I currently have about 2500 miles on a rebuilt motor. The heads are stock and were rebuilt at the same time. I currently have some excess oil use (about a qt in 300 to 500 miles). I do notice slight blue smoke on start up and don't see any smoke at any other time. I am wondering if it might be the valve stem seals? I do not know what type were used. If so what would be the best type/brand to relplace with?

Thanks in advance,

Mike

 

I would suggest perfect circle style which seats on guide. Little O ring should go on after retainer in lower grove before keepers are installed. Many times seal is left off or installed prior to retainer. When valve spring is compressed seal is pushed out of place, oil then can run down stem to guide.

 

Are you referring to positive stop style verses umbrella style? Do Positive stop style use o rings as well?

 

I have no advice being a rookie as to which style to buy....I do know that the engine will "burn" the oil while at highway speed so that the "cloud" is not evident.

The spark plugs never fouled, but had oil residue on them.

New valve stem seals dropped my oil usage problem to 1/2 qt. every 4,000 miles, and also stopped the puff of blue smoke on cold starts.

 

I have always installed them since they where there. Most of the time a positive seal is on intakes and Vinton umbrella type seal is on exhaust. Originally Chevrolet just used the little O ring and the umbrella spring cap at retainer. Valve seals can usually be seen when valve cover including if little O ring is out of place At 2500 miles engine should be "broke in", if you did not DIY the engine I would contact builder/installer/shop before I did anything. If this is a DIY project pull spark plugs see if one or more has heavy deposits.

 

Is there any reason not to use a positive seal on both intake and exhaust valves?

 

Years ago when I called them "Vega" seals I did. Exhaust valves do operate at a higher temperature ... probably why they use a different seal now.

 

I changed my factory O ring seals and used both umbrella and O ring on my 100,000 mile original motor
No more blue smoke at startup

 

This is good news... Gotta do mine on cylinder 7 here soon... But gonna do a compression/leak down test first at the local shop... I wanna let the shop take a look at everything and eventually have a dyno tune done... Just to get a baseline to start with... Easier for me to work some OT and get paid to do my job, then pay the PROS to do theirs... I like to tinker, but don't have the trained ear yet... Later on I'll tackle this stuff on my own... But for now, knowledge-experience-tools-and a proper shop make the decision of paying a shop to look into it a better decision at the moment... ;-)

 

Winter of 2013, I did my BB valve seals over.
The perfect circle type seals I found previously installed were ripped in half on several intake valves.
An old head job by an unknown source had machined the intake guides for possitive control type seals on the intake and left the exhaust side alone.
I searched this site and the internet and found a guy who is nothing but valve seals.
I installed the blue Viton seals on the intake and he found me some narrow umbrella seals for the exhaust side. It didn't need them but it was one those while I'm at it things.
Whoever did the work replaced the springs with a double spring setup.
With the guides machined and the double spring set up my otions were limited to after market setup for seals.
The little oring on the stem is for small block application only.
My BB had 3/8" valve stems. After market heads like AFR will have 11/32nds" so make sure to check your valve stem diameter.
I thought about going with the stock setup but w/o knowing what cam if any was installed when the springs were changed out we would not know where to begin to order a stock style single spring setup as we didn't know what lift we had.
I just used what I had already and found through some internet work the viton seals.
I had a puff of blue warmed up on restarts and on decelleration.
It is gone now, just left with it sneaking past the rings
From what I'm being told here.
Marshal