Automotive or custom pistons?

jason32038

Chief Petty Officer
Joined
May 25, 2009
Messages
555
I am just curious but...arent automotive pistons stronger? Has anyone done any machining or milling to install auto pistons in any forces? I have an '86 85 hp and was wondering if I could make mine bulletproof. I know proper fuel mix and idle mixture settings are important but wouldnt it be nice to not have to worry about every melting a piston again? Pistons can be custom made. Any ideas?
 

tater76

Senior Chief Petty Officer
Joined
May 7, 2010
Messages
712
Re: Automotive or custom pistons?

I like your train of thought ;) but the only thing that would concern me is piston weight and tolerances.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Automotive or custom pistons?

There are automotive pistons with crossflow crowns on them???
 

pnwboat

Rear Admiral
Joined
Oct 8, 2007
Messages
4,251
Re: Automotive or custom pistons?

The Wiseco forged aluminum 2-stroke pistons for the Force motors are pretty stout. They even come with floating wrist pins just like the forged 4-stoke high performance automotive pistons that they make. No need to modify automotive pistons. The dome of the 2-stroke pistons are completely different than any automotive 4 stroke piston. Rings on 2-stroke motors have a pin to prevent them from rotating around the piston in the ring grove. Rings on 4-stroke automotive pistons are not. You would have to do a lot of re-working on an automotive piston.

Attached are pictures of a couple of forged pistons by Wiseco. One on the left is 2-stroke Force piston and a second one on the right is a 4-stoke Chevy piston.

3151PS.jpg wiseco_piston.jpg
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,927
Re: Automotive or custom pistons?

A friend had a Jersey Skiff with a 283 and he spent tons of money with special pistons and cams and EVERYTHING.
Trying to make the best/bullet proof.
He did nothing with the carb.Burned a hole in #3 ran too lean.
With the right amount of $ you can TRY anything.
The factory/wiseco produces a very good item.Then people get in the mix and don't do proper maint.Then the bullet proof is shot.
It would be tough to modify an automotive piston.See pnwboat's pics.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Automotive or custom pistons?

You can NOT modify auto pistons. They do not have full skirts and will not pull a vacuum in the crankcase. Thus: the engine will not induct any air and will not even start, much less run.

Stock auto pistons were cast, I don't know about new engines. So: Stock auto pistons are or were not stronger than stock outboard pistons. Aftermarket forged pistons are equally strong for auto or marine use.

Usually, you don't need to worry about melting a Chrysler or Force piston unless you run the engine lean. On a lean run, even auto engines will self destruct so don't think about making your engine "bulletproof." Concentrate on correct set-up and good preventive maintenance.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,618
Re: Automotive or custom pistons?

99% of factory auto pistons are cast pistons just like the 2 stroke engine. The only forged pistons are aftermarket or come in a Hi-performance engine. I am not Wiseco piston fan.....
 
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