BC

I think there may be an issue, but I don't know if its just me or its a wider concern.

I had my heads rebuilt, and they have been sitting waiting for the moment of engine assembly, which is currently upon me finally. While I was figuring out some other stuff today, I got bored and decided to take Todd up on his advice:

Go inside the oil rails on my heads, and check what was in them.

So I did, and to do it I had to take the little 3/8 inch sized "freeze plug" type things off of the ends of the heads. What did I find?

I have been trying to take pics, but its difficult as I flash a light into the other end to see the surface of these oil gally/rails, but...

Its got brown and black sooty grit in it, hard enough to feel with my fingers. I stuck an ear bud (sorry - I live in an english household, my wife's foreign words sometimes take over - I should say Cue Tip?) into the holes as far as I can go, and its really gritty in there.

So a warning - when you have your heads rebuilt, maybe check with how the cleaning is done prior to rebuilding - do they use a media blast material? Can it get stuck in there? It may prove a very good thing that I looked in there.

I'll try harder to get some pics.

RyanPerrella

I tried to remove those giant plugs but had no luck whatsoever.

I figured thats the coolant passange and not too interesting.

What "oil rails" are you talking about?

BC

There is a round area at each side of the head. Its how the oil is fed to the lifters, as well as the chain tensioner.

At each corner, there are freeze plugs (small ones)

RyanPerrella

yeah you need pics. I think i know what your talking about its a like a long tube thats part of the head casting. I think this is a reason why blasting is one of the least prefered methods of cleaning heads. I soaked mine for days in a diesel, carb cleaner solution.

Which plugs are you referring to? the ones where the check ball goes inside of the head? I was thinking you had the large 2-2.5" plug removed from the front of the head.

BC

No, those are already out. These may look like they aren't removable, but they are just small freeze plugs.

Mrmerlin

The plug is for the oil anti leak down valve, so oil wont leak out of the head and return to the pan via the pressurised passages. If you get your heads redone these plugs should be pulled out and the O ring seal replaced on the plug, the lines should be flushed out with carb cleaner , more than a few times, the spring and the ball should be checked and finally the ball seat should be checked to see if its loose, if its loose then you have the potential for the oil feed being cut off to the head and then the cam will seize in the cam caps and then the belt will snap. If the ball seat is loose it can slide upwards and cut off the the oil passage way to the cam and tensioner and lifters, I have seen it happen on a fresh set of heads. I f the ball seat is loose then you try to peen the tops of the seat to the head and also apply some green loctite setting formula let this cure for 24 hours before putting th head into service. You can use blue loctite on the set screw that holds the aluminum plug, this plug is accessed from inside the cam housing on 32 valve engines, the set screw is outside of the head

RyanPerrella

ahh yes, i hadnt pictured this from brendans post. But i am very familiar with it.

Yes replace o-ring, and check that ball and spring and seat arent binding and move freely.

Vilhuer

Post pics Brendan, they don't get it. Very good advice on oil check valve but offtopic in this thread.

Bill Ball

Brendan's description didn't sound quite like the check valve to me either, but I gather it is. There is a small threaded rod in the side of the head that retains the valve's cap. The cap top is threaded to accept a M6 bolt to pull it out, as shown in the picture below. We removed them from Dennis's heads before rebuilding.

Vilhuer

Bill, see part numbers N 011 918 1 and 911 101 182 00 in PET. These are different thing.

Mrmerlin

Thanks for the picture Bill, the only thing not shown is the ball seat this part is tapped into the head and is usually a tight fit so you might not see it unless your looking for it. It is positioned under #5 the ball

BC

Sorry for the late reply guys. This is such a committed group. The ball check valve has been out since I took the heads off the car in 2003. That may be why during he rebuilding process the dirt was able to enter where it was no welcome -

BUT -

I am talking about the "not really supposed to be" removable freeze plugs at the end of the oil rails in the heads.



And what I do is lightly drill and tap them then screw in a bolt to use with a slide hammer. And they come out.



Now because I can't get the photos properly, I can see the dirt inside the tube (and grit, sand like stuff) but you can't so just take my word for it.

BC

Yes, very good advice. I will make sure that it is very clean on reassembly. Was there not some devek-ism hat said if you put something else there the oil would not go to the head as much or as little? I don't know.

But no, I was not talking about the ball check valve. I was talking about the oil rail freeze plugs.

BC

Another crap picture of what it looks like when the plug is removed:

Adam Geist

When my brother had his 32v heads rebuilt, the machine shop insisted the oil galley plugs be pulled before the heads went into the parts washer.

When installing new plugs, be careful as there are two sizes - of course my brother found out the hard way. The plugs he received (Porsche part) seemed to be too tight of a fit and would start in the hole but not go in. Rather than using extreme force to install the plugs (and possibly damaging the head) he measured the diameter of the plugs and the inner diameter of the oil passage. The plugs were way too big.

A phone call to one of the big 3 comfirmed he received the wrong size plugs and he eventually received the correct ones.

Adam