305(LG4) valve stem seals

malibu79

malibu79

Not-quite-so-new-guy
Are there any positive valve stem seals that would fit directly on my 305, without any machining or so? The engine is from a 79 Malibu...

The oil smoking when the engine starts makes me sick....and the OEM style rings/umbrella are more a half assed solution i think
 
1320John$$$

1320John$$$

Master Mechanic
Sep 18, 2019
428
93
Pennsylvania
Are there any positive valve stem seals that would fit directly on my 305, without any machining or so? The engine is from a 79 Malibu...

The oil smoking when the engine starts makes me sick....and the OEM style rings/umbrella are more a half assed solution i think
How many miles are on the engine
Valve guides aren’t known for there durability and if they didn’t do proper preventive maintenance oil changes you know
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
27,204
113
Kitchener, Ontario
this is what I don't understand, the valve seals are leaking on a 79 vehicle and the complaint is about valve seals that have lasted for around 40+ years are now leaking..... :unsure:
 
1320John$$$

1320John$$$

Master Mechanic
Sep 18, 2019
428
93
Pennsylvania
this is what I don't understand, the valve seals are leaking on a 79 vehicle and the complaint is about valve seals that have lasted for around 40+ years are now leaking..... :unsure:
Ya replacing the seals probably won’t heart I think he is looking for a quick fix for excessive guide wear
 
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MrSony

MrSony

Geezer
Nov 15, 2014
5,375
113
Des Moines, Iowa
The quick fix for excessive guide wear is new seals. You'd be amazed how well replacing brittle or missing 40 year old rubber with nice bendy supple rubber works.
 
airboatgreg

airboatgreg

Royal Smart Person
Oct 2, 2016
1,789
113
Without a lot of work the umbrella is the only option. Don't forget the PCV SYSTEM AND THE OIL DRAIN BACK HOLES.
 
69hurstolds

69hurstolds

Comic Book Super Hero
Supporting Member
Jan 2, 2006
3,639
113
While we're not forgetting things...don't forget redoing the valve guides because I think that's where you're main issue is, not just the stem seals. It sounds to me you have more than an umbrella seal issue.

It's a 305. Unless you want to stay stock, maybe another option is to get a 350 and build it where you want it, even stock is better than the 305, and slide it in place. You'll have plenty of time to fix the original problem afterwards, and everything should bolt right back in. Plus it'll be more fun to drive!
 
lilbowtie

lilbowtie

Comic Book Super Hero
Jan 7, 2006
2,892
113
Canton Mi
Are there any positive valve stem seals that would fit directly on my 305, without any machining or so? The engine is from a 79 Malibu...

The oil smoking when the engine starts makes me sick....and the OEM style rings/umbrella are more a half assed solution i think
Then don't try a half *ss solution and fix it right.
 
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MrSony

MrSony

Geezer
Nov 15, 2014
5,375
113
Des Moines, Iowa
If it only smokes when it starts, it's valve stem seals. And if the valve guides are that worn, you can bet the seals are worn as well. Only "other" fix is to remove the engine, remove the heads, take them down to the machine shop and have them do a basic valve job and replace the guides as well as a surface job because all that moving and machining will probably gouge the sealing surface in one way or another. And new springs, retainers, keepers, and seals and probably a valve or two of some are severely pitted or galled. Probably machine the guides for the newer style positive seals. Not to mention the cost of labor.

OR

Replace the seals in a few hours over the weekend with a $7 parts store tool and a home made fitting to fill the chamber with air or bring the piston of whatever cylinder you're working on to tdc and shove paracord in there to keep the valve from dropping. Also get a thin stick magnet that will fit down the guide just in case. And if new seals solve it, hey, at least you only spent around $50 and a few hours of your time. If they don't, still only $50 and your time.
 
Last edited:
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