Xnke

You could try it, but it's going to remove a lot of your cam base circle to get the geometry correct. You will also need lash pads. You can get Ferrea to make you any valve you like.

So I figure it's well past the time these photos came up... Sorry for the delays, Derek. 1.75" OD stainless steel tubing, with tubing lengths selected to boost as much as possible the upper-middle RPM band as that's where the head is going to be making the big power. (4800-7800RPM) The low-end isn't going to be suffering, either...unless the collectors get cut shorter than 10", and if the collectors are left a LOT longer (like rear of the transmission mount long) then the BMW sound will start coming out. Will have more photos for you once the back three tubes are fitted and tacked. Am trying to work it so I can hand-deliver these prototype headers myself! Would love to get a chance to see this project "in the white".

Call Del West or Ferrea for you Ti valves-most places don't list them as they're a custom part.

If the cam, with its reduced valve spring pressure, was designed for TI valves and retainers, you must either run TI parts or run lower RPM's. If the valve spring is spec'ed for TI, then it's TI. Either you'll need to run them or you'll have to run a different spring or rev to a lower RPM. The valve spring required to keep the rocker on the lobe is determined by RPM and controlled weight-meaning the combined weight of the rocker, retainer, valve locks, the valve, and some people include 1/2 the weight of the valve spring itself. Changing the controlled weight will mean changing the spring. I would be sending the torque wrench in for a calibration, too, or at least getting it checked out. Tripley so if it's a clicker type wrench. For harmonic problems, you can do your best to reduce torsional stresses by running a good damper (you're doing this already with the BHJ) and getting the flywheel weight down and the flywheel diameter down. Reducing the diameter helps more, as you're running the smaller diameter clutch. An engine with a smaller diameter, but equal weight, flywheel will have a lower torsional stress than the larger diameter wheel. The smaller diameter exerts a lesser torquing force than the larger diameter flywheel does on the back end of the crank. This reads like crap but it's 2:15 AM and I've been using power tools. Hopefully it makes sense in the morning.

Probably doesn't have the fabrication equipment for aluminum. 30mm carb throats are going to be too small for a performance application-40mm would be the minimum size I'd go for.

If this is the head for the project we spoke about, Tony is right about the compression, and you'll have to just order race gas. Won't make what you need it to make otherwise...

Considering that if you have the Dowel Pin in the #3 position, and the cam sprocket was actually timed to the #1 dot on the outer of the cam gear...there is no possible way that the engine ran. The cam would be out of position by nearly 90*!

Setting the body jig up to get the headers started-I know Derek is happy to hear that!

I have a stock flywheel and pressure plate for the 3.4 camaro engine in the floor here-A normal 225mm Nissan clutch disk fits fine on this LuK 3.4 V6 flywheel/pressure plate. Will fit the FS5R30A splines, too. The 350Z pressure plate fits on the stock 225mm clutch bolt patter too, has a much higher clamping force. It doesn't however fit the V6 flywheel.

No. You need to physically measure the piston-to-valve clearance as it will vary according to the cam timing, the lift doesn't matter so much. A stock cam will have the valves hit the pistons if it's not timed correctly... The only way to know how much piston-to-valve clearance you have, is to do a shit-ton of somewhat advance trigonometry, or measure it in the assembled engine. Use a set of checking springs, and roll the engine through a complete valve cycle, using a dial indicator and pushing the valve down with your fingertip to feel for piston contact is a viable method if you are NOT going to tear the engine down. It's not exact but it is "good enough" If you aren't opposed to pulling the head, claying the piston dome, bolting the head back on with a used headgasket and rolling it through the cycle will give you exact measurements.

Jack the car up in the air and let the axles come to full droop. If you can compress them enough to get them in and out at full droop, you shouldn't have an axle binding at normal ride heights-the axles have to get longer the lower the car sits. Rotational clicking may be that you've broken the cage in the axle-I did it with only 180HP on a used set of Z31T CV axles. Also could be that they need to be re-packed with grease. The shift-clunking is probably the differential bolts going through the mustache bar. I have replaced/retorqued/overtorqued/yamabonded the damn things into place and my clunk goes away for about a week...then slowly comes back as the two big studs start whacking around in the mustache bar. Next fix is a pair of tubular bushings to make the stud shanks a press fit into the mustache bar.

Did you recently buy this from ISKY or is it an "isky regrind" that you got from someone else? Also, did you set you valve stem heights exactly equal? Without equalized stems, or even with them and slightly not-right lash pads, each valve runs on a different cam profile...

That's the difference though, Six_Shooter-Your flanges are probably thinner than the most likely Modern Motorsports/Checquered Flag ones the OP has. They're IIRC made with 3/8" material. I made my flanges with some 7mm plate I had and the difference in clearance is, as you would expect, quite a bit.

ANTIPRIUS!

Felpro gasket is 88mm. There are tricks to get 250+CFM out of some of the castings, but I do not know if the E31 has enough meat to do it. Personally, I have gotten 221CFM at 0.520" lift with N42 and P90 castings, and there is more left in it. Tony Knight at Knight Racing Engines in Australia does a lot of documentation on his work with the L-series, recently he made 240HP out of an L20B restricted to stock bore and stroke, running a flat-tappet cam still. It involves welding and a lot of hand-reworking, I am looking to apply his recent documentation on an E88 casting soon.

You really aren't reading what is written here, are you? STOCK LONG BLOCK. Just run a STOCK ENGINE. Do the tuning, get it tuned, and it will make your goals. IF you want to exceed the limits of a stock engine, THEN spend the money on a bored/stroked/forged engine. People say the "A" grind camshafts (look on the back of the cam) do well up to the 400HP range, I would take a stock cam and send it out for a regrind. Doing a cam swap invites problems all it's own, so for the money, STOCK LONG BLOCK.

42 degrees of timing is about 20* too much for carburated turbo applications... 24* max at idle, 32* at 3000RPM, and pull 1* per 1.5lbs from 2.5lbs of boost and up is the starting point I use for boosted L28's.

Definitely should have more. At 10lbs, you should be seeing 250HP depending on what turbo, what exhaust, and the tune. Stopping the pull at 5500RPM is DEFINITELY leaving power on the table, but if the clutch is slipping you know you've got work to do first. It may have started slipping the clutch when you hit 200HP, after that it won't matter, the rest of your graph is meaningless. Isn't it nice to find the limits of your driveline on the dyno?

I've got a set of cam towers bored for roller bearings on the cam journals, but requires a hardened steel cam, same as if it was a roller cam. Eventually...

Solid mounted motor requires solid mounted transmission. Mixing solid mounts and rubber mounts invites broken mounts and broken cars.

Personally I think this works rather well... I know what it cost me to build similar units, and I've also inqured as to what it will cost me to buy them ready-made...it was cost-prohibitive to make the prototype for myself.

Peak torque won't be inside the L28's revs-per-dollar, I'm afraid. Studying K20A engines, they peak at 8000+ RPM, pretty much regardless of displacement, headers, cams, induction...they just want to rev. On the other hand....that should point to an engine that just needs to be spun harder if you want more power...

Header materials showed up friday, they're in the shop waiting on me to get back from work this week. Will start stripping my Z's manifolds off thursday to allow for the test fitting the header for the KN20 head. Going to try to fit the headers such that the engine can be leaned either direction and they still clear the floor. May wind up with a removable collector, would be a better way to go in any case. Will allow for a header that can be tuned from 6000 to 9000RPM, which is the only place that I believe we'll see gains over a well-prepped 2-valve head.

You need to sonic check the block and make sure it can take a 90mm overbore.... Most can't. Most blocks will top out at 88 or 89mm, if you want them to last. Why bother going to 90mm for less than a race-only engine? Going from stock at 2.753L, to 88mm at 2.883L, to 90 at 3.015L, you've not gained much other than room for valves. Even stroking it only gets you 3.168L...

Ah, well we can just turn 'em straight up out the hood....Zoomies!