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shaving more than .08?


David K

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greetings my fellow hybridz indulgees,

 

Im gathering info for a buddy building an N/A L6 to go into a 240. Parts to go on this engine are as follows.

 

Triple Solex's

Mikuni manifold

cam (new lash pads, etc)

header

f54 block flat pistons

p90a solid lifters

 

The head is going down to the machine shop sometime next week. Its for sure going to get the .08 shave and shim. We are both wondering if we could take off more material, like .10 or .12? We are concerned about valve/piston interference.

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'70 240 L28/E31 big valve' date=' ported/polished, 44 Mikunis, cam, header, 2 1/2" mandrel exhaust, EI, MSD, GC coilovers, Tokico 5-way, R200 LSD, front crossmember slotted for bump steer, Autometer, 280ZX 5-speed, and much more!

 

Jon[/quote']

 

Sounds pretty much like what I wanna do in my car!!!

 

So yeah, with the solid lifters, there's only one way to find out I guess for the car we're doing. IF IT DOESNT WORK WE'LL TRY SOMETHING ELSE! haha

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Check this out: http://www.geocities.com/zgarage2001/p90.html

 

If you haven't already seen it it has some good info.

 

Also' date=' I thought P90a was the hydraulic head.

 

Jon[/quote']

 

There are lots of P90As that are not hydraulic, mine included. I believe Nissan started re-doing the latest head casting with solid pivots for factory rebuilt motors.

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I had .100" cut of an E88, no shims either. It pulled hard to 7K. I think the retarded valve timing helped but can't say for sure. As for going "crazy nuts on the cam". You can't go crazy nuts with the lift with stock springs and it's pointless to go real big on a stock head.

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I had .100" cut of an E88, no shims either. It pulled hard to 7K. I think the retarded valve timing helped but can't say for sure. As for going "crazy nuts on the cam". You can't go crazy nuts with the lift with stock springs and it's pointless to go real big on a stock head.

 

As to hopefully help this problem for the springs, We were going to stiffen the springs by hopefully adding the correct washers underneath them. I know it's not the titanium springs that everyone may have on their civics, but this is the closest thing i can think of, or get a set of springs for the head via motorsport or anyone who makes them. Any suggestions?

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You would need shims under the valve springs because of the longer valves, which will get you the correct seat pressure, but it still won't help them with the main problem, which is coil bind. If you run a cam with anything over about .460 lift you'll need aftermarket springs. The aftermarket springs are actually longer, and the retainers are differently shaped to accomodate them. This and the higher spring rate (less coils per inch) allows the valve to move farther before the coils bind. I put Schneider valve springs and retainers from MSA in my last buildup, and so far have not had any problems, except that when my machinist was working on the head he found that at full lift the retainer actually hit the valve seal, so he had to turn down the bottom part of the retainers in a lathe to fix. Make sure you don't get a spring that is too stiff, as they will wear out the rockers and cam quickly, some of the aftermarket stuff is really stiff, but I can't remember which. I also can't remember the seat pressures and the compressed pressures of my Schneider stuff, but my machinist thought they would be fine for a long time.

 

This stuff can get pretty complicated. Ask as many questions as you can if you're in doubt at all...

 

Jon

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