Big Dave

Well...I know a lot of you were waiting for these.

First, we start off with a little cleaning from Wednesday:

Big Dave

1. Cam removal Special Tool 9226, on loan from Dave Roberts
2. Cam bearings and cams removed (all pics are of passenger side head)
3. Cams moved over to new heads to await installation.
4. Cam gear is clearly worn and no longer usable.

MORE TO COME...

Big Dave

1. Old head, lifters removed - view from top
2. Head gasket exposed
3. VALVES!!!
4. More valves...1 is visibly bent

Big Dave

1. More valves
2. Yet more valves
3. Even MORE valves!
4. Is there any reason why I can't re-use all of these?

Big Dave

The pistons look dirty, but OK

Big Dave

No visible damage to the cams.

Big Dave

P.S. The fact that only the cylinder nearest the front of the engine has visibly damaged valves is consistent with my compression test that showed ZERO compression in that cylinder. The remaining three held some compression. I assume that if the valves were bent, they would not hold any compression at all. Yes? No?

AO

Dave-

I think we need a close up picture of the valves. I assume you are being sarcastic about asking if you can use them... right?

Some look pretty bad, but hard to tell.

AO

So... you were being straight up? The pics look like there are bits missing from the valves.

If your compression was only bad on one cylinder, then I'd say the other valves are probably okay. If not... well I guess looks can be deceiving.

Big Dave

Andrew:

The heads I received have all new valves. I was asking about these being re-used (picture). I need to replace for Kevin (86.5-Tiburon) any bent valves when I send my old heads to him.

AO

Now I understand... but I can't answer the question... 'cause I dunno!

Good night.

jpitman2

IIRC, its preferable that cam followers/hydraulic tappets go back into head bores they came from...As long as you havent had metal fragments circulating in the oil, they should be ok. Valves that look ok, AND when heads and seats have been re-ground and lapped, and show a consistent seat mark, also should be ok for use.( Just spinning them up in a lathe or grinding machine should show up bent heads quickly.) And the edges (esp exhaust) are still acceptable thickness - thin edges are much more prone to burning.
jp 83 Euro S AT 48k

Nicole

Gosh, are you saying that in almost 20 years you never cleaned your pistons??? Shame on...

...well, I'm just kidding!

This is pretty interesting stuff. Please keep documenting your progress!

Tom. M

Dave,
When I did my head...I couldn't even tell they were bent. We poured some water down the port and the ones that were bent were obvious...you could see seepage past the valve after a bit of time. Due to the water tension forces...I would suggest using a solvent or similar to test forleakage in every port.
I got lucky, only two bent valves and I re-used everything except the bent valves obviously. Also., the WSM suggests a new cam chain after a valve piston collision, however, I re-used mine..and so far so good....

Later,
Tom
midlman@rennlist.net
89 GT

SharkSkin

That head isn't resting face down directly on concrete is it?