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Hi all,

I need to drill two extra holes in my 9 stud block to get my 11 stud head fixed
and I can remember there is a description somewhere on my pc how to do it but its gone.
Can anyone help me with some information or experience?

I'm sure there will be someone on here who knows better than me but the last one I did I put the head on, spot drilled through the extra holes with a tight fitting drill to get my reference points then, as the engine was in the car, I covered the the entire top of the block in masking tape then used a drill with a mag stand to make sure the stud holes were at 90 degrees to the mating surface. I also shortened the studs on the lathe by a couple of mm and had a quick measure up at the water pump end to make sure that I didn't break through into the water pump recess.

Although I'm not sure if that actually matters as I think the factory drilled blocks just went straight through anyway?

I had a hoover (or Dyson, can't remember) hose alongside the drill to catch as much swarf as possible.

After that I just tapped the holes out, removed the tape, put the studs in, refitted the head etc and drove off sedately down the road!

Perfect way to do it with engine in car

You can otherwise use a head gasket as a template.

I've always used head gaskets as templates. I'd never do it with a hand held drill, this needs to be straight. I've got one 10studded engine due to a not vertical table on a drill

For this type of operation, I make a tool consisting of a guide tube welded to a foot that is bolted to the block. This tool keeps the drill parallel while you're drilling.

Regards
Al

I use the first method, more or less identically. Although the crux of the matter is making the hole vertical. Its easy to wander when doing it by hand.

A well greased drill and tap will help catch the swarf too.

If the engine is in the car I would never attempt this. It'd be much better for you to run the 11 studded head with only 9 studs. You don't need 11.

OK,

my engine is still out so drilling itself is not the problem.
My main concern is that if I break through into the water pump recess the block is not useable any more. Is this so ?

It is not so, most of the stud drillings in an A series block go into the water jacket.

Just use some thread lock on the stud to seal it.

wolseley 1000 wrote:OK,

my engine is still out so drilling itself is not the problem.
My main concern is that if I break through into the water pump recess the block is not useable any more. Is this so ?

you just need to make sure that the stud doesnt go to far through and stop the water pump from turning - i made this mistake on a well skimmed 970 block, i doubt its a problem on a 1275

OK,

thanx all, my head feels better now and I think I know what to do next weekend.....

Make sure and use the correct size drill but .I had a customer years ago attempt this , he used a drill but that "FIT" the holes in the head , then proceeded to drill the block .Yeah the studs fit .............nice and loose !!!!!!

Craig

Hi Craig,

have just bought some drills of a friend of mine that works for a specialised company here in Salzburg. They produce these drills and I first couldn´t believe it that they are so expensive. The drills are of a special cobalt HSS material so they sell for EUR 10.- each in a regular shop. The one for the near side of the waterpump is 6.3 mm and the other one is 7.8 mm.
Will do a test drill and tap before .