strange oil burning behaviour?

I took the rings off this morning and the expanders seem to be incorrectly made/finished .
On 1-3, the ends of the rings do not butt correctly. One side will be flat and the other stepped up, so when you put it on the piston they overlap. On #4 they are both barely stepped up and meet normally but still do not provide very much tension.

I will post pictures tonight.

I'm not really impressed with cp's quality, when I got the pistons all of the oil drain holes had burrs that I had to remove. And now this.

fast242 said:

The burning of oil at decel and probably significant cylinder vacuum could be due to poor valve guides. When my group-6 head was burning oil like crazy, it did it most when at decel or high vacuum in the intake manifold. When I took it off, I had serious side play at three exhaust valves. Not too sure what you did to your head and what got fixed before you put the head back on. Just a thought. And my car had good compression for the most part.

PJ

Click to expand...

Check the guides and seals before the head goes back on. I bought some nice heads one time, put them on and it would smoke like hell when you got back on the gas after a decel. Pulled it apart and there were NO F***ING GUIDE SEALS! Man was I pissed.

I was reading this and wondering if 4 was the good cylinder and the other 3 had the problem. I was thinking oil rings, I had this same problem a couple years ago when I built a SBF for a friend. We were in a hurry and I didn't set the oil rings in right on 2 cylinders. It ran fine at the track but was using a little oil. When we finally tore it down we found the oil rings in 2 holes improperly installed That's why I never, except for that one instance, rush an engine assembly.

Heres the pictures.

#1-3 pistons look like this, the oil rings sit flush with the piston. Or even slightly recessed.


#4 the rings are pushed beyond the sides of the piston.


Expanders as they sat on the pistons.





As you can see, only #4 butts together normally. The others are not made correctly and provide no tension when installed.






What I meant when I said I was in a hurry was that I did not notice the ends of the expanders were like this. I have only built a few engines and most used stock rings where the "wave" of the expander is going up and down instead of in and out like these. With the oem style there is almost no way to have a problem.

John V, do you think there is something we can do about this? Don't you have a contact at cp, maybe you could forward the pics?

Is it possible the expander were correct and have-since broken?

MrBill said:

Is it possible the expander were correct and have-since broken?

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I think there would be huge scratches in the cylinders if that happened.

I also looked closely at the ends and they have a ground finish to them, they don't look like they snapped off.

I contacted cp about this and sent the expanders to them. Two of the rings were broken off, they said they have never seen expanders break in this way and they don't think they could have broken like this on installation.

They are going to send me 4 new expanders which is very nice considering it has been 3-4 years since I put the engine together.

I sent pictures of the bores and they say I should be okay to re-use the other rings, there is some wear in the thrust areas though.

Intake side, all cylinders look the same.


Worst exhaust side.

Huge picture if desired: http://i.pbase.com/o6/81/744881/1/128968615.4l09Fhc4.DSC_0109.JPG

The camera really brings out the detail, I can barely see these scratches with my eyes and they cannot be felt with my fingernail. I don't really want to increase the bore clearance by having the cylinders honed again. The compression and leakdown were always very good/even, there was no excessive blowby/crankcase pressure. What does turbobricks think?

I will put some new bearings in since I already have it all apart. Now I am just waiting for the JVAB Soooper Bitchin™ Squirterizational mod kit.