Is this cylinder head scrap?

58A - 71E · Post by **58A - 71E** » Thu May 28, 2009 8:31 am

Just had the the heads vapour blasted and it has revealed a few surprises

Looks like all the spark plug holes have been helicoiled in the past and I was surprised at the poor quality of the casting in the combustion chambers. Anyway, No3 cylinder looks like this,

Thoughts?

johnM · Post by **johnM** » Thu May 28, 2009 8:46 am

James

when are you going to get some good news

no expert but it doesn’t look too good.

Gary71 · Post by **Gary71** » Thu May 28, 2009 9:19 am

Put some P38 in the holes and you'll be fine

I wouldn't put it back on, but having said that it's not like any water is going to leak through is it

...and it's probably been like that since it was new.

roy mawbey · Post by **roy mawbey** » Thu May 28, 2009 11:00 am

James,

If you look on www.356registry.com "356 talk" forum page 3 thread:
"detailed picture of head anyone have a replacement" you will see in red the photobucket listing you can open up. One of the photos shows the same picture as yours so you can get an impression of how good yours is.

This guy has a crack from the spark plug into the combustion chamber and asked about the possibilities of welding. You will see if you enlarge his photo some other casting marks apart from the crack.

In yours I see the valve seats are also affected with chipping!!. As you mention "Helicoiled " spark plug threads maybe (its difficult to see) its had a problem in the past and someone has tried to repair.

I would have thought though with the inlet tract though also very pockmarked from the casting this would not have been caused by other factors.

Providing the valves can seat properly and their heliocoil is okay could you not work on the head to remove the pitted marks to some degree. I doubt it would cause much effect on the running and on the inlet tract side might even improve gas flow.

The 356 registry photo shows what seems to be a smooth ( apart from some marks ) a true circular spherical formed combustion chamber. On one of your photos the chamber looks out of round almost as though material has been added in places. ( maybe the photo??)

Maybe PRS would give you a better idea of whats good or bad, they might lead you in the right direction as they will have seen many heads!!. I would ask them!

Best of luck
Roy

hot66 · Post by **hot66** » Thu May 28, 2009 11:06 am

if you do nothing to the pitting in the combustion chamber , are you not going to get some pretty severe hotspots around the pits ?

Dakota · Post by **Dakota** » Thu May 28, 2009 11:40 pm

Hi
the pitting is almost certainly from the motor sitting with water in the combustion chambers and I think the helicoil insert is standard fit from the factory , as for a cure the worse pits could be welded but as you appear to have stock normal, read common, heads you would be better off looking for a better pair, they should not be too dear for a decent pair, drop me a line if you have any issues finding any , C's, super Nineties, etc are much dearer and harder to find in good nick, Bill

cubist · Post by **cubist** » Fri May 29, 2009 8:49 am

There are some good heads out there... picked up a pair of A heads from Norwich which turn out to be late C/912 type. Not a bad £99.99 ebay find

mad · Post by **mad** » Wed Jun 10, 2009 3:04 pm

£140 the pair

58A - 71E · Post by **58A - 71E** » Wed Jun 10, 2009 7:14 pm

http://www.ddk-online.com/phpBB2/viewtopic.php?t=21034

Well thats the recession for you, gone up from £110 posted

mad · Post by **mad** » Wed Jun 10, 2009 8:40 pm

yep, i left a cushion for negotiation