cygnusx1

I have a basic question. Piston to cylinder clearance notation. In the FSM they call for 0.0014 "middle of the road" Piston to Cylinder clearance. Is it a misnomer? Technically 0.0014" is the spec for the difference in diameter between the piston and the cylinder from the FSM. Piston to Wall clearance should be ( CylinderdD - PistonD ) / 2 It looks like when everyone says Piston/Wall clearance, including the FSM they are really just quoting ( CylinderdD - PistonD). It seems like this can cause some confusion. ??? Regardless, my new pistons are about 0.0028" smaller than my new bores which makes the wall clearance 0.0014"

Will do. I have a dial indicator in my tool cabinet. Three pistons in and three to go...paused for tornado warning...or should I keep working.

The shop quoted me the bore and hone, and then I asked them to fit the pistons to the rods and end gap the rings for me. The machinist was really cool and only charged for the block prep. I got the block back this morning, so I fit the main bearings, plastigauged it, and then torqued it down for good. The crank spins nicely. Tomorrow I'll knock in the core plugs, install the rings, pastigauge the rods, and get the pistons all installed. 33-40ft-lbs for the stock main cap bolts seems low to me, but I tend to have gorilla hands. I will be using ARP for the rod bolts and head bolts. Sears had a Craftsman 75ft-lb click wrench on sale for $50 today! My lucky day.

You are correct sir! Quote from the Megamanual- setup section "For example, if you set the upper limit to 6000 and the lower limit to 5800, then in: Spark Retard mode: Spark would be applied normally (from the advance table, etc.) until you reached 5800 rpm. It would then be cut linearly as the revs increased to 6000 rpm. Note that the spark is retarded with rising revs between 5800 and 6000, as well as when the revs fall. Fuel Cut mode: Fuel would be applied normally (from the advance table, etc.) until you reached 6000 rpm. Fuel would then be cut completely, and restored ONLY when the revs dropped to 5800 rpm. Note that the fuel is NOT cut with rising revs between 5800 and 6000, only as the revs fall."

I am going to dive into the MS manual again a dig out the section about rev limit / fuel cut. If that doesn't clarify it, then I'll ask Matt at DIY. BLOZ UP, I tend to agree with you because a gradual fuel cut, as conceded above, is a BAD idea. I don't have my MegaStim handy, or I would test it out.

BOOM!! I am not convinced that this is not the cause of my car detonating on the race track a few weeks ago. Hear me out. My tune maintains AFR 12's all over the upper ends of the map. It is not dyno tuned, but tuned with datalogging and correcting. Tuned without a rev limiter. Little by little I have developed a pretty stable map for my car. When I switched to EDIS, I shut off spark cut limiter, and went to fuel cut limiter. I set my fuel cut start point to 6500rpm's and end point to 7000rpm's. That means that the fuel cut gradually happens from 6500 to 7000. So in theory, for example, at 6750, half of my fuel is now gone! To me that is BAD!! Full throttle, full boost, and half fuel. All of a sudden the AFR's are up in the 18's or so. Then a few visits to the 6700 rpm range on the track and BAAAM three rear pistons lose their skirts, and the head gasket went to lunch. Tell me I am wrong?

I used a generic "bent SS pipe/silicone coupler/t-bolt clamp" kit from ebay, and with a hacksaw, I had the intercooler installed in under two hours.

The block is ready to go and I am having the shop do my ring end gaps as well. I didn't want to screw around with a hand file or pay $60 for a grinder that I'll only use once before I lose it in my garage. I am having him set top and mid ring gaps to 0.017" (@0.020 overbore). It might be a tad bit wide, but with the heat I am throwing at this motor I would rather be safe than sorry. Now all I need to do is hunt down some gaskets for the turbo, borrow my buddies torque wrench, and begin assembly. I deburred the inside of the block and was surprised to see the amount of casting flash that flaked off by hand

You are not an idiot. It's how we learn. How I do at least.

I would never paint my urethane airdam unless I lived out in the desert. It scrapes everywhere.

I would. Sounds like you are more than half way there already. May I ask why you were removing the towers?

I don't know. BMW's for years have battled "crispy-chicken" valve and intake port deposits. I have seen them get really bad in a short time.

The admin cleaned up the thread. Bravo! But those valves really look nasty. The flows in those ports must be way down from when they were new. Yikes!

Oh yeah, if you try to get technical or act mature in there, you are basically taunted. That is some nasty carbon build up. I hope the BMW powered guys in here take note. Ron?

As long as I can remember working with BMW's, back to the late 80's, they have always had issues with carbon buildup on the valves. I remember a "standard" procedure, at the dealer where I worked, where customers were charged enormous cash to have their intake/exhaust manifolds removed so that the valves could be blasted with some sort of snorkel/scuba device that fired and sucked back walnut shells through the head ports. Check out these posts over at the E90 forums. I'll probably get flamed over there for my comment. http://www.e90post.c...ad.php?t=521296 What the heck? Is is solely because the direct injection does not spray the back of the valves? On second thought, this problem existed for BMW before DI. When I ask technical questions on the BMW forums, the threads, no matter what topic, always turn into a discussion about how much wheel gap my 3 series has.

"Laser-based spark plug (Takunori Taira) Two or three lasers are focused to ignite fuel in more than one place" This is the key to the whole laser thing. You are no longer restricted to a single ignition point, in a fixed location by design.

Would love to see a photo of how the PO wired the starter if he modified it from factory. Did you consider that your flywheel might be missing a tooth or a few? Remove the starter and look at the teeth on the flywheel. It would be strange, but not impossible.

I got the parts today. Everything looks good but I am not sure about the ITM head gasket. Does anyone have any experience with them? The cork pan and valve cover gasket will be tossed, or saved for future spares. Thanks for the advice on that. I hate oil leaks. I don't have a press so I will ask the shop to separate the old pistons. As far as assembling the new wrist pins and pistons to the rods, should I attempt the oven heating of the rods (400deg) and freezing of the pins, for a hand assembly, or do you think I should pay the machine shop to do it? I didn't ask for a quote on that yet. Realistically, how hard is it to get right, or should I say, how much working time do I get when sliding in the pins? I read where TonyD also used Teflon pin buttons, even with the pressed in pins, which is nice peace of mind, but I don't think I'll need that for my relatively tame engine.

I have those on my 76. The original metal ones. What's the deal with them? Were they dealer or factory options? They seem to get loose at the ball-socket. I rigged mine up to be tighter but I am always afraid the head is going to fall off!

Yes, 50 series will fit the car much better. Wheels look nice.

The track is beautiful. Especially in the Fall. They resurfaced the entire track a little over a year ago and it is so smooth. It was like driving on clouds.

Yup, I will check the pistons and logbook all the measurements.

I am not sure how the broken skirts came about. There is an odd chance that they broke when we restarted the motor, to get it off the truck, up my driveway, and into my garage. The jumper box got wrapped in the throttle linkage causing it to stick. She bounced off the rev limiter for a second or two, in a dead cold state, before I killed the ignition. We will never know for sure. The phone camera accentuated the crosshatch by about 10x. See a few posts up, to see what it looks like to the naked eye. It's possible someone took a hone to it before I owned the motor. The ID of the bores is inside factory spec. It's going to be bored 20 over next week anyhow.

..and piston # 6,5,4 #4 fire ring...note the flame path into the cooling jacket, lower right. However...look at the bores.

While I'm at it...lol. There is nothing else so true. Not even a torque-plate milled L block. I will ask the machine shop if they have a torque plate for the L if not, I'll keep you in the loop. Thanks for the generous offer!! I ordered the whole engine kit today from RPM Rons. I thought it was a good deal. http://www.rpmrons.com/Nissankits.html $535 for +0.020 ITM Pistons, wrist pins, all clevite bearings, chrome rings, full gasket set, turbo oil pump, and timing kit. I am cleaning up the E31 "A" cam and spray bar, to install in the P90A that was rebuilt last year. Should I bring the E31 rockers over with the E31 "A" cam? Both sets of rockers look good. All I need now is some job interviews to pan out so I can get ahead again.