Author Topic: Have the head off - M42 - questions (Read 4774 times)

waldo · « **on:** March 30, 2010, 07:23:52 PM »

- Where is the oil check valve in the block? How to remove to check? Is it prudent to replace?

- Factory paper gaskets or RTV?

- Best way to remove carbon deposits from pistons? Valves?

- What is the best way to clean out the head and block before reassembly?

- Any other points to ponder?

Notes:

I had a horrible time breaking the exhaust studs free. Ended up cutting the exhaust and backing them out after removing the head. TCPG was chewed up but not failed. Cylinders still have the cross-hatching and look dreamy. Head looks pretty good, too. Timing components (that I see) look like they have been replaced as it has the nylon type rails instead of the steel. Timing was set to 0 deg on the cams but was off a bit.

Thanks, hopefully this all will end in a positive note.

KenC · « **Reply #1 on:** March 31, 2010, 01:40:26 AM »

1. In the bottom of the lower timing case. The part has been updated by BMW; buy all new parts associated with mechanism.

2. High quality RTV

3. Kerosene and/or carb cleaner

4. Kerosene and/or carb cleaner

5. Replace your cam gears if they're worn, and check for damaged chain guides

rob_e30 · « **Reply #2 on:** March 31, 2010, 06:49:34 AM »

1. Some bocks have an oil check valve between the number 2 & 3 cylinders at the top of the block. They call it a non-return valve and it fits into the oil vein. It's fairly small.

waldo · « **Reply #3 on:** March 31, 2010, 06:58:25 AM »

/\ The small check valve is what I was looking for. Is fitment/replacement required?

Thanks for the replies. I will pick up a check valve for the lower timing case. Can this be accessed with the lower pan off?

monko141 · « **Reply #4 on:** March 31, 2010, 09:44:40 AM »

The small check valve in the head is not necessary. Neither one of m42's that I have broken down have had one in it. The check valve that Ken is talking about is the oil pressure relief valve. And no you have to take the upper pan off.

Phreon · « **Reply #5 on:** April 01, 2010, 07:03:48 AM »

I recently did my head.
I used the gasket set from Pelican and RTV from Advanced Auto Parts.
I posted pic's here.

http://www.m42club.com/forums/showthread.php?t=11162

P

DesktopDave · « **Reply #6 on:** April 01, 2010, 07:28:26 AM »

Isn't there a check valve in the oil filter housing? It looks like some stuff is pressed in, but if that's what it is...it doesn't look removable.

waldo · « **Reply #7 on:** April 01, 2010, 09:27:04 AM »

Phreon - your thread was useful pulling it off, thanks. The head is still off as I am on holiday, but it will go back on Monday.

My block did not have a check valve between 2 and 3, and its been opened by a PO as it had a Goetz head gasket and the E12 bolts.

I think I am going to wait to do the bottom end stuff (oil relief, bearings, seals, etc) until next winter. The head and timing stuff looks so good I am going to keep it that way.

Phreon · « **Reply #8 on:** April 01, 2010, 01:01:13 PM »

Look in the head for the valve too. I have heard it can be in there.

Its held in the block by a rubber gasket.

waldo · « **Reply #9 on:** April 05, 2010, 12:32:53 PM »

The check valve was not in the head, either.

One thing I noticed while I was setting the timing - when an exhaust valve was opening when turning the crank I am guessing the chain was tight enough that it was compressing the tensioner, rotating the guide out. I replaced the tensioner when the head went back on before I started to set timing, so I am assuming the internal spring is not enough to keep the guide pushed in when that cam is working. Anything to worry about?