1.5 head on a 1.6 block

[leaky]

Those of you with alot more experience than I may know if it is possible to install a 1.5 head on a 1.6 block. (Diesel that is). If so, what mods are needed and if not why not. A friend gave me a factory new 1.5 head some years ago and as I no longer need it for a door stop and my car needs a refreshened head ...... well what the heck eh!

[82vdub]

Short answer is yes, with an adaptor. The 1.5 uses 11mm head bolts while most 1.6's use 12mm head bolts - which you may have issues getting the 12mm head bolts through the smaller passages in the 1.5 head. Read this thread too:

viewtopic.php?t=7936

[leaky]

Thanks for the info. That's encouraging; I assume others have done this swap successfully. Wonder what size drill to use for enlarging the 1.5 head bolt holes, and where to get the "adapter" you spoke about.

[82vdub]

You should be able to get the adaptor from Jack, the owner of this website (www.vwdieselparts.com).

Also, just drilling out the passages in the head may not work well. There may be coolant passages close to the bolt passages in the head that would cause issues. I'm not this versed at this aspect of the 1.5 heads. I'll let others comment, but it may not be something that you can't "just" drill out.

[leaky]

Humm. That's a disturbing thought. The 12mm bolts have about .005 clearance on my 1.6 head so it looks like a drill slightly larger than say 33/64 ths would do it, but then as you say will I hit a coolant passage somewhere. Maybe I could ream the 1.5 holes just big enough to get the 12mm bolts through and hope for the best. These little diesels are sure trickier to work on that my model A Ford.

[82vdub]

I only cautioned on the oversizing of the bolt passages as it may be an issue. It's likely that it's not, but I just didn't want someone out there thinking they can just drill them out without thinking about it and then they find that they've opened up a coolant passage or something. I honestly don't know, but someone else on this forum likely knows. It should be able to be done without an issue, but I am not 100% certain that it can is all.

Isn't everything tricker to work on than a model A?

[Diesel Dean]

Yes it will work I have a 1.5 head on my 1.6 diesel with about 15,000 miles on the combo. I bought the adapter from Jack you have to push it in the block at the oil return hole. I drilled the hole out for the head bolts just big enough to slip thru. The washer is to big on the 12 mm 1.6 bolts to fit in the recessed hole on the 1.5 head. I had to grind them down to fit in the 1.5 head. I just held the bolt with the washer againts a bench grinder and let it spin as it ground down the washer.

[leaky]

Thanks to 82vdub and diesel dean for the info. I shall go for it and I'll post the results either way. Thanks much. Yes everthing is more complicated than a model A Ford. Henry used gravity to get the fuel to the carb. How's that compared to the fuel system on diesel.

[mattbondy]

If you are going to drill the holes yourself you may want to consider having a special drill made. In a situation like this you take a drill of the size you need and have the end cut to act like a guide. I dont really know the specifics but I guess it is shaped so that it has enough contact with the existing hole to guide the drill. My father had to do this during some custom work on his old Yamaha RZ500 sport bike. I think he had the drill fabricated locally and the city I live in is not all that big.

[tedshark]

I have been using a 1.5 head non hydraulic on a 1.6 hydraulic block without any adapters I did drill the bolt holes out a little but it was very little some bolts actually fit.