madkaw

HP numbers are all over the place when you start digging deep into these forums. I think Jeff is getting 180+ on his L28 with SU's. I saw 155 RWHP on my L24 with SU's, but no dyno on the triples. I figure 180 with the Mikuni's. "feel any difference" relative to what? To each other with the same mods? With a light car 20HP will feel different and being able to run full ignition advance with a 79 head might be 20hp difference. There are some good threads at Hybridz that talk about heads and there potential. The P79 is an excellent street/mild race head. Shaving and bigger cam give good results. The 42 is a great all out head but will need quite a bit of work to get there. I don't see mention of a cam in either engine. It's all in the head on these motors!!

That's a close call. The 54/79 combo is definitely a better NA combo. A more modern combustion chamber = more CR=less detonation=more timing=more power. You could sell the old motor as a complete runner and save your pennies for triples on the 54/79!! As far as turbo charging, neither set-up is that good, so planning a future based on that will be tough. you would need to aquire a p-90 to put on the n-42 for future TCing

Just post up the numbers on the block and head! I.E. N42, 54, P-79 whatever you see. Looks like a zx damper to me, got one in the garage right now.

Looking at the pic I'd say you have a late model L28 in your 71! Did I miss something or did you say this was a 71 240z because that is NOT a 71 damper or timing scale

Had a break thru with the Mikuni's today. I have been tuning on these for a long time and have done well in all areas except the transition zone. It's the zone where the carbs are leaving their pilot jets and moving on to the main jets. This zone showed up as a very lean spot to the point of stumbling and my O2 gauge showed +18 on the scale. What I did was actually close some of the holes that were on the bleed pipe inside the emulsion tube-thus making a stronger "suck" on the main jet from the venturi WITHOUT richening WOT. It was kind of a last ditch experiment that I wanted to try before saying "good enough". Just exciting to find another angle to tuning the triples and getting closer to FI drivability.

It's hard to figure out what you are asking because of your poor grammar. Pretty much everything is interchangeable on the L motors. The P-90 will bolt on any L28.

Ummm- L28 HAS forged internals already ( crank & rods). You would be pissing money away for anything else. It's all in the head. P-90 shaved would be great, but you need the flat tops to compliment that. Might consider finding a zx flattop motor and work the head( p-79), or just use the block with your P-90. As far as detonation, using a modern design chamber like the P-90 or 79 should help deter that.

Those are float bowl vents and should be left open to atmospheric air. I thought you had already gone back to your previous timing before this. As stated earlier, you need to get this issue resolved(timing). If you are going to own a Z , this is right to passage to work on these engines. There are hundreds of threads on this so get searching

Not sure how you figure .012 by looking at the timing cover fit. If .012 was taken off the block then the cover should have been machined too. Surely the machine shop gave you a stat sheet? Shims can be used , but unless you are over .030 total I wouldn't worry about. You can always run the 2nd notch on the cam gear. I'd measure piston above deck height to see if you need to run a 1.25mm HG

I would go back over everything you wired with the Pertonix and make sure nothing is loose . Pics of your wiring? It will hard to get past the issue of your timing being Way Off. For me, I would have to have that right first. 35 degrees is saying something is wrong and needs to be addressed. Checked for vacuum leaks?

Pretty long thread over at Hybridz covering this. All out race motors !!

Reading your post again it seems to point to when you messed with the carbs. Have you done the drop test on the carb pistons? Are you familiar with SU carbs?

Start from ground zero. Like said above , check timing by finding TDC compression stroke and assuring the rotor is lined up with #1 cylinder . Put your timing light on each cylinder wire to check for spark. Did you buy the coil and pertronix igniter as a kit? The coil impedance needs to match. So if you bought a coil for a points ignition it won't work for electronic. Ohms resistance should be around 1 ohm for the proper coil.

Like he said... Process of elimination. I doubt it is induction or exhaust

You should be able to find .040 over pistons for the L24. My engine is .040. I would not consider l28 pistons, not enough block for that. L28 engines can be found for a reasonable price and it would be cheaper then expensive machining costs. Search- search and search again, it will save you tons of time and money.

It's nice how the gears will change the personality of your drive. Stepping out the rear is fun too! When you go back under there recheck every bolt. 1/2 turn loose on the diff cover/moustache bar or LCA will cause a clunk.

Probably on worth a couple hundred - but I'm offering 500$ :)cool father son project GO USAF- my daughter is an USAF officer!!!! Welcome to CZCC and the helpful staff here

Harbor freight ? Get a 3 finger puller- universal type

It's probably not going to take much , but DON'T pry on it. Use a puller, it will pop pretty easy, but prying will not get you anywhere. Any puller that you can make work.

Might want to read the directions first-

Yep, I guess you just missed that fact about the flange. That's what makes the swap so sweet! As far as the RT mount, everyone seems to have experienced the same thing as far as the tight squeeze. I had to beat mine into submission also!! Now my car has the T-5 trans(borg Warner from the ZXT) and the flange will not change out from the r200 diff, so I had to have the Subby flange redrilled to match the DS(PITA)

I'm with you as far as the 'fun factor'. It's the total package of sound , feel. The triples are a unique fun for the inline motors. Not too many engines have this option. It's not about the numbers, or I would just say turbo charge it. I will admit that frustration of tuning triples might diminish the fun. I have been lucky with my Mikunis, pretty much set them - forget them. You never did say if you have driven a triple carb? Wish we all lived closer to swap out keys!!!!! Sounds like your L24 is built just like mine( except for the triples)

Guy, always glad to see some engine building going on here at CZCC! A couples notes of discussion-I am suprised you have made so many engines the same way,i.e., same cam ,etc... Your choice, but thought a little variance to spice things up or experiment maybe with a different cam. Have you driven a triple carbed L engine yet? Your combo begs for a hard hitting induction system with accelerator pumps!!!!!!! How does the destroker compare to the L24? I like your engine build, but probably never go that route. I think I would rather make the full stroked L28 spin up faster with lightened flywheel/clutch and cam set-up. I have a P-79 head for anyone interested. Came off a runner and I won't be using it. The chambers look great on the P-79, but I'm set up for square exhaust

Put a Pertronix Unit in there an ditch the points- you won't regret it

Oops - didn't see the previous post and pic Stephen - you might be screwed with that cover. I did the whole r200 LSD thing with the big finned cover and had to make a large Heim joint to connect the LCA's. so either dump the cooler cover and put a stock one on or you have some fabbing to do