[diesel doc]

I am working on a 5.7 chevrolet engine in a 1988 pickup. I got a rebuild kit from Federal Mogal. It had been opened and it said on the label it was a master kit less pistons. It came standard, standard, standard.
The problem is, I can't get the pistons to load in the block. The oil rings are what's stopping them from going in. They act like they are too big. I took all the rings off the piston and just had the oil rings on. The piston still won't go in. The compression rings are fine. It seems like the oil ring expanders are too big or something.
Anyone got a sugestion or ran into this before? I haven't, in all my years I have not had a problem with chevrolet rings.

 

[poncho62]

Are the grooves cleaned out well enough?

Thats all I can think of................

 

[[email protected]]

350 pistons come with either shallow or deep ring grooves. Sounds like your rings are for the deep groove pistons and your old pistons are shallow groove. You are going to have to replace one or the other.

 

[Blazin72]

This might be a stupid question but I'm going to ask it anyway. Are you using a ring compressor when you are trying to install the pistons? Also, I've found that on occasion an oil ring will pop out from between the compressor and the block before the rings make it into the bore.

 

[RPM]

350 pistons come with either shallow or deep ring grooves. Sounds like your rings are for the deep groove pistons and your old pistons are shallow groove. You are going to have to replace one or the other.

They could be 3/16 or 1/8 thick or thin, but I have never heard of a shallow or deep ring.

The rings have probably been mixed up and you have something like .030 oil rings in a std box. Check the gap on the oil ring rail. just like you would the other rings.

 

[Bumpstick]

One other thought...? Did`nt the 87 and later TBI engines have metric rings...? Seems like I remember something to that effect...? You noted no pistons so are you re-using the old ones...?

 

[[email protected]]

86-89 Vin code K. Shallow oil groove. You have a Hastings 139 type ring and need a Hastings 5615 type ring. Or other manufacturers equiv.

 

[diesel doc]

Thanks! To Bobcrman

I returned the ring set to the parts store with the information you furnished. I don't understand exactly why and what. I know that the oil rail expander was too big and would not compress enough to allow the piston to fit in the cylinder. The parts store traded me another set of rings, and they worked just fine. I WANT TO SAY THANK YOU! I had a customer screaming for his truck and I was at a dead end. So Thank You Again!!
Now just what was the deal with two different sizes of oil ring expanders. I have been putting Chevrolet V-8 small blocks for 30 years and never ran into this before. I probably should just stay retired, but people keep finding me and begging for help.

Thank's

 

[[email protected]]

GM engineers, in their quest to justify their existence, have been doing little things like that for years. You get used to it when you are in the machine shop business..Wait till you work on mid ninetys 4.3's. These can be a real headscratcher.. Different heads, pans, rods, pistons, cams, rockers, cam bearings, timing sets, etc. Same years different VIN's.