MAG58

Go to the eye doctor please. I had the same thing, they wash out your eyes and all is good. Blindness is a bad thing.

Lapping refers to "hand seating" the valves if you will. A lapping compound (basically grease with some grit mixed in) is applied to either the seat or the valve, then the valve is inserted and spun against the face. In doing so, the lapping compound makes a small 'cut' if you will on both the valve face and seat ensuring that both have 360 degrees of contact and the best possible sealing.

You could use Carbon Fiber... That would be hot.

This is what happens when we get such reliable cars! But seriously, It is sad. Unfortunately, Like jeff said, auto parts is a business (and a big one at that) and it's much more lucrative for them to prop up all the SUV's coming out of Detroit rust city than it is to help us Z owners out. Different strokes for different folks I guess. Good taste is a rarity these days

If they were lapped, they should already be properly seated. When you start to get lots of popping back through the intake or backfiring, I can tell you they're not properly seated.

The biggest thing to get over when you first start polishing is dealing with going at the right speed and not using too much polishing compound. You want to move slow enough to be effective, but not so slow you build up alot of heat in what you're polishing. Using polishing compounds are correct, but getting too much just causes black smears and takes you twice as long.

I can totally agree with that. The needen't be compared. It's like comparing a turbine to a piston airplane. Completely different beast. But I'd like to clarify a few common mis-conceptions: They're not as un-reliable as many think. I've seen and driven rotaries with 200k+ and they still all post 130+ per face on both rotors. It's treating them like a rotary that makes them live. Treating them like a piston engine and they die fast. People think that it's louzy that a full bore, 13B, PP rotary that sees over 10K (I don't care how you want to compare engine speeds, that's truckin') wont last over 20,000 miles. Find me a comparable 2ish Liter 4 cyl (comparable power from NA and equal combustion events per revolution) that sees speeds over 8k regularly puts out 300hp on pump gas (rotaries either have 8.5 or 9:1 cr) with big ol' cams that does see that kind of engine life and I will be surprised. Rotary power curves are different too. They're less parabolic, and tend to make all their power at the top end, where they like to sit. Remember, the factory quoted torque curves for the 1991 Prototype cars placed the 787B 4 rotor at the top of the list. It made more torque than all the 3.5L V12 cars and more power to boot. (600+ hp at 7500 with 10.0:1 CR aint bad for a 2.6L NA motor in my book) The only thing rotaries fall short on is oil consumption. Again, treating this motor like a 4 stroke piston engine kills it. Allowing a bit of 2 stroke oil in the motor to keep the apex seals safe means a little worse emissions but a much longer lived rotary. Beyond that, it's all about preference, and if I had the money, I'd put a 3 or 4 rotor in a Z in a heart beat. The 2 rotor weighs just over 200lbs. That's a power-to-weight ratio I can get behind.

I feel you all believe that this is going to be an all out balls to the wall, slobbering monster. I'm just trying to get a head the L28 for cheaper than the price it takes to do a full port and polish on a standard L head. Then it would be economical enough to consider. If that's the case, all that money you had to dump putting a different motor in there could be used for useful things, like turbo's and bottom end . All that aside, I'll have updates when the engine is running, and probably a how-to. There are too many people here who feel this is a sensitive subject to just be gradual about it. That said, The DOHC L is going into a different project (just you wait) Because I'm attempting to put the whole M104 in my 240Z, it's just too pretty to say no!.

This turbo, however looks like it's electronically controlled, and if you had the computer to run it, you could end up having a turbo setup with crazy fast spool and awesome response and still put out big numbers. I'm excited.

I think they can be compared, eccentric shaft speed vs. crank speed, because pistons move at vastly different speed than the crankshaft, and equally rotor speed is different than the eccentric shaft. Just because a big name magazine says that the rotor spins once for every 3 eccentric shaft revolutions doesn't mean it's still not spinning that RPM. That's not what they're saying either. Would you have a piston speed gauge in your car as opposed to a tach? I doubt it, and if you do I'd like to see it. If you want to compare the two, compare rotor speed to apex seal tip speed and compare eccentric shaft speed to crankshaft speed. There's no need to get hostile. I don't understand why when some engine or idea goes against accepted norms that have been around for a while they get all indignant and defensive. What makes everyone think they've been doing it right for all this time? If you quote wins, they've only been winning against themselves...

Aw, isn't that cute? With the getting rarer hard top too! Nice find.

If you have crud in your oil from that recockulous fram filter it could make it act like glue, or the ball has a little rust on it, or the ball has a wear line from banging in and out of the seat it sits on, these could all make it stick.

I had "pin it to win it"

My current L28/F54 with DGV's gets roundabouts 23-24 cruising to school and back.

Racing Beat had a few 13B's spin 12K before. Let's see a 1300cc motor do that for long.

VGT... I'm scared.

Dear lord. I HATE rubber cones. With a passion. I want to find Alex Issogonis's grave and defile it for that little engineering decision. And Yeah, I get that alot, I built an A+ for a guy who wanted to spin a complete 3 main stroker 8500 without a main strap and with stock cooper s rods. He's older than me so he obviously knows better. I've seen what happens when a Mini rod decides it wants to vacation with 2nd gear...

Jasper's right, the return spring got it self lodged in there. Replace the pump or take that big nut off and un stick it.

Ah the glorious world of British cars. Ten hours of work per hour of driving. Not including tea time. Though I like that setup more, having the sump of the engine containing the gearbox like my mini is a bit un-nerving...

Don't do this to me...

At least the officer understands the necessity of having some relaxants while working on a datsun.

Apparently there is a back story to this... Please, whore the crap out of this thread.

101? That's two hours of my life I'll never get back... But I did beat jeff.

Before you put it on did you have the head pressure checked? I bought two P79 heads off running cars, both ended up having cracks in the water jacket.