So as I was putting my engine together a while ago I used kb 107 pistons in my 360 with file fit rings. I was talking to my grandpa and uncle about what a good end gap would be, we went slightly smaller than what was recommended with the pistons. (My grandpa used to run 12 and 9 on his hemi cars with no problems!) The first ring is about 24-25 thou and the second ring is about 19 or so thou. I know the second ring doesn't really matter as much and it can be the same as other pistons. But because they are hypo ones the top ring should have a wider end gap, and for whatever reason we didn't realize that initially, we just used the typical gap my uncle uses in his engines. Now the engine is done up to the heads and still on a stand so I could take it apart again and increase the ring gap if I have to, I just don't really want to if I don't need to. It recommended about 26 thou and up in the paperwork that came with the pistons, so I know my end gap is a bit smaller smaller than that. I've been doing some research and been reading that some people recommend running 28-30 thou, as being too loose Is better than too tight. This engine is a street car that won't really see the track or high loads for extended periods of time, no nitrous, forced induction or anything, so that in itself dictates a smaller end gap. Is my endgap too small? Or should I take the pistons out and increase the end gap?
Ring end gap potential problem
- Thread starter DartVadar
- Start date
-
Yea thought so, well, guess my weekend consists of increasing my ring gap a few thou. Don't really know why I didn't follow those instructions closer in the first place, well I guess you can always learn.
txstang84
Well-Known Member
Sorry, was writing while you were replying...you got it already.
Obviously I have to take the pistons out to do this but can I just take one piston out, file the rings, put it back in bolt everything up, turn the crank and go to the next one? Reason being is camshaft and timing chain are in and degreed, would like to do this without taking everything apart again. And can I use the same head gaskets? Heads are torqued down but obviously the engine has never ran.
80fbody
Well-Known Member
Certainly can do one piston assembly at a time. That's how I'd do it. Write on the piston with a sharpie with the gap when done. That way you won't 2nd guess yourself that they're all done. I'd re-use the gaskets. write on them as well so they go back exactly as they were removed for best results.
Take your time removing the piston so nothing gets nicked. Use rod bolt boots/tubing & it's good to have a 2nd set of hands to catch the piston. Keep everything clean. Again, take your time.
Take your time removing the piston so nothing gets nicked. Use rod bolt boots/tubing & it's good to have a 2nd set of hands to catch the piston. Keep everything clean. Again, take your time.
moper
Well-Known Member
x2 - and I'll add use something to push on the piston not the rod or rod bolts when you remove it. I use wood (like a piece of broomstick) so it doesn't mar anything and put it on the pin boss to avoid beating up the piston.
So all the pistons are out and the rings are now what the instructions with the pistons told me to set them to. I really messed this up and I'm super glad I took them out to check, the top ring was set to 18 thou! Scary to think about what would have happened if I ran it like that. I actually wrote Down the ring gaps this time. I guess it's better to have these problems while the engine is still on the stand than after a ring butted and wrecked something.
A minor setback but worth it, should be done the motor soon now and can finally drop it in my dart!
A minor setback but worth it, should be done the motor soon now and can finally drop it in my dart!
nm9stheham
Well-Known Member
Good thing you were thinking things over! I would never re-use the head gaskets unless I was Ok with maybe re-dioing them again; they can set into a slightly different location while being installed and will not seal as well. It does not make sense to take a chance (....unless you are stuck in the desert with no options).
surfer121
Well-Known Member
Since the OP never fired the motor and went through retorque he should be fine
when these pistons first came out we all used them in our stock car motors, with the flat top rule we had . opening night was a disaster for the amount of engines lost (all bow ties) they didn't follow the directions on the box. I did and got our first win of the season with a car that never had been on a track until hot laps that night.
My uncle said it was fine to use the old head gasket, I just cleaned everything really well the make sure no oil or anything was on the mating surface.
The engine is done now, literally spent all day yesterday working on it and got it all done. I'm 100% sure that everything is right as it should be now!
The engine is done now, literally spent all day yesterday working on it and got it all done. I'm 100% sure that everything is right as it should be now!
-
Similar threads
- Locked
