LZ22 head spacer shim?

[datzenmike]

Nothing adds up. Air can't be coming out but it is. Valve must be open but seems to be closed.

[toshts]

Was able to get my machinist on the phone today, he was mainly concerned about the clearance of the valves and if the piston was just slightly hitting them.

 

Here's a vid of the valves/piston while turning over by hand, looks like plenty of clearance? 

https://drive.google.com/file/d/1w7q5V8cF81eC7r6wkiD1ln1jJf1_H3C6/view?usp=sharing

(did two full rotations, second one I moved the boroscope around a bunch)

 

I'll throw it down the intake and record that next then compression test then run it with the valve cover off to watch the valves. Machinist also said that distortion from torquing down the head is out of the question, the way he inspects seats/guides is with it clamped down to account for distortion. It all looks pretty damn good in the video (I think??) but it is a littler blurry. 

[datzenmike]

Looks fine. 

 

 

L20B valve lift is 0.413" unless reground. Less by 0.010" and 0.012" valve clearance so more like 0.403" and 0.401"

 

 

Pros:

Gasket thickness is about 1.2mm  

Z22 has not only a dish of 9.32" but there are valve reliefs cut into them. 

Z22 pistons don't quite reach up to the top of the deck. Only 0.005 of a mm basically nothing but everything helps.

 

Cons:

The head was milled 0.020"??? half a mm,  was that it? This moves the valves closer to the pistons.

 

I think he means the distortion, little that it is, is around the cylinder tops from the head bolts pulling the block up into the head gasket. If picky this would affect over boring and ring seal. Not at all a big deal unless big bucks racing. 

[toshts]

Okay! More info!

 

Compression test showed 200-210psi in cylinder 1,2 and 4 along with only 90psi in cyl 3. When I was complaining about only have 190 up from 180 I should have considered I was using a different compression tester than before, this is the same one I used with my stock z22 so I did infact gain ~20psi. And it is still the same cylinder being the problem child. 

 

Pulled the carb and stuck the boroscope down the intake and recorded both cyl 3 (bad) intake valve and cyl 4 (good) and I think you can see the gunk sprayed up around cyl 3 valve from it not closing?

 

Cyl 3 vid (bad)

https://drive.google.com/file/d/1QD2-3YkPYz4jvIJ71RjuQqw0XBpbYnSn/view?usp=sharing

 

Cyl 4 vid (good)

https://drive.google.com/file/d/1vNT5ZR_dakVx411-ZbGjOQxqC3sRhA_y/view?usp=sharing

 

 

[toshts]

3 minutes ago, datzenmike said:

Looks fine. 

 

 

L20B valve lift is 0.413" unless reground. Less by 0.010" and 0.012" valve clearance so more like 0.403" and 0.401"

 

 

Pros:

Gasket thickness is about 1.2mm  

Z22 has not only a dish of 9.32" but there are valve reliefs cut into them. 

Z22 pistons don't quite reach up to the top of the deck. Only 0.005 of a mm basically nothing but everything helps.

 

Cons:

The head was milled 0.020"??? half a mm,  was that it? This moves the valves closer to the pistons.

 

I think he means the distortion, little that it is, is around the cylinder tops from the head bolts pulling the block up into the head gasket. If picky this would affect over boring and ring seal. Not at all a big deal unless big bucks racing. 

Cool I thought it looked good too but I don't know what to look for other than them hitting. My machinist milled 0.026" but it was previously machined (different types of valve guides in it) and the head thickness was only 4.19~ with my harbour freight calipers and you said a new one is 4.248 so most likely a whopping 0.04-0.05~ removed.

[toshts]

And here's a vid of the leakdown test, still coming out the intake

 

https://drive.google.com/file/d/1SYGA6MyM6qRLQl0r9WIxBpIW3ZeqGDRt/view?usp=sharing

[datzenmike]

Re: videos

 

Can't really tell. Obviously everything has been thought of and tried and all the usual suspects accounted for. The problem you are sure is air blowing out the intake of #3???

 

For the cost of a head gasket and peace of mind, pull the head back off and the seat may show where the valve makes contact in an ellipse not a circle. This could be a very slightly bent valve or seat is off to one side.

 

With head valve side up and valves closed and relatively level pour some gasoline in the chamber. If the valve is properly seated it should hold gas over night. A leak will be obvious.

[datzenmike]

That air leak is undeniable.

[toshts]

11 minutes ago, datzenmike said:

Re: videos

 

Can't really tell. Obviously everything has been thought of and tried and all the usual suspects accounted for. The problem you are sure is air blowing out the intake of #3???

 

For the cost of a head gasket and peace of mind, pull the head back off and the seat may show where the valve makes contact in an ellipse not a circle. This could be a very slightly bent valve or seat is off to one side.

 

With head valve side up and valves closed and relatively level pour some gasoline in the chamber. If the valve is properly seated it should hold gas over night. A leak will be obvious.

 

9 minutes ago, datzenmike said:

That air leak is undeniable.

Yeah it's pretty bad. Enough to lose over 100psi I guess. That's probably what I'll end up doing, I gave my machinist another call and sent him the videos he'll look over them when he gets a chance and give me a call back but something definitely not right. 

[datzenmike]

It's so slight it could be over looked. Also if the valve is bent it might drop into place on the seat and even less to see on inspection. It's a closed valve, move along, nothing to see here. 

[banzai510(hainz)]

total guess here could a valve stem keepers be wedged causing valve not to close. get valves cheaked or new valves

[toshts]

On 8/14/2025 at 2:27 PM, datzenmike said:

Re: videos

 

Can't really tell. Obviously everything has been thought of and tried and all the usual suspects accounted for. The problem you are sure is air blowing out the intake of #3???

 

For the cost of a head gasket and peace of mind, pull the head back off and the seat may show where the valve makes contact in an ellipse not a circle. This could be a very slightly bent valve or seat is off to one side.

 

With head valve side up and valves closed and relatively level pour some gasoline in the chamber. If the valve is properly seated it should hold gas over night. A leak will be obvious.

Heads back off 🙂 filled the cyl 3  head chamber with coolant with the valves closed and it immediately streamed out of the intake port. Replaced a head on a Honda b series last week that had the timing belt break and die on the freeway, you could see the marks on the pistons where the valves had hit and even that head took a couple hours before coolant started to drip. 

I'll either drop the head off at the machine shop again today or just throw the new valve in myself depending on how much it'll run me/if the guides are messed up. 

[datzenmike]

That's why you should change timing belts when the factory says to, way cheaper than a valve job or new head. Even sooner. Cam stops with valves open and the engine keeps turning hitting them. Never seen an L or Z series chain break so that won't happen on them. If no marks on your piston then it was bent when assembled. Mechanic laid the head valve side down and bent one. 

 

Won't affect the guide but best if you lap that new valve with lapping compound.

 

Next time use gasoline or better furnace oil or diesel fuel. It's less flammable and thinner and will pass through where water will not. If it will hold diesel over night that's a tight fitting valve. 

[ggzilla]

Hand-lapping new valve works perfect, A hand lapper is only $6 at AutoZone or Amazon.com

 

Thanks for the tip, Mike. I always used water to check for valve leaks, and it seemed to work, but next time will use fuel. I see that some recommend IPA isopropyl alcohol, but that's mostly water I think

2 hours ago, datzenmike said:

use gasoline or better furnace oil or diesel fuel. It's less flammable and thinner and will pass through where water will not. If it will hold diesel over night that's a tight fitting valve. 

[toshts]

And now for the answer we've all been waiting for... 

 

Bad seats 🙂

 

Valves were not infact bent just really messed up seats, he recut them along with the valves and pressure tested it to confirm a perfect seal. Parts get here Thursday so it'll finally be up and running as it should soon. 

 

On 8/18/2025 at 12:31 PM, datzenmike said:

That's why you should change timing belts when the factory says to, way cheaper than a valve job or new head. Even sooner. Cam stops with valves open and the engine keeps turning hitting them. Never seen an L or Z series chain break so that won't happen on them. If no marks on your piston then it was bent when assembled. Mechanic laid the head valve side down and bent one. 

 

Won't affect the guide but best if you lap that new valve with lapping compound.

 

Next time use gasoline or better furnace oil or diesel fuel. It's less flammable and thinner and will pass through where water will not. If it will hold diesel over night that's a tight fitting valve. 

For sure, it was a buddies Integra they bought recently with like ~250k miles on it no idea the previous service history but by the state of everything it probably didn't have much lol. I'll keep that in mind next time I test valves, had already swapped the head just wanted to see the condition of the old one.

[toshts]

And we're back on the road 🙂

 

Runs fantastic, way more power and I didn't even push it. New clutch feels amazing and the 620 trans is actually a lot tighter than my original one. Setting the timing was a little goofy, I don't think my marks/timing light are giving an accurate reading as it currently says I'm at 20 degrees advanced initial but it doesn't ping and still seems to want more even though I haven't put premium in yet. Got a lot of rattles to sort, get proper hoses instead of what I had laying around, remakes some brackets and make new ones for my junkyard power steering setup along with an exhaust and it'll be great. 

[datzenmike]

As this is not a stock engine there are no timing specs for it. It's a Z22 but much higher compression and single plug so timing will be more advance than a Z22 but less than an L20B. Maybe 10? Just keep advancing till it pings under very heavy throttle and then back it off till it stops.

[toshts]

Been dailying it for the past week and while there's a ton of little things to sort it's been great. Was able to sort out the timing, I've had it at around 9 degrees advanced with my tank half premium and half regular but was able to put another 4 gallons of premium in so I might start trying to increase it. With the current setup it feels pretty similar to the z22 up to 3k rpm but above that it's night and day it's much more rev happy and makes way more power up high. Need to make an actual exhaust still before I feel comfortable pushing the timing too much, it's pretty hard to hear pinging with how much it currently leaks. 

However I think I'm running into some fueling issues, either flooding or heat soaking or both. When I step on it sometimes it'll have a delayed response or when I ease into the secondaries it won't make any difference until I get them halfway open or so then it'll suddenly pull way harder. Also I noticed on a full throttle pull today I had a fun cloud of smoke out the exhaust, truck was warm and had been running for a while, didn't smoke before and didn't smoke on any subsequent full throttle pulls. I do have the married intake/exhaust and I'm sure it's baking the intake, I did make sure the flap was in working order before installing it but still. I'm also running the y fitting from the stock mechanical fuel pump to have a return line, a facet electric pump and weber 32/36.

 

 

The y fitting is currently a lot further away along with being higher, thinking if I move it lower and closer to the carb it'll have an easier time cycling fuel and preventing vapor lock? 

 

This is what the plugs look like after 4 gallons of gas worth of driving, took them out right after testing some wide open throttle pulls today. Plugs were brand new bpr6es upon the final reassembly of this motor, also have a set of 7s to try once I start pushing the timing. 

[ggzilla]

1 hour ago, toshts said:

Need to make an actual exhaust still before I feel comfortable pushing the timing too much, it's pretty hard to hear pinging with how much it currently leaks. 

You need a quiet exhaust to hear pinging. Or you can use detonation cans, sort of like headphones for listening for pinging

https://www.google.com/search?q=detonation+cans

[datzenmike]

What smoke??????

 

White is usually steam, but extreme oil burning is also white. Is the oil pan dip stick correct? could it be over filled?

Blue is excessive oil burning. Rings, valve guides worn out.

Black is over rich or choke on. Unburnt gas is black carbon. 

 

The 32/36 is a 'progressive' carburetor in that the secondary only begins to open when the primary is over 50% open. It opens regardless of RPMs unlike a vacuum operated secondary that opens depending on engine demand, not the driver.

 

Wire the heat riser valve closed on the exhaust manifold. If you drive in the winter let it work. 

 

The return line MUST have a restriction in it. The stock L20B is simply a pin hole to allow gas back into the tank.

 

 

 

 

Plug reading is an art. After a full throttle run pull over immediately and examine them. Even driving home will soot them up.

 

 

The L and Z heads have the same cam and valve specs but the L head breathes much much better than the Z series above 3,500 so yeah the difference is noticeable.

[toshts]

8 minutes ago, datzenmike said:

What smoke??????

 

White is usually steam, but extreme oil burning is also white. Is the oil pan dip stick correct? could it be over filled?

Blue is excessive oil burning. Rings, valve guides worn out.

Black is over rich or choke on. Unburnt gas is black carbon. 

 

The 32/36 is a 'progressive' carburetor in that the secondary only begins to open when the primary is over 50% open. It opens regardless of RPMs unlike a vacuum operated secondary that opens depending on engine demand, not the driver.

 

Wire the heat riser valve closed on the exhaust manifold. If you drive in the winter let it work. 

 

The return line MUST have a restriction in it. The stock L20B is simply a pin hole to allow gas back into the tank.

 

 

 

 

Plug reading is an art. After a full throttle run pull over immediately and examine them. Even driving home will soot them up.

 

 

The L and Z heads have the same cam and valve specs but the L head breathes much much better than the Z series above 3,500 so yeah the difference is noticeable.

White/blueish, looks like oil to me but it might have been excess fuel and been more blackish than blueish my windows are very dirty didn't have a good look and wasn't able to replicate. Punched a mark on the dipstick when I assembled everything and put 4.5qt in and yes I'm very much overfilled, about half a quart maybe a full quart. 

I do drive in the winter but for now I'll probably wire the riser closed as it's pretty hot right now.

Return line has the restriction just a lot higher and further away than I had before.

 

 

[banzai510(hainz)]

after yrs of owning my 521 w a 1.75in superturbo muffler i would get a quiet turbo for a truck. Summit has some 1.75 and 2in usa made quiet turbos. In morning my 521 sounds likd a wanna be go faster 510 w a weber dgv. Walker is one brand and there is another brand.

[toshts]

50 minutes ago, banzai510(hainz) said:

after yrs of owning my 521 w a 1.75in superturbo muffler i would get a quiet turbo for a truck. Summit has some 1.75 and 2in usa made quiet turbos. In morning my 521 sounds likd a wanna be go faster 510 w a weber dgv. Walker is one brand and there is another brand.

I've got a thrush turbo and it's pretty quiet, just have a flex pipe from the headers to the rest of the exhaust that leaks like crazy with a janky flange connecting to the manifold. Still need to actually make a real exhaust for it

[datzenmike]

8 hours ago, toshts said:

White/blueish, looks like oil to me but it might have been excess fuel and been more blackish than blueish my windows are very dirty didn't have a good look and wasn't able to replicate. Punched a mark on the dipstick when I assembled everything and put 4.5qt in and yes I'm very much overfilled, about half a quart maybe a full quart. 

I do drive in the winter but for now I'll probably wire the riser closed as it's pretty hot right now.

Return line has the restriction just a lot higher and further away than I had before.

 

 

 

I put a wide band on my car. The last word in what your air/fuel ratio is. Bit expensive but at least no guess work. WOT in the high 12s, idles and cruises around high 14s.

 

4.5 qts would be ok if you also changed your filter. Next time you change the oil see where 4 quarts comes to and try to keep it there after the filter fills up. 

[banzai510(hainz)]

the trush 3 chamber classic is quiet. just get aluminize pipe run out the back will last a long time. im on 25yrs. exhaust shops are alot more exp than when i did it. so when motor perfect then do exhaust.

 

quiet 1.75 but sure there is a 2in if needed. dont need anymore than that on a daily L motor

https://www.summitracing.com/parts/aph-3743

Edited August 31, 2025 by banzai510(hainz)