cgmeredithjr

Tony, thanks for the guidance. I have decided to go ahead and rape the ZX and most likely install the motor mated to some type of 5-speed in my zero rust 1976 280Z...SLEEPER Cleve

You are correct, dropped it off today at the machinist and preliminary diagnosis is that it was not installed properly. Having the entire head gone through...obviously. I'm going to pull the bottom end and go through it also (#5 rod bearing probably took a beating) and then will start playing again. Cleve

Here are some pics from when I initially took off the head to fix some leaks a while back. Cleve

Maybe the valve bent and then when it returned to the seat it caused the seat to become dislodged due to uneven strike? Cleve

Pulled the head before all of these shenanigans to fix some leaks and everything "looked" normal...not sure if you can tell when a valve seat is going to let loose. Cleve

Good points, here is what I found so far, valve seat for lunch anyone?

Is Jeff P running an automatic? I don't think a PT76GTS with a .96 turbine housing flowing into a 4" downpipe and exhaust is stonewalled. On the intake side, open compressor inlet for testing, 3" plumbing from compressor discharge to intercooler inlet and then 3.5" plumbing from intercooler outlet to 90mm TB...maybe I have a banana in my tailpipe? No matter what the boost, the dyno plot flatlines around the same RPM. Cleve

If a motor ramps up fast enough with no resistance (the tires lose traction)it can easily go into a mechanical over rev. When the tires broke loose out on the road, the motor accelerated from 6000RPM to 8000+RPM in a millisecond. The limiter is there to of course assist in preventing this scenario but it cannot always catch it in time...do you believe that a modern stability management system can save you from an imminent crash? Microtech is set up to cut fuel. I'll know more when I pull the head and have it inspected, maybe it needs better springs and valve train set up, I did not build it remember. Yes, they can and will bend valves if over revved, I did not say that they bend valves just for the hell of it. Cleve

Hoover, did you look at the dyno sheet I posted, it's a pretty darn flat line. Don't be fooled? All the big HP cars that I have owned have been turbocharged except for one built N/A C6 Z06...I understand your point, but I am not a newbie in this arena. Cleve

Tony, the point is that I believe this motor is making more than the Dyno Dynamics is reading, how, I don't know, but what is that flat line on the graph...is it the TH400 slipping? Everyone at Forged thought this thing was making MUCH more than the reading based on what they were seeing and hearing (not scientific I know). I know what a 518AWHP car, 565RWHP car, and a 637RWHP car feel like, I have owned them all...this car hits harder and pulls harder than all of them. Automatics can be difficult to get a good reading, so they say. On the road, the car accelerates hard from 5500 to 7500 or so, yet on the Dyno Dynamics it flat lines starting at 6000RPM (this is right where it is starting to pull the hardest on the road). I was on my way over to the DynoJet for a comparison when I bent the valve or valves. Any ideas? I think the readings would be much different with a manual behind this motor. Cleve

LOL, sorry, I just assumed from some of your previous "holier than thou" posts that you were implying something else. Anyone who has raced with these motors (road racing) knows that it is very easy to bend valves when there is an over rev situation (usually missed shift). The motor ramped up so fast at 36PSI that I was caught unaware and the rev limiter was unable to stop the zing. I apologize, Cleve

No, he was implying that I was just guessing that it had a bent valve. He admits that he is a prick, I find the banter quite fun. Cleve

First I did a quick compression test and determined that #5 had ZERO compression which meant either the piston went bye bye or a valve must be stuck open. I determined that I bent a valve by removing the valve cover and observing that the #5 intake valve lash pad was missing and the #5 valve spring was compressed with no pressure from the corresponding rocker arm...valve was bent in the open position and could not return to closed position...I do know a little bit about engines Were you trying as usual to be a prick with this question? Cleve

Unfortunately, I bent the valve after the dyno session...would be a good excuse though. I had done a compression test when I first took delivery of the car and it was 125-130 across the board, but who knows, maybe as the testing was progressing, the valvetrain took a beating. I'll have the head off in a day or 2. Cleve

Come on Hoover, I thought you had built some Z cars in the past. It's copper head gasket sealant which you spray on both sides of the multi-layered steel head gasket to get a good seal...you really did not know this? Cleve

No boost leak, sampling at the intake manifold. Cleve

Tony, Did you bother to read the rest of the post? Cleve

36PSI (which is ridiculous I know)...I have had a LOT of BIG HP cars and this thing is making a lot more than this dyno sheet implies. I have never had a TH400 car and that must have something to do with this graph flat lining like it is. As soon as this pull was done yesterday afternoon I got in the car and was on my way over to DynoLab so that we could get some comparison numbers on a DynoJet. Well, being the NUMBNUTS that I am, I had to have a taste of 36PSI on the street on the way over there and let her rip in 1st at about 35-40MPH...well when it hit, it hit hard and immediately roasted the ET Streets and banged the rev limiter (probably went a good bit past it) and I managed to bend at least one intake valve (#5) and probably a few more (threw the lash pad on 5). I'll be pulling the head this week and will keep everyone updated. This engine is going to be nasty with a proper manual attached to it. "I like fast cars and faster women, that's why they call me the cruiser" Cleve 280ZX Turbo Dyno 509RWHP1019100001.pdf

509RWHP Dyno Video. It's not breaking up, the cell phone speaker is overwhelmed with the amount of noise this POS makes! http://www.youtube.com/watch?v=gPmlvX8YQhs

Look closely Tony, the wheel wells have already been clearanced, no tire cutting issue, thanks for your concern. Working through some tuning issues with the engine, made 509RWHP today on the Dyno Dynamics, I'll post the graph tomorrow. Cleve

Lots of squat, but this POS rust bucket actually tracks STRAIGHT down the road under load (only 435RWHP of load so far )

The amount of ignorance on this board is simply amazing. I'm not the guy that built this car or originally posted absurd claims about the power it supposedly made (798 at the wheels)...I'm the one with the balls to purchase it and test it. Everyone here is watching the testing process as it unfolds, what else do some of you dbags want? Get off your soap boxes, you are taking this whole car thing a little too seriously. I specifically bought it for the engine package (add up all those parts and tell me what you come up with) and if I do not sell it, I will drop it in a road racing chassis and mate it to a 5-Speed race box and will have fun with it at Road Atlanta...I'm not a drag racer. The fact that it has made 435RWHP so far on no tuning and low RPM should show some potential. Cleve

Speaking of fail, I just watched your dyno pull video...408 on a VG30DET with a 35R all the way to 7000RPM, pretty lame if you ask me. Cleve

Ignorance is bliss isn't it? How exactly did this thread fail? The point was to see if anyone could guess the HP just by visual and sound...several posters thought it made a lot more than it actually did...which was the point. Microtech adaptor came in so it will hopefully be back on the dyno at Forged next week. Dyno Queen?...nope, just a fast POS. Cleve