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Bastard_510

Hot LZ23

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240sx KA24E 's are close with only 2.8cc dish (and floating pin) if you could get rid of the 1.55mm deck.  Copper, you could run as thin as you like if the two surfaces are flat. I decked my Z22 block 1mm and made a 0.020" copper gasket for a total of about 0.04137" from piston top to bottom of head. That's less than a stock gasket..... but this was for a K24E head I was planning to use.... still have it, waiting for me to take notice of it again.. 

 

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Just a dream. Sometimes it's better to travel with hope than to arrive.

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On 2/8/2019 at 3:42 PM, Bastard_510 said:

hello all. Ive been working on this engine and some things have changed. im going with the 6" rods and i now have a graph of the wall thicknesses and 90mm will be no problem for my z22. im now at 12:1 static but with the cam i have on order and if i advance it 8 degrees its 8.2:1 dynamic . 

 

i bought some new old manley 44mm p90 valves that are necked and swirled. ive seen a few posts of people saying they were going to use them in a A87 head but i never saw a post of the finished job. does anyone know if i can use the stock seats? i measured about 1/32" of seat that would be the 30 degree cut all the way around which i think should be enough once i grind the 45. if not do p90 seats fit or will i run the risk of hitting a water jacket? thanks!

 

 

your going to have to put the valves deeper into the head and blend out the chambers with p90 valves as they are shorter. you could use p90 seats as well. 

i think they are .100ish shorter overall and the tip is a little shorter as well. you need to get the stem height back up to the stock installed height or you will have all the problems.

If your 45 cut doesnt hit the outside of the seat, then run it with the stock seats... well as long as it still doesnt have the brass intake seats.. get those out of there.

 

l20b valves are 4.53 inches long and the p90 ones are 4.45 inches long. 

 

I used ferrea valves in mine which are the shorter ones. i had to put them deeper in the head and blend it out. It works good but if you havin't bought the valves yet your better off getting the pep stainless ones or the si ones as you can get the longer length ones. I didnt know of these till way after mine was in the car and running.

 

12:1 isnt going to be happy on pump gas, Ive tried. it will happily run on avgas though 🙂

I am refreshing my motor this year and i have opened up the chambers quite a bit, hopefully i can get down to 11:1 with the flat tops and get away with 94 and octane boost. 

 

If you go to a 90 mm bore you might as well go to 45mm intake and 38mm exhaust, new seats, cut the chamber out to the edge of the gasket, make it a stump puller.

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Fuel requirements depend heavily on the cam profile. It is not unheard of to run such high compression on pump gas, with proper tuning.

 

Before you make a cam purchase, give Rebello a call. They have been redesigning L cams for years and years, and still are, while most cam grinders sell the same old profiles that were available in the '80s. A lot has been discovered since then. Elgins has custom grinds that they make for Rebello, but I don't think they offer them for sale without going through Rebello.

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I found a beat up a87 head and practiced opening up the seats. It turned out well. I do have brass seats and since the head is already coated and the valve guide concentricity isn’t that bad I’m going to try to use them. After i was done positioning the seat angles on the junk i came up with 40mm stem hieght which matches my reference. They fit very nicely. They are swirled, necked, stainless valves that had been in a box for 20 years. 

 

Ka pistones wont work with the 6.002” scat rods  so custom pistons are the only way to go. These pistons will be flat tops and come as close to 0.0 deck hieght as i can get it. From what i measured the block is a little taller than what stock should be .05mm=.0019”. Hopefully that is all I’ll need to take off to get it flat. Then i can send out measurements for pistons. 

 

I would go through rebello for a cam and make power but i don’t have that kind of money when i probably won’t notice the difference. 

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L20B, Z20 and Z22 deck height is 227.45mm.

 

You can go to 1/3mm above the deck safely with piston height as the gasket is about 1.2mm thick.

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You need hardened seats unless you are burning leaded gas, I suppose you might get away with brass seats if you drive like a 90 year old half blind old man who only uses the top 1/4 inch of the gas pedal, but this is a counterdiction to the heading of this thread which is "Hot LZ23", this makes me think the whole pedal is going to be used.

I put a brass seated head on my first L20b with 260Z valves in it, I drove from Washington State to Florida State and back on a trip I made which may have been 8000 miles total on the head(less than 6 months), by the time I got back I had already ran out of adjustment on a couple of the valves, I had to remove the head and have hardened seats installed and another valve job, my machinist said no one told him that it needed hardened seats, it was my first super head, I never made that mistake again.

The machinist also told me if I kept my foot out of the pedal I would not have had this issue, I told him that would be impossible as I was using the truck for work and my foot was more than half way into the pedal all the time. 

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Pump the brakes

like i said I’m not willing to remove seats, remove guides, remove the oil repellent coating, reapply the coating, hone guides, and start another valve job.

 

this engine is only running 15 miles at a time 30 round trip and maybe a 400mile drive to see some family once a year. Not across a nation claiming mountains and flying down a freeway at 90-100 for hours at a time. 15 miles and some fun here and there on the weekends. 

 

The seats are are not really copper they are burillium chopper alloy. They can be as hard as cast seats and are great at exchanging heat. They are used in high performance applications, perfect for my “ hot LZ”.  they work best with titanium valves and are recommended. 

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What 'oil repellent coating'?

 

The bronze seats on earlier Datsuns were used when gas contained lead anti knock additives. The lead lubricates the seat and reduces the wear. Valves don't work harder just because you step on the gas harder. The rings and bearings might but all the valves do is open and close faster. Wear (if any) accumulates over time and distance.

 

 

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i think i said it before but the head and block are glyptal coated on the walls and oil valleys. it took 18 hours on the head to prepped  and almost 20 to do the block. its hard to take it off with solvents but once baked it bonds to the walls permanently...unless you put it in high heat to remove valve guides or seats.

if it fails then ill go through the trouble then but even the head instructor at the local college said they will be fine. 

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This is over kill for a car going 30 miles or 400  once a year. Glyptal used on a block is to provide a non stick surface to shed the oil faster so it returns to the pan faster. Something that is sometimes used on racing engines not a street car. You should see about a crank scraper and windage tray first if you want to control oil spray. Your red line on a longer stroke Z22 crank is 6,500 on stock crank and rods. (a much shorter stroke L16 is good to over 8K on stock parts) You'll want a cam and valve train that reflects that. Don't over cam it, you won't be using it.

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I think I already mentioned that if you're using a Z22 crank and a long (6") rod, that KA pistons wouldn't work, but you've figured it out.

 

You mention not going to rebello because of cost. How do you know what it will cost if you don't give them a call? If it costs $100 more to get a modern cam profile through them, doesn't that seem like money well spent?

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no its not its a crazy race engine that might sit on a stand once my other project is done... mike i used the product i think i know what it does. oil cools when its in the pan so ill apply stoffregen's logic of if it cost a little more why not do it. the coating cost me $70 including supplies, a couple of free days and a case of beer to do. there are only 2 areas for oil to return on an L head. the front drain is not used under acceleration so the only drain on hard pulls or in corners would be the back single hole. 15miles at 3500 -4500 rpm with a pull or two to 7k. ill drive it like an asshole just not for long periods of time. 

again its done, im not taking it off, and it has a purpose.

 

stoffregen i went in to this wanting to avoid rebello. im sure they make great modern cams and i know they make great engines but its kinda like everyone saying "ka swap" for me. id rather send the money to an old guy in a shop directly then go through a big company. 

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On the subject of valve seats, I'm running 44mm stainless valves on the 'bronze' seats with no issues with pump gas.

And they are absolutely necessary for titanium valves, which I have, thanks to Nazkar race teams dumping good parts after one dyno run, or one event on eBay.

I just have to cut the stems, re-grove, cut the heads to 44mm, and put in custom guides or sleeve the stock guides to fit 5/16" stems.

Hell, they only cost $40 for a set of 8 intakes, so I have extras to play with.

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fLTUVOI.jpg

 

This is a U67 head so '75-'77 L20B. You can see the intake is definitely 'brass' colored. Very hard, which is to be expected.

 

Yeah I call the old stock seats 'bronze' but that may just be short for 'copper alloy'. I thought un leaded gas was introduced in the mid 70s and banned in the '90s.

 

I've never seen L20B valves worn down into the seats... that would be my '78 truck and current '76 710 although I did have a  car (710?) engine in my 521 but this was in the '70s so lots of lead then. If constantly having to loosen the valve adjustment that would indicate the valves are sinking. My truck had huge miles on it and I vaguely remember setting the lash on it.

 

Did Nissan ever change to hardened valve seats? I've read that they did but by part numbers the 11098-N6810 intake seat was used '75 through '80.

 

 

I've messed with Z22 and Z24 from '81 and up  720s and the Z20E from '80 and '81 Z20E engines and they don't have the brassy colored valve seats. I've compared the valves from the Z series engines and the look the same size as the L20B ones but a mm or so longer. These might be a source for hardened seats.

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2 hours ago, Bastard_510 said:

no its not its a crazy race engine that might sit on a stand once my other project is done... mike i used the product i think i know what it does. oil cools when its in the pan so ill apply stoffregen's logic of if it cost a little more why not do it. the coating cost me $70 including supplies, a couple of free days and a case of beer to do. there are only 2 areas for oil to return on an L head. the front drain is not used under acceleration so the only drain on hard pulls or in corners would be the back single hole. 15miles at 3500 -4500 rpm with a pull or two to 7k. ill drive it like an asshole just not for long periods of time. 

again its done, im not taking it off, and it has a purpose.

 

stoffregen i went in to this wanting to avoid rebello. im sure they make great modern cams and i know they make great engines but its kinda like everyone saying "ka swap" for me. id rather send the money to an old guy in a shop directly then go through a big company. 

 

Only meant that the law of diminishing returns would apply. Oil would also transmit heat through the block sides and the engines are tilted up at the front so all the oil goes down the back drain but the oil from the jet on the front cam tower. I guess you could also do the inside of the valve cover but it definitely cools the oil on it.

 

What about an oil cooler?  I have one on my 710's L20B. It's a mixture of ZX turbo and Ford oil cooler parts. On a hot day climbing a mountain I hit just under 190F once. If the gauge is right. (talk about diminishing returns 😄 ) Everything was free but the $50 special high pressure hoses and clamps.

 

Definitely get a KA24DE or E high volume oil pump from the D21 Hardbody. They have longer internal rotors and move more oil per turn. Same top pressure but much higher pressure at idle and up. I've had one on every Datsun I've had. Goos insurance.

 

I was serious about the crank scraper and windage tray.

 

 

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On 9/27/2018 at 7:38 PM, Bastard_510 said:

 Nothing worse than going to put the cam gear on and having the blue pos tool pop out. 

Forgetting to remove it is worse...

 

 

 

Z22 crank & block bored to 88.5mm, open U67 head (44?mm in/ 38mm ex) semi dished JE piston custom pinheight full floating on l20b rods, isky .490 cam,

I've put over 30,000 hassle free mi on this setup, it has gone over 7000 many times.

Glyphed the block and custom pan.

Drives on the freeway on 87, but 91 eliminates problems.

 

Cooled by a stock 3 core radiator, never overheated.

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A member reported when tearing down an engine finding a chunk or wood between the timing chains.

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23 hours ago, Bastard_510 said:

 

stoffregen i went in to this wanting to avoid rebello. im sure they make great modern cams and i know they make great engines but its kinda like everyone saying "ka swap" for me. id rather send the money to an old guy in a shop directly then go through a big company. 

I can appreciate that, but Rebello is anything but a big company. I think they define the term "cottage industry".

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1 hour ago, datzenmike said:

A member reported when tearing down an engine finding a chunk or wood between the timing chains.

I found a screwdriver once with "Kurt Farry" scribed on the handle. Bay area guys will know who that is.

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On 2/15/2019 at 9:08 AM, Bastard_510 said:

i think i said it before but the head and block are glyptal coated on the walls and oil valleys. it took 18 hours on the head to prepped  and almost 20 to do the block. its hard to take it off with solvents but once baked it bonds to the walls permanently...unless you put it in high heat to remove valve guides or seats.

if it fails then ill go through the trouble then but even the head instructor at the local college said they will be fine. 

 

then dont heat it. you can simply just cut the old seats out. this doesnt mess with the guides or anything like that.

you can simply remove the old seat, if you confirm the size you can essentially just bang a replacement one in, as long as you have the required crush. I've put them in with 7 thou crush and they are fine. you will want to complete your valve job after seat replacement as this will usually distort the neighbouring valve seat.

 

if your going through this effort you should get rid of those brass seats, you will be adjusting the valves every 1000 miles otherwise. i've ran two heads completely out of adjustment due to stock valve seat sink.

22 hours ago, datzenmike said:

fLTUVOI.jpg

 

This is a U67 head so '75-'77 L20B. You can see the intake is definitely 'brass' colored. Very hard, which is to be expected.

 

Yeah I call the old stock seats 'bronze' but that may just be short for 'copper alloy'. I thought un leaded gas was introduced in the mid 70s and banned in the '90s.

 

I've never seen L20B valves worn down into the seats... that would be my '78 truck and current '76 710 although I did have a  car (710?) engine in my 521 but this was in the '70s so lots of lead then. If constantly having to loosen the valve adjustment that would indicate the valves are sinking. My truck had huge miles on it and I vaguely remember setting the lash on it.

 

Did Nissan ever change to hardened valve seats? I've read that they did but by part numbers the 11098-N6810 intake seat was used '75 through '80.

 

 

I've messed with Z22 and Z24 from '81 and up  720s and the Z20E from '80 and '81 Z20E engines and they don't have the brassy colored valve seats. I've compared the valves from the Z series engines and the look the same size as the L20B ones but a mm or so longer. These might be a source for hardened seats.

the U67 I used to build mine had sunken valves, I've had an L16 with a 210 head that ran out of adjustment, and an A87 that did it as well, I also have another A87 closed chamber head that needs new intake seats as well.

 

22 hours ago, datzenmike said:

 

Only meant that the law of diminishing returns would apply. Oil would also transmit heat through the block sides and the engines are tilted up at the front so all the oil goes down the back drain but the oil from the jet on the front cam tower. I guess you could also do the inside of the valve cover but it definitely cools the oil on it.

 

What about an oil cooler?  I have one on my 710's L20B. It's a mixture of ZX turbo and Ford oil cooler parts. On a hot day climbing a mountain I hit just under 190F once. If the gauge is right. (talk about diminishing returns 😄 ) Everything was free but the $50 special high pressure hoses and clamps.

 

Definitely get a KA24DE or E high volume oil pump from the D21 Hardbody. They have longer internal rotors and move more oil per turn. Same top pressure but much higher pressure at idle and up. I've had one on every Datsun I've had. Goos insurance.

 

I was serious about the crank scraper and windage tray.

 

 

for a limited fuck around car you dont really need any fancy oil control stuff...  I recently did one of the ishuara johnson crank scrapers for mine, as paying 1500 for a oil pan is bullshit. I didnt have any oiling problems last time around, but for 80 bucks it cant hurt to keep more oil in the pan.

 

i agree with mike, get the high volume pump.

 

i didnt run an oil cooler either, not sure if im going to install one too.

On 2/15/2019 at 11:05 AM, G-Duax said:

On the subject of valve seats, I'm running 44mm stainless valves on the 'bronze' seats with no issues with pump gas.

And they are absolutely necessary for titanium valves, which I have, thanks to Nazkar race teams dumping good parts after one dyno run, or one event on eBay.

I just have to cut the stems, re-grove, cut the heads to 44mm, and put in custom guides or sleeve the stock guides to fit 5/16" stems.

Hell, they only cost $40 for a set of 8 intakes, so I have extras to play with.

pics or it didnt happen.

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People...why are we arguing about something that’s already done and has a purpose? 

 

IM NOT CHANGING SEATS 

 

the seats have miles on them and they had no problem when it was on a running engine 2 years ago. 

Unlike most of you all i have access to the tools to put new seats in and do a new valve job. So if it did happen it would cost me just time. I’m not going to put seats in cold. .007” cold?????? No the last thing i need is to ruin this head. Maybe that’s why your head had problems. Shaving all that aluminum off the seats bore...maybe the seats didn’t seat all the way. 

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Sunken valves on the bronze seats could also be due to too high of exhaust temp due to out of tune engine.

My bronze seats hold up just fine, and I roll up 1500 miles a month, mostly above 75 mph freeway miles, or equally hard stop light pulls.

 

Said head that's on the engine now:

DSC09170.jpg

 

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Were the exhausts copper/bronze/brass alloy even The U67 I pictured does on the intakes but the exhaust look like steel.???

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16 hours ago, Bastard_510 said:

People...why are we arguing about something that’s already done and has a purpose? 

 

IM NOT CHANGING SEATS 

 

the seats have miles on them and they had no problem when it was on a running engine 2 years ago. 

Unlike most of you all i have access to the tools to put new seats in and do a new valve job. So if it did happen it would cost me just time. I’m not going to put seats in cold. .007” cold?????? No the last thing i need is to ruin this head. Maybe that’s why your head had problems. Shaving all that aluminum off the seats bore...maybe the seats didn’t seat all the way. 

my heads not ruined? its come apart after 4 years of use and alot of nitrous for a refresh.

yeah cold. never had one fall out. works for me. 

your decision i guess. im just advising you of what ive observed with dattos ive had over the last 10 years. 

 

8 hours ago, G-Duax said:

Sunken valves on the bronze seats could also be due to too high of exhaust temp due to out of tune engine.

My bronze seats hold up just fine, and I roll up 1500 miles a month, mostly above 75 mph freeway miles, or equally hard stop light pulls.

 

Said head that's on the engine now:

DSC09170.jpg

 

how many times have you had to adjust valves since install? looks pretty.

 

all im trying to get at is lots of people have this issue, and if the heads at the machine shop why wouldnt you try and eliminate the possibility of this happening. they are not going to make your 120hp datsun make more power. sure maybe they might work out for you, but when we have posts explaining how to shorten pivot posts so you can run the head a lil longer with this issue..

 

 the ones ive had sink valves were stock motors and did quite a bit of on highway commuting.. the 620 i had essentially would run WFO from bc to alberta and back with the 4 speed so 5000-5500 all the time. they probably wernt tuned up the best either.

 

 

ALSO,

This.

https://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwjZk8ib-MPgAhU0Mn0KHYWcCi8QjRx6BAgBEAU&url=https%3A%2F%2Fwww.rhdjapan.com%2Fkameari-l-type-adjustable-timing-chain-tensioner-l6.html&psig=AOvVaw2k_Wscz2nJb6GBSnf4SDKS&ust=1550533141816596

 

lil chunk of metal fabbed up and a roll pin, your tensioner battles are over.

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