Sign in to follow this  
Mark Gregory

Using Diesel pistons for Gasoline engine pistons ? ?

Recommended Posts

Someone mentioned to me you can switch the gas pistons for diesel pistons . They did it on an old engine they could not find the correct size gas piston . I do not know if they needed an over sized piston or what . Has anyone else done this ?

 

Share this post


Link to post
Share on other sites
54 minutes ago, Mark Gregory said:

Someone mentioned to me you can switch the gas pistons for diesel pistons . They did it on an old engine they could not find the correct size gas piston . I do not know if they needed an over sized piston or what . Has anyone else done this ?

 

 There is so much technology in piston design that you could never find a diesel piston that would correctly perform in a gas engine.

This myth probably started with the diesel Oldsmobile engine that looked basically like a gas engine converted to a diesel.

Share this post


Link to post
Share on other sites

Possibly on something like a larger hit and miss engine, but in general diesel pistons are going to be too heavy for automotive engines. They are usually much more robust than gasoline engine pistons.

 

 

Greg in Canada

Share this post


Link to post
Share on other sites

There are company's who will make any kind of pistin you want. Diesel pistins would be heavy with really thick tops. Not good for a gas motor.

Share this post


Link to post
Share on other sites

There are company's who will make any kind of pistin you want. Diesel pistins would be heavy with really thick tops. Not good for a gas motor.

Share this post


Link to post
Share on other sites

Also  just putting a diesel piston in a gas engine will be so out of balance as to shake the engine apart and pound the bearings to dust.

  • Like 1

Share this post


Link to post
Share on other sites

Just to clarify a few things.

 

It doesn't matter what pistons you use, if they are a different weight from the ones you take out, you need to have the reciprocating assembly balanced.

 

Diesel piston design can vary a lot. If they are just flattops, they can be used just fine, ASSUMING you can achieve the correct compression ratio. If the pistons have weird contouring of the combustion face, that can cause a problem.

 

Back when they were newer, there were kits to convert Olds diesel motors to gasoline. The diesel pistons were reused. Only the cam and heads were changed.

 

 

Share this post


Link to post
Share on other sites

I would only go there as a last resort.  I can't imagine the chances are too good you could find pistons of similar weight (or lighter) than originals, wrist pin to top of piston dimension must be pretty close and then you have to worry about skirt clearance with the crankshaft counterwieghts (if any).  Egg offers pistons for some rather obscure makes.  https://egge.com/

Share this post


Link to post
Share on other sites

I don't see why anyone would play around trying to find diesel pistons for a gasoline engine or for that matter old pistons for a tired engine.  I bought a set of forged pistons for my Pontiac, one week delivery $200.00 each including pins and rings.  I will never need to replace them.  Last time around 35 years and 185,000 miles ago I was able to get cast pistons for $12.00 each.  That was a great deal but that was 35 years ago.  My time is worth too much to hunt all over for something that I may or may not find.  One phone call and a week later the pistons arrived at my door.

My Grandfather had a stout box about 12" x 18" x 12" high, in it he saved every nail that could possibly  be reused.  He would dump some out a pick through through them to find some that he could straighten and use.  He could nail with them but the always bent on me.  Today I have several drawers with tacks, brads, casing, finishing, box, common, roofing and panel nails.  When I finished building my own house in 1976 I sorted the left over nails and splurged another $20.00 on nails to have on hand if I needed them.  I have never straightened or bought another nail since then.  Just open the drawer, pick out the needed nail and finish the job.  As an example of my stock on hand,  I have never used a finishing nail where a casing nail was needed, unlike a lot of journeyman carpenters.

Maybe living through the Depression made people save everything and substitute things that would do instead of the proper item but we are not in a depression and my time is just too valuable.

Fix it correct and only fix it once.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this