l28 L28 rebuild needs advice

[RS02]

Hello everyone I'm Lance. As you may saw earlier I bought a 240z with a L28 in it( The owner didn't even tell me he have a L28 in it until the car has been delivered all the way across America). Now the engine is out and apart and I'm ready to rebuild it. This engine is a N42 block with dished pistons and I'll guess it's a early one since the number stamped is small. It's got a E88 head and 3-screw SUs which I believe came with this car in 71. I'm not sure about the specs of the parts but it seems pretty stock to me. Anyway I have completely disassembled the engine and the block looks fine except those tiny tube inside coolant passage is broken (I removed coolant plugs and there's pieces of rusted metal so I cleaned it and saw this). If that's ok I guess I'll go get the rebore and honing done, as well as a new set of 280z valve and new flattop pistons. I might regrind the camshaft and make the duration longer. This engine is for daily driver so I don't want to be too aggressive. What are the things I need to worry about? I've done quite some research and bought a couple books. Throw some questions and advices at me so I can make sure I'm doing everything right. I'll post some Pics later.

[Zed Head]

Which books?  How do you know it needs a rebore?  Have you checked the parts against the specs. in the FSM?

There are different versions of the E88 head,  Probably best to know exactly what you're working with before paying for machine work.  You might decide to buy different parts.

[siteunseen]

Squirt some water through the holes on top of the block and see which hole feeds the broken tube. I imagine it's a coolant line but I would find out for sure if it were mine. Once you get the hole figured out there's a colored diagram out there that shows water and oil circuits.

Tomorrow Monroe's How to Rebuild L Series engine is all you need and of course this forum. I've rebuilt two with these guys and that book, great combo. 

[RS02]

6 hours ago, Zed Head said:

Which books?  How do you know it needs a rebore?  Have you checked the parts against the specs. in the FSM?

There are different versions of the E88 head,  Probably best to know exactly what you're working with before paying for machine work.  You might decide to buy different parts.

Figured out it's a late E88 because it's got the 35mm intake instead of 33mm. Thanks for telling me. I'd better start looking for E31 or N42 heads now.

Edited September 13, 2016 by RS02

[RS02]

21 minutes ago, siteunseen said:

Squirt some water through the holes on top of the block and see which hole feeds the broken tube. I imagine it's a coolant line but I would find out for sure if it were mine. Once you get the hole figured out there's a colored diagram out there that shows water and oil circuits.

Tomorrow Monroe's How to Rebuild L Series engine is all you need and of course this forum. I've rebuilt two with these guys and that book, great combo. 

Lucky me! Already got the book before starting this whole project! Of course I will start try to figure out what that broken tube is.

[RS02]

Anyone who know what year this E88 head is? I searched but there's so many different opinions. This one looks like a 72 head but it doesn't have that square spark plug area like many other early E88s... I'm searching for any high compression heads except late E88s. Is it worth trying to buy a E31? There's not much heads for sale in U.S.  any advice is welcomed. 

[Mark Maras]

 I don't have any advice as to which head to run but keep an eye out on Craigslist, Seattle and Portland. There are still some bargains to be found.

[Zed Head]

3 hours ago, RS02 said:

Anyone who know what year this E88 head is?

You could measure combustion chamber volume.  It's easier than it seems, the hardest part is finding something that is graduated in cc's (Edit - actually, you can always convert any volume to cc's., So any fairly accurate liquid measuring device will work).  For what you're doing you don't really need 1/10 cc'.s, 1/2's will work.

Edited September 14, 2016 by Zed Head

[siteunseen]

If you put new steel valve seats in that head and the larger valves, do some port grinding to match a Nissan head gasket and unshrouding the valves that head would be a good one.  Get some flat tops out of a ZX motor and you'd have a good compression ratio.

Those gaskets are still available from Nissan.

 

[moelk]

Like Cliff said in the post above^ If you change the seats and valves (as you mentioned) and just clean the ports to match the gasket its not a bad head to use.

I have that head on my engine with those changes done to it.

After you have changed the seats and valves you should measure your chambers, bigger valves increase the volume, at least mine did.

I had 49cc if I remember correct. I had the head shaved to reach 44cc to get to the cr I wanted. 

But if you run stock camshaft keep it below 10 cr.

 

 

Edited September 15, 2016 by moelk

[RS02]

9 hours ago, moelk said:

Like Cliff said in the post above^ If you change the seats and valves (as you mentioned) and just clean the ports to match the gasket its not a bad head to use.

I have that head on my engine with those changes done to it.

After you have changed the seats and valves you should measure your chambers, bigger valves increase the volume, at least mine did.

I had 49cc if I remember correct. I had the head shaved to reach 44cc to get to the cr I wanted. 

But if you run stock camshaft keep it below 10 cr.

 

 

 

17 hours ago, siteunseen said:

If you put new steel valve seats in that head and the larger valves, do some port grinding to match a Nissan head gasket and unshrouding the valves that head would be a good one.  Get some flat tops out of a ZX motor and you'd have a good compression ratio.

Those gaskets are still available from Nissan.

 

Thanks man. I did want to use this head but people kept telling me that the chamber design of late model E88s are just not good for proformance. Now I'm not sure if I want to find another one or just use this. I will get my old camshaft regrinded to a more aggresive one and that might actually work...

[RS02]

New plan: if I use the E88 head I have now with

44 and 35mm valves

Regrind cam valve lift 0.430 and Duration @0.050" 230/230

Flat top piston(87mm)

New springs

Porting

What do I do with the rocker arms? Can I do something and use it again? Or do I have to buy new ones? If this works I can really get the engine rebuild going.