Cylinder Head Advise 280ZX

[Huw]

Would welcome some advice/suggestions/help.....


Having managed to get the head off my engine, on inspection one of the head waterways looks slightly corroded. The rest all look fine, is this going to be a problem?

The engine only has 48K on it and ran fine but has been laid up for a very long time.

Also the cam has worn badly on two of the lobs so will need to be replaced. Am I correct in thinking I will need to get the machine shop to reseat the valves so they are all level with each other?

Thanks in advance

Huw

 

[rallymanDP]

Huw

That waterway will certainly new welding before the head is skimmed. Won't cost much - perhaps another £40 or so - the machine shop will be able to have it done for you.

Don't see why the Valve seats need to be replaced, but the Machine shop should be instructed to lap all the Valves in as a matter of routine.

 

[pmac]

Huw

That waterway will certainly new welding before the head is skimmed. Won't cost much - perhaps another £40 or so - the machine shop will be able to have it done for you.

Don't see why the Valve seats need to be replaced, but the Machine shop should be instructed to lap all the Valves in as a matter of routine.

that waterway will indeed require welding up and skimming. Make sure whoever is doing it has a preheating oven and doesnt just blob in some weld on a cold bench.
Untill you remove the valves and examine the valves themselves and the seats its hard to tell how much remedial work is required. I think Duncan is a bit optimistic in hoping that a lapping in session will do it.
I should have a spare cam if you need one. Worn lobes are not good. May be part of a larger picture. You need to check valve guides and all the reciprocating arms etc very carefully. Especially on the lobes that are worn.

 

[Alphabettispaghetti]

Looks like a good time to fit a lumpy cam

 

[pmac]

Looks like a good time to fit a lumpy cam

Nope!
it doesnt
Just recondition it properly . Do a little porting and raise the compression ratio to 10:1 ish and re install.
IMO....................IMO.....................IMO

 

[Huw]

Thanks for your advise guys, I thought it would need welding. Let me know how much you want for the cam Pmac, my car is a 79 280zx. I guess I should replace the rockers and spring also? I will check the valves this weekend.

One last question, loads of rust came out of the block when I removed the core plugs, this usual?

Cheers

Huw

 

[pmac]

Thanks for your advise guys, I thought it would need welding. Let me know how much you want for the cam Pmac, my car is a 79 280zx. I guess I should replace the rockers and spring also? I will check the valves this weekend.

One last question, loads of rust came out of the block when I removed the core plugs, this usual?

Cheers

Huw

well its common. TBH Im not surprised given the corrosion on the head.
i have scrapped several engines including 280 engines due to excessive block and head corrosion.

 

[pmac]

Let me know how much you want for the cam Pmac, my car is a 79 280zx.

email sent.Only just got round to this today.

 

[Huw]

Pete didn't get the email.

It maybe academic now anyway. I maybe looking for a new engine. The block has heavy pitting where the head waterways sit on the block surface. See pic. Can this be repaired or is it fit for the scrap bin?

 

[pmac]

Pete didn't get the email.

It maybe academic now anyway. I maybe looking for a new engine. The block has heavy pitting where the head waterways sit on the block surface. See pic. Can this be repaired or is it fit for the scrap bin?

Strangely i dont see it in my sent items either??????
Easiest to call to discuss. 07778 411568 Or PM me your number and i will call you

 

[STEVE BURNS]

Strangely i dont see it in my sent items either??????

Sorry slightly off topic
I know it does not apply to Pete but IMHO it is better to use the PMs to contact people on here as some times although there is the facility to contact people by email on here as well quite often people change their email address but forget to either change/inform the club of these changes

The club also tries to use the email system to remind users that renewal subscription is due if they want to continue their club membership and of course if you have changed your email address this reminder would not get through

 

[Rob Gaskin]

Pete didn't get the email.

It maybe academic now anyway. I maybe looking for a new engine. The block has heavy pitting where the head waterways sit on the block surface. See pic. Can this be repaired or is it fit for the scrap bin?

Huw, I can't tell how deep the pitting is but you may get away with the block skimming. The problem is that you will need your C/head skimming too when it has been repaired so that needs to be taken into consideration. I don't know what the tolerances are re piston height, compression ratio, valve timing etc.