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Head Gasket Change

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I looked in all the usual places but didn't find anything. Has anybody written a good guide on replacing the head gasket?

I'm wondering things like, what sealant if any to use and how to replace the timing chain?

I'm not 100% sure how the timing chain is aligned.

Ive got a '75 e12 head on there, the block has no date.

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Guest Anonymous
I looked in all the usual places but didn't find anything. Has anybody written a good guide on replacing the head gasket?

I'm wondering things like, what sealant if any to use and how to replace the timing chain? I'm not 100% sure how the timing chain is aligned.

Ive got a '75 e12 head on there, the block has no date.

You ask about a good guide. How about all the commercially available guides, e.g, Haynes, Chiltons, Bentley, Clymer, or even the shop manual?

Much of this information has been discussed many times on this forum. You mention looking in all the usual places, what are those? CD posted several pages of updated head bolt tightening procedures within the past 2 days. You could look through those posts without breaking a sweat.

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uh, yeah, I did look through those threads on the bolt tightening, no I didn't sweat, but I wouldn't say they were that helpful for a novice such as myself. I don't have a Haynes, so I thought I check here first. but thanks for stating the obvious... Every time I post here people reply as if I'm supposed to know everything already. If I did I would be here, well I can figure out what color to paint the car or what wheels would look good on my own.[/code]

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Yea, you need that haynes manual, it has lots of good info, Most will say no sealant on the head gasket itself, except the front cover & the small area around the hole where the oil comes up near the front. As to which sealant to use, I've used a few over the years, & most recently switched to permatex ultra grey, so far I think it's the best, for the front cover. To change the timing chain, you should really change the timing chain guide if your going to replace the chain, as well as the tensioner rail. I'd ask why change the chain, if you don't have maintenance history, it might be good idea, but to change the guide rail & guide, you need to pull the lower front cover too. These chains don't break, like timing belts, they go for 100K or more easy. So for just a headgasket, I'd not mess with a chain replace. But if you do, the trick is to rotate the chain to the top, take the link out, connect the new chain & slowly turn it in, then disconnect the link & connect it together, unless you pull the lower front cover. If it overheated before this, check the block with a straight edge besides the head, it's rare, but the block suface can warp. Also clean the cylinder head bolt holes of any remaining oil,grease etc.. Qtip, air nozzle, etc.. I also reuse headbolts, & flywheel bolts, but search enough & you'll find some who disagree with that.

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No particular endorsement for one over the other. The usual tactic seems to be consulting more than one source to look at the mission from every angle before jumping in. If you can grab the original repair manual, in original binder form or reprint.

BMW 1602 and 2002, 1959-77 (Haynes Manuals) (Paperback)
ISBN-13: 978-0856962400

BMW '02 Restoration Guide (Restoration Guides) (Paperback)
ISBN-13: 978-1855204515

BMW 2002: A Comprehensive Guide to the Classic Sporting Saloon (Hardcover)
ISBN-13: 978-1855203341

BMW Repair Manual, BMW 1602 1802 2002
p/n 01 51 9 699 551 (NLA)

BMW Repair Manual 1502-2002 on CD
p/n 01 56 0 004 532
This one is available from your BMW dealer or from online vendors. 

BMW Parts Manual, for a bunch of models, including the 02 (that's not the title, just the way I think of it)
p/n 72 00 0 301 255

Welcome aboard.

William

Edited by shipm_8

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Kind of long-winded, but here's my advice:

Get the Haynes manual as a starting point. The BMW shop manual (typically referred to as the "Blue book") is excellent if you can find one.

Start by reading everything you can get your hands on before tearing the engine apart. Don't rush this - take plenty of pictures and notes. Use plastic baggies for the nuts/bolts/washers you remove and label the bag with a Post-it note inside. I put the removed parts into several cardboard boxes and stored them in the trunk and backseat during the rebuilding process.

Be prepared to uncover some additional problems when the head is removed.

Don't assume your engine has "standard" parts. The head gasket may be a different thickness/type, the valve guides/seats/seals may need replacing and your head needs to be checked for cracks/warpage. There's nothing worse than replacing a head gasket then doing it again because another part caused it to fail the first time.

I replaced my head gasket, rod bearings, piston rings and oil pump (I'm a newbie) last year and used all the great graphics here in the FAQ and the shop manuals along with excellent guidance by Rob Torres of 2002 Haus. The long distance phone calls and e-mails to him were worth every penny.

If you haven't already done so, join the BMWCCA and enlist the help from your local club chapter. I have lots of helpful folks near me.

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Ive got a '75 e12 head on there, the block has no date.

The engine block should have a year stamped into it below the exhaust-side near a freeze plug (see picture). The VIN is stamped into the engine block on a flat surface (seen from above) just behind the starter.

The transmission number should also be stamped into the bellhousing just behind the cylinder head.

post-8235-13667605395754_thumb.jpg

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First (and only) time I have done it was 20 years ago. At that time there was no internet here, thus no FAQ, so I was on my own. The engine was on my wife's deceased '74 2002A, and I subsequently installed it on my Schwarz '76.

I used the Haynes manual and it worked out great. As a matter of fact, it worked until two weekends ago when my head gasket finally gave up the ghost!

Read as much as you can, take your time, and I'm sure it'll work out great.

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Some really simple advice from a shade tree guy:

Get a set of plastic ramps and have the front-end up. You can't get it high enough on jack stands. That alone is worth a million bucks. You'll need the space under there to get at things, like your lower set of bolts attached to the exhaust manifold. (or you can unbolt the down pipe from the header, and leave the header on)

to get a good start, you have to drain your coolant, and for some reason many people don't know to use the drain plug on the pass side of the engine block. This is a good way to start-off, since you reduce the mess factor.

In order to remove the head, you have to pull the timing gear off, without messing-up the timing. You need to loosen the timing chain tensioner. It's the bolt head that sticks out - pass side of the timing chain cover. Loosen it and HOLD ON to it, it is spring loaded and will want to shoot off. Not high pressure but you'll have parts flying around. Once you have the chain loosened, you can proceed to undoing all the bolts holding the gear on. I learned a very helpful trick here: When you remove the gear, you have to keep the chain on the teeth around the TOP and BOTTOM gear in place, so you don't mess-up the timing. Before you pull the gear off, take a zip cord & wrap it through the chain both sides below the gear (pic attached), this keeps it wrapped on the gear. Take a bungee cord and put one end through one of the holes atop the gear, attach the other end to the top-ctr of your hood. (you have a bracket there) This will keep the gear pulled upward, taught, and in place while you remove the head. (pic attached)

That seems to be the trickiest part of the task.

and now everyone can tell me how crazy I am.

Scott

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post-1748-13667605404324_thumb.jpg

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I hope the large number of helpful responses reaffirms your decision to ask for help. Nobody simply learns these things without some guidance and direction from people with more experience. We aren't all mechanics by nature, but we can all enjoy the hobby to the extent we are able. Good luck with the procedure and keep us posted on how it goes.

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I hope the large number of helpful responses reaffirms your decision to ask for help. Nobody simply learns these things without some guidance and direction from people with more experience. We aren't all mechanics by nature, but we can all enjoy the hobby to the extent we are able. Good luck with the procedure and keep us posted on how it goes.

well said there buddy..oh yeah..polishing the rims is a PITA!!

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I looked in all the usual places but didn't find anything. Has anybody written a good guide on replacing the head gasket?

I'm wondering things like, what sealant if any to use and how to replace the timing chain?

I'm not 100% sure how the timing chain is aligned.

Ive got a '75 e12 head on there, the block has no date.

there is no sealant used on a head gasket

curious - is the head gasket blown? if not leave it alone.

the alignment is done at Top Dead Center

there is a line scored into the top of the front of the camshaft where the toothed gear mates to attach the timing belt

the line should be centered under the oil distribution pipe the runs fore and aft over the top of the valves.

TDC is a mark on the flywheel you can see thru the timing window on the bell housing on the transmission. you need to be at tdc to align the crank/cam shafts.

why replace the timing chain? the slide rail and chain tensioner should be replaced if you do the headgasket.

fwiw, i've done 6 motor rebuilds and never replaced the timing chain. the oil pump chain is another matter.

personally, the haynes manual is ok, but the clymer's manual is better, if you can find one (found one at my local library).

here's another reference you'll learn to like

realoem.com

2002's are in the archive section, and all 2002's are "sedans", not coupes

best of luck

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Thank You all for the helpful advice! My faith is restored. For those of you who where wondering, its a long story as to why Im replacing the head gasket. typically one thing leads to the next till you've rebuilt the entire car right? When I got the car the bushings in the front end where all shot, and the sub frame was bent beyond repair. Also all the front timing covers leaked oil. I got a replacement sub frame and took the engine out, that way easy to rebuild the front end and easier to get at the timing covers. After a very successful front end rebuild I turned my attention to the engine. When I took off the front timing covers I noticed two things: a blue puffy mystery sealant (not fromagasket or something sane like that) and that the section of head gasket that hangs out when you take off all the timing covers was quite severely cracked as if the previous owner had broken it during install and just used it anyway hopping for the best. For this reason I decided to replace it, rather than get it all put back together only to find it still leaking or worse. So there you have it.

-Aron

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Its not unusual to find the head gasket cracked at that spot. Especially if the front cover gaskets have been changed in the past. As you found a good glob of RTV will normally seal it just fine. You just need to have everything clean and oil free for the sealant to work well.

My .02 cents

KC

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