Cylinder Head question for a 280zx

Ped

Ped

Club Member
Hi all, my head gasket failed on the Zed, so it went into the garage and the head was sent off for checking. The verdict is that it is "too far gone" and needs to be replaced. :eek:

I have placed an ad in classified, but could someone advise which heads would fit my engine. I would imagine that it is just the head I would need so would swap over the valves and camshaft from mine.

Bit of advice would be welcome. And if anyone has a good head spare I would be interested. Is this a specialist 'Zed only' job, or will most machine shops be able to sort it?

Also are the heads stamped with a number?

Mine is an 1979-1980 model L28 and is unmodified.
 
grolls

grolls

Well-Known Forum User
Ped said:
Hi all, my head gasket failed on the Zed, so it went into the garage and the head was sent off for checking. The verdict is that it is "too far gone" and needs to be replaced. :eek:

I have placed an ad in classified, but could someone advise which heads would fit my engine. I would imagine that it is just the head I would need so would swap over the valves and camshaft from mine.

Bit of advice would be welcome. And if anyone has a good head spare I would be interested. Is this a specialist 'Zed only' job, or will most machine shops be able to sort it?

Also are the heads stamped with a number?

Mine is an 1979-1980 model L28 and is unmodified.
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I would get some advice on the head before you bin it. If its warped a lot can be skimmed off to get it straight again, even some cracks can be welded if needs be depending on where they are of course.


You need to clarify exactly why the head is too far gone and yes the heads are stamped with a number and letter. No doubt one of the engine builders will come back to you one you gain the clarification.
 
richiep

richiep

Club Member
grolls said:
I would get some advice on the head before you bin it. If its warped a lot can be skimmed off to get it straight again, even some cracks can be welded if needs be depending on where they are of course.


You need to clarify exactly why the head is too far gone and yes the heads are stamped with a number and letter. No doubt one of the engine builders will come back to you one you gain the clarification.
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Most definitely what grolls said. You really need to know exactly what "too far gone" means. As, tbh, it could mean something as simple as "garage can't be arsed to fix, get machined, will take too long cutting into tea breaks etc., let's take the easy route". :rolleyes:

79-80 - it'll be an N42 head unless swapped for later engine with a P90 head at some point. They can take a good skimming if warped (I've been running one with nearly 2mm skimmed off for years - obviously in a rather high compression, cammed engine). Basically, don't bin it until you know the exact details as people can advise on here.
 
Ped

Ped

Club Member
Thanks for the feedback so far. I will get some more details of exactly what the issue is. I would prefer to reuse what I have if at all possible.
 
Huw

Huw

Club Member
Sorry to hear about the cylinder head mate. I have got to echo what the guys have said above, I had a similar story with my cylinder head being told it was scrap. Mainly because the firm I went to originally couldn't be bothered with it. But it does depend on what the actual fault is, which you need to find out.

The machine shop I finally used welded the corrosion around the waterways, skimmed it about a 1mm, sleeved the valve guides and replaced the valve seats. So it goes to show a lot can be done with these cylinder heads to repair them.

Let us know what you find out.

Huw
 
SeanDezart

SeanDezart

Well-Known Forum User
Agreed with the others.....and you'll not know if a sourced second-hand one doesn't need work too....at least using yours you'll stay as she left the factory.
 
Ped

Ped

Club Member
Spoke to the garage just now, so there is a fracture around the valve seat running down the valve stem around cylinder 3 or 4. I have asked for the guy at the machine shops number, so will get the low down tomorrow, I hope. I will collect the head tomorrow too, and will see if there are any pics I can post to show what's going on.
 
Mr.G

Mr.G

Club Member
If source a compatible replacement head and you know the history and it's not had any faults.. you may get away with just changing the valve stem seals.
 
Ped

Ped

Club Member
I picked up the head from the garage today, and it is an N42. Still have not spoken the the guy at the machine shop, but as I understand it, there is a crack between intake and exhaust valves at the narrowest point as shown in the picture. I have adjusted the contrast in the pic to make it clearer. I think what he is saying is that it runs into the valve stem. You can see there should be a nice sharp casting between the two valves, on mine it looks corroded/worn away. This seems to be the problem area.

N42_L28_head2.jpg


Here is a pick of the whole head. You can see how discoloured the valve marked with the blue cross is. Note also the colour of the valve to the right in the next cylinder. It looks like it is on its way out too, there is the same corrosion in the same place.

N42_L28_head1.jpg


Guess I will just need to wait and hear what the machine shop guy has to say...
 
grolls

grolls

Well-Known Forum User
I think you need to get the valves out and the area cleaned (not with a wire brush) to see how bad it is as many cracks can be sorted although I would say the cost of repairs would probably be similar to the cost of a decent SH head but without the risks associated.

I assume a head would be in the region of £200... perhaps some of the others may know better.
 
Ped

Ped

Club Member
richiep said:
Way overpriced IMO, as are the other engines on eBay at the moment. An N42 engine suitable for rebuild went for a more realistic £260 a few weeks ago.
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I agree, I thought £400 was a bit steep too, a couple of hundred would be more like it.

PS: Richie your mail box is full.
 
jonbills

jonbills

Membership Secretary
Site Administrator
Offer him £300 and I'll go halves with you. (you can have the top half, I'll have the bottom!)
 
Huw

Huw

Club Member
Peter

I bought a head from Geoff Gale in Bristol about a year ago (ex Auto Active - his web site is still active with contact number even if the business has closed.). At the time he did have several he was trying to shift. Might be worth dropping him a line to see if he still has any left? Bit of a long shot I know.

As a last ditch, If you get really stuck for a head, I do have a N42 that I was going to rebuild as a spare for myself. It is bare with no valve gear or cam so you would need to source all that, plus it does need machining (skimming and pressure testing and would suggest getting the valve guides and seats checked). Didn't really want to part with it but if it helps you out of a hole mate.

Huw
 
Ped

Ped

Club Member
Huw said:
Peter

I bought a head from Geoff Gale in Bristol about a year ago (ex Auto Active - his web site is still active with contact number even if the business has closed.). At the time he did have several he was trying to shift. Might be worth dropping him a line to see if he still has any left? Bit of a long shot I know.

As a last ditch, If you get really stuck for a head, I do have a N42 that I was going to rebuild as a spare for myself. It is bare with no valve gear or cam so you would need to source all that, plus it does need machining (skimming and pressure testing and would suggest getting the valve guides and seats checked). Didn't really want to part with it but if it helps you out of a hole mate.

Huw
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Hi Huw, thanks for the info I will drop Geoff Gale a line. And thanks very much for the kind offer of the head. I am going to have a search around first, but will keep yours in mind. Nice one mate! :thumbs:
 
Ped

Ped

Club Member
jonbills said:
Offer him £300 and I'll go halves with you. (you can have the top half, I'll have the bottom!)
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It's a big lump of metal, the engine is "unknown condition" and it's pretty far from me, plus the ad states: "I have seen these engines as bare blocks sell for £700+ before grab yourself a bargain"... oh, and the starter motor and gearbox are not included. He could at least pressure wash it for £400... :D
 
Ped

Ped

Club Member
I picked up a spare head from Geoff Gale in Bristol today, his last N42. It will go off for testing and cleaning up on Tuesday, so will see how it goes. Thanks for the suggestions and help tracking this down!
 
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