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View Full Version : Head bolts - I think I might have goofed !



Zeuk in Oz
01-28-2006, 07:04 PM
Put the repaired & reconditioned head back on last night using new Torx-head bolts instead of the original hex bolts.

Tightened everything according to Bentley.

This morning I was reading Bentley again and noticed the word "washers" .

Should I have taken the washers from the old bolts and used them with the Torx-head bolts. The new head bolts look like a bolt head & washer together and didn't come with washers.

Thought I had better check now before I reassemble everything else.

Does it matter ?

Do I need to start again ?

Anton CH.
01-28-2006, 09:13 PM
If it does the same job, I would't see why it would make a difference.

myles
01-28-2006, 09:26 PM
According to the etk an m20 525i should have a torx head bolt and a separate washer

Bill R.
01-29-2006, 12:02 AM
torque sequence that they posted with the new bolts. Here
(http://www.bimmer.info/%7Ebill/m20headbolts.pdf)



Put the repaired & reconditioned head back on last night using new Torx-head bolts instead of the original hex bolts.

Tightened everything according to Bentley.

This morning I was reading Bentley again and noticed the word "washers" .

Should I have taken the washers from the old bolts and used them with the Torx-head bolts. The new head bolts look like a bolt head & washer together and didn't come with washers.

Thought I had better check now before I reassemble everything else.

Does it matter ?

Do I need to start again ?

Zeuk in Oz
01-29-2006, 01:11 AM
Thanks again everyone for your assistance- just goes to show that the ability to do stupid things never stops !
I am a little annoyed, however, that they were not supplied with the new bolts - that would have made everything crystal clear.
I presume that I now need a new head gasket and new bolts plus new rocker cover gasket - oh well I live & learn !
By the way Bill R, thanks for the new tightening protocol, however that is the one I used as that is also what Bentley recommended.
At least I can say that when I instal the new bolts it will be the second time I have put a BMW head back on !:D

Dave M
01-29-2006, 03:49 AM
Zeuk, I just did the same job on an M50 head and most of the washers stayed 'put' on the head through the process.

To get this straight, were the original head bolts installed without washers? The new set of head bolts I used arrived without washers, but I used the existing washers for the insall.

Anyhow, hope you figure it out,

Dave M

Zeuk in Oz
01-29-2006, 04:04 AM
Zeuk, I just did the same job on an M50 head and most of the washers stayed 'put' on the head through the process.

To get this straight, were the original head bolts installed without washers? The new set of head bolts I used arrived without washers, but I used the existing washers for the insall.

Anyhow, hope you figure it out,

Dave M

Mine is an early M20 motor from which the head had never been removed. These early motors came with hex head bolts and washers.

I ordered a set of new head bolts - torx and they were supplied without washers. What confused me was that they look a little like a bolt head with a washer and so I used these without the washers from the hex bolts.

Obviously this was wrong and I now need to remove and re-instal the head.

My stupidity and lack of experience !

I wonder if the village idiot has died or retired and I am about to be inducted soon ?

BobHarris
01-29-2006, 04:17 AM
Is it not possible to remove each bolt, put the washer on and replce the bolt one at a time, like the procedure for broken bolts mentioned in BillR's bulletin?

All the best

Bob

pundit
01-29-2006, 04:26 AM
Is it not possible to remove each bolt, put the washer on and replce the bolt one at a time, like the procedure for broken bolts mentioned in BillR's bulletin?

All the best

Bob
That's I would have thought. One bolt at a time.

Zeuk in Oz
01-29-2006, 04:44 AM
That's I would have thought. One bolt at a time.
Possibly, but given that I have to buy new bolts anyway, for the cost of a new head gasket I might as well do it properly.
I haven't done any more to the car since I bolted on the head, so have not much to lose as far as time or effort is concerned.

"Experience makes us wiser but not necessarily richer" - old Swedish saying. :D

genphreak
01-29-2006, 07:41 AM
Possibly, but given that I have to buy new bolts anyway, for the cost of a new head gasket I might as well do it properly.
I haven't done any more to the car since I bolted on the head, so have not much to lose as far as time or effort is concerned.

"Experience makes us wiser but not necessarily richer" - old Swedish saying. :DThe only reason I can think of for the washers is that they would prevent localised friction problems when torquing (as aluminum is easily fatigued). Given that the steel in the bolt is actually elongating under the stress, the idea of the washer would be to prevent the strain occuring around the friction surfaces of each hole.

Now you have already done whatever damage is caused by this, so what benefit can be had from taking them out just to apply the washers and then do it again. I might be going against more experienced others here, but I cannot see how (in use) the normal heating & cooling of the head could possibly require washers either, so I simply wouldn't worry about it.

Just make sure that next time (if there is one) you have a set handy (as any damage has already been done but is hardly going to be critical).

Of course it will make you feel better doing it all over again.

If on the other hand you were to remove and replace each bolt (with a washer) the tightening prcedure should be the same as normal- however I have to say I am less sure about this statement than my 'don't worry about the washer' suggestion. Actually, Bill R's wonderful pdf answers this question fully, even though yours has not been run yet.

You will get nothing other than peace of mind from doing the gasket again- in fact, surely an arguement can be made for leaving it as it is and testing to see everything else that has been done is good: I mean, imagine if the oil sprayer bar (or anything else) is round the wrong way or something else required you to remove a bolt later, a third gasket replacement would simply drive you potty!

I really don't think things are so critical, unless you had boosted the old donk. :) Nick

Bill R.
01-29-2006, 11:20 AM
with the washers on them. I don't think you need to replace the head gasket again or even remove the head.



Thanks again everyone for your assistance- just goes to show that the ability to do stupid things never stops !
I am a little annoyed, however, that they were not supplied with the new bolts - that would have made everything crystal clear.
I presume that I now need a new head gasket and new bolts plus new rocker cover gasket - oh well I live & learn !
By the way Bill R, thanks for the new tightening protocol, however that is the one I used as that is also what Bentley recommended.
At least I can say that when I instal the new bolts it will be the second time I have put a BMW head back on !:D

Zeuk in Oz
01-29-2006, 06:53 PM
The only reason I can think of for the washers is that they would prevent localised friction problems when torquing (as aluminum is easily fatigued). Given that the steel in the bolt is actually elongating under the stress, the idea of the washer would be to prevent the strain occuring around the friction surfaces of each hole.

Now you have already done whatever damage is caused by this, so what benefit can be had from taking them out just to apply the washers and then do it again. I might be going against more experienced others here, but I cannot see how (in use) the normal heating & cooling of the head could possibly require washers either, so I simply wouldn't worry about it.

Interesting that you should say that Nick ! I initially had the same thought but thought I would ask the question.

On reflection, however, I feel that given the vibration of the motor combined with the heating and cooling, I wondered if some further damage could occur and therefore feel it is probably better to err on the side of caution !

The other question that also occurred to me was whether the torx-head bolt might have been of incompatible material to the washer.

Obviously not !

genphreak
01-29-2006, 08:12 PM
Interesting that you should say that Nick ! I initially had the same thought but thought I would ask the question.

On reflection, however, I feel that given the vibration of the motor combined with the heating and cooling, I wondered if some further damage could occur and therefore feel it is probably better to err on the side of caution !

The other question that also occurred to me was whether the torx-head bolt might have been of incompatible material to the washer.

Obviously not !Yes and you can always leave replacing them till your first valve adjustment... :). Nice if you want to import them adn get the thing running adn/or test anything else.