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Broken valve spring?

  • Thread starter Thread starter razooki
  • Start date Start date
For assembly oil I just use left over (still new) 80W90 gear oil mixed with some 20W50 Golden Spectro 4 engine oil. Sticky as anything, and if it's a little cooler out, almost as thick as grease. You can almost spoon this stuff on. Don't be shy with it either, you can never put too much lube on. It'll just burn off, or flow through your engine. Everything that moves in the engine should get some on it.
 
Thanks again for all the advice everybody. Well, I took out one of the exhaust valves using Steve's spring compressor tool so here are some pics of the valve and the exhaust port. It looks like it someone took a grinder to it and polished it? Regarding the valve seals - I tried pressing one in with my finger but the small spring came out. Can I just seat it gently and then have it seat all the way down when I re-assemble everything? I would think that the spring keeper would seat it all the way once the springs are in place and compressed. I'm still going to lap the valves but I was excited to try the compressing tool tonight.

GS850001-1.jpg

GS850002-1.jpg

GS850004-1.jpg
 
I use a socket to install the valve guide seals. Use an extension and tap gently until the seal seats down over the guide - lip on the seal seats in the groove on the guide.
 
Ed thanks for the suggestion of using a socket to install the seals. A 10mm deep socket worked great. Now a have the head installed with new seals and lapped valves but I could not leave it alone so I removed the bottom end to take a look at the pistons and rings (the PO had replaced #4 piston so it only stood to reason that he would have inspected/replaced the other piston rings but one never knows). Anyway I'm a bit confused about measuring the piston ring end gap once the rings are re-installed.

1. Obviously I measure with a thickness gauge where the ends meet right?
2. Why measure at the gap and not anywhere else along the ring? Just curious.

Raz
 
Well I'm glad I took out the bottom end to look at the pistons. It looks like the PO has installed 1mm over pistons. Now if I want to inspect the pistons and the rings will I be looking for the same specs as for the standard ones? That is should the ring end gaps, ring thickness, groove witdth, etc. be the same?
 
razooki said:
Anyway I'm a bit confused about measuring the piston ring end gap once the rings are re-installed.
Click to expand...
The only proper way to measure the end gap that I know of is to place the ring in the cylinder, push it with the piston to make sure it's squarely installed, measure the gap. Since it's hard to use the pistons that are mounted to the crank to to this, maybe use a spray can that is about the same size or use a try-square to push the ring down the same distance at several places around its perimeter.

I would presume that for an oversize piston, the end gap would be pretty close to the same as for stock.

Any measurements concerning the side clearances on the rings would have to be discussed with the piston manufacturer.

.
 
razooki said:
Just curious what would cause a bent valve? I plan to change the valve seals while I have the top end out but what else should I look at?
Click to expand...

Usually a bent exhaust valve comes from over reving ( missed shift ) etc. The piston is chasing the exhaust valve home on the exhaust stroke. If the valve hesitates ( floats ), the piston will catch it.

This is why you always have more PTV on the exhaust side when building an engine.
 
OK, so far I have measured everything (piston diameter, ring gaps, ring grooves) except for the cylinder bore since I do not have a dial bore gauge. Everything is within spec. The question is if the cylinder bores are also OK, can I just re-assemble everything or should I deglaze the cylinders before installing everything?
 
Probably lots of opinions on this, but I wouldn't get that far down in the engine without honing and putting in new rings. Probably cost about $50 to have a shop hone them (or to buy a hone), and $90 for new rings. It would suck so bad to tear it down that far, put it all back together, and then have marginal compression.
 
doctorgonzo said:
Probably lots of opinions on this, but I wouldn't get that far down in the engine without honing and putting in new rings. Probably cost about $50 to have a shop hone them (or to buy a hone), and $90 for new rings. It would suck so bad to tear it down that far, put it all back together, and then have marginal compression.
Click to expand...

Normally I would agree but the purpose of my tearing it down was to inspect it. If everything is within spec as per the manual I don't see why I would need to replace the rings (about $200). I am pretty sure the pistons are 1mm over since the rings have an 'N' stamped on them so honing is out of the question.
 
OS pistons will be stamped appropriately on top, and that N just denotes which ring it is and which side goes up I think.

Doc is right about the rings cost assuming they are STD size. I'd replace them. If you don't want to, just stick the engine back together. There is some controversy about the necessity of honing if you are going to reuse the old rings and I'm in the camp that doesn't hone.
 
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