ozconnection

I did what you want to do. N42 block with a P90 head but I run with VG30DETT JE forgies with custom rods. My R/S ratio is now 1.72 so it revs like an L24. Compression is around 8.3. Pefect for off boost response and still low enough to run decent boost for power. "A" grind stock cam and 1mm oversize valves on both intake and exhaust. I'm running it in ATM, sounds unreal with a 3 inch single pipe and headers, I will do the turbo switchover after a couple of thousand kms. Good luck.....my combo runs beautifully.

Looks fantastic! Well done. You're going to enjoy the looks you get with that car!!

Nigel, here's one locally http://www.ebay.com.au/itm/Datsun-Z-240Z-260Z-280Z-ZX-P-90-Cylinder-Head-/230671106028?pt=AU_Car_Parts_Accessories&hash=item35b511bfec

This is from my Datsun 240C P230 series, its an L28

Use a carburetor intake manifold gasket, not an efi one. That's all you'll need to do.

And you're asking who? L20AET's were in some 331's

EFI gaskets don't seal well on carbed intake manifolds. Use a Carb (260Z twin carb) gasket.

And, instead of the reversionary step being at the head/manifold interface, that reversionary pulse is allowed to reach the venturi in the carb which totally changes the way the fuel is metered through the carb. Can you say "rich mixtures" and "Standoff" Thank god for WBO sensors!

Yeah, weld 'em up. They will disrupt airflow, acceptable if an injector is there, unacceptable if there isn't.

Interesting project you have there!! There are two 4 speed boxes that you could be talking about. They are both descended from the very good L3N71B transmission. One is hydraulically operated (L4N71B), the other electronically (E4N71B). The earlier hydro box is the one I have experience with and has proven itself to be very reliable in service. The usual rules apply, regular servicing and an adequate oil cooler up front. A one way valve will be needed for the vacuum line to the modulator valve so it see's only vacuum not boost. There are plenty of hot up bits too btw. Good luck with it mate.

http://datsport.com/chains-valves-heads.html any good?

To be able to answer your question, we'll need more information about your Holley What size is it? 390, 450, 600 etc Is it a square bore or spreadbore? Vacuum or mechanical secondaries? Mechanical or electric choke? New, reconditioned or bought from a swap meet and used as is? Does the carb need an overhaul? I think its your carb playing up but what about the rest of the engine? Is the engine in good condition? Does the engine sound like it runs on all six cylinders? Do you have a vacuum guage hooked up and what does the needle do when the revs drop/increase? Does it do this when hot and/or cold? Have you installed the induction yourself? Was it running good and suddenly started to play up or have you just done an induction upgrade and it's been doing this ever since? How much static advance do you run? Points or electronic ignition? Has it been sitting for a long time? Have you done any other mechanical work to this engine recently? Ported head, cam size and compression ratio? Do you have any experience with L Series engines and/or Holley carbs? Your intake manifold is something that I ran on my L28 for a year or more. That's an awfully big plenum under the carb so getting the engine to be torquey and responsive can be challenging! That setup will give you a good top end (for a 4 barrel setup) compared to others that I've used over the years. I 'think' you have a vacuum leak and it's probably the secondary throttle blades not seating correctly and your idle is rich (if you've got 1.5 turns out on the carb) but I need to know what carb you've actually got to confirm this. Do you use an o2 sensor? How are your plugs looking? Get back to us with some more info and we can go from there.

Yes call if you can by all means..... Did something special catch your eye Tony? Wanna share? Couple of stock L series camshafts perhaps? Long live the Vodaphone! Sorry to go so far off topic, blame him but

What sort of stuff did you see? Did you happen to have taken any pictures? Aaaaaaarrrrrrggggggghhhhhhh, I gotta get over there and check it out, one day Thanks Tony

Yeah, try this stunt and you'll be explaining yourself to Mr Policeman...... "it's a terrible thing!" LOL Chuck it on a dyno, gets the results without a world of hurt for you or your engine.

I'll just pass on a few observations I made when I was playing around with camshaft timing on my L28. Idle fuel mixtures need to be tweaked when changing cam timing. Your poor idle with low manifold vacuum and the A/C on when the cam is in position two is indicative of poor torque, despite the new cam position and increase in idle speed ignition timing. Go to your tailpipe and listen to the tone. If your idle is splashy and sounds like "mmmmmmpmmmpmmmmmmpmpmpmmmm", then you're too lean. Richen it up a bit and see what happens. This is easy, easier than the solenoid option at this point and tweaking the mixtures costs nothing to try. I'm running 22 degrees ignition advance at idle and my idle drops about 50 rpm when the A/C is turned on. I actually tune my idle with the trans in drive (auto transmission) to simulate real loads in traffic. Maybe you should tune your engine with the air on if its a manual shift car so it's never an issue when its turned on? My AFR at idle is about 12.8 - 13.2 to one and has 16-18 inches of vacuum at 750rpm in gear (drive).

What type of engine are you building? That might be helpful. I bought JE forged slugs for my L28. I used 300zx tt pistons and had rods built to suit. I later found out that L14 rods could've been used instead, the only mod would be to make the small end 22mm's to suit the pins. Needless to say, I now have a set of those rods on the shelf, just waiting......

I hope the Toyota and Honda guys are better at measuring their rods than we are! (does that sound strange? I'll blame Tony) How long is a stock L20A rod? Anybody?

You guys take things way too seriously. He's only having a muck around with some stuff. I like what Rsicard is suggesting, an interesting, unusual and functional setup for sure. The Arizona 4bbl is good for the street, providing good low to mid range torque. The Clifford is excellent for top end power. Choose your poison and have some fun!

Awesome Nigel.....thanks.

I don't consider myself as an expert, so can I reply? P90 head has 44mm intake valves. Compression ratio will be different with the two different heads. That will influence your power significantly. Both heads are fairly detonation resistant because of their quench, I think you can get away with the 47 head if a)compression isn't too high for the fuel you're going to use b)you don't have to overly retard the ignition timing to avoid pinging c)you select the right thickness HG to get your compression to where you want it. Your quench won't be as good with the dished pistons compared to flat tops with either head but it will work.

Nissan headgaskets.....the blue packaged ones are made in Oz buy a company called ACL for Nissan. The others "may" be directly from Japan but who knows? I know, I've got too many hg's, and that's not all of them

Too late tonight, but I'll get a photo or two of that universal "XX" Nissan HG on here tomorrow. Tony, good memory buddy! Cheers.

Nice rockers and stuff! What's the deal with that head?..I can't see any quench with those chambers at all.