Head Gasket Questions!

[Diseazd]

17 hours ago, nkopp said:

Ah, its a 240Z L24. Will do on cleaning tomorrow and re-post. Thanks!

If it’s a 73, they came with valve relief pistons. If it is from a 73, the E88 head was an open chamber head which it seems to be. Like I said before, I’m pretty sure that head came with an L28 exhaust valve and early L24 intake valves. 

Edited November 27, 2022 by Diseazd

[Reptoid Overlords]

Oops. I missed the part where the OP said he has an L24. And when I saw turbo my mind wrongfully went straight to L28. I always forget about those earlier blow-through turbos. This is why I don't help my kid with school things like reading comprehension and math haha.

[nkopp]

First off, wow! Thanks for all the comments and discussion!

Sorry for the incomplete history too. The car was in California and Washington primarily and it's a 1972. Previous Owner took their turbo back and left me the SU carbs. I've cleaned them up and they should be ready to go after some tuning. I do have some additional info from the glove box that I can put together at some point.

The someone who let the chain drop was me! My main reason for getting into the engine at all was to put a helicoil in for the long water pump bolt. That one and another were stripped and causing a big leak after I refilled (in addition to the small leak from the drain). I knew I was taking off the timing cover and figured as long as I was doing that, I might as well take off the head and see what I was dealing with. Seems like a good thing I did (though maybe I should have blocked the chain anyway)!

Aside from taking off the timing cover and doing the helicoil, I spent some time today with Goof Off, parts cleaner, and compressed air. It's all pretty stubborn, but maybe you can see a little better what's going on with these pictures (I worked mainly on these two cylinders, so that's what I have pics of). Any other tips on getting this stuff off? Maybe there's a polishing pad of some kind? I was able to unclog most of the rusted out ports by sticking the air gun through the rust and then blasting it back in my face. I'm planning to go a little more methodically at that this week.

Regarding the boil out, I'd really like to avoid taking the whole thing out. Is what I'm dealing with here beyond what a flush of some kind could help with?

Thanks again, appreciate the help and patience. If not obvious, this is my first project and it's been great stumbling into the car community. Between a couple forums and the handful of neighbors telling me about their projects, this has been really fun! 

Edited November 28, 2022 by nkopp

[Patcon]

I think I would consider taking out the freeze plugs/casting plugs and shooting high pressure water through the block to flush it out. My concern is there are large pieces of rust in the jackets and they are fouling the holes at the head gasket. You have them cleared now but when you add fluid back into the motor that debris will circulate again and stop those points up again. Causing random overheating that seems undiagnosable

[dutchzcarguy]

16 hours ago, Diseazd said:

If it’s a 73, they came with valve relief pistons.

Just some info then.. i got overhere a orig. L24 from a euro 240z and has NO valve relief pistons.. maybe in the states but i don't think that's right..

Back to the '72.. 😉 

Did your engine have a turbo on? then your c.r. will be much to low for normal aspiration system engine i think.. (sorry not my speciality so i now shut up 😉  unless the engine didn't work with the turbo because of a to high c.r.)  Maybe someone with that knowledge can chim in.

[nkopp]

Umm…. That sounds bad. I’ll add calipers to the shopping list and brush up on some math. 

Most recent previous owner definitely was messing around with this, so who knows. Could be they gave up? 

Edited November 28, 2022 by nkopp

[Zed Head]

What's the casting number on the head?  I circled where it should be.  Post a picture of it, it will show if the head has been shaved by its distance from the surface.  It kind of looks like it has been.  Also, take a picture of the back of the cam shaft.  There should be a letter stamped in to it.  And take a picture of a cam lobe or two.  You can tell if it's been ground by the size of the lobe.

[siteunseen]

I agree with Diseazd, looks like an e88. Square exhaust, round chambers. But the cast code will be definite like Zed says.

 

[dutchzcarguy]

On 11/26/2022 at 11:51 PM, nkopp said:

some work to do behind the timing belt

Not a belt... a chain, and as it's very flexible (in your pic i can see it's bend a bit sideways..) tells me you need a new distribution set..

[nkopp]

Had a chance to get into this again today. It’s an e88. Photo below, does it look like it’s been shaved?

I did find, however that the engine number on the block does NOT match the warrantee booklet that was in the glove box issued to the original owner. It is still an L24 though.

I thought I had seen a matching engine number elsewhere in the paperwork, but I don’t see it now. Will go back through the stack sometime this week to check. 

I also took some measurements. Bore is spot on at 83.0mm.  But stroke seems too long at 81.2mm (Monroe book says it should be 73.7mm).

I threw this all into Summit Racing’s calculator and got displacement of 2635cc and compression ratio of 8.66:1.

I assumed 1mm for the gasket, 0mm for deck height, 44.7cc for the compression chamber (based on some googling), and 7cc for the valve relief (from the Monroe book, maybe they’re from a 260z?).

I forgot to grab shots of the cam, will see what I can find later this week on that.

Does any of this help clarify what I’m working with?

A couple new questions:

* I can’t get much more stuff off the surfaces. Any other tips on cleaning? Have been leaving a rag soaked in Goof Off pinned down with a magnet and that helps, but it’s slow going.

* Any idea what’s going on with the photos below? It looks like some of these channels might be intentionally blocked up with something?

Thanks again!

Edited December 5, 2022 by nkopp

[Racer X]

5 hours ago, nkopp said:

Had a chance to get into this again today. It’s an e88. Photo below, does it look like it’s been shaved?

Yes.

5 hours ago, nkopp said:

I did find, however that the engine number on the block does NOT match the warrantee booklet that was in the glove box issued to the original owner. It is still an L24 though.

What number is stamped on the plate attached to the right strut tower in the engine bay?

5 hours ago, nkopp said:

I also took some measurements. Bore is spot on at 83.0mm.  But stroke seems too long at 81.2mm (Monroe book says it should be 73.7mm).

Appears that the engine has been stroked. A different crankshaft and connecting rod combination, and likely pistons with a different pin to top distance.

 

[Zed Head]

10 hours ago, nkopp said:

Bore is spot on at 83.0mm.  But stroke seems too long at 81.2mm (Monroe book says it should be 73.7mm).

 

10 hours ago, nkopp said:

It is still an L24 though.

Are you sure it's not an L26?  The LXX would be stamped on the block.  And where are you going to find an extra 2.2 mm of stroke?   Seems like a lot even for a reground crankshaft.  Not an engine expert...