From digest.v4.n776 Wed Jun 26 17:49:02 1996
From: "Harvey Chao" <Harvey_Chao_at_smtp.svl.trw.com>
Date: 26 Jun 1996 14:55:40 -0700
Subject: M20 Cylinder Head Bolts
Ref. Previous list discussions about replacement of old style hex head bolts
with Torx head bolts on all M20 engines (Produced through 3/89)
There have been several recent posts about replacement head bolts on 2.7L
engines used in E28 and E30 engines. I have been trying to track down
official info on this and several of you have contributed with accurate
information. One of you did also request, if I located Official info to pass
it on to him, so here it is.
The local dealer was unable to find such a bulletin in their files. They
were, however, able to confirm that yes, there is a problem, yes they do
recommend the replacement, yes, whenever a car comes in for service with the
old bolts and they become aware of it, the do recommend replacement . . .
I called BMW NA and they were unable to identify this bulletin based on my
input of the nature/subject and approximate release date.
BMW NA refered me to another organization who they said would identify
and send me the bulletin. This outfit (Central Letter Shop, although sending
me several service bulletins was not able to provide the specific info.
Thus, by going through official BMW channels, such a bulletin does not
appear to exist.
I have managed to obtain a copy of Bulletin 11 03 90 (3044) from an
Without typing the bulletin in it's entirity, the information is as follows:
Group 11 Engine
Bulletin No. 11 03 90 (3044)
Woodcliff Lake NJ Oct '90 Service Engineering
This service information bulletin supersedes S.I. 11 03 90 (3044 dated April
'90). It incorporates warranty information.
New Cylinder Head Bolt
All M20 Engines (produced through 3/89)
An improved cylinder head bolt has been introduced for use in the M20 eignine.
The new head bolt designated ASA 14, is grade 10.9 and is identifiedy by the
Torx head and a black surface finish. The ASA 14 bolt has been used in
production as of April 1989.
Whenever engine repairs necessitate cylinder head removal, all 14 old style
head bolts should be replaced with the ASA 14 bolts.
Further, in instances of head bolt damage (e.g. head broken off) all 14 head
bolts shoud be replaced one by one without removing the cylinder head.
Revised Torque Angle method of installation is as described in Bently, Torque
to 30 N-m (22 ft.lbs.), torque angle all bolts 90 degrees, torque angle all
bolts 90 degrees, waiting and running time requirements no longer used. Bolts
should be clean and lightly lubricated with oil. all bolts should thread into
the block by hand. Bolts which cannot be threaded in easily shoudlbe examined
and the corresponding threaded bore must be cleaned.
Revised torque angle values can be found in Tehcnical Data fische #4 dated
Under no circumstances shoudl the old and new head bolts be mixed in one
Part Number of new bolts is: 11 121 726 478 - head bolt - is a set of 14
Parts and labor reimbursable under the provisions of the BMW New Car Limited
Warranty. (Which I guess means that all of us'ns is now on our own on this
now. A set of bolts with BMW CCA discount cost me $30. An independent
mechanic estimated 1 hr labor to install. I will have it done next week when
I get annual service and a valve adjustment at my independent mechanic)
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