valves sticking

6501 Views 11 Replies 5 Participants Last post by shoebox, Mar 30, 2013

Zee

Discussion Starter · Mar 28, 2013

so I recently discovered that my valves (driver side) are sticking. they rattle nothing really serious yet.

anyone have any solutions to this? I know a lot of ppl swear by seafoam through a vacuum line, any suggestions?

I know ill have to take apart the motor later on but right now is not a good time.
thank you!

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Racy Roadmaster

· #2 · Mar 28, 2013

I havent heard of valves sticking since I was a kid,and that was a long time ago. I am not saying that you dont have sticking valves,but its just that I havent been around any for years. Be prepaired if you want to go the Seafoam route to possibly create some problems along the way,sometimes when you break up all the carbon and stuff,you can partially clog the cat. converters.I may use the Seafoam in your fuel to
try and clean up the valves or else use the mystery oil,that is a good upper cyl. lubricant. ed

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cocobolo95

· #3 · Mar 28, 2013

A vacuum gauge is a good tool to see if your valves are sticking. With engine idling, gauge will show normal vacuum, which is 15-22 inches with 3-5 inches down flick every time the affected valve or valves try to open.

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shoebox

· #4 · Mar 28, 2013

Like Racy said, that is not something very common today. If that is really happening, I would be more inclined to remove the heads and have them reworked, 'cause there is potentially something more serious going on.

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Zee

Discussion Starter · #5 · Mar 28, 2013

okay so ill give you the symptoms and if you know any possibility please tell.

on cold starts I get rattling it goes away when the car warms up but not completely. this is not ticking btw.

if I turn the car off for a couple minutes and turn it back on ill get the rattling again for a while.

I don't see any difference in performance but they rattle ALOT worse when its cold out. warmer days is not as bad. and the reason I thought maybe seafoam cuz if the valves were corroded wouldn't they stick too? I use chevron 91 all the time but the owner before me was really bad with the car care. ive never used an oil cleaner only fuel additives like lucas injector cleaner every now and then.

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Zee

Discussion Starter · #6 · Mar 28, 2013

i also heard lifters could go bad and i can test them by just pressing them down. if they collapse theyre bad.

im gna change the oil today to get the atf out. should i seafoam it before or just wait til i can actually get a chance to take it apart? i have to reseal the intake manifold anyways cuz its a little leaky but like i said. time is short.

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shoebox

· #7 · Mar 28, 2013

Can you post something where we can hear the noise? A rattling sound when cold can often be attributed to piston slap, but I am not sure it fits your scenario exactly. Valves don't rattle, IMHO. Could be funky lifters, but could be a lot of things. Hard to diagnose a noise when you can't hear it.

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steveo

· #8 · Mar 28, 2013

i've seen lots of sticky valves, but not usually on this type of engine. usually happens either from running really rich for a really long time (a ton of carbon packs up in the guides) or from poorly planned engine building, where the valves bind in the guide. this condition tends to gets worse as the engine heats up, as the guides and the valve stems both expand a bit.

with the fairly loose tolerances that GM builds their valvetrains to, heavy carbon buildup is really the only way a stock LT1 would bind up in the guide.

if you are confident that you do have carbon packed up in the guides, which i doubt, a bit of shock treatment might be necessary; pulling your valve covers and carefully giving each valve a drift & hammer treatment might break a bit of carbon loose and get you running again.. i did that recently on a lawnmower engine with sticky valves (it had a stuck choke, and had been running like that a very long time). it was stuffed up so bad that every time i drifted it, the valve came up a bit further.

but forget all that stuff. rattling in the valvetrain is usually:

- misdiagnosed exhaust leak @ manifold to head
- misadjusted lifter preload
- a valve spring issue of some kind
- a screwy rocker
- a bent pushrod
- a sticky lifter

im going through the same crap right now. i'd check everything on that list in order; if everything is alright, get some new lifters. it's the only thing you cant really check just pulling the valve covers off. replacing lifters is great too, it's so freakishly easy to find the base circle and set valve lash with the intake off..

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steveo

· #9 · Mar 28, 2013

forgot your other question... always seafoam your top end right before an oil change. if you have very heavy carbon buildup, some of it will certianly end up in your oil sump.

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Zee

Discussion Starter · #10 · Mar 29, 2013

i think i do run rich. the cars basically stock and i get about 11-12 mpg on grandma driving.

ill make a video. not sure how to post it on here so ill just put the link from youtube.

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Zee

Discussion Starter · #11 · Mar 30, 2013

okay so i seafoamed the oil and drove for about 30 miles and changed it. the rattling is gone haha. oil had 500 miles on it but came out nastyyy.

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shoebox

· #12 · Mar 30, 2013

The noise may be gone (maybe not for good), but you still don't know where it was coming from.

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