Head bolt question, 11mm 12 point?

[offalot]

Im putting another head back on my 81 caddy 1.6 and I ordered some new 11mm bolts for it. The bolts came, sure enough they are 11mm but they are the 12 point heads. Im thinking (from what Ive read)these were for a slightly later gasser. Also heard they were indeed stretch bolts and are an upgrade to the 6 point non stretch. So can someone confirm this and let me know which torqueing procedure to follow? Thanks.

[VW Jon]

Do not use them, as they are for a gas engine, and are stretch bolts. The 11mm diesel bolts are hex head and are not stretch bolts.

[Fatmobile]

Are they longer than the hex head ones.

On the 11mm blocks;
the stock allen head bolts are too short and stress a small area.

I worked on a 1.5 with the triplesquare bolts.
The guy said because it was a german Rabbit the head bolts are 12mm, even on a 1.5. I'm not sure he was telling the truth.

He probably used the gasser headbolts when he did the head gasket,.. but we never had a problem.

[82vdub]

In some information I have, aftermarket gas and diesel 11mm head bolts have the same replacement part number, thus they are the same. That's aftermarket and not saying that it's right either.

If you truely have a 11mm block, search this forum for others who have had these blocks and have not installed head studs in these engines. If it were me, I wouldn't waste my money on changing a head gasket on a 11mm block without bucking up the funds and installing head studs.

[hagar]

offalot : if you got them from Jack ? use them. . We (the forum) will help you with torque.

hagar.

[libbybapa]

If the threads are 11mm, then I would strongly recommend getting a set of ARP studs. Be cause of the short length and poor engagement of the 11mm bolts and the resultant stress on the block that fatmobile mentioned, they are extremely prone to cracking the block. The head studs can be gotten new for $100 and although somewhat expensive, can be reused and are considerably less expensive than replacing the block if the stock bolts cause it to crack.

Andrew

[hagar]

offalot : I agree with Andrew 100% ,if you have the mula ? get a set of studs. I am a stud fanatic as well . BUT no mula ? I will use anything. ----yes anything.

I will send you a set of bolts for free if you have no mula. All VW headbolts have plenty of clamping pressure if WE do it right. , read my lips.

hagar.

[VW Jon]

Jack told me specifically: DO NOT USE!! and so that is what I am going by.

[hagar]

Jack did not sell them to you ? EH?

hagar

[offalot]

Sorry for the delayed response, it was a rare beautiful day here in Ohio and I was taking full advantage of it. As far as the length, they are maybe 1/8" shorter then the 6 points. I really wish I could bone up and get ARP's but Ill spare you the money woes and just say they really arent in the budget right now. I just had to buy a "new" head last week.So should I just go back to the 6 points?

[libbybapa]

Use the longer bolts. The 6-pt are not stretch bolts and are reusable.

Andrew

[Fatmobile]

If the 6-points are longer use them,
don't use something shorter.

If the original bolts don't look all corroded you can use them again.

[vwtyp133]

Yes... on using the 6pt 11mm bolts. They were OG from the factory on '77 through '80(the 1.5L engines & even a few 1.6L). Chase the threads in the block & blow the crud out of them, so that all that torque you put into tightening the bolts is really tightening the bolts, rather than just fighting residue on the block's threads or crap in the holes.

A light coating of oil on the clean bolts before insertion will also assist in getting accurate torque readings. A heavy application of oil might keep you from snugging the bolt all the way down in the hole, sacrificing needed clamping pressure. Some water in the hole can do that too, plus... when it turns to steam while running... can crack the block. Trust me on that.

That said, studs are worth it.


J.R.
SoCal

[hagar]

offalot : I forgot to mention a couple of very important issues . Here we measure the exact depth of holes in block. . Cleaning is not good enough I had material packed in bottom of a hole in a 1.5 L so hard it had to be drilled out. ALL head-bolts in ALL diesels stretch. .So why did VOW go to stretch from Torque ? . Because that takes friction out of getting good "CLAMPING" pressure.

Here we reuse ALL bolts. why ? we go by "Fingerspitzengefuehl" . And we check the bolts at least every year. . Many years of success. . Hard to argue with performance.

That is why I like studs. , they use all the thread in block. , bolts do not.

ARP studs ? good choice I seem to remember that ARP stands for American Raceway Products.

Yes studs do stretch . . Our secret procedure is coating top of block with epoxy and using "Belleville Washers". Those washers do wonderful things all over the place . , We use as many as possible in parallel on each bolt..

wonder and hagar.

[82vdub]

Chase the threads in the block & blow the crud out of them, so that all that torque you put into tightening the bolts is really tightening the bolts, rather than just fighting residue on the block's threads or crap in the holes.

A light coating of oil on the clean bolts before insertion will also assist in getting accurate torque readings. A heavy application of oil might keep you from snugging the bolt all the way down in the hole, sacrificing needed clamping pressure. Some water in the hole can do that too, plus... when it turns to steam while running... can crack the block. Trust me on that.

A couple points to make:

If you're going to chase the threads to clean them out, one way that you don't want to do is to use a threading tap to chase the threads. If you find a chasing tap, that's ok to use, but using a threading tap will actually remove thread material in the block which would weaken the clamping ability in the block. A threading tap makes the threads, while a chasing tap cleans any existing threads. A threading tap is also tapered at the end and would not end up "cleaning" all the threads to the bottom of the hole like a chasing tap will do.

As far as oiling bolts/studs, typically, there are different torque readings that should be used depending if the threads are dry, or lubricated (and by lubrication methods). If you oil the threads and use a torque number meant for dry threads, you would likely be over torquing the bolts/studs. This could be catastrophic.

IMO, ARP (American Racing Products) is one of the finest, if not the finest, aftermarket bolt manufacturer. If any head comes off any diesel of mine, it's going to have studs installed, no question.