Chris, can you leave the thermostat out? Will the EFI work properly without it? Also, What type of temp gauge do you have and where is it plumbed into the engine. If electric, check the sending unit & and the gauge it self.
Didn't say what heads, manifold, and EFI unit you have.
When it [& you] have cooled off a little , try opening the cap to see if you have circulation . I'm not up on changes to the "newer" small blocks but I've heard about reverse rotation water pumps & different heads & manifolds ????
dave
The only other that I can think of at the moment is severely retarded timing that makes an engine run hot...
I was thinking of leaving the thermostat out. I am now getting good flow out of the bottom of the block. Checked both sides. Not sure if the efi will like if the t-stat is out. The temp gauge and sending unit are VDO. Goes into the pas. side head. The efi is Fast. It has its own temp sensor in the Manifold. Manifold is Jegs. Nothing special. idle-5500 rpm range. Heads I'm not sure who makes them. They are vortec heads. Bought them new online. They are cast.
Everything worked with the old heads. After it cools again I'm going to remove the plug from the head on the drivers side. see if I get any fluid out of the head.
Checked the timing. good fires right up. Idles smooth. I noticed that with the efi it's not running super super rich like it did with my holley carb.
It's running better then it ever has. Other then the over heating problem.
hmm. Don't think it's running lean.
Let me see what the efi says. The efi has 8 injectors. Didn't think lean would be an issue.
Head has fluid.
Been squeezing the hoses, getting air bubbles, and adding fluid each time it goes down for 15min now.
Have it topped off right now. Need to go to the store will check if it went down when I get home.
Having the temp sender in the head can sometimes indicate hotter temps than in the intake manifold. If the mixture is lean or the timing is retarded the exhaust temp will go up, which will in turn heat the head up in the exhaust area; close to where the temp sender is.
You said the EFI sender is in the manifold. Does the EFI controller allow you to see the temp it is seeing? I would think that it does. If so see if the two readings are close. If you can't see that info, then an infrared thermometer aimed near the thermostat housing should give you a good reading.
Also, having 8 injectors doesn't mean the engine isn't running lean. Fuel pressure and injector pulse width/air flow determines mixture.
Having the temp sender in the head can sometimes indicate hotter temps than in the intake manifold. If the mixture is lean or the timing is retarded the exhaust temp will go up, which will in turn heat the head up in the exhaust area; close to where the temp sender is.
You said the EFI sender is in the manifold. Does the EFI controller allow you to see the temp it is seeing? I would think that it does. If so see if the two readings are close. If you can't see that info, then an infrared thermometer aimed near the thermostat housing should give you a good reading.
Also, having 8 injectors doesn't mean the engine isn't running lean. Fuel pressure and injector pulse width/air flow determines mixture.
The temp on the efi is way lower then the head temp.
The efi turns the fan on when it hits the right temp.
Can't be any more air in that coolant system. Not getting anymore air bubbles and it is topped off.
I just tryed again, starting and stopping the car to let the efi temp catch up. When it got to 185, the t-stat still didn't open.
With my holley carb I had the timing at 12 deg.. That's where it is now. Maybe I should change that down to 8.
OK, you can do this....pull your thermostat out. The Spring, which is the heat sensing element should be toward the motor, with the cone and support pin toward the radiator. If it was in correctly, that was not your problem.
If that is right on the money, take your themostat completely out, put the housing back on. Now, start it up. Is it still running hot? Now think about this a moment, how fast is it getting hot? Within 3 minutes or 5 minutes?
If your thermostat removal still has it running hot, its one of 3 things,
1. The timing is off, but you didn't say you moved the distr.
2. The EFI is leaning out the mixture for some reason and/ or is jacking with the timing to comphensate.
3. Your waterflow is blocked or impeded somewhere, either the head gasket install is wrong, blockage in the heads or block.
This is all part of hotrodding....don't let it rattle ya. Are they the right heads?
Just take your time....and double check all the stuff the guys told you to check. No stuffed rags in the water ports while you cleaned the block off with your scraper?
Knew a guy that put paper towels into the water ports on a big inch Brodeck, pulled the heads between rounds.
Experienced builder too....it can happen to any of us....
Don't let it rattle ya....how much more compression do these heads you have on now have? Just a little? The lower you set your timing, the harder the motor will work to stay running as you back the timing back toward 0, the more advance you give it, to a point, will make it easier. At 8 you should be OK as long as the EFI isn't fighting you. Might have to put it in learning mode. and bump your timing back, maybe increase your dwell (shot size slightly)....
If the EFI temp is lower than your gauge reading I would say your heating problem may not be as bad as you think. The EFI is seeing the water return to the radiator and IMO a better indicator of actual engine temp. The old sender location may not work well with the new heads. I would move the temp sender to the manifold before I chased this problem any further.
Didn't feel like removing the t-stat tonight. I did adjust the timing down to 8. Redid the setup on the efi. Now the car won't run.
The fast efi hand held gets a comm error and the engine turns off, and the hand held reboots.
I play with it tomorrow. Maybe the fix will come to me in my dreams. lol.
When you changed heads, you also had to pull the intake manifold which also means you pulled the distributor. I bet when re-installing the distributor you missed the mark by one or more teeth or possibly 180 degrees, and it will run 180 out but not very good. I would recheck the whole timing issue by checking the valve position on #1 when the the timing marks are lined up - I am assuming the timing gears and chain have not been touched. The distributor rotor should be pointed to #1.
My guess is you are off by about one tooth retarded - the engine should run fine at 8 degrees - but it sounds like when you are set at 8 degrees for spark the valve train is at before zero and your EFI is saying ( I quit ). This also can make an engine run hot.
I haven't even messed with it yet today. I slept in.
On my way out to get more fuel for the car, food, and drink for me. Then I'll start racking my brain.
Hotrod46: I can feel the heads are way hotter then the manifold and when it gets around 200 on that temp gauge I see the headers starting to change colors. I know its way hotter then it should be.
Be very careful there....if your headers are turning on you and you can feel the diff. in the heat from the heads, don't let it run too long like that. Big danger sign.
When I said this....
1. The timing is off, but you didn't say you moved the distr.
2. The EFI is leaning out the mixture for some reason and/ or is jacking with the timing to comphensate.
There is usually a start up procedure for each EFI system. I figured once you got it started you got it roughed in and put a timing light on it since you said you were at 12. That should have been fine.
Double check all your grounds on your EFI, all your connectors and make sure it is all plugged up correctly, all the sensors are put into the right holes, where they are supposed to be.
Is the motor running smooth or is it missing/backfiring, running rough as hell? Is everything OK EXCEPT for the temp?
One other thing, while the motor is running this time, look at your exhaust exiting your pipes. Is it smoking any? If so, what color?
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