L Head to Z22 Block

[Dime Dave]

I am in the process of building an LZ23 engine (Z22 bored to 89mm). The block is a Z22 and is siamesed between bores 1/2 & 3/4. Jason Gray’s info says the block should have has all the coolant passages that the L head needs and a few more. I have modified the Z22/24 head gasket for all the passages in the L gasket, but I found that my block was missing some of the passages that are in the L20B block I was comparing it to.

 

L20B Block posted by Sealik:

 

The Z20 block appears to have all the needed passages that the L20B does.

Z20 Block posted by Sealik:

 

My block doesn’t have all the 8mm +/- holes that are on the passenger side of the block. The only one of these that it does have is to the rear of the #1 spark plug.

My Z22 block

 

I also noticed that Wayno’s LZ23 doesn’t have these other holes either.

Z22 Block posted by Wayno:

 

My question is. Are the 8 holes on the passenger side of the block needed with an L series head? Does not having them affect cooling or should they be drilled out? And being the Z22 block is siamesed, does drilling them out mess-up the engine cooling because the Z22 block has siamesed cylinders and the L20b & Z20 do not?

 

In doing my final comparison of the L & Z head gaskets, I found missing block holes and decided to drill them out with a 5/16” drill bit. I hope I haven’t disrupted the coolant flow between the block and head because the Z22 block is siamesed.

 

Does anyone have any thoughts on this?

[Sealik]

Here's a quote (PM) I got from Byron...510Realm, who has built a few LZs

I heeded his advice.

 

..."There are a few more holes I recommend you drill in the block. The water circuit though an L block and a Z block is different, as you’ve already seen by properly enlarging the water passage at the back of the head.

There are also 2 holes at each cylinder (on the L head spark plug side) which need to be drilled. If you look at the bottom of the L head, you’ll see either round or teardrop shaped holes which need to pass water between the head and the block. Some guys have not done this, and it works but head gaskets are short lived. The problem is that excessive heat builds up around that side of the block – after a few thousand miles, you can actually see scuffing on you new pistons from the heat which is not being dissipated. I’ve built many LZ motors over the years, and still run them in my 510’s today. This is a highly suggested mod when building LZ motors".

 

Thus....I drilled 7 in block....9 in L HG

 

[hang_510]

dave i use the nismo HG and only needed 1 additional hole.

 

i drilled the same 7 block holes for coolant flow.

i cant recall the size, just matched it to the holes in my head. ;)

 

real easy to see with the HG lined up.

[Dime Dave]

I'm using a Z22/24 HG with the holes added (same as in the picture Sealik posted above). I cut off the front cover section and grafted on the L cover section using sealant to fill the joints.

 

The Nissan Comp HG doesn't have as large a firing ring diameter as the Z22/24 HG. The way the chamber on my head was relieved around the intake valve it exposed the Comp head gasket. The Z22/24 HG has a larger diameter firing ring diameter. Even though it is a round firing ring, I chose it because it didn’t hang out into the chamber area to be a potential hot spot/failure point. The Z22/24 HG made for a better fit with my 89mm bore and reworked combustion chamber combination.

[Sealik]

I'm using a Z22/24 HG with the holes added (same as in the picture Sealik posted above). I cut off the front cover section and grafted on the L cover section using sealant to fill the joints.

 

The Nissan Comp HG doesn't have as large a firing ring diameter as the Z22/24 HG. The way the chamber on my head was relieved around the intake valve it exposed the Comp head gasket. The Z22/24 HG has a larger diameter firing ring diameter. Even though it is a round firing ring, I chose it because it didn’t hang out into the chamber area to be a potential hot spot/failure point. The Z22/24 HG made for a better fit with my 89mm bore and reworked combustion chamber combination.

 

 

That's what I somewhat figured.

89.5 bore....leaves about .010 to the Nismo HG...a little close.

Compression with those pistons...?

Head you are using?

Pics of your SSS EM... :D ...?

[wayno]

I was going to ask the same thing here in the next couple weeks, whenever i get my stuff back from the machine shop, :unsure: I always get put on the back burner when a racecar engine comes in, I guess they need it done fast so they can keep racing. :( Now I beleave my question has been answered, I need the holes, I hope I don't screw this up. Hang_510, the nismo HG your using is for a Z22/24?

[Sealik]

I was going to ask the same thing here in the next couple weeks, whenever i get my stuff back from the machine shop, :unsure: I always get put on the back burner when a racecar engine comes in, I guess they need it done fast so they can keep racing. :( Now I beleave my question has been answered, I need the holes, I hope I don't screw this up. Hang_510, the nismo HG your using is for a Z22/24?

 

That HG is good up to a 90mm bore....but....one might consider enough clearance to eliminate "hot spot/failure"

[justin 620]

I have a few questions: where do the holes go to? Is there a coolant passage below the surface of the block? and if so, how deep would I have to drill to hit said passage?

[wayno]

I have a few questions: where do the holes go to? Is there a coolant passage below the surface of the block? and if so, how deep would I have to drill to hit said passage?

 

Use your old L20b headgasket to place the holes in the proper place, I can't remember what size drill bit I used, but it wasn't very big, maybe a 1/4 inch bit, and it barely fit between the cylinder and block side on the inside, there's not much room in there.

[justin 620]

So I just drill until I hit an open space?

[wayno]

So I just drill until I hit an open space?

 

 

That's what I did, but the first hole was an eye opener, I realized I could break the bit off if I hit the cylinder wall itself, or the block side, and i was real close the first hole, I also realized that the bit I was using was the biggest I could use, because it was hitting on both sides in there, I beleave it was a 1/4 inch bit, but don't know that for sure anymore.

Maybe I posted what size it was in my LZ22 thread, I just don't remember anymore.

http://community.ratsun.net/topic/31213-waynos-lz22/page__hl__wayno__fromsearch__1

I do beleave I made the holes in the headgasket first, using the head for the placement of the holes, I then placed it on the block to mark where the holes were to be drilled, then after I was done I thought I could have used the old L20b gasket, just double check everything before drilling the holes.

[Sealik]

ttt

[Z-train]

Here's a quote (PM) I got from Byron...510Realm, who has built a few LZs

I heeded his advice.

 

Some guys have not done this, and it works but head gaskets are short lived. The problem is that excessive heat builds up around that side of the block – after a few thousand miles, you can actually see scuffing on you new pistons from the heat which is not being dissipated.

________________________________________________________________________________________________________________

 

If this were the case then you see this issue on ALL Z-22s as the Z-22 head doesn't have the holes either.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Sealik]

If this were the case then you see this issue on ALL Z-22s as the Z-22 head doesn't have the holes either.

 

It was explained in my unedited PM from Byron.....

 

Besides.........The Z22 does not have a L head on it.

 

......"There are a few more holes I recommend you drill in the block. The water circuit though an L block and a Z block is different, as you’ve already seen by properly enlarging the water passage at the back of the head.

There are also 2 holes at each cylinder (on the L head spark plug side) which need to be drilled. If you look at the bottom of the L head, you’ll see either round or teardrop shaped holes which need to pass water between the head and the block. Some guys have not done this, and it works but head gaskets are short lived. The problem is that excessive heat builds up around that side of the block – after a few thousand miles, you can actually see scuffing on you new pistons from the heat which is not being dissipated. I’ve built many LZ motors over the years, and still run them in my 510’s today. This is a highly suggested mod when building LZ motors".......

 

I used a 1/4" bit. I drilled the holes in the block to match the larger portion (position wise) of the teardrop water passages in the stock L HG/head. This somewhat 'centered' the holes on the deck....between the cylinder and outside of block.

[justin 620]

 

 

The L block has three holes in the front left of the block, where the Z block only has 2, do you need to drill that one as well?

[Sealik]

 

 

The L block has three holes in the front left of the block, where the Z block only has 2, do you need to drill that one as well?

 

Negative...just those eight 1/4 inch holes...actually only 7....one is already 'open' in the Z block.

9 holes in HG