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Hartge head info needed

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86_6series
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Hartge head info needed

Post by 86_6series » Fri Sep 07, 2018 1:13 am

Can anyone tell me the specs of Hartge heads for the m30 engine.

Chance for me to buy a head purchased in '92 for an 86 635Csi.

12,000 miles on head. In those days was it just a head swap, or

were there other mods that were done along with the head.

Could it be a B35 style head that would bolt onto the stock B34

block and lower compression? Would the bigger valves and hotter cam

compensate for the lower compression?

Thanks for any and all input. Going to post on Bimmerforums and My E28 also.

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jps635
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Re: Hartge head info needed

Post by jps635 » Fri Sep 07, 2018 10:34 am

a few references to hartge heads in attached. (Do a ctrl f)
Attachments
High Power M30.pdf
(233.65 KiB) Downloaded 29 times
'85 635csi JPS (RA2-66)

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Re: Hartge head info needed

Post by bpoliakoff » Fri Sep 07, 2018 6:01 pm

JPS Unless I carelessly read the information you attached, it did not cover the issue of compression loss due to the larger combustion chambers in a B35 head versus smaller piston crown on a NA B34 piston thereby causing power loss. I am taking it for granted that the Hartge head is a B35 head taking advantage of the larger combustion chambers, ports and valve sizes and believe that is what the OP is addressing. If it is a reworked B34 head, then it is indeed something to be grabbed up by an owner of a B34 motor looking to enhance power
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
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jps635
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Re: Hartge head info needed

Post by jps635 » Fri Sep 07, 2018 7:58 pm

To OP, found this as well - may be of help: http://www.retrosport.es/BMW_Hartge_H6S ... _1979.html
'85 635csi JPS (RA2-66)

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Brucey
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Re: Hartge head info needed

Post by Brucey » Fri Sep 07, 2018 8:16 pm

IIRC you can get the CR increased/back again by skimming a B35 head when fitting it to a B34 block with B34 pistons. However this has two important knock-ons

1) that the upper timing cover housing needs to be skimmed to the same height, and cannot (easily) be used with a standard height head again and
2) that the valve timing is altered (retarded). Slotted camshaft sprocket mountings and an eccentric location pin may recover this.

A third consideration is that the tolerance for wear in the camchain is reduced; the tensioner will reach full stroke and become ineffective earlier on in the wear life of the chain.

Obviously the head/piston should be checked for clearance any time you are skimming a head.

BTW the Hartge head is meant to work with the Hartge camshaft in B34 motors. If you can't lay your hands on one of these rare beasties, use a standard B35 cam instead; it is very similar.

cheers
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Re: Hartge head info needed

Post by bpoliakoff » Sat Sep 08, 2018 12:36 am

Point being is that at the right price, tyhis should be bought if even to be put on the shelf to use in a complete future rebuild. it is a rare enough item .

An engine should have a complete rebuild around it.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.

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Re: Hartge head info needed

Post by Pod » Mon Sep 10, 2018 5:04 pm

bpoliakoff wrote:
Sat Sep 08, 2018 12:36 am
Point being is that at the right price, tyhis should be bought if even to be put on the shelf to use in a complete future rebuild. it is a rare enough item .

An engine should have a complete rebuild around it.

+1

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Re: Hartge head info needed

Post by 86_6series » Tue Sep 11, 2018 9:29 pm

Well, I guess you all convinced me.
I'll put in the pistons. do I get the stock B35 pistons, or do you guys recommend
something more exciting?

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Re: Hartge head info needed

Post by bpoliakoff » Wed Sep 12, 2018 12:28 am

Look at the replies to your post on Bimmerforums. It isn't just a matter of putting in pistons. It is a total engine rebuild, with everything matched up. Pistons fitted to the bores, pistons fitted to the combustion chambers, block decked for straightness head trued it could be warped. There aint no cheap way out. It isn't just a matter of slapping in pistons and throwing on a head. That's a waste of money and a good head. How do you know the wear in the bores and what size pistons will fit?/ On and on it goes. Are you throwing any size pistons in a worn engine?/ Better start doing your home work. Best bet is to pick up another engine and have it rebuilt accordingly and then swap it in. Will your stock ECU run it? Will you need a chip?

Pick up a few books at Barnes and Noble and start doing some reading before you jump into the fire
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.

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Re: Hartge head info needed

Post by Brucey » Wed Sep 12, 2018 11:52 pm

in the simplest terms there are 'bolt on bits' and 'properly built/tuned engines'.

A lot of the extra performance in the latter engines comes from having parts that match one another better than the ex-factory tolerances permit. This is done by selective matching (eg in race series where modifications to OEM parts are not allowed) or by a combination of this and careful remachining where necessary. In this way you can get all the CRs, combustion chamber volumes and squish clearances identical on all six cylinders, to tolerances that you might never achieve by simply taking parts and bolting them together. This in turn allows you to keep all six cylinders working in the same way which means that you don't have one cylinder that starts to misbehave (eg detonating) or is producing a lot less power than the others; either thing will hold the engine back.

BITD Hartge heads were sometimes sold as 'bolt on performance' but in reality the gains were often nothing like they should have been if you just did that; you would get a lot more out of those bits by building the engine properly around them.

cheers
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86_6series
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Re: Hartge head info needed

Post by 86_6series » Sun Sep 16, 2018 1:04 am

Thanks to you all.

I'm taking the B35 Hartge head and my stock B34 block to an engine builder in Nyack NY.

Yep, I could not believe that one of the best engine builders on the east coast is Charlie Olsen.

I remember buying performance stuff for my 510 Datsun from him in '74.

He's going to check it all out, suggest options and work with me on things that I can do myself

more for the challenge than to save some money. Building an engine is something I always wanted to do.

So it'll be a winter project and I'll update as often as possible.

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Re: Hartge head info needed

Post by bpoliakoff » Sun Sep 16, 2018 2:40 am

You are 100% going about it the right way. It isn't a matter of just matching pistons to the head. They have to be matched to the bore size as well and after all these years the odds are your bores are worn evenly if slightly. Do the whole thing right and end up with a big smile on your face.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.

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