LZ22 Engine

[MicroMachinery]

Ok, so after a long period of desertion, and putting the engine up for sale then taking it back down, I'm ready to continue this thread.

 

I got the ACL bearings in the mail, and I'm very pleased with how they were packaged and the quality of the parts. They have my business.

 

I got the engine block and parts back from my buddy's hot tank, so I used a couple cans of brake clean to remove the residual solvents, dirt, oil, etc. I started taking the measurements a few nights ago, and it looks like the crank is going to sit nicely in the new bearings.

 

After checking those, I moved the engine block into the empty house I used to live in that sits next to the shop, and fired up the wood stove. With temperatures in the 40's and high humidity, it makes for terrible painting conditions. After the engine had sat next to the stove for a few hours, it was warm and alot of the moisture in the block casting had found it's way out. Now it's time to paint.

For the painting of the block, I used Duplicolor Engine Enamel that I bought at the local Napa. I grabbed a can of the etching primer, and a can of "Pontiac Blue". The "Poniac Blue", is as close to the factory Datsun blue as you can get in over the counter engine paints.

 

Bare naked block, stripped and ready for primer

Engine block primered, with the first light coating of the Pontiac Blue.

Engine block after the first and second light coats, then the medium wet-coat.

 

Last night I got the piston rings de-burred and gaps measured, so the next step will be sliding the pistons into their bores and measuring the oil clearance on the rod bearings.

 

This build is going to take a little longer; a friend of mine is interested in learning about engine building, so he has been standing alongside while I work. I'll stop and explain what I'm doing, and have him help me with the measurements just so that he can get his hands in on it, which in turn ends up taking a bit longer.

[datzenmike]

There's a high failure rate with Z engine h/g's. Mostly due to lack of maintainance. The L series seem more tollerant of abuse and being ignored. One thing to watch is the after market Z h/g. They tend to supply 'one size fits all' and this means the cylinder fire ring may stick out into the cyklinder slightly more than it should. It is then exposed and erodes away. When fitting a gasket be sure it is just slightly larger than the bore.

[MicroMachinery]

Thanks for the heads-up Mike. I went and measured the bore size of the head gasket and compared them vs. the cylinder bores:

 

Head Gasket Bore: 3.468"

 

Cylinder Bore: 1)3.425" 2)3.425" 3)3.425" 4)3.423"

 

So it appears that head gasket diameter is about .043" larger than the cylinder bore. That's around .0215" on each edge. I would think that would be enough. What do you think?

[datzenmike]

Half a mm should do it.

 

Just measured my Z24 h/g and its 90.17mm so 1.17mm/2= just over half a mm

 

Measured an old L20B and it's 85.34mm on an 85mm bore.

[MicroMachinery]

Ok, then .0215" equals out to 0.5460999999999999mm, so that should work.

[MicroMachinery]

Got the crank put in and torqued down for the final time today. Also plastigaged the connecting rod bearings' oil clearance. Everything's as it should be. Pistons are next to pop in. Probably do that tomorrow, as well as drop the head off at the machinist.

 

By the way, has anybody ever had trouble with reusing stock connecting rod bolts? I was thinking about getting some ARP's, but if I don't need to, then I'd rather not.

[datzenmike]

Slip the ring(s) for that cylinder into the bore and push down a couple of inches with a piston top. Measure the end gap. If too small you can carefully grind and smooth it. Too tight the ring will expand from the heat and snap or score the bore or break the piston lands or all three. No need to do the oil control rings.

 

Be sure to stagger the end gaps 180 degrees from each other to prevent compression blow by from easily getting out.

 

End gaps must not be aligned along the front to back or the side to side axis of the block. Instead pick one of the four 45 degree directions. This avoids end gaps above the piston pin ends (front/back) and also the piston thrust direction. (side)

[MicroMachinery]

Last night I got the piston rings de-burred and gaps measured, so the next step will be sliding the pistons into their bores and measuring the oil clearance on the rod bearings.

 

 

Slip the ring(s) for that cylinder into the bore and push down a couple of inches with a piston top. Measure the end gap. If too small you can carefully grind and smooth it. Too tight the ring will expand from the heat and snap or score the bore or break the piston lands or all three. No need to do the oil control rings.

 

Be sure to stagger the end gaps 180 degrees from each other to prevent compression blow by from easily getting out.

 

End gaps must not be aligned along the front to back or the side to side axis of the block. Instead pick one of the four 45 degree directions. This avoids end gaps above the piston pin ends (front/back) and also the piston thrust direction. (side)

 

Hey, good lookin' out Mike. I measured the gaps the other night. I'll definitely note that 45 degree tip, though. I could have easily spaced that and forgotten. Thanks.

[MicroMachinery]

Alright. So I've decided to do any head work further down the road, as 1) removing the head isn't that difficult of a task, and 2)I'm probably not going to be going fast enough in the snow and ice to notice the top-end difference. Basically, I just want to get this thing into the 4x4 so I can keep the heirloom out of the ditch as the weather is getting feisty.

I've decided to go with ARP Connecting Rod Bolts, as I'm not sure what the state of the current rod bolts are. I'd rather put down a little extra coin and know that the weakest link in my bottom end has been secured. On that note, I have become aware that one of my pistons is slightly sticky when pushed to one side of the connecting rod; meaning, if I hang the piston upside down, and move the piston all the way to the side of the wrist pin pivot, it doesn't(without the slightest touch) drop back down and even out.

Perhaps a pic better demonstrates my concern.

Now, I wouldn't say it's a hard spot. Probably better put as a dry spot? I can just barely put pressure on it and it swings down into the normal hanging position like so.

Also, it only acts this way if the connecting rod is pushed all the way to the front side of the bore in the piston.

If pushed the the rear, or centered, it doesn't do this at all. Swings freely.

 

This should be ok, right? The way I see it, is if the piston never reaches that angle, then it will never have to experience a scenario in which that friction becomes an issue. Also, if in fact it isn't just a "dry spot", won't the aluminum expand enough to make this a non-issue anyway?

I do understand, that in the most extreme of conditions(which are a mechanical physics impossibility), that this spot would be touched thousands of times in a minute. What I mean is, if I went for a 5 minute drive, at an average of 2k RPM, this spot would be touched 20k times. Now remember, only when slid to the very front of the piston pin bore, and cocked completely to the side, to where the piston skirt touches the rod, would this slight "friction" even occur(thus the mechanical impossibility). At 20k times, this friction COULD become a factor, but given the mechanical impossibilities, this wouldn't be an issue. Is this logic flawed?

[MicroMachinery]

Ok. So today in preparation for sending the head off for the valve job, I did some head scratching on how to open up some water holes in the Z22 head gasket. Pic of the difference between the two.

Here's another shot of them stacked, L20b on top of the Z22.

I went down to my machine shop to ask what to use, since the gasket has a metal shim running through. The machinist suggested some hole punches, and lent me his set.

Got everything back to the shop and set out a 2x4 to begin the hole-punching process. Everything was traced out, ready to go... and...

... I blew it.

 

Seems as though these gaskets I got are some seriously tough pieces. I don't think I'll be able to easily cut holes out. I got 2 of them, and the first one is obviously ruined. I may just go ahead and get the Nismo gasket, even though it's way overpriced, IMO. Meh...

[Guest kamakazi620]

Wow and WOW killer!!!!!!!! sell me the motor after you run it for awhile!!!!!!I wanna use a KA fuel injection frankensteined on yer frankenstein

[MicroMachinery]

That would be sweet. I'm gonna run it through the winter, and possibly sell it next year. I'll keep you in mind.

[Guest kamakazi620]

That would be sweet. I'm gonna run it through the winter, and possibly sell it next year. I'll keep you in mind.

Thanks MAN!!!!!! i'd LOVE to use it in ma new 620 w/fuel injection

[mike]

...I never even thought to check for the coolant holes when I swapped heads on my LZ22. It runs a tad on the warm side but not too bad, I just figured it was because of the stock 510 radiator... I did chamfer the oil hole on the U67 to get better flow though.

 

Instead of shelling out the money for a NISMO gasket or buying two and ruining a perfectly good L gasket for the timing cover, I just trimmed the Z22 gasket and used great stuff between the timing cover and the head. It doesnt leak at all. I did put a decently thick bead on it and when I installed the timing cover I put the bolts in but didnt snug them down untill the gasket maker had a chance to cure. I also smoothed out the inside bead and made sure there wasnt a bunch of crap that was going to come loose and clog something up.

 

I also noticed that you said you werent going to do any headwork... I port/gasket matched an early L16 intake and the head when I swapped it over. I found it smoother at idle and easier to tune in. I was running an A87 before that was in good shape in good shape with a desmogged L20 manifold that had bigger ports than the head... I bought it this way...

[MicroMachinery]

Hmm.. very interesting. I'm going to be running a U67 head and a desmogged L20b intake... I haven't measured the difference between the intake runners and the intake ports on the head, but I've read that as long as the runners are equal to or smaller than the intake ports on the head, you're ok. I was also told that an L16 manifold would choke out an LZ22. Doesn't sound like that was the case with yours.. or am I reading it wrong?

[datzenmike]

One is upside down compared to the other. The L is looking down onto the top of the gasket and the Z22 is looking up underneath. Can you flip and take another picture?

 

[MicroMachinery]

Yeah, I'll do it tomorrow when I'm at the shop. The one pic has the L20b on top of the Z22.. but I'm sure you saw that.

[datzenmike]

I'd just like to have a good picture like that of the two that are easy to compare. No big deal.

[HRH]

Don't reuse the rod bolts, spring for the ARP set at the very least. Stock Nissan rod bolts are 40 years old and they sucked to begin with. The weak link in the L block, says so even in the Datsun Bible.

 

Use the Z22/24 head gasket. The 20B is too small. You'll make hot spots. The last time I did one of those, I cut the entire portion of timing cover gasket off with tin snips, and sealed the timing cover with RTV only. Worked fine, just have to be very careful with the application and let set 24 hours. Or you can also snip off the 20B timing cover gasket and put it in there, using rtv for the back edges.

[mike]

Matt, its funny you say not to use an L20B gasket... thats what the PO had on there, it didnt work out so well.

 

As far as the L16 intake on the LZ22 Ive probably got 5 or 6 hours of hogging it out, both the runners and the bowl side... I could have cut the time down alot but I only had a fine bit. I wouldnt even try running a stock L16 mani.

 

I think my old A87 was off of an L18, it had pretty small ports, and with the L20 manifold the step was going in the wrong direction.

[MicroMachinery]

Don't reuse the rod bolts, spring for the ARP set at the very least. Stock Nissan rod bolts are 40 years old and they sucked to begin with. The weak link in the L block, says so even in the Datsun Bible.

 

Yeah, I ordered ARP Hardware and it should be on it's way.

[MicroMachinery]

Ok, so I got some pictures of the Z22 HG up against the block. I don't want to get creative with "paintbrush", so my finger points to the places where the coolant passages are in the block, but not the HG.

This is the largest one.

Then there are these two. It looks like the HG has holes, and it does, but those were the bad ones put there by me. :rolleyes:

Then there's this one that is partially covered by the gasket.

Over all, it doesn't look like it would kill me to use a HG that hasn't been modified(other than the timing cover segment, of course). I may just run it, and if I don't have problems, great, and if I do get a little warm, I'll deal with it; it's not like I'm going to be able to use that extra Z22 gasket on anything else <_< . I don't think it'd become really necessary until summer-time anyway, and by then, I'll probably be ready to do some porting on the head; kill 2 birds with one stone.

 

Oh yes, and this one's for you D-Mike.

[datzenmike]

 

 

Here's the same area on a Z24 block. I suspect that both adjacent cylinders are joined together and water does not flow between them side to side.The hole goes diagonally down between the cylinders where they touch and allows coolant through. This area at the very top of both cylinders is exposed to the most heat when the cylinder fires.

 

 

Can you see if the cylinders are joined together on yours?

 

Thanks for the oic.

 

.

[MicroMachinery]

I'll get more pics tomorrow, but yes, the cylinders are "siamesed", as I believe it's called. The cylinders are joined, but there is a port that runs diagonally down between them for coolant to flow. In the meantime, here are some pics of the Z22 HG put up against the L-series head.

^^^ Again, the 3 gross looking holes pictured here are in the gasket that I destroyed trying to modify for maximum coolant flow.

It looks like overall, however, it has decent coverage without having to modify.

[MicroMachinery]

Ok, so I returned with some more pics. D-Mike, all cylinders are joined, save for the #2 and #3 cylinders. They have a gap between.

Also, I just wanted to confirm the Siamesed cylinder walls.

 

Got a few other things done, too. I decided that I may go ahead and match the ports, so I needed to figure out a good way to keep the intake manifold and gasket from sliding around. I found some dowels that would allow the bolts to pass through with a little bit of clearance, so I drilled holes that went in about 1/4" in both the cylinder head, and the intake manifold.

Pics of the dowel in the intake.

Here's one with the gasket held in place by the dowels. Pretty neat, huh?

 

I also went ahead and chamfered that oil hole in the head to ease the flow of the oil restrictor.

With gasket

 

One more thing I was looking at that caught my attention, is that the Z22 gasket isn't that far off from working with out ANY modification, from the looks of it. Here's the coverage that it gives on the front of the head.

^^ The only potential problem I see here with using this gasket is in this corner. BUT, if grafting or RTV were going to be the solution anyhow, why couldn't one just graft one of those eyelets/bolt hole wings off and graft it onto this corner? Any input?