Just Quick "302-Ring" question..

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Sep 10, 2010 | 02:46 PM

timbersteel

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Just Quick "302-Ring" question..

Got a '92, 302. I have just got my heads back and before I get them back on, can I simply pop the #8 piston out, and give it a honing, and then put in either standard rings or .010 over, depending on how much honing it takes to break the glaze.

The reason for my asking is I did a compression test about a month ago and #8 was the lowest with 120, but with a teaspoon full of oil it was 160. All other cylinders were in the 160-150's on the driver side and 140's-155's on the passenger side. I am in the process of rolling standard size main's in, so the underneath of the block is accessible.

Sep 10, 2010 | 05:56 PM

Beanscoot

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If the bore is still within dimensional tolerance after "breaking the glaze" honing, you can simply put in new rings with the old piston (assuming it is also okay). If the wear is more, then the cylinder must be rebored to the first oversize and the piston and rings replaced with oversize.

I don't think .010" is available for this engine, the first oversize is .020".

The old Ford manuals state that it is okay to bore just the bad cylinders, and I have done this in the past with no ill effects. The reason is that oversize pistons were made to the same weight as standard.

Sep 10, 2010 | 10:40 PM

timbersteel

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Thanks Beanscoot!

Would bad valve stem seals, high deposits of carbon and a bad head gasket give ill-effects that would say perhaps worn rings?

The reason I am asking is because I just got the heads back and the guy said that he could see where the head gasket was bad in spot and the amount of carbon was terrible. I aslo checked the piston and the cylinder bore(haven't popped it out yet, just from what I can see while rotating the crank) and #8 appears to be in better shape than most of the others with better compression. He aslo regrind the valves and they look terrific! I'm sure that would have to help some.

Sep 11, 2010 | 01:07 AM

Beanscoot

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You should ask the man who reground your valves what he thinks. How were the old valve stem seals? If they had failed, then most of your oil burning will be fixed with the valve grind, assuming it included repairing guides if necessary and new seals.

While you are replacing the main bearings, check the rod bearing clearance with plastigage. If they're withing spec, I wouldn't change them.

How come you are changing the main bearings?

Sep 11, 2010 | 02:08 PM

timbersteel

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When I got it, I could hear some diesel sound on startup and then fade away. Since I had the bottom off to change oil pump and clean the engine, I went ahead and checked the mains. Had 2 in the starting of the copper. Checked the clearances, still within spec. The Machinist changed guides too. All was original from what he could see.

He Beanscoot, 1 more question. The main's I pulled out so far have a stamping on them with "04 99". The new mains I picked up have a stamping "07 09". Looks like a date stamp to me. Is this right? If so, someone was in the bottom end around '99 or 2000.

Sep 11, 2010 | 02:17 PM

Beanscoot

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Those do seem like date codes. Stock Ford bearings have date codes, so probably the replacement ones even if aftermarket do as well.

Sep 11, 2010 | 02:22 PM

timbersteel

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The "Fm" logo is on the one's I've pulled so far. It's a good gues that someone was in the lower end already. Also looks like they changed the main oil seal. It's a plus it's not leaking!

Thanks Again for your help Beanscoot!