Hi all,

I hope everyone enjoyed the long weekend. My question for you all is this: Can the valve stem seals be replaced without pulling the heads (I heard there's a trick but am skeptical) and if not, can the heads be pulled without removing the engine? Forgive me if my questions make me seem like an idiot 😂 it's just that I've heard so many different things from people-I respect the opinions of you all on here.

Mike

 

yes it is possible to remove and replace the valve seals with the heads on the car, but personally I would recommend pulling the heads and doing the job on a bench.
Bending over the engine compartment doing a very tedious and risky process where the risk is high of loosing a couple of the tiny valve stem keepers, or forgetting to rotate the piston close to TDC and then dropping a valve into the cylinder then having to remove the heads anyways. Not a job I would want to do.

If the seals are bad, high probablility that oil is being sucked into the cylinders and has gooped up the intake ports and is filling up the exhaust ports with carbonized burnt oil. You would want to at least clean the heads and / or perhaps do a quick valve job.

 

I have replaced valve seals without removing the heads on a couple of GM and Ford motors. It was a breeze.

I do agree with Joe above that it is more pain staking with the probability of loosing keepers or dropping a valve into a cylinder. I took measures to ensure that I was very careful not to loose or damage anything.

I no longer have the tool it was lost to a friend that "barrowed" it a long time ago. It was a simple design that I used plumbing supplies to make. First you need a nipple with threads the same as the spark plugs, I recall using about a 6" piece of black pipe next then a air compressor coupler on top. As Joe mentioned rotate engine by hand so each cylinder has valves closed, apply "special tool" into spark plug well, add compressed air. Bobs your uncle.

 

I have am air compressor to spark plug adapter that I purchased 30 years ago for when I changed valve springs on an Alpha 1600 engine. I believe that you can use the line that has the spark plug fitting from a good cylinder compression tester. My compression tester has the spark plug adapter, followed by a foot of flexible hose and then a quick disconnect with a pressure relieve push button on the other end.

One of the reasons I would be apprehensive to try to change the seals on the car is that I have taken apart several AJ series 4.2 heads using the small valve spring compressor, and I had a couple of problems. 1. the keepers when they popped free from the the valve spring cap would fly off the valve stem. 2. after I pulled out the valve spring and removed the valve, I could not for the life of me get several of the valve stem seals to pull away from the head. The seals work as the base for the valve springs and they can get stuck very tightly to the head. I had to reach into the valve stem hole in the seal with a pair of needle-nose vice grips and pull/wiggle the seal, half destroying it as it was pulled off the head.
I can imagine trying to pull a stuck seal out while having the valve stem in the way. I'd make sure I had a pair of pliers that could grip the outside of the seal, (round slippery oil soaked shape) and that they clear the valve stem, before I even stared the project. You have to consider that you are reaching down a couple of inches into a blind hole with a fairly fragile 5mm valve stem stuck in the middle.

 

Thank you all for the great advice, heads are coming off. At that time, may as well have them ported and polished!! Cheers to all.


Mike