MadMaxDallas

I don't understand how you say that, when you witnessed a l28 with sus put 190 to the wheels on a dyno. - Whoops, posted on my dads account this is from 78zstyle.

I have just experienced the same, see my gasket. I took the head in and had it checked. They said it was flat and ok. I used a feltpro gasket too. I feel it might have been lean too. I had put 441 injectors in and adjusted the afm to compensate but did not use a wide band sensor and display. I am going back to original injectors and settings till I get a wide band to get it set right. On a side note, I also found a bit of flashing in the water gallery, thought it was a leaf, that may have helped make 5&6 hotter. Since these are the problem areas anyways. Also noted this time I ordered a different feltpro gasket, the holes were different we will see if it any difference. Maybe somehow I got a na gasket before? Did not know there were any differences. But what I noted is the water pass through holes around 3&4 were blocked on the new gasket. Which would probably force the water further down towards 5&6 before returning.

UPDATE: I must be getting old, guess I freaked out when I saw the valve full open. Of course they are not like that in relationship to the pistons while running. Going to bed ... Ignore thread ..

Ok while taking care of my son's cars. I finally got a chance to work on mine. Knew I had a blown head gasket between 5 and 6. This is on my L28ET with P90 head I had redone and ported a bit awhile back. In the mean time doing some swapping I got a fresh built lower end with balanced crank, .050 over pistons but they were flat top. So I went and looked up the calculations and with a P90 head compression will be about 8.6 which is ok, even for turbo. But when I was breaking down my engine I noticed that the valves extend beyond the plane of the head surface. With flat top pistons it would be smacking the pistons hard! Now I want to know if anybody has ran flat top pistons with a P90 head, I guess a 1 MM (.050) gasket may give it some clearance but I want to know as a fact if this works from somebody who has ran flat top pistons with a P90. I guess the alternative is to sell this beautiful block, and go ahead and redo my block. But thought this combination with less than 10 psi boost would be a good combination.

You have a PM - 78zstyle.

Yes, you assumed correctly. When I say "Got my wideband to read correctly" I mean I got it to read correctly in megasquirt, I used the software that came with the LC-1 to modify the voltage readout per another user. Triggering RPM's through the coil. My MSQ is attached.. Obviously you know you have to change the file extension to .MSQ. megasquirt201204011313.txt

78zstyle - I am running 6 PSI. I got my wideband to read correctly now.. I had to mess with the LC 1 output. I can't really tell in that graph where it happened, but I can tell you that the problem started in the first couple minutes, then went away for a little.. then came back.

What do you recommend I do? The entire section would have to be replaced at minimum. I want to see if I can get some money out of it to repair it myself if possible.

My drivers side rear tired shredded itself.. destroyed the inside of the fender well.. and mangled my quarter panel pretty good.. What you cant see is about 3 inches of material that is folded up underneath.. Looking like the insurance wants to total it =\. Anyone have experience with the valuation of a totaled z? - Sorry didn't mean to post on my dad's account.

Yeah my tranny does that too, what I do now is put it in 5th and then reverse and it works every time.

You may already know but the ecu between rpm set points are a linearization for instance if you have 2000 and 2500 as set points and rpm is 2250 both set points effect calculation

We are at fat daddy's hope to meet up with cowtown z members tonight!

Boost is like a drug, little sample of 15 lb boost and your hooked. But is bad for engine health taken daily. LOL

Ummmm let's get that fixed lead foot. And a few hundred more miles out of this head gasket lol

Just got my 3 inch exhaust done by Lewisville mufflers (lorenzes) muffler shop in Lewisville Texas. 337 out the door with a magnaflow muffler...cool guys and did a great job..I would recommend them. - 78zstyle

Car on right is 81 zxt Non the less your engine is looking nice.

Today found bad injector connector. Truly running like a sewing machine. Will take a little road trip from Dallas to lost wages on Wednesday and looking forward to giving it to my son to fix this beauty up!

Looked around a bit, but i can not find a table for the 02 sensor (stock) I see that the wide band sensors should be around .5v would that be the same with the single wire sensor? I still have one miss to chase out but no more smoke etc. Seeing around .8 volts during idle and of course going up and down when I rev the engine.

Thanks everybody for the starting pointers. I ended up wiring the temp sensor over to the cyl head temp sensor, and ran much better, cleaning a few connections and doing a regular tuneup will finish it out to running like it should. I do want to get a better fine tune on the fuel. I have not done it yet but was thinking since the 82 engine had a o2 sensor, of using that with a ohm meter to see if I can get it fined tuned at the afm. I will do a search on that. If not will have to take it to a shop with a c/o tester to get that done. Found a few other threads out there that helped a bit too. Especially on things like the resistance value charts etc in case somebody has these sort of problems in the future. Here are a few links to similar problems. http://www.classiczcars.com/forums/showthread.php?43173-Running-rough-then-stalls and this one http://www.classiczcars.com/forums/showthread.php?42574-MPG-timing-fuel-and/page4&highlight=mileage Thanks again guys. Even after building 4 engines now, these little beasts can trick you.

So that's what that extra sensor in the thermostat housing is. Yes we did use the housing and sensors from the 79 in it. I will have to check the sensor to make sure its working correctly, and that makes sense now. The body came from my business partners son. To make a long story short, he got it from his father, it has only 74,000 miles on it. The interior is extremely nice, due to how they had stored it. He had taken the head off, and was going to rebuild it. But ended up finding a 74 which he liked more. That is why we didn't put the 79 head on the 82 block. He decided to do a v8 conversion on the 74. So we bought the car, and about 4 engines and tons of pieces, including mega squirt, 6 turbos including a brand new Garrett t3/t4, custom down pipes etc. for 1K. My son needed a car running in a short time, so we threw in new bearings, pistons, timing chain etc over a few days and stuffed it in the body for him to drive to a new job where he got transferred. So back to this car, after getting it fired up, it was running a bit rough and we found out in a short time the gas was bad. We drained the tank through the fuel pump and put new gas in. It was still a bit dirty and we pumped it out again. Put in new gas and it was running pretty good. I took it for a drive and it was running well, hitting on all 6 strong. Drove it around a few blocks expecting to seat the rings etc. So drove a bit further. Put in 20$ in gas and went and got it inspected, it passed. On way home, went around a corner and it started sputtering. Thought that was weird but started again, and got it home. That night when son got home started it up, ran a bit rough when cold (later found cold start injector was not working) but still started, and when warmed up ran pretty good. Then I took it for a bit longer drive, and it seemed to be using a lot of gas. Ran great and was going to take it on the highway. Before I got there, it started running rough and decided to head to the house. Didn't make it there. Even when cooled off. Next day, we discovered we were not pumping any gas, and found gas tank had a cracked seam. (So gas was going out it) So we took the tank from the 82 donor car that had been running great before son spun a bearing in, and the fuel pump, and put it in the 79. Then I thought the injectors might be fouled from all the trash, and pulled the whole fuel rail and injectors from the 79 and put them in the intake. Now he had to make his trip and I had to clean up my garage. I have been thinking about all this and doing other chores around the house. As my son says, compression is good, it has ran great at least for a hour, so I am thinking sensors or still trash somewhere in the lines. I will get a pressure gauge and put on the fuel rail. Then test all sensor back to the ECU, if that all looks good, and if I don't find anything, then it must be something with distributor even though spark looks good and timing is right. Remembering this has ran pretty good other than running rich. Enough rambling need more coffee and thoughts.

Actually after reviewing the schematics, there is no CHTS in the 79. Could it be possible they are using the water temp? (I am his dad working on it). As far as dished pistons. Injection volume is based off of the MAF sensor. Since their dished the compression is lower, but the actual air volume is higher. So With some tweaking of the AFM this can be adjusted out. I have a 81 turbo, and put in larger injectors and was able to adjust it down to what it needed to be by adjusting the AFM. In addition, the engine that came out of the 79 which was the original had dished pistons..

Few months ago, I polished and ported my head myself, not to the beautiful head you did but none the less I did the best I could for a first time. I had the seats touched up by a head shop as I did nick one. I can feel the difference, it does "breath better" and now that I have done it one time, I want to do more, bigger exhaust valve, more material removed etc. Now for my question, while I was at the head shop, I was looking at the "vortex" heads, and wondered if leaving some meat up along the valve stem and spiraling down one side to the bowl would make a nice vortex to support the exhaust flow out the runner, but still support the valve stem better. Or is there really still enough valve stem support without doing this and just clearing down to the bowl on the back side of the valve stem like most seem to do it? Attached is my garage head work.

How did you flush up the bumpers? Is just the side skirt off and moved back? How much of a difference with the vacuum advance, been thinking about switching my 81 from the mag pickup to a vacuum advance, did you have to change anything else?

I have the exact same car. What paint manufacture was it, do you have the numbers for the paint too?? How close of a exact match was it? I am currently in the process of swapping the automatic with my other z's 5 speed. Expect to have that done this month.