cracked head

[nervas]

removed my cars head and saw some cracks on it there where spark plugs are srewed and one crack betwen intake and exhaust valves. Is it very bad? I'll try to go to workshop where they are fixing heads, but it is interested to know what are you doing about it..

here is pictures of engine head

http://www.interneka.lt/gallery/audi_s2_engine

you must see full size, that it would be possible to see cracks


any comments please

[porkkis]

This is my head:



Factory advice is that it should have been replaced. Man who made the valve job for me said that no need.

Now driven 35k km with that and no probs.

[nervas]

porkkis:
what boost are you running, and how much HP?

how deep is the crack?

and why it always is on the exhaust size?

[porkkis]

More thermal stress on exhaus side.

I'm running a chipped std setup.

The crack is almost all the way up the plug threads.

The risk is that if the crack widens the valve seat can pop out and that's the end of that engine. Atleast the head and piston.

[porkkis]

And I have to say one thing. "Knowledge increases pain". This is what we use to say here

Quite many of you might drive with such head without knowing about it

[quattronutter]

porkkis:
what boost are you running, and how much HP?

how deep is the crack?

and why it always is on the exhaust size?

almost every old 10v turbo head i have seen is craked between the valves,i done over 60k with the same in my old one

[nervas]

And I have to say one thing. "Knowledge increases pain". This is what we use to say here

Quite many of you might drive with such head without knowing about it

yes that's true...

[nervas]

almost every old 10v turbo head i have seen is craked between the valves,i done over 60k with the same in my old one

one friend of mine is doing ~350Hp with 10v cracked head and still going. He says that to leave that as is..

[Mark Halligan]

This does seem to be common on these heads, here are some pics of my old and now spare head, that came off of my old engine.

Every combustion chamber has cracks in the same place.

[Mark Halligan]

This chamber has two cracks.

There are some places that advertise the fact that they can repair/weld cracks like these. Even if you don't go that way, IMHO, its probably a good idea to at least have the head pressure tested before you use it again.......just to be sure.

[sorens2]

Mine has the same cracks in every cylinder. Done 200000 km now. 30000 of them with 400+ hp and 1.7 bar boost. No problems. And we are talking 30000 km of almost hardcore test here. So it has been ponished a bit this head. Still going strong.
Put yours back together and turn up your boost...

Søren S2

[porkkis]

My head was pressure tested. Of couse.

Welding the crack was also an option, but the valve seat would have had to come out first and new one done and the total price for that job was a bit too much IMO.

[90quattrocoupe]

My head was pressure tested. Of couse.

Welding the crack was also an option, but the valve seat would have had to come out first and new one done and the total price for that job was a bit too much IMO.

Hi,
I have run type 1 and type 4 air cooled VW motors since 1970. Still have a 914. Air cooled, since they only have two valves, cracked between the valve seats. A good machine shop can groove out the crack, weld it up and machine everything back to nomal. Better than new.

It seems to me, that this procedure would be cheaper than procuring a new head, which eventually, will do the same thing. Try to find a machine shop specializing in VW aircooled heads. I have had this done with stripped out spark plug threads, too. Much better than helicoils, as you keep same expansion materal.

I have been running repaired heads on my 914 for 16 years and they have never cracked again.

Greg

[nervas]

thank You everyone, will go to check under pressure

[SteveH]

Audi technical says the cracks are OK if they don't run further than two thread widths up the spark plug thread. I have them on my 3B head, it common and nothing to worry about.