Coolant weeping from head after gasket replacement

I did set TDC and everything lines up - crank, head, flywheel ball.

I set all the valves to a snug .012.

I started it up - didn't take much encouragement - and it runs fine with no leaks or other obvious issues.

However I have a noisy, clattering valve (seems like #1 exhaust through the stethescope) which was loud at first but then quieted when the engine warmed up - is this normal after a rebuild? Is it a break-in issue? It was only loud at idle, after 1500 rpm it went away before going away entirely. Thoughts/concerns?

I will run it for a while then retorque to 100Nm. Thanks Don I have your number and I appreciate the offer - you may be hearing from me at some point!



sfdon said:
Forward is correct!
I can't say how much I hate angle torques- it's a bizarre deal when 1 bolt gets 70 lbs and the other 90 lbs.
I would re torque to 100 Nm.

I got a tough question for you- did set TDC for your crank and head?
Does the engine rotate when done gently by hand?
Feel free to send me pm if you want my ph. Number
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Did you pre-tension your cam chain?
That could be the noise.
 
I primed the tensioner piston with oil and pumped it per the manual until oil came out the semi-unscrewed cap, is there someting else I should have done or should I redo it?

sfdon said:
Did you pre-tension your cam chain?
That could be the noise.
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Its important to get it primed in case of a backfire.
If the noise is gone then it is prob. ok!
 
could be a sticky valve in a new guide.
New guides have been terrible for the last year.
Did you hand inspect the rocker pads?
 
My money is on a dry start tensioner. Makes a helluva racket for a little bit. Should go away and not be back like Arnold.
 
Second page of this thread, it was asked if the "dimples" are present. I didn't see a response to that item. It's my understanding that these are cast in the head and must after any skim or cut be still visible - it's BMW's way to tell that the head has not been cut to less than minimum thickness. IIRC the minimum is 121 mm?

Still, I can't think why skimming a head a little too much would create a coolant leak. But, now that you've apparently done the timing chain tensioner correctly and it started up okay, initial noise went away, I think you're okay. The initial noise may have been attached to the matter of the oil spray bar being dry when first started.

My "old pro" reference would have one crank the newly reassembled engine with the spark plugs out, until the oil pressure idiot light goes out. Then you know you've got oil pressure at the top end where it's most needed; you put the plugs in, and off you go! (we hope).
 
Yes it's quite a rattle and will pursue the tensioner further. If it doesn't go away in time is there anything I can do to free it up a little short of pulling the gear cover again? I am thinking of unscrewing the tensioner screw a little while the engine is running (with plenty of rags in place) to free it up? Or with the engine off can I pull it out and flip it 180 degrees without losing the prime? I am still using 20w-50 oil although I switched from Castrol to Valvoline Racing.

Also, how much pressure should it take to move the piston back and forth with a screwdriver? Should it move easily or be very firm?

Honolulu, I didn't notice any dimples, I though Don was referring to scratches or gouge marks but I don't think the head has been skimmed more than allowed.

61porsche said:
My money is on a dry start tensioner. Makes a helluva racket for a little bit. Should go away and not be back like Arnold.
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No.

Loosening the cap will drain the oil , not fix the tensioner. The caveate is that if your were dry starting again- pour oil down the upper cover side and fill up that resevoir- takes about a 1/4 quart. The tensioner is submerged. That's why oil pours out. Stick a piece of plastic under that rags/s.

You skimmed the head. If your tensioner was at it's travel limit dimension or stuck internally( old, gummed, etc.), you have to work on it or replace it. By work on it there is a free length spring dimension check. The head/ slipper is two piece with an interference fit and a sort of one way internal valve/ cup. That interference on a backfire or from old age can be reduced from optimum. I reworked mine by pulling/ streaching it to the dimension in the repair manual. I had more time than sense and what the hell... I'd have to wait on a part anyway. You need calipers to do this though.

Usually, if you got the cap on ..the tensioner slipped in place on the chain. But there is a normal wear pattern or direction. Could be you need to flip it. 50/50 shot you got it right or wrong on the original wear pattern.

Usually, the tensioner straightens it self out by filling up that resevoir with oil when start up occurs. That little hole you saw is really the shock absorber relief.

The only other odd occurence is the chain. Two things can happen. First the cam gets shoved backwards which if the clearance on the chain to cover is tight can rub. Makes the same kinda noise. My guess is that tolerances stack up, wear patterns change, and it usually settles down. Second, if you use a new chain or master link chain. The master link should go forward and not to the cam side AND staked. That link is wider than normal and can cause an issue with a slight rub.

Maybe this will help someone.
 
The "dimple" is a cast in indicator of head height as Honolulu suggests. Head height is 129 mm
with a suggested max cut of 19 thousands. By inspecting for dimples you can quickly check for an overcut head.
Heads that are over cut can give problems with dowels that are taller than their recesses that keeps heads from coming together on the block.
Heads that are overcut can also get a valve tap from hitting the piston.

Tensioners need to be tight as hell before starting an engine - use a big screwdriver and a quart of oil and simply pour the oil in bit by bit at the #1 cam area while manipulating the tensioner. You will know it is done when it no longer moves.
Almost every new tensioner I have seen for the last 3 years has been defective.
You must make sure the tensioner is set between the yoke of the piston.
 
They have the wrong shape- the don't fit in the yoke of the piston w/o being bent first.
 
Thanks to you guys it seems like the tensioner was indeed the culprit. I removed it, turned it 180 degrees, adjusted the spring length to spec (I'll probably get a new one but wanted to see if it had any effect), reinstalled and pumped/bled the piston.

Started her up and no clacking as before.

So for now no runs, drips, or metallic noises - will take it for a drive for the final verdict.

You all are friggin awesome, thanks.
 
How many beers did you drink!? Delighted for you! I think.I need thicker oil or to revisit the tensioner.
 
Thanks - I took it for a drive and all seems well, ran great even with minimal carb tuning, feels strong and crisp.

I've been drinking since my return...unfortunately wine because we don't have cask ale here!

The faulty tensioner setting really puts out a horrific sound, between that noise and the coolant I thought I was looking at pulling the head again and was despondent (so much so that my wife almost felt sorry for me), so far so good and will retorque to 100Nm per Don's suggestion after a few more miles and heat cycles.

30csl said:
How many beers did you drink!? Delighted for you! I think.I need thicker oil or to revisit the tensioner.
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In my situation I think when I reinstalled the piston after the head was rebuilt I did so upside down to the wear pattern from the last 40 years, this likely prevented the piston from moving freely until the engine warmed up and/or sufficient oil pressure moved it into position. I also checked the spring length and mine was 1/4" under to I stretched it back out, maybe this also added the proper tension for when the engine is cold. I'll probably replace the spring instead of relying on the stretched one but this may be worth a check in your circumstance.

30csl said:
When you say faulty tensioner setting what do you mean?
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