Cylinder head rebuild

[merlin's S4]

I have a newly modified 7a head which needs putting back together ready to fit my S4. The original valve guides are still in the head but would you advise getting new ones pressed in or should the originals be ok?

Is there anything else that I should be looking to renew? I'm planning on replacing the stem seals and the hydraulic lifters but I really don't want the cost to get out of hand!

Cheers!!

[Jamo]

Are you fitting the valves from the S4 head? as they are sodium filled.

[terrybullwon]

Are you fitting the valves from the S4 head? as they are sodium filled.

I Am sure he is

You need to check for play in the valves when they are in the sleaves. In one of the audi manuals it tells you how to test it

[spink]

[QUOTE=merlin's S4;359669]I have a newly modified 7a head which needs putting back together ready to fit my S4. The original valve guides are still in the head but would you advise getting new ones pressed in or should the originals be ok?

QUOTE]

you need to check them/have them checked to be sure.Inlets will more than likely be fine but the exhaust side could need renewal.1.0mm for inlets and 1.3mm for exhaust.They are only a couple of quid each anyway so well worth doing while you are in there.

Its only the S4 exhaust valves you need to use,the inlets are same on all the 20v heads.

[Error404]

Worth doing it IMHO mate, as Spink says they're not very expensive and probably fairly well worn even if within spec

[s2_bo]

You can get new ones from GSF, dont get them from audi as they charge way more.

You could bring the head up to totnes and have the guys at the machine shop here test the VG for play, then if they need renewing they could just do it for you. They can also seat in your new valves and skim the head if that still needs doing.

HTH.
bo

[baltiboyS2]

Get the changed bit of a weakness on audi's the exhaust guides wear out the inlets are always fine
Dont get me wrong the exhaust will still do the job but you will be able to see the wear once you test them and they are pennies anyway

cheers Raj

[aelred]

If you are changing the guides it is advisable to have the seats and valves recut to be concentric, a 3 angle cut will be ideal and not any more expensive then the 2 angle.

[20Vcqdriver]

My head overhaul will be in next months Audi driver. Not a difficult job if you have access to a press (I 'borrowed' the one at work). Longest job was re grinding all the valves in. Also makes a massive difference if you have the correct stem seal removal tool and spring compressor that I borrowed once again...and made my own valve guide removal / insertion tool. Saved a fortune doing all this myself.

[merlin's S4]

If you are changing the guides it is advisable to have the seats and valves recut to be concentric, a 3 angle cut will be ideal and not any more expensive then the 2 angle.

Thanks for all the advice so far!

The valve seats were recut while the waterways and hall sender mount were sorted but it appears they only did a 2 angle cut! The head also had the exhaust manifold stud holes drilled and was cleaned and skimmed but then it bloody well should have been gold plated for what it cost me!

Looking at the valve guides again, it does appear that the exhaust guides have significantly more play in them than the inlets as suggested. Obviously I'll get them all checked properly but hopefully I'll just have to replace the exhaust valve guides.

Has anyone got a cheap source for the hydraulic lifters? Lightweight ones would be nice!

[Rusty]

Make sure you get a proper flow-job done on it

[volcano rs]

Worth doing it IMHO mate, as Spink says they're not very expensive and probably fairly well worn even if within spec

not expensive to buy ,but not cheap to fit and set up .

[merlin's S4]

With regard to hydraulic lifters, has anyone heard of FAI automotive? I've found these on ebay @ £26 for 10 http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=004 I've asked the seller what brand they were and how much they weigh, response was FAI Automotive and 68g. What do you reckon?

[Error404]

Custom Auto Craft sells OEM ones for good money IIRC mate

[merlin's S4]

Custom Auto Craft sells OEM ones for good money IIRC mate

Thanks! Yeah I've spoken to Paul at Custom autocraft. Think his are Febi and weigh 65g which is definately OE quality. But although that's a good price it's nearly twice the price of these for a set of 20.