I took the car out for a short ride last night, and boy was it fun!!! The soggy low end that the motor had when it was in the IROC is gone, and it it feels great right from idle right up to around 4500-5k. I didn't push it any higher than that yet, but it feels like it's breathing better up higher too, so I think the ported intake and runners were a success. There's no doubt that the motor is more powerful than it used to be, and I haven't even tuned it yet. I also found that once it's warmed up, you can really hear the lope to the cam. Once I bring the idle rpm down where it belongs (it's still up near 1k now), I think it's really going to sound great.

Now if I can just get my damned datalogging to work so I can actually tune it...

that's great to hear!

Did you discover why the first several chips weren't cooperating with the car?

No. I may not have built the 32k bin properly to fit it on a 27c256. Not sure why the EEPROM didn't work. I didn't spend much time troubleshooting.

I'm interested in seeing numbers on this also... I have a stock TPI intake sitting at my parents' that I'm thinking of using, both engines I'm running have Vortecs (carbed 350,in the '78 Malibu and TBI 383 in the '92 pickup).

I'm not sure when I'll have numbers. Spring at the earliest. In the meantime I still have to swap in the 10 bolt from the IROC, and get the !%#^( datalogging to work so I can tune the damned thing.

Just read this thing from start to finish.....took about 5hrs!lol

Looks like all your hard-work is paying off! I'm thinking about going l31 with the TPI as well.

Funny part is when I started reading the thing I thought for sure it was finished since this thread has been floating around for what seems like 4EVER, not to mention 7 pages! hahaha.

Any progress on the tuning?

No. The roads are salty here so I can't drive it anymore, and I haven't had time to troubleshoot the datalogging problems. Chances are I won't get back to it until spring either, because the car is about to get moved from the garage to the carport so I can move my next project in. I just bought a Grand Cherokee that needs a motor.

you need to quit putting things in front of that lsx swap sir

That Jeep is what's going to pay for the 9" rear for that project.

oh, carry on, lol

bringing this back from the dead. I've driven the car a couple times this spring, and once it warms up it seems to run pretty well. At midrange rpms when under load I've got some sort of noise that I haven't identified yet. My first reaction was that it was spark knock, but it certainly doesn't sound like the typical spark knock, plus if my knock sensor is working, the computer should prevent me from hearing anything. It runs poorly at startup, and I have to use my foot to hold it at 1200+ rpm to prevent stalling until it's warm. I need to try throwing new tunes at it to see if I can fix that issue.

I also installed a seat cover on the passenger seat so that I can stick my son's booster seat up front and my daughter's baby seat behind it and start driving it more!

Been following for a long time. Glad to hear you have the car out and are starting to enjoy it!

Log the car form dead cold, things to look at are, target afr, iac steps, timing and injector pw, look at the o2 readings, if your (can't remember it this car is maf or sd) maf tables set up correct (or VE table) then target AFR should be spot on, if not the something is set up wrong, like different injector with the wrong battery compensation setting in that table would need to be fixed first.

I really didn't read your entire thread so just giving you an idea where to look.

Problem is, the datalogging won't work, so I can't see anything.

Today I took the car for its first real ride (everything up to now has been up the street and back). When I pulled in for gas I noticed that it falls on its face when I blip the throttle instead of revving. It kept stalling when I let out the clutch. Coming home the temp crept up, then I could smell coolant. I pulled over and coolant was boiling out of the overflow. I let it sit for a while, then went up the hill toward home. Temp shot right up again so I pulled over and walked the rest of the way. I went back with a gallon of coolant and added it. It took the whole gallon and I still couldn't see it in the radiator. I nursed it the last mile home and parked it. My wife followed me and said she could "see" my exhaust, "like on a cold morning."

Sounds like I lost a head gasket.

That sucks, pressure test the system also check oil for water before you make a diagnosis, also what ecu do you use?

dang....

I checked the dipstick, and it seemed fine. The oil didn't smell funny and it looked fine too. Tomorrow I'm going to check a couple plugs, then start it up (after I fill the radiator) and look at the exhaust for myself. I'm crossing my fingers that I didn't scorch anything. I just can't understand how it overheated so bad. This tune shouldn't be any leaner than what I had in the IROC for years.

My needle never got into the red, but it looks like I boiled almost all of the water out of it.

Did you check your heads for the vortec crack before you installed them?

Yeah. The heads were SDPC vortecs with only a few miles on them when I got them.

Pre-update update: I forgot to mention when I first posted this that a couple weeks ago I pulled the thermostat and verified that it's functional, and pulled the water pump to verify that it was also functional. I put the car back together and filled it with coolant (this time with the t-stat housing off so I could visually verify that it was full) and started the car. There was clearly a small amount of white smoke in the exhaust. I drove the car and it never got above about 195. After leaving it parked in the carport for a while, I started it up and pulled it out, and there's clearly a coolant smell lingering in the carport. I definitely cracked a head or lost a head gasket.

Update:

I pulled 2 pair of 062s from a pick -n- pull junk yard in PA over the weekend. One set looks meh, the other set looks great. I'm going to take them apart and send them to the machine shop to get tanked & fluxed. After I determine how many good heads I have, I'll move forward with setting them up for higher lift. Hopefully both sets will be good so that I can sell a pair to offset my costs. Pics to follow.

I forgot, dis you set up an external coolant bypass for the vortecs?

That is only needed if you bypass the factory diverter setup and put a valve in the heater core.

Also forgot to mention, I had nearly the exact same sealing issue with an undecked 305 block using that style of shim headgasket. Went back with a rubber embossed steel shim and new head bolts, never had another issue.

I didn't use a coolant bypass because I have unrestricted flow through the heater core.

I didn't deck the block, but I did go over it with a file prior to installing the head gaskets, and prior to overheating the car, I didn't seem to have any headgasket related issues that I'm aware of.

Back when I was putting the heads on, the general consensus on nastyz28 was that I was better off with the thinner head gaskets in order to maintain optimum quench as opposed to thicker gaskets to lower the compression. I'm probably going to stick to that approach when I do it all again.

The felpro 1094 shim is not supposed to be used with lightweight heads.

Not sure if those are the shins you used. But I could not find a good shim gasket for late model heads.

I have in the past but avoid them now, after looking at felpros bulliten on them.

They make two different shim style gaskets. One is just plain steel but the other is covered in rubber. The rubber embossed shim is .016" thick. I have used them in several builds with both lightweight and 305 heads. Have not had a single issue with the rubber embossed shim. Use the older torque specs, not the newer. The newer stuff is torqued to lower values than the older engines.

The issue is the little beads that seal, they don't get fully covered by lightweight heads.

Felpro includes a little paper with a picture to show the issue.

No disrespect but there is NOTHING that will not seal on a Vortec head with a 1094 shim style gasket that is rubber coated. My issue was from the deck not being flat and the rubber coating sealed the small seap I was having. I was not getting water into the oil, rather exhaust gases into the cooling system, which would push coolant out of it at WOT.

No dissrespect taken.

I'm just going off what the package said with the 1094 gasket I ordered about a month ago said.

If felpro says not to use it, I'm not going to.

when did vortecs become "lightweight" heads?

They have a "scalloped" edge. The edge along the bottom of the head, thus making them lightweight heads.

All factory gm cast heads after sometime in the 1970's are this way.


http://craig.backfire.ca/pages/autos...htweight-heads

http://image.superchevy.com/f/107427...nder_heads.jpg

I drove the car again yesterday. Prior to the drive I checked the radiator and it was down 3-4". I topped it off, then drove about 5 miles to the local store. Ran fine. Didn't quite get all the way to the normal 190* range. When I came out of the store, it started hard (it took me 5-6 tries before I could keep it running), and kept wanting to stall when I let the clutch out. This was the same behavior it exhibited prior to the time it overheated. Driving home, temps stayed at around 190* until I decided to drop it to 3rd gear and floored it. I wound out 3rd, and some of 4th, then slowed back down. The temp started to go up... and up... and up. It peaked at around 250, then came down almost to 200, then back up, etc. I pulled into the yard and noticed a lot of steam coming out of the exhaust now, unlike the almost unnoticable amount previously.

I have another set (actually 2) of Vortecs that I'm going to have the machine shop go through, but before I put them on, I need to figure out if there's something wrong with my cooling system. One person suggested that the cracked head could cause me to overheat, but I don't buy that... unless it's literally consuming massive amounts of coolant, I don't see how a crack in the head can cause me to overheat. I think that I may have a problem with the radiator that just never came to light with the 305. What do you guys think?

Head gasket leak can most definitely cause an overheat situation. The leak isn't causing the heat really but if combustion gases are getting into the cooling system then it causes air pockets. If the pocket gets big enough it will keep the coolant from surrounding the thermostat, which doesn't allow it to get hot enough to open. It is basically the same as when filling a cooling system for the first time. It often gets air bound and the T-stat won't open.

You doing a pull through 3rd gear likely introduced a large amount of air into the system causing the T-stat to start to close.

if it was a bad radiator it would have still cooled back down to normal temps after the run through 3rd gear which it didn't.

It is obvious the gasket is blown. And if coolant can get into the combustion chamber you can bet combustion gases can get into the coolant.

Very likely to have a crack in the combustion chamber, I've had it and it acted just like yours.

Did you check the dipstick after running the car? Having a similar problem with my engine, I would check the dipstick prior to running the car and it looked normal. After I ran the car and checked it though, it looked all milky.

I was thinking along the lines of Lilski. I was having a similar problem with my engine once I finally got it running. Mine turned out to be a head gasket issue. I had air pockets in my system causing it to get real hot. Does your radiator get pressurized after only running it for a minute or two while it's still cold?

I don't know. I hadn't checked that.

Thanks for the info guys. I hadn't realized that the head gasket / head crack could cause an overheat condition.

Sounds like you cooked the head gasket when it overheated.
Check your lower rad hose to see if it collapses when you are under heavy throttle. Mine collapsed and I had to put in a coil/spring to prevent it.

how exactly would one check that?

Also, I sincerely hope that all I did was cook a head gasket, but I'm not counting on it. My plugs showed no signs of coolant on them (though I didn't re-check after the problem got worse), and since the vortecs are known to crack, I'm expecting the worst.

Pinch the hose with your hand to see if it has the spring/coil in it.

Start the car and rev it up when it is warm. Watch the hose as you rev it to see if it collapses. Should be able to tell right away.

and then?