New age heads! they crack, and the problem isn't getting any better.
Used ones seem to be hard to find, and when you do find them, those are cracked as well.
So far, we haven't made TOO much of it, but on some heads, the cracks are too big to ignore, and threaten the integrity of the seats.
New heads are over £900 each plus vat, plus they come with nothing.
This is how they tend to go in the first place, and we've seen much worse.


This next one is a head from a pair we had written off due to bad cracking. We removed the seats, ground out and re welded the head, then fettled for the finish. We then fitted new seats. The advantage is that the weld is stronger than the original material, plus we are able to get a much better finish inside the port throat, with better seat angles. We're working on a price, which should at least be a decent saving on the cost of new bare heads. We could of course fit larger valves at the same time if required.

 

Nice work there Alan,is there anything in particular that causes this issue?
How often does this occur then?Is it a regular thing?

 

Dont you just love minty clean engine internals

Nice work

 

good work

 

It's just something we've seen with the AVCS heads. I'd say it's a material issue, and it's only coming to light when you pull one to bits and take a look.
I haven't yet seen one that actually failed as a result of this problem, but it certainly doesn't look good, and I'd be reluctant to start a nice engine build with heads in that state!

 

Hi,

we echo this problem, and also find it on version 5/6, below is a pic of an avics head in the same state








The other side is as bad.

We cannot risk fitting these as the cracks go right under the valve seats all it takes is a seat to pop out and its game over.

Nice to see someone thinking outside of the box, taking the bull by the horns and seeing just what can be done to salvage these heads, especially as bare castings are circa £800.00 + vat each.

Cheers
Kev

 

Oh god my build might be costing more

 

Oh, I'm a glass half full person!

 

Great Job guys.

I CNC'd my chambers on my 2.5 build (Spec C heads) and did a similar thing with the plug areas. QAlthough these were not cracked. I wasnt going to give them the chance to. Took them flush to the plug.

 

Shame you didn't want a demo car to look at my v4 sti heads Alan as when I was chatting with Martyn the other week we thought this would be a good area to explore on mine!!

 

We can certainly accomodate.
For our usual fee.
Plus expenses.

 

i was on the understanding that version 3 and 4 heads did not suffer from this and it was 5/6 that did, i take it this is not the case then

 

You aren't wrong, although the new age versions are more frequently found to be at fault from our experience.

 

Can you PM me some rough numbers and options of what's involved with 'sorting' the heads please Alan

 

You shouldn't need to do anything with the V4 heads. V3/4 is phase 1.5 and dont suffer from the cracking.

 

Sorry, that last post from Screechy was about modifying the heads for better performance. I knew that, and so did he, we just didn't pass it on to a wider audience. Thanks for your input there.

 

Cheers Alan. Yeah sorry my query was a bit misleading. I was down at Enginetuner a few weeks back and talking to Martyn about getting a bit more power (again!). From the rest of the work they have done we decided that the heads would be a good area to explore and that was what I was talking to Alan about.

Thanks anyway guys, at least that's one thing that should work in my favour then.

 

Screechy has a 2.5, which why we're recommending head flowing and big valves. Open up that area, and they start to pick right up at the top end.

 

New age with Cosworth plus 1mm valves. We can also offer Farrea stainless options for a bit less cash.

 

Shiny!

 

Yours!

 

Whats the rough cost for a set of the above heads with +1mm Cosworth valves?
(supplying the heads not new ones)

 

Hi Nic

Are your heads the new age avcs? if so, are they cracked?

 

Yep new age JDM avcs and let's say worst case they're cracked. (not taken them off to check yet).