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Engine Specific Info and Questions => IDI Engine => Topic started by: rabbit_diesel on June 27, 2007, 09:51:12 pm

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: rabbit_diesel on June 27, 2007, 09:51:12 pm

I found a cylinder head for my 1.6 N/A block.  It turns out that it is an 11mm head and I was wondering if I could some how make the 12mm bolts fit.  The bolt holes are just a bit too small would it work to drill them larger?   If so, how much larger should they be compared to the bolts?

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: saurkraut on June 28, 2007, 05:46:09 am

I'd be concerned about the compression ratio.  Its probably a 1.5 head, which would have smaller swirl chambers.  If you put it on a 1.6, your compression ratio will be higher, and thats not a good thing.  By my rough calculation, the CR would be 25.3:1.


Does the Thorpedo still exist?

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: myke_w on June 28, 2007, 07:26:55 am

I've done it, works like a charm as long as it's a 1.6 head.
Just drill out the bolt holes with a large enough bit and do it with a drill press NOT WITH A HAND DRILL.

You'll need 12 mm bolts, and an extra 11mm head bolt washer per bolt.

The way to tell if if it's a 1.6 or 1.5 is the size of the oil drain bump on the front middle of the head.

small = 1.5

large (like your old one) = 1.6

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: rabbit_diesel on June 28, 2007, 08:35:54 am

Yes, I am sure it's from a 1.6 block.  I'll make sure that I get them straight.  So I will need two washers per bolt?

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: myke_w on June 28, 2007, 10:51:43 am

correct, 2 washers per bolt, you may need to grind the edges to get them to fit too.  Let  us know how it turns out.

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: tylernt on June 28, 2007, 07:22:11 pm

http://forums.vwvortex.com/zerothread?id=3116475

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: rabbit_diesel on June 28, 2007, 07:47:02 pm

Thanks Tylernt, that is good information! Especially on this Exact topic.  :wink:

Title: Would 11mm size bolts head fit on a 12mm block??
Post by: rabbit_diesel on June 29, 2007, 11:29:17 am

Quote from: saurkraut

Does the Thorpedo still exist?

Yes, it is still around.  I was actually thinking of getting their vegetable oil to run in my jetta :lol: .  Have you ever been there?