Head cracking

[nip]

hi al,l whipped off the head today, had a quick look at the head looks good but then had a closer look at the spark plug holes and noticed these slight cracks inbetween valves, heres a few pics [IMG]http://i9.photobucket.com/albums/a76/nipsta/PICT0072-
[IMG]http://i9.photobucket.com/albums/a76/nipsta/PICT0080-1.jpg[/IMG]



is it still ok to use?, have also been reading that a good high percentage of the s2 heads do this. thanks

[Acidburn]

not good to see, what sort of power you going for? has anything been done to the head i.e. porting/polish?

[Jamo]

Cracks here are normal on the 20v turbo, depends if it's gone all the way through, common consensus on the forum and audi manuals are they o.k within a certain limit.

I cant remember the exact details, but should be easy enough to search for.

[driftin jo]

Most high mileage heads have small cracks , high HP or standard, unless they are bigger than this you are not going to loose any compression due to them and there is no reason that they will just get bigger than they are . Unless your building 600+ hp motor I wouldn't worry about using the head again.

[nip]

not good to see, what sort of power you going for? has anything been done to the head i.e. porting/polish?

about standard, but while the heads off thought of havin it ported and polished

[nip]

Most high mileage heads have small cracks , high HP or standard, unless they are bigger than this you are not going to loose any compression due to them and there is no reason that they will just get bigger than they are . Unless your building 600+ hp motor I wouldn't worry about using the head again.

cheers , is there anything that can be done to fix the cracks as in welding

[nip]

Cracks here are normal on the 20v turbo, depends if it's gone all the way through, common consensus on the forum and audi manuals are they o.k within a certain limit.

I cant remember the exact details, but should be easy enough to search for.

will find out the extent when i strip the whole lot

[bernsaudi]

So what's the position on trying to get heads welded up then? anyone had any success with this?I've got two or three like that hanging around waiting for someone to repair them.....

[nip]

So what's the position on trying to get heads welded up then? anyone had any success with this?I've got two or three like that hanging around waiting for someone to repair them.....

alright berni, are your heads worse that this

[bernsaudi]

The worst one had about a dozen cracks in it, that was the one off my old engine which was 180k. One of the other two was off a 90k motor which had been running desperate lean for ages that was almost as bad. Havent chucked them yet, was hoping that if I leave them in the corner for a year or two they may fix themselves

My brother thinks he knows someone who may do them.

[nip]

The worst one had about a dozen cracks in it, that was the one off my old engine which was 180k. One of the other two was off a 90k motor which had been running desperate lean for ages that was almost as bad. Havent chucked them yet, was hoping that if I leave them in the corner for a year or two they may fix themselves

My brother thinks he knows someone who may do them.

sound berni keep me posted mate, btw seen ur nephew few weeks ago in town

[bernsaudi]

Ive just got back from Santa Pod..been with him all day up there. Could only get a 14.2

Would have got high 13 if I'd been concentrating and put some decent fuel in.

[JP]

Cracks within the chambers in those locations are normal. they tend to form around casting flaws coupled with the fact that part of the spark plug thread is left exposed. Free flowing ported heads suffer less from this issue. Especially if doing a 30 degree cut into the aluminium with a multiangle seat combo as you'll find most of the cracks in picture dissapear as they are only visual surface cracks.

So long the cracks don't exceed beyond the first thread of contact with the spark plug they are considered fine. Even if more it is not the end of the world. The 7A head I used for my build had a crack that went beyond the seat which could cause the seat to drop out. So machined out the seat welded the crack, rethreaded the spark hole and pressed a new exhaust seat in. Has run 500+ happily for a year. recently pulled the head of and no new cracks have developed and the repair is as new.

hth

[Rocco]

dont worry for these small cracks

my current head has the same cracks as you,and for the moment no problem with RS2 Turbo or k26/27

[sorens2]

Mine was the same.
Did 50k miles with 450-500 bhp and still going.

Soren S2