Cylinder head hole diameter for water manifold?

[bn-01-wso]

Hi. Does anybody know the diameter of the holes in the cylinder head for the water manifold found on 3B / ABY / ADU / AAN. I need to mount the water manifold on an 7A and i dont know at what dimension to tap the holes. Thanks

[martinjs]

Tapped holes are M6

[bn-01-wso]

Tapped holes are M6

I am not reffering to the bolts but the water holes. See picture

[SteveH]

I think you got the dimensions for the tapped holes from Martyn, as this is what you asked for in your first post?!

I've just measued my 3B head and the water rail openings are 20mm.

[bn-01-wso]

I think you got the dimensions for the tapped holes from Martyn, as this is what you asked for in your first post?!

I've just measued my 3B head and the water rail openings are 20mm.

I think i wrote the wrong question. I was reffering to water rail openings if that's what you call them. Thanks alot for the measurement.

[Thuppu]

I can arrange a jig if needed.

[martinjs]

I have reamed the large holes before 19.85mm and its fine.
Just put a dab of oil on the seals when installing.

[bn-01-wso]

I can arrange a jig if needed.

Thanks alot for the offer Thuppu but i have a friend here locally who can help me out with this. He is also building a Dacia 1300 (renault 12) with 20vt mid engine and he has acces to all the required tools.

[grundey]

I can arrange a jig if needed.

A DXF from your jig would be useful

[Thuppu]

Sorry, I don't have any dxf of if. I have typed/edited it by hand to our laser cutter.

[Macchris]

nice tool Thuppu
i meditate in my head to do the full job from a 20V 7A head cylinder to 20VT head cylinder but i dunno how it could be cost... any idea here ?
thanks

[pasbogdan]

Today i just finished my 7a.
19.76 mm i measured on a spare head.Did mine on the milling machine using tilting orbital tabble(milling bed) to get the manifold face perpendicular to horisontal milling head.Will get you some pics on monday with it finished.

[pasbogdan]

And others:

I used drilling starter bit,2 drills and final pass with boring head to get it to 19.76.
After that i bolted a manifold on existing middle holes and eye centered 6.5 mm drill into manifold hole,drilled with 5 mm and threaded after that.But without an orbital tilting table will be litle harder to center the face of the manifold perpendicular on horisontal head.If you have milling machine with bigger axle movements it is doable with vertical head.

[pasbogdan]

Can give you the coordinates,and refference points when will get the cps plate done.

[bn-01-wso]

Hi Bogdan. Thanks for the info. My friend just laser cutted a template for the holes and we will be drilling the head in a few days.