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Rebuild Z22... how to do it right


poopypants720

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Also thanks to a conversation with kenturtles I've found I don't have much to worry about regarding valve clearance and with stock springs can get away with up to .555" of lift before they bind.I'm going for the ka pistons, 270° duration cam with as much lift as schneider can grind (hopefully at least .480"), port and polish on the head to meet headers diameter and at kens suggestion, going to see if I can get the valves back angle cut to 30°

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There are two chamber sizes. The most common are the Z22E (200sx)m Z22S (truck) and the Z24...I have done all three and a second time to check the results. I measured 57cc on all three.

 

There is a smaller head used on the Mileage Option 720 with a Z20 S. (carb) It had 9.0 to 1 compression and the head volume I have worked out to be about the same as the open L head... about 45cc.

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<br />There are two chamber sizes. The most common are the Z22E (200sx)m Z22S (truck) and the Z24...I have done all three and a second time to check the results. I measured 57cc on all three.<br /><br />There is a smaller head used on the Mileage Option 720 with a Z20 S. (carb)  It had 9.0 to 1 compression and the head volume I have worked out to be about the same as the open L head... about 45cc.<br />
<br /><br /><br />

 

Wow, really? Is that one of the 4 plug heads though or still 8? I think a smaller hemi head would be awesome.... And if 8 plugs not much in the way of distributor modifications or worries for failing visual inspection.

 

Where was this head available? US, Ca, over seas?

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Sooooo.... 8.44:1 compression...

 

Any idea how many cc are lost by shaving the head 0.030mm?

 

I can't believe the change in cr just from the change in deck height/compression height between the .05mm and 1.55mm.... A difference of 9.33cc....

 

I'd like to be in 9+:1 cr range if possible... But how to do that now is the question. Shave the block? Bad idea?

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Take the Z22 block and over bore to 89mm. This will allow the use of KA24E pistons. Use your Z22 rods if they are 145.9mm long or find L20B rods as they are the same. Yes the KA pistons have a negative 1.55mm deck height but this is good as the increased bore volume plus the smaller dish would have raised the compression too high anyway. This negative 1.55mm adds about 9.6 cc of volume to the combustion chamber so... Z22 bored to 89mm, KA24E pistons on Z22/L20B rods with Z22 crank and head will have a compression of 8.469 ... big friggin' deal. It'll work and you have a 2300cc motor when done.

 

 

BTW the VG pistons have almost no dish (1cc) but have way too low a pin height ...negative 3.75mm over the stock Z22 pistons. If run in a stock bore Z22 (87mm) the compression would drop to 7.2

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Any idea how many cc are lost by shaving the head 0.030mm?

 

I'd like to be in 9+:1 cr range if possible... But how to do that now is the question. Shave the block? Bad idea?

 

0.030mm??? about 0.18cc. Did you mean 0.030" or 0.76mm?? That removes 4.725cc from the head and gives an 8.96 compression.

1mm removed from the head equals 6.2cc and gives a 9.12 compression.

 

Removing material from the head or the block effectively adds slack to the timing chain. 1mm adds 2mm of slack. If your timing chain is old it may need to be moved to the next number up on the sprocket.

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I did mean inches, sorry. I was caught up going back and fourth having fun calculating my own cr with a calcuator that required both in and cc, so I was converting all my mm-in.I would love to take off a full mm from the block just to get that cr but really don't want to deal with the timing chain issues... 2mm slack isn't something that can just be taken up by the tensioner?

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Also found I should be able to acheive the 9:1 compression ratio I was shooting for along with more displacement, along with a better breathing head, along with zero clearance issues and zero time chain modifications (getting a new one in my rebuild as it is ;) ).

 

list of rebuild specs for my z22 are as follows....

 

-Bore over to 89mm and replace pistons with smaller dished KA24E truck pistons

 

-Port and polish the head to give the clearest shot to the valves and better take advantage of my headers.

 

-Port intake manifold to match new port on intake valves in head.

 

-Back cut the valves to 30°.

-Regrind the cam via Schneider Cams to the following specs: 270° duration, .480"-.490" lift, 114 Lobe separation.

 

-check for initial need to mill head and block mating surfaces and shave off extra from head to .030" under stock.

 

-replacing Weber 32/34 DFT with a Weber 38 DGES

 

 

Should cost me just under 2g after everything... Am I crazy? Lol. Oh well will be fun. Already tearing down the motor for pulling... Will update with pics tomorrow.... And more questions...

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Hmmmm.... Zero dish ka pistons???

 

Nismo part

12010-40F10(through 40F12 for different stages) 89mm flat top.

 

12010-40F72 bore of 89.5mm.....

Wow... Don't think I want to bore that large.

 

But its again another way to effectively raise compression without doing irreversable shaving to the block or head.

 

 

Sooo im down to a bare long block sitting in my engine bay with the exception of the distributor and the intake manifold.... Except the intake manifold doesn't want to come off...

 

A few of the bolts are impossible to get a 6 point socket onto and I'm worried that an open end wrench won't A) have enough leverage to break them loose and Bwill strip the heads... Especially since the most forefront lower intake bolt won't even come loose with a 6 point socket and breaker bar and is starting to strip.

 

Pb blaster is no help in getting it unstuck either....

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I was hoping to be able to avoid taking off the head and just bring in the entire engine in long block form to the machinist....

 

I should prob take it off myself anyhow so I know exactly what's going on with so much oil being burnt right now anyways. And remove the cam for grinding so the machinist doesn't have to worry about waiting for it.

 

Also the haynes manual is fairly vague regarding where the different hoist points are on the motor for when I go to pull it. Does the fsm have a better description or a visual diagram?

 

I'm thinking I need to pick one up... In the meantime could I get a heads up on where the best mounting points could be?

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Thanks for the tip on just pulling the head mike. It made getting enough leverage and top weight onto that stripping bolt possible. Had to still pull all the other bolts first and do a lil wiggle on the IM to let lose all the rust seizing it. The threads were actually clean it was just in the manifold itself where it was locking up from corrosion.

 

Also got a better look at the condition of my block and head... As far as the mating surfaces go and the cylinder walls, its not looking too bad at all...with my inexperience at this I can't tell anywhere that there was an obvious blow out of the head gasket. The thing that's got me worried is the gobs of white corrosion and rust coming out of the im water jackets and what's visible inside the head and the deck of the block....

 

All cylinders had very black tops to the pistons and the combustion chambers on the heads and valves were looking horrible too with tons of build up which isn't silo that apprising considering all the white smoke that always blew out and rate of oil consumption.

 

Snapped a ton of pics... The one thing that tripped me out the most was the size of the water jacket holes in the top of my block...

 

IMAG0222.jpg

 

Heres some more of the block, head and intake

 

IMAG0214.jpg

IMAG0220.jpg

IMAG0219.jpg

IMAG0225.jpg

IMAG0221.jpg

IMAG0227.jpg

IMAG0211.jpg

IMAG0208.jpg

 

 

This one show some black between cylinders 1 and 2... Is this from head gasket issues?

IMAG0209.jpg

 

IMAG0206.jpg

IMAG0207.jpg

IMAG0245.jpg

IMAG0244.jpg

IMAG0242.jpg

IMAG0239.jpg

IMAG0233.jpg

IMAG0232.jpg

 

 

Where can I get another, not rusted out fitting for this part of the manifold?

IMAG0240.jpg

 

 

IMAG0234.jpg

IMAG0238.jpg

 

IM gasket blew out at the water jacket under cylinder 2... Leaked when hot...

IMAG0235.jpg

 

IMAG0236.jpg

IMAG0237.jpg

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