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Bastard_510

Hot LZ23

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Hello guy happy Wednesday. I'm currently in the final stages of paining my lz build but I have a major problem. 
 

This build is a high budget build, well kinda. I'm spending everything I can on parts ( 2.5-3k) and I'm machining it. 

A87 peanut head ported to 38mm im the process of polishing the chambers and runners

Z22 block 89mm

Z22 crank

L20b rods

Forged ka24e pistons from arias 3520300 -11.5cc and will be cut for valves

Kameari performance twin idler Gear kit to replace the tensioner because the head and block are decked so I can't use spacer on the cam tower...also they look cool

Some sort of coated bearings I haven't decided yet

Schneider cam 270-80F .480 lift

I'm trying to find 44mm sidedrafts if not I'll get the 45s

The block , rods, and crank will all be machined

 

The problem

 

The piston comes up 1.55 mm short of the deck 

 

I've seen Mike on here saying it was ok and it gives valve clearance but I'm using a peanut. For me its far too low to for the quench clearance (.110") I would like it to be .049-.60."

 

Has anyone decked that much or does anyone know how much i can take off before it its too weak to be useable

 

The block , rods, and crank will all be machined

 

 This will probably never see the track and will mostly be a freeway runner. if anyone has any advise or sees anything wrong with this please let me know

 

 

 

 

 

 

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I took 1mm off the Z22. Seems ok but I never completed the 2300.  One day maybe. I also took 1mm off the head (KA24E head that is) in order to bring the compression up.

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This is not a new problem.

 

20 years ago I worked for Rebello Racing. Back then we figured out the best way to build a 2300 was with custom pistons. The only way really, since there isn't a good piston available over the counter that has the correct pin height for any Datsun rod length.

 

So if you're going to use custom pistons, why not use the long rods out of a Z20? The N85 rod is just about 6" long, and helps smooth out the power from the mid range to peak RPM, essentially flattening the torque curve. It also helps stabilize the reciprocating assembly to provide longer life. This is not true for all engines, but the L series does benefit from a longer rod, pretty much in all cases.

 

Bite the bullet and get yourself a set of N85 rods and a custom set of pistons. You will be glad you did.

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I built mine with custom cp flat tops and a u67 head, 4 years of nitrous spraying and its still alive... get cp or je to build you some custom pistons with the valve reliefs and the dish you need to get the CR you want.  If you have the block surfaced try to measure what you took off cause if you have pistons built at a 35.5mm pin height your pistons are going to stick out of the bores .010-.015. just something to think about if your head gaskets only .040 thick.

 

 

I have the L20b rods as well but next time I will be getting rods built so i can spin it a little more and spray it harder.

 

dont waste your money on the idler kit, just slot your chain guides so it keeps it tighter and use a new chain. degree your cam in. better off spending the money for pistons instead of this.

coated bearings is probably also a waste of money for this... just use clevite tri metals in it.

 

 

 

 

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That's my point. If you're going with custom pistons, spend the $200 for a set of rods too and have the long rod motor.

 

Scooter is absolutely right on the chain guides. Make sure to slot the holes on the curved guide, not the straight guide.

 

The coating on bearings wears off and affects the the bearing clearances. I only do it on race motors which get rebuilt once or twice a season.

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Your compression is going to be pretty high with an 89mm bore volume squished into a peanut head. That 1.55 deck space above the piston (adds 9.6cc to combustion chamber) helps keep the compression reasonable. Flattops would be off the chart.  

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ill look into pistons. i have a personal vendetta with the tensioner and spending 700 to no longer deal with one popping out is worth it to me. Nothing worse than going to put the cam gear on and having the blue pos tool pop out. 

 

stoffregen im looking into it now. that would bring the rod ratio to 1.68 from 1.58 and a piston speed of 3923 at 6500...should i look into custom rods also? 

 

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Mike, you have to open up the chambers anyway to match them to the big bore, and that helps bring down the CR. 

 

In the long rod 2200, I like to use a KA24DE piston, which has a heavy dish. This piston needs to be cut down to fit, but the reverse dome offers excellent squish characteristics. 10:1 is common for this combination, but I've run them as high as 12:1 on the street. The 2300 needs a custom piston because of the increased stroke, but the same principles apply.

 

For a street motor, making 220-240 hp, stock N85 rods with ARP rod bolts are perfectly fine. That said, custom Chinese H beam rods can be had for pennies these days. Someone here on ratsun used a set in their long rod motor, so it may be worth a search.

 

Edited by Stoffregen Motorsports

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Z22 block bored to 89mm

KA24E pistons.

L20B/early Z22 rods

 

Compression with a closed chamber head is......... 10.39

Above with open chamber head................................. 9.87

Custom flattop pistons that reach the deck............ 12.15

Above with open chamber........................................ 11.31

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make your chain tool out of wood it will be so tight in there it will be hard to get out... problem solved.. i made one out of good birch plywood and it works mint.. i got the template to make it off here i believe. its in a long lost thread but im sure you can find it.

 

just arp bolt and get the stock rods shot peened, I think your going to run out of camshaft before you get to rod flinging territory anyway.

 

if a rod hasnt come out of mine turning 7500 and a 100 shot of squeeze you should be fine. 

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i found CNC z20 rods for under 400 with full floating bushings. I might try to wing it up to 7500 now but I’m not sure. I’m looking into the piston measurements and what size bore i can go. Hoping for 89 but 88 will do also. I just finished taking all casting marks and imperfections out of the oil trough in the head. My order of glypthal is on its way. Because i can and have the time. More updates to come. Stoffregen do you happen to have the the piston measurements for the z20 long rods?

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I used to run my 2200 with stock N85 rods up to about 8200. The valvetrain took more of a beating than anything else at those RPMs and required valve springs about once a year.

 

No I don't have the measurements. Call Rebello Racing and order from them. They have a couple manufacturers they use, like JE, Wiseco, etc. The pistons they will sell you are not off-the-shelf, but Rebello builds enough of them that they have the design ready to machine.

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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!

 

 

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Never never never over cam your engine. It's better to have less and want more that to have too much and wish you had less. If you have to retard the cam what's the sense???? and what about all the other cam events that are now out????

 

 

 

 

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i sorry i meant advanced. if anything the duration of the cam needs to be longer and i could take a few degrees out of an adjustable sprocket. this is all at 100% efficiency so i could leave it at 4-5 degrees advanced and it would be fine and run at around 8:1 so like 75-80 %. 

 

also retarding a cam, to a point, makes more power at high rpm .

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The duration or overlap can't be adjusted. You can advance or retard when valve events happen but they all stay relative to each other. If you advance the cam say 4 degrees the intake opens 4 degrees sooner but shuts 4 degrees sooner. Same with the exhaust.

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12 minutes ago, datzenmike said:

The duration or overlap can't be adjusted. You can advance or retard when valve events happen but they all stay relative to each other. If you advance the cam say 4 degrees the intake opens 4 degrees sooner but shuts 4 degrees sooner. Same with the exhaust.

 

Yes Mike that is how a single cam works.

what i meant was a different cam would work better but im not paying for a custom grind. ive already did the math and i already talked to people about the cam. im really here to update and figure out seats

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The last 2200 I had for myself had 12:1, but the cam I used was large and was fine with street gas. Sounds like you've figured this out for yourself.

 

L motors generally like the cams to be a tad advanced.

 

Valve sizes? boy, I can't remember, but large. Very large. Is this an open chamber A87 head?

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Aren’t the seats the same size for all l series

Edited by Andres131313

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Good question. The L28 can have 44mm intakes while the L4 cylinder max out at 42mm. I wonder if you could grind out a 42mm seat to 44mm as it's only 1mm extra all the way around?

 

Generally the L 4 cylinder intakes range from 38mm to 42mm. Exhausts from 33mm to 35mm? A single seat size that is ground to fit would make sense.

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its a closed chamber. I dont have enough heads to compare. I'll just order and measure. a single angle seat is difficult to do and get a perfect contact placement on the valve. The 30 keeps it away from the margin and the 60 keeps it from the fillet. This allows the contact patch to move on the valve during heat cycles. if this didn't happen or if it was off I would burn my valves. A slight 30 is all I need I think. I'll try monday and see how it goes.

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16 hours ago, Bastard_510 said:

 

Yes Mike that is how a single cam works.

what i meant was a different cam would work better but im not paying for a custom grind. ive already did the math and i already talked to people about the cam. im really here to update and figure out seats

 

I see what you mean now. A different cam altogether with different duration and overlap. The trouble with too much is the bottom end suffers where you drive it the most. Same with valve seat and exotic valve face angle cuts. Keep it simple and it will be trouble free and last longer.

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A closed chamber A87 head with that large of a bore is not ideal. I assume you are going to (or have someone) open up the chambers to match the bore? This helps immensely with squish.

 

There are modern cam profiles available for big displacement L motors. I had a custom hydraulic profile cam ground for my last 2200. Its opening ramp was not as violent as some, which helped with valvetrain durability and maintenance.  It also made great power down low, but still made power up to around 7500 rpms. With dual 44's, it made 210 hp. That was back in the 90's. Now, they are making around 240 hp with a slightly different grind.

 

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If you are running any piston with a dish, a closed chamber head aka a 'peanut' you have no quench area to begin with. Add to that the 1.55mm below deck height of the KA pistons. All you gain is higher compression over an open chamber head. 

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the whole plan right now is to have them flat top. ya my hope is to test to see how thick the wall is and use the stones ( from grinding seats) to open it up a bit sideways .  ill end up following that around and making it match the chamber. bottom end doesnt bother me ill be driving at 3-4,500 anyways.  im ordering this cam from elgins cam in california
 seat- seat: 284 

.050 :240

cam lift: 320

4-7k

 

its marked as "wilder than the one above for serious autocross"

ka pistons won't work. ill have to have special ones made and a copper gasket 

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