plugs or use a inspection camera
A - Jeff and Allen correct   ;D
B - Mohawk correct  C""
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 13:15:16 PM
Thanks Lazy. I will for sure keep an eye on it and report back. I'm going to add a second outlet too. I'm big on symmetry anyway and the single outlet doesn't look right or fit well with a V8. In my eyes.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 13:41:25 PM
A few more photos for those needing stuff to look at during the apocalypse.
Angled helm boss I machined up.
Flywheel drive block/spline.
Poor mans H bar mocked up for length checking. 1350 series. It might cope with the Lexus.
An earlier pic of shaping up the bissaloy skid plate.
Title: Re: New Perron Mitchell hull
Post by: Swift12 on March 28, 2020, 14:17:23 PM
sorry if I started something jimmy jet.....wasn't intending too rain on your parade but seems like good discussion ensued. someone told me the other day that 90% of what we worry about doesn't happen so Id go with that and like the guys say....if it aint broke dont fix it.....Id test it and see what the go is...might be perfect!
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 28, 2020, 14:23:26 PM
No, its all good honestly. If we can  all get better ideas out there that will provide better, cheaper and more reliable boating then its good chat.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 28, 2020, 15:50:32 PM
Ive been running h bars same as youve done there for 25 years ... its a superior set up too most  B))T
Title: Re: New Perron Mitchell hull
Post by: Swift12 on March 28, 2020, 19:10:25 PM
I wouldn't disagree mohawk....when i ran my motor last i had a small drip of water coming out the O2 bung on the manifold on the right side...they were both loose....either it was condensation or water coming back during idle! I would have thought that the hose rise manifolds would not have allowed that....i can imagine if its mist that was condensating around the loose bung the the O2 sensor wouldn't last long....
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 28, 2020, 21:02:23 PM
I watched a mate with a real lumpy cam ls3  eat 4 o2 sencors in 1 hour once.. they would work if he held his foot down ,  but when he slowed to idle  , they would take a dump.
He was with a very experianced tuner too , not a back yarder
Title: Re: New Perron Mitchell hull
Post by: Swift12 on March 28, 2020, 21:46:24 PM
interesting...I have heard they dont like idle in any setup so stick one in...check the tune...take it out....it might last a run or two... I have killed them in the race car but generally get a few meetings out of them...they hate condensation....the best thing is to ensure they only heat up when the engine starts and not before....my ECU turns on my heater on the car 20 secs after the start...thats enough time to blow most condensation out....if the condensation hits a hot sensor....boom its done. sorry  hi-
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 28, 2020, 21:55:44 PM
yup , like most things jetboating there is plenty of theory and good intention , but very little hard fact...
My favourite are the engine weight and boat speed threads  sl
Title: Re: New Perron Mitchell hull
Post by: Allen M on March 30, 2020, 09:11:34 AM
sorry if I started something jimmy jet.....wasn't intending too rain on your parade but seems like good discussion ensued. someone told me the other day that 90% of what we worry about doesn't happen so Id go with that and like the guys say....if it aint broke dont fix it.....Id test it and see what the go is...might be perfect!
I have another saying and that is if it can go wrong it will go wrong in a Jetboat. c0H
Double check everything and listen carefully to other people?s experiences.
That?s what this forum is all about  B))T
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 30, 2020, 09:30:10 AM
I build bridges and we say the same as Allan ... I always build a boat with the intension of having too fix it on the bank or in a motor camp .
Thats one big advantage of doing the fitout your self ( and not a bad job either in mohawks book  ;D )
Title: Re: New Perron Mitchell hull
Post by: Allen M on March 30, 2020, 19:48:29 PM
Leave it as the experts have said if you want ...
But heres a list of thing i noticed from 7 months of using the every second weekend .

Idling on the hose with bugger all water running you could clearly notice the idle stumble and drop .

White puss would build up under the rocker cover ( but burn off on a long run )

oil in the sump stayed spotless most of the time.

After stopping on long and short runs , restarts were instant but rough as gutts for a second or two.

I moved the water down stream twice , each time starts and puss got better ..


Note , the header and exhaust system were identical too what i had on the M18a for 5 years without issue.

Not trying too bum you out , and the symtems arent going too hurt the motor so dont change what aint broke , I also take expert advice with a pinch of salt ( usually theyre trying too sell you something  :P )
Been thinking about this Mohawk, All the symptoms you have described above sound like you could have a leaking head gasket or cracked head.  C""
To have your oil go milky with a warm running engine and missing at idle you?ve got quite a lot of water sloshing about in your cylinders.
A small amount of water would turn to vapour and burn off with no noticeable effect.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 30, 2020, 20:12:23 PM
Been thinking about this Mohawk, All the symptoms you have described above sound like you could have a leaking head gasket or cracked head.  C""
To have your oil go milky with a warm running engine and missing at idle you?ve got quite a lot of water sloshing about in your cylinders.
A small amount of water would turn to vapour and burn off with no noticeable effect.
Anything is possible , but its got alot better each time i move the exhaust water further down ... Ive had no sludge in the rocker cover since and the oil in the sump is clear as day. 
All the symptems i listed were from when i first built the motor and they have all gone now.
Title: Re: New Perron Mitchell hull
Post by: Warwick Marflitt on March 30, 2020, 20:37:28 PM
Some more boring reading about wet exhaust design and ideals......

https://www.sbmar.com/articles/designing-a-marine-exhaust-system/

2) Always use gravity to your advantage

Water flows downhill so, if you have a system that holds water (water jacketed risers for instance) and this system fails internally (it?s not IF it is going to fail, it?s WHEN it will fail), where will the water go?? Into the turbo/exhaust manifold/cylinders?? Think about YOUR riser or elbow should it fail internally where you can not see it and what might happen. Remember, WET risers are an absolute no-no for any long term application unless they are ?coolant cooled.? Internal failure of ?wet elbows? and custom water jacketed risers is an old and ongoing problem, regardless of material choice and/or other claimed construction features. (See Tip #7).
Title: Re: New Perron Mitchell hull
Post by: blairm on March 30, 2020, 23:08:23 PM
Hi,
The Build is looking good!
To give you some confidence I have a very similar set-up with my exhaust that works well.
Lexus v8, Jacketed out of the log manifold, bends inside the drum facing each other, single outlet to the transom.
I did aim to have the bends inside the drum in the upper 2/3 to give as much volume as possible before water would find its way back to the motor.
Main difference you have more horizontal distance from the logs to the drum, and your welded to the drum, I ended up using a rubber joint that the water feeds over.

Just a heads up I'm not sure what pipe sizes you have used for your jacketed section but I did get caught out with some small stones finding their way through and blocking at the water inlets.  Added a course filter/strainer after the sand trap as a safety and haven't had any issues since. (to be fair at the time it was some make it or break it boating)

Drum is always a good temp under power with loads of water running through it, can warm up a bit at the top when trolling not a real issue can still touch it (if your fast). If your doing a bit of slow stuff I'd consider adding a feed to the top of the drum like in the photo of karls setup you posted. There always seems to be enough water to keep the rubber joints cold just warm on the top of the drum.

I have tried to add a photo for your reference but my computers is not playing game. Will see if it works.

Good luck.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 31, 2020, 00:03:21 AM
Great info, thanks. Eases the mind some more. Good tip on the stones. Why do they get through the sandtrap but not sand?
Also curious about the rubbers? To stop potential cracking? Cheers, I appreciate it.
Title: Re: New Perron Mitchell hull
Post by: Warwick Marflitt on March 31, 2020, 14:12:45 PM
So what happens when at full power high speed you have to stop in a hurry. Spin and shut down the engine! Where's the water, going to drain too? Gravity will pull the water down hill to the lowest places in the system!
Here's my interpretation on the two types.... I may be wrong If so tell me please and I will correct or you can change my pics..... Also... What happens when they fail internally???
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on March 31, 2020, 14:33:34 PM
I dont think there is any way of protecting any motor with any type of manifold if it fails internally.
Title: Re: New Perron Mitchell hull
Post by: mohawk on March 31, 2020, 15:35:49 PM
Mine was basicly the same as the bottom photo when i had all the trouble
Now its like the top photo ...
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on March 31, 2020, 16:23:19 PM
Quote
to be fair at the time it was some make it or break it boating

  ;D ;D ;D ;D
Title: Re: New Perron Mitchell hull
Post by: Allen M on April 01, 2020, 09:18:39 AM
My money is on the bottom system being the safest and quietest.
My previous boat initially ran the top setup and even with exhaust flaps fitted if you ran aground at speed water could rush up the pipe into the engine.  hhh
This isn?t possible with the bottom setup.
With the bottom setup the balance tube should be as large as practical with exhaust from engine entering at least 100mm into the the balance tube well clear of the bottom, preferably facing the centre. This will eliminate any risk of water sloshing about in the balance tube getting ingested back into the engine and
 give you the best performance, quietest, water ingestion proof exhaust system. B))T
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 08, 2020, 19:42:22 PM
I've given the Lexus the carb treatment, it was always the plan. I have a Pertronix billet distributor that I modified to take a bearing in place of the lower bush by way of a pressed on boss. The 1uz heads are symmetrical so have an unused cam cap at the back which is an ideal place to set up the dizzy. A lot of people go off the front but I needed the room that way. I slotted the cam in the mill to become the drive and put a boss onto the dizzy shaft.
Its sealed in the cam journal with an o ring.
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 08, 2020, 19:48:58 PM
I like the look of the manifold on the engine and all the crap/covers removed.
The black plastic piece is a 5deg carb angle plate to bring the carb back to level that I milled up. The engine is tilted back 5deg to match the Colorado which is mounted on a wedge.
Title: Re: New Perron Mitchell hull
Post by: Warwick Marflitt on April 08, 2020, 21:16:20 PM
The things we can do when were given the time eh! Fantastic job.....
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 08, 2020, 21:19:23 PM
Thanks Warwick. I did those bits a while back and only just gotten round to posting. Got a better photo resizing app which takes the ball-ache out of it!
Title: Re: New Perron Mitchell hull
Post by: Jeff B on April 08, 2020, 21:45:58 PM
Looks like a stock car intake manifold?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 08, 2020, 21:57:29 PM
It is, its an early Harcourt manifold. Its a bit of an unknown performance wise in this application, we will see I guess! May not be suitable at all, but at least its designed for a carb as opposed to dropping a carb on an injection manifold. Although thats been done succesfully. I started fabbing a manifold using the factory runners and the new starter motor is bigger than std so fouled it. I will modify it and see how its goes also. Manifolds are a dark art.
Title: Re: New Perron Mitchell hull
Post by: Kakapo76 on April 08, 2020, 22:16:57 PM
I've given the Lexus the carb treatment, it was always the plan. I have a Pertronix billet distributor that I modified to take a bearing in place of the lower bush by way of a pressed on boss. The 1uz heads are symmetrical so have an unused cam cap at the back which is an ideal place to set up the dizzy. A lot of people go off the front but I needed the room that way. I slotted the cam in the mill to become the drive and put a boss onto the dizzy shaft.
Its sealed in the cam journal with an o ring.

Thats a very tidy setup- nice work.  b>
Title: Re: New Perron Mitchell hull
Post by: Swift12 on April 08, 2020, 23:42:29 PM
Maybe a silly question but I?m interested....why go to carbs  and ditch fuel injection.....is there an advantage?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 09, 2020, 00:22:55 AM
No not silly. In my case I have enough knowledge (just!) and tools to deal with a carb and distributor should I have an issue. I can carry a spare coil, fuel pump and ignition module on a big trip (I have a couple planned), and more or less be good to go in a couple of hours if something dies and have more chance of fixing it on river. If things got really bad and the engine was submerged, as long as I can get fresh oil and fuel then I could probably be running again the next day provided it didn't hydraulic of course.
I've had a couple of carbed V8 ski boats and once correctly tuned proved super reliable, easy to start and maintain.
For what I can do, to help myself, its the simplest setup.
Title: Re: New Perron Mitchell hull
Post by: Swift12 on April 09, 2020, 07:30:45 AM
Ah thought it might be simplicity...lot to be said for that.....I converted my race car to a full electronic throttle for automatic blipping reasons and to be honest created more problems than I solved....I can understand if it?s possible to have a whoopsie being able to get it going again. If I submerge mine I?m going straight to the insurance company...after I cry a while... l-l
Title: Re: New Perron Mitchell hull
Post by: Ross Goldsack - JBNZ President on April 09, 2020, 11:26:25 AM
Quote
If I submerge mine I?m going straight to the insurance company...after I cry a while... l-l

Nar giving the inside of the engine a wash isn't usually too much of a drama. The best thing to do is get it going ASAP.
The LS1 powered boat pictured was going again the same night and back on the river the next day. Some times you can get away with siphoning 10 or 20 litres out of fuel tank and letting it settle out.
Really need 10 litres of oil and 2 oil filters and a bottle of meths 🤞🤞🤞

Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 09, 2020, 11:30:37 AM
Dead right about get them going straight away, get them hot! I've seen drowned dirt bikes both 2 and 4 stroke and a fully submerged eggbeater running again real quick!
Title: Re: New Perron Mitchell hull
Post by: Swift12 on April 09, 2020, 11:56:39 AM
Nar giving the inside of the engine a wash isn't usually too much of a drama. The best thing to do is get it going ASAP.
The LS1 powered boat pictured was going again the same night and back on the river the next day. Some times you can get away with siphoning 10 or 20 litres out of fuel tank and letting it settle out.
Really need 10 litres of oil and 2 oil filters and a bottle of meths 🤞🤞🤞

oh poor bugger but he doesn't seem to worried...looks like he is holding a beer!..... >>@
Title: Re: New Perron Mitchell hull
Post by: Matthew Feaver on April 25, 2020, 00:47:58 AM
Awesome progress on this mission. Looking great. Impressive seeing your self fabricated components. Bloody awesome. What is going to be your carb choice for the 1UZFE?
Title: Re: New Perron Mitchell hull
Post by: Jimmy Jet on April 25, 2020, 22:03:33 PM
Thanks a lot. I'm lucky to have a few options on carbs. I have a Holley 390 which I own, Holley 600 which I can borrow but will probably settle on a Quickfuel 450. I will start it initially on the 390. People tend to go too big on carbs. Honestly, its pretty experimental but prepared to fail and refine.