When I dismantled my engine, every cylinder had compression rings where the gaps had lined up.

If that's the case, why do we bother setting up the orientation when we install the pistons?

I have always set my ring gaps so the compression ring gaps are set 1" each side of the wrist pin center line. I set the oil ring scrapers 1" each side of the seperator gap and all of that is on the piston side opposite the compression ring gaps.

This matches up with my Ford book. But I have seen other orientations. So I guess I'll continue with the Ford way even though the rings will rotate over time and the gaps will line up.

Any thoughts or opinions on this?

 

Because some DILL'DOE did it last time.

 

That "DILL'DOE" was me......LOL. I set them up right. Now, a few thousand miles later, I disassemble the engine and find all the compression ring end gaps lined up.

I never had this happen in any other type of engine I've rebuilt....er...that I've noticed....plus most of them are still together running fine, so I don't know yet.

 

There a few reasons
1: Ring travel
2: You made a errorr and have proven your human
3: You moved the rings when you removed the piston and didnt relized its

 

1/ Ring travel....yep, I can see that. Just not sure if there's anything that can be done about it with regards to original orientation methods.

2/ Yes, I make mistakes, but I don't think I made 8 mistakes, and what I found was gap alignment in every cylinder.

3/ Moved the rings on dissasembly. That's what I thought when I first noticed the problem. So I was careful after that and can confirm this was not the reason teh gaps were lined up.

Back to #1....I wonder if the vibration/pounding due to the detonation troubles I was having could have caused the rings to rotate to this final position?

For those of you that dont know, the outer ring on my harmonic balancer slipped and I adjusted the timing based on this. Over 20 degrees too far advanced. Finally a piston gave way. I should have known.....top end (high rpm) wasn't feeling right.

 

Ring travel is most comman with weak rings. It maybe a good idea to replace all the rings

 

Dohh!! LOL sorry bud! Other/most FE's I've plled apart do not share this same issue (none of them) so ?? Couldnt say really. Thats only been about 5 now so ?

 

No problem Redmanbob (named after the chewing tobacco, pray tell?) I will be changing rings. Old ones were hastings....new ones are a different brand.......I forget at the moment.

Actually, I am a little concerned about a related matter. New rings have a very light oil ring spacer. Nothing like the heavier hastings units.

 

You probably had/have an irregularity in the cylinder wall. was it honed without a torque plate? Was it honed with a rigid hone or just a flex hone? An odd shape in the wall with cause all the gaps to eventually line up. The rings always rotate at a rather slow speed during engine operation - at Sealed Power they embedded radioactive pellets in some rings to check this stuff out, and found that they rotate at a completely random speed and direction - even changing - but in range of 12-20 RPM.

 

Your saying they watched this via Xray ?

 

I believe that they were able to trace the motion that way. The engineering guys do CRAZY things in research - much of the really cool stuff was done in the 40s/50s. This may well have been done in a single cylinder test engine that looks nothing like an automotive item. They also used to run radioactive oil (!) to measure oil consumption....

 

Cool. :) I know-ed that one already. :)
Didn't know they had measured it tho.

2 stroke engines have a steel locating pin in the gap so the ring can't spin.
All the rest of them spin. It's a common newsgroup argument. ;)

Alvin in AZ