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I thought it might have been the head gasket... but I just got the valve stem seals replaced.


We took the head off and sent it to a shop to get new valve seals placed in...

However, it looks like they've ALL unseated



Look between the spring. See the shiny part between the middle of the spring? That's my valve stem seal. They're all like that.

Aren't they supposed to set IN the head, not ON the head, on the valve?

SuperK wrote:Aren't they supposed to set IN the head, not ON the head, on the valve?

Yep they should be locked in to the top of the valve stem sleeve section, they kind of audibly 'click' on with a decent amount of pressure.

Get your complaining hat on.

In the top left, you can see the valve stem seal between the spring.
Also noticable in the bottom right.

Are these seals too high? Or are they setting at the correct height?

I take you're getting lots of blue smoke then? I'm not familiar with that engine, I know on the KL heads they were seated very low. Are they all evenly high? I bet someone who's worked on the valvetrain will know right away. It's a pretty basic task, I'd be suprised if they didn't seat them right

I just don't understand what exactly could be wrong. The head was vacuum tested and wasn't leaking... new stem seals... new head gasket, but each cylinder is getting doused in oil whenever I run it, and smokes like the dickens

We pulled the head off again... Did a compression test, running 185-190psi in each cylinder...


But, with the valve cover off and the spark plugs removed, we turned the engine over (with the starter) and oil started puddling from the top of the piston and dripped lower....

However, there's no real tell-tale sign of valve stem seal leakage. There's a ton of oil, enough to leak out to the exhaust manifold.

Turn the engine a few turns and that's enough to make oil seep over the pistons.

The head gasket looked very well seated. No signs of leakage, no breaks.
Oil clean, antifreeze clean.
The cylinder walls look perfect. no scarring, no wear. The pistons look perfectly seated as well.
Is there a possibility that something is gummed up? It's ONLY oil that's coming in, I don't know exactly what else to be looking at.

I'll take a picture of my stem seals on the B6 head I have and post here tomorrow
so you can compare and see if they are the problem.

(The head is on a bench so I can get to em easy)

That'd be great!

I've been told that the rings unseat when you remove the head. Any truth to this?

Sounds like BS to me. What on earth would cause the rings to move if you remove the head? Its not like the stress of the headbolts in the block deform the cylinder walls...

If the rings were not oriented properly when the engine was assembled I think you could see this. One time, before I knew what I was doing I assembled an engine with the wrong rings. 0.020" over pistons have 0.020" over rings to go with them as do the other oversizes. I put .020" over rings on .040" over pistons and they leaked like a bastard. Take the rings off one cylinder and check end gap. I'd bet $100 it's the rings one way or another.

Ryan wrote:Sounds like BS to me. What on earth would cause the rings to move if you remove the head? Its not like the stress of the headbolts in the block deform the cylinder walls...

actually it does... headbolts torqued down will distort the cylinder walls a little bit... ever heard of torque plates? they bolt it to the block to simulate the head being bolted on when they hone the cylinders so the cylinders will be straight and true when the actual head is bolted on

SuperK wrote:That'd be great!

I've been told that the rings unseat when you remove the head. Any truth to this?

and that is bs the rings do not unseat when u take the head off... its pretty dam hard for the rings to turn inside the cylinder.

fieromx3 wrote:

SuperK wrote:That'd be great!

I've been told that the rings unseat when you remove the head. Any truth to this?

and that is bs the rings do not unseat when u take the head off... its pretty dam hard for the rings to turn inside the cylinder.

Exactly what I was getting at. Of course the stress of several TONNES of tension in each bolt will distort it somewhat, but no chance it would be enough to harmfully affect tolerances, or move rings around. Mazda isn't that stupid, and if they were, they'd be much more "Zoom Zoom Boom" and way less 300+k

I saw a renowned professional engine builder on a very expensive 440 six pack install the rear main oil seal backwards AND install the cam shaft 20º advanced.

Mistakes happen.

It looks like they are on when the top is parallel to the 2nd coil with space
in between it if that makes sense..

if not: