Valve stem seals right or wrong?

[bhm1712]

http://www.summitracing.com/int/parts/s ... /year/1979

looking at these on Summit,

says they dont require machining but also says positive stop type seal. Is that right? if you search for 1979 pontiac firebird 6.6l valve stem seals you get 3 choices on Summit. 2 of them require machining and this one doesnt.

However, if you look the part number up it shows a different seal than whats shown on Summit.

http://www.ebay.com/ctg/Sealed-Power-ST ... /115156777


im confused. If its right and they dont need machining work that might help control my oil burn issues without removing the heads to have them machined for positive type stem seals which lock onto the guides.

[thebandit92]

Not 100% sure but i think i used these http://www.summitracing.com/int/parts/s ... /overview/ they are 4 pence each at Rockauto.I think both those other types need machining but might be wrong,i bought a full gasket kit so they came with that.A few people said use the other type as they last longer but the way i saw it was the ones already on the heads had probably lasted from new in 77 so don't see why new ones of the same sort shouldn't last as long again.

[bhm1712]

Thanks Jimmy!

[thebandit92]

[jonbullnose]

yeah all the positive stem seals need the top of the valve guide reducing in diameter by a bit its not far away but not quite tool used to be avalible from ames performance and real steel , yes the o ring type is the correct ones for a std head they are a little bit rubbish if left for long periods between starts they go brittle and split and fall off positive are very good but also has the flip side that i would only fit them to engines that have had the guides fitted with olite guides as this engine is ment to run with a bit of oil by pass to lube the guides i have seen seized valves on engines fitted with positive seals as they do there job to well and let very little oil by

[bhm1712]

I've put this job on hold again for the moment, still can't work it out what's going on with the engine.

I've had dad follow me and he says there was NO smoke out the pipes at all for over 10 miles. I just get the bit of blue smoke on startup when the engine is hot. And yet I'm losing 1 quart in 400 miles. Seems a lot of oil to be burned for virtually no smoke. The worst it's smoked was when I topped the oil up and I must have poured it directly on top of a valve because she smoked big time for a few miles after that but then Stopped again. Then there my compression test results which came out great for an engine of its age and assumed mileage (100,000+)


I don't have to clean the plugs regularly either - number 1 and number 3 do have oil on the tops of the plugs when I take them out but the electrodes are always serviceable.

At the moment whilst it's not embarrassing me with smoke out the back all the time I'll keep putting the oil in!

[bhm1712]

It's like a continuous oil change without the work!!

[Jeff73]

What grade of oil are you useing?? i found my car used a bit of oil untill i put 20/50 oil in to the engine not a syintheic type of oil for latter cars

[bhm1712]

I'm using 20W50 classic motor oil from Comma. Previously used Valvoline Maxlife high mileage 20W50 but I can seem to buy it anymore.

[jonbullnose]

humm strange well it can only go a few ways
1, your burning it (most likley)
2,oil leak
3.oil leaking into coolant
4,crank case getting pressurized and venting lots of oil vapour into the air
5.headcraked from oil way to exhuarst hence no showing on the plugs
you are losing it at about 3ml per mile so you may or may not see that amount if your getting smoke on start up you have most likley got either missing oil stem seals (perrished) happens all the time with the oring type over time or may have headgaket oil way to cylinder leakage do you know if you have the metal sheilds over the valve springs?
put a peice of white paper over the exhuarsts and rev hard see how much oil is coming through if you have a craked head often it will only open the crack up when really hot