Nathanl91

Hey guys, hoping to find some help here.

So here's what's up, bought an 88 base coupe, that appeared to be in good shape, little puff of oil smoke on start-up( old chevy figured just tired valve guides) but would go away immediately after the first 2 seconds. But last night sitting in the drive-thru at the local food joint, she started smoking, just while idling..
Now I've noticed she sometimes smokes at idle, and if I rev it up gives a good puff sometimes...

I'm starting to think my rings are going?
Any other possible issues, the car doesn't act like the motors dying, runs strong starts right up every time.. Just smokes lol

Any help?

If my motor is toast, crate 350 or rebuild a 350? Which will be more cost effective( car has 305 currently)

five7kid

iTrader: (14)

Welcome aboard thirdgen.org!

Sounds completely like valve stem seals. The factory ones get hard over time and crack, letting oil into the cylinder when the engine is sitting, or under high vacuum conditions. The valve stems & guides usually don't wear - in fact, the seals leaking helps lubricate them.

Sorry to dash your 350 excuse, but a few hours with an air compressor and valve spring compressor will be about all it takes to replace the valve stem seals.

Nathanl91

Haha a the car is my daily I'm ok with my motor being ok

Just wasn't gonna put another 305 in if it was time
I was kinda hoping it was te heads.

What symptoms point to this vs rings? Just so I can learn haha

Thanks for the help and welcome ill be here a lot haha

Pics for fun lol pic

five7kid

iTrader: (14)

Smoke at start-up and at idle. The reving smoke is just pushing out what has collected during idle.

If it smoked under power, that would indicate rings.

Nathanl91

Kinda what I was thinking, if I floored it, it should be all James Bond getaway scene style, but it doesn't do that, a little puff when I first get on it then its fine until it sits or idles for a bit

Richboll

Sounds like valve stem seals to me also. It's been a lot of years since I've replaced a set but I think that 57kid is right. There should be either links on here or youtube that will show you the way to do them. Good Luck!

Nathanl91

Alright, now the question.. I'm seeing positive stop seals and umbrella seals, which ones fit my heads?

Sounds like the positive stop ones need to have a spot to be pressed into, does my motor have these?

five7kid

iTrader: (14)

You have to cut the tops of the valve stem guides to use the positive type seal. You have to remove the head to have this done.

The umbrella type should fit over uncut guide tops.

Nathanl91

Alright so umbrella type it is, if it requires removing heads I'm dumping this 305 lol

Nathanl91

http://m.oreillyauto.com/mt/www.orei...2402&ppt=C0146 o-ring

http://m.oreillyauto.com/mt/www.orei...2402&ppt=C0146 unbrella

Do I need both? Or one or the other?

sofakingdom

iTrader: (1)

You don't want either the O-ring OR umbrella type seals. Not by themselves or in combination with anything else. They are useless.

You want "positive" type ones.

http://www.summitracing.com/parts/fe...make/chevrolet

All the O-rings do, is keep any oil that happens to be on top of the retainer, from running down the stem. Weenie.

Umbrellas stay stuck to the valve stem and ride up and down as the valve moves. All they do, is keep oil from splashing up under themselves. Slightly less weenie, but still weenie nonetheless.

"Positive" seals fit tight to the outside of the guide and stay attached there by way of a metal band that clamps them in place, and fit tight to the stem but allow the valve to slide through. Actually EFFECTIVE.

If you're going to go through the effort, use something that will actually DO something.

Schrade

Static compression test, with leakdown time, in order here???

Check spec for leakdown time...

Nathanl91

Positive seals require machining the guides I was told

Summit also says those fit lt motors not my old lo3

I am getting a compression tester tomorrow

sofakingdom

iTrader: (1)

AFAIK those fit 305 heads; fit em last time I put em on some anyway.

Always lots of excuses for not doing stuff the right way, eh? (nothing personal, just in general)

Don't bother with a compression tester. Won't tell you diddly about oil burning. It's PERFECTLY possible for the compression rings to be PERFECT and the oil rings to be destroyed; or vice-versa.

But apart from that, about 99.999% of oil-burning in old Chevy motors is because the valve guide seals are bad; and the rest is merely because they need valve guide seals. Virtually NEVER the rings. If there's something wrong enough with the rings that they're causing visible oil burning, you'll be tearing the motor down for something else A LONG TIME before a bit of oil smoke will concern you. Work on a few hundred over the course of a few decades, you'll see.

Nathanl91

I'm all for doing stuff right, just don't want to sink a ton of money into a 305 of unknown condition.. I plan on building a mild 350 once I'm confident this guy is gonna get me to work for a while..

Nathanl91

So autozone lists a felpro kit for exhausts that is unbrella and oring

They list intake set as oring and positive type... I'm confused as to what I need?

sofakingdom

iTrader: (1)

Exhausts aren't near as critical as the int, being as how there's no vacuum on the other side trying its hardest to suck oil past the seal like on the int, and whatever passes that way, doesn't go into the cyl, but instead just into the exh port.

Personally I'd put positive on both and forget about O-rings or umbrellas.

Not alot of money, so it's all good there.

Nathanl91

According to the interwebs the felpro positive seals fit with no machining... So could I put this set on both intake and exhaust?

Or all the valves different sizes?

sofakingdom

iTrader: (1)

Yup, you can put em on all of em.

Nope, all the same size. (where the seals go anyway)

Nathanl91

Seals are done and the smoke is gone thanks guys..

sofakingdom

iTrader: (1)

Glad to be of service.

Richboll

Glad to hear it.