Check and double-check - assume nothing...

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
You guys that are building your own engines - Heads UP!

This is a first but probably won't be the last.

Notice anything wrong with this piston?

Check out the wrist pin being mis-drilled - this engine is in the process of being built for my GT40. It would have had a short life.. SRP did replace the whole set but you have to keep your eyes open.


IMG_1131.jpg


IMG_1132.jpg


IMG_1133.jpg


BTW - the pin holes were all machined too tight as well.. Don't think you can just pull these or any pistons right out of the box, hang them on rods and slap them in the bores..

Well - at least not if you want the engine to last...
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
(Trying this again - My last post seems to have gone into the Bit-Bucket)

I've used Ross pistons on many Competition engines and have had excellent service from all of them with never a failure. Matter of fact, I've had to do very little pin fitting and even balancing as they were most nearly perfect right out of the boxes.

This engine (my 331) is not being built for all out competition and therefore is on a little more restricted budget. Hence spending $220 for pistons rather than $800.
 
What length rod are you using to put the pin in the oil ring? Most the 5.400 rod 331's I've seen don't have the pin through the oil ring.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
5.4

That's part of the issue. The pin is too high and also offset too far.

It's basically an Eagle stroker kit.
 
Have a set of those here, pin height in relation to oil ring groove is same and dimpled rail is used to support bottom rail of oil ring. That appears to be standard to this setup with SRP, but in your case Randy the main issue is the pin is offset??? or is it just offset in relation to the pin boss.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
The pin offset is more on one side than the other (it's actually drilled crooked). It's also higher on this piston than the others. It would seem that this piston was not clamped in the jig in the right location when it was drilled. My only real point in posting this was to tell people not to just assume that all is well.
It's part of the difference between a shade-tree mechanic and a professional.

Jack - Have you used the Eagle kits before? What were your findings / thoughts?
 
[QUOTE

Jack - Have you used the Eagle kits before? What were your findings / thoughts?[/QUOTE]

No Randy, have not used full 'kits'- have used individual parts from Eagle along with most manufacturers though and have as yet to find a 'Dud' like that.- plenty of rumours abound in these 'shakey' Isles and if you believed them all you would be scared to use virtually any component from any manufacturer. The way you have handled the problem is correct & I am sure SRP etc will be much happier for it as they can trace back to that date of manufacturer & check for other faults & deal with them.[[ Well hopefully so! ]]
As you quite rightly point out its all in the checking prior to final assy- no point in crying for help after it fails because of some manufacturing fault that you or I or whoever assembled it failed to notice prior to assy. If your going to drive it harder than Granny on a sunday you have to make sure its fit for the purpose:).
 
Back
Top