Cylinder head hole diameter for water manifold?

**Macchris** · 19 July 2016, 08:09

would you please give me the info too please ?
thanks

**pasbogdan** · 24 August 2016, 19:33

Forget to write things down.I did it with translation(if this is the term for measuring something and with the same tool marking on other part).
Took reference parts the 90 degree angle flats(face and exhaust side) and got some m6 screws into aan cps holes.Also some precision paralels flat to allow me to find a position for my caliper.Measured,extracted half of the bolt and marked on the other head.And used the smallest hole starter to get in the exact middle of the mark on the milling machine.Will do a drawing next time i do one,with exact coordinates.

Attached Files

**etsola** · 17 December 2016, 22:09

Anyone ever made those drawings of that jig ?

Anything else to consider when converting a 7a head to a 3B (so no cam sensor bracket needed) ?

Thanks

**90/90qs** · 19 December 2016, 04:31

Originally posted by Thuppu

I can arrange a jig if needed.

Hey I could use a jig! My AAN head has spark plug cracks and I always fear it's longevity. I have 3 7A heads but my shop was not interested in an "experiment".

**jlw3141** · 28 October 2020, 03:05

Bring this old post back up. I would love specs or a drawing for this template as well! anyone willing to make an accurate drawing? or sell me a copy of their jig..

**varia** · 29 October 2020, 15:40

Originally posted by jlw3141

Bring this old post back up. I would love specs or a drawing for this template as well! anyone willing to make an accurate drawing? or sell me a copy of their jig..

you can measure the water manifold (3B or AAN) and draw your own.

**jlw3141** · 29 October 2020, 17:47

Yes I'm aware.. and I guess that's what I'm going to have to do but I was trying to get the spare 7A head all ready so I can swap it in to my 3B without too much downtime on the car..

Sent from my SM-G960U using Tapatalk

**Error404** · 31 October 2020, 17:53

Why not just pay to have it done professionally? I do this job frequently for people and it is not an expensive job - £135 inc VAT for the water manifold machining. You can’t do it yourself anyway using equipment the average DIYer has at their disposal - the water ports need to be machined accurately, not simply drilled out, otherwise it will leak. I’m sorry I won’t give the info away - gotta earn a living somehow.

EDIT: It’s not a technical job for a machinist to measure it and carry the work out, but it will definitely be more expensive than sending it to someone who already knows how to do the job

**LukasR** · 1 November 2020, 07:30

I highly agree with Error404. Send the cylinder head to get it done by experienced person who knows what's his doing.
Those cylinder heads are fetching serious money and they are harder to find.

**Error404** · 11 December 2020, 22:01

My service here, for reference

Modify Audi 7A 20v Cylinder Head to Turbo Specification

https://www.ultraperformance.co.uk/modify-audi-7a-20v-cylinder-head-to-turbo-specification

We can machine your Audi 7A 20v cylinder head to convert it to turbo specification, or modify your 3B or RR cylinder head to ABY/ADU/AAN specification by adding the cam/sync sensor mounting boss to the front of the cylinder head.Firstly we drill & tap the mounting holes and mill the water ports into the intake side of the head to prepare for the turbo water flange. The ports are chamfered to aid install without damaging the fragile o-rings and the mounting face is skimmed. We also offer a service to create an additional coolant port at at Cyl no.5 which improves coolant flow to the rear of the cylinder head.Next a shallow pocket is milled into the front face of the head to receive a machined boss with the locating dowel and mounting holes for the cam/sync sensor. The is fixed using high tensile socket cap screws and sealing in place with high temperature RTV sealant.All works are carried out to a high standard of accuracy on CNC machinery.Please note: in order to carry out these modifications it is necessary to remove the exhaust manifold studs from the head. We can do this for you, however this is charged at an additional rate of £50 which includes an allowance for up to 3 damaged studs to be machined out and rectified with thread repair inserts. If additional thread repairs are necessary, these are charged at £18 each. On particularly old and/or corroded heads it is not uncommon for most if not all the studs to need to be machined out and the threads repaired. Please bear this in mind when you are assessing the condition of your head prior to sending it to us.

Cylinder head hole diameter for water manifold?

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