I replaced BHG on 1990 Supra 7mge/na. I used a felpro gasket. I initially could not get the car to start after the replacement. But I put a new MAF on her and FINALLY got the timing right and she started but is STILL overheating. Im very frustrated. Should I have used a MHG and also the shop shaved 20 thousands off the head (which I think is alot) but they also sold me a metal 20 thousands of an inch metal shim to get it "right" again. I did the work about 6 months ago but just got her running today but overheating. I hope I didnt put the shim between the gasket and the head instead of between the block and the gasket. I know thats dumb but it was awhile ago. If I did would that screw things up and cause it to continue leaking?? I used ARP bolts and torqued to 90 ft pounds ( is that TOO tight). IM going to check the thermostat, water pump, and the radiator looks kinda ugly and old but I gotta BAD FEELING!! Any thoughts or input would be appreciated. TKS....(first headgasket job Ive ever done)!!!
1990 7mge BHG Repair.
- Thread starter mark0206
- Start date
wtf a metal shim? yeah that's probably your problem.... should have just used a thicker gasket though if they needed to shave off so much i would have just picked up a new head.
Never heard of a metal shim on a 7M and I have no clue how that would supposedly seal...
Check through everything else, check for contamination in the oil or coolant, but i'd guess that shim may have caused a problem.
Check through everything else, check for contamination in the oil or coolant, but i'd guess that shim may have caused a problem.
IM not sure it what type of metal it was now (maybe aluminum) but it was shaped to fit on top of the block to make up for the difference in the shaved head. It was made exactly to fit this motor(7m). It wasnt specially made. They were available, so Im assuming they are used frequently if you have to have too much shaved off of the head. Although now Im wishing I just would have gotten a new head!
I have heard that these generally don't work too well. I think felpro makes a head shim for the 7m, but not positive.
My 7mge keeps overheating even after a new head gasket. The coolant backs up and into the reservoir and then out of the overflow and onto the ground. Water-pump..Radiator...thermostat all seem ok. HELP!!! At one time "snake oil" crap was put into the system to try to seal the head gasket. I wonder if this crap clogged the cooling system!!
I would say that shim would be ok to use if you have two head gaskets, one on gasket in between the head and the shim, and the other gasket between the shim, and the block. But If you did that, then you would have a much larger thickness.
In your case, I would have had the block taken in to be machined, if they did that much decking on the block. Or I would just have gotten a decent head that you could have had worked on with less material taken off.
But I would defiantly say that your problem is that your shim is causing it to overheat. I would say take it back apart, and see how straight your head is still, and if it is straight, then just throw a new HG on there and try it like that. On the other hand if you are trying for performance out of your car, and not just to get it running and drive it, I would get a new head, because if you use that head with that much material taken off it could play with your compression ratio, and you could detonate your engine and blow your HG again, if you put in too much boost.
In your case, I would have had the block taken in to be machined, if they did that much decking on the block. Or I would just have gotten a decent head that you could have had worked on with less material taken off.
But I would defiantly say that your problem is that your shim is causing it to overheat. I would say take it back apart, and see how straight your head is still, and if it is straight, then just throw a new HG on there and try it like that. On the other hand if you are trying for performance out of your car, and not just to get it running and drive it, I would get a new head, because if you use that head with that much material taken off it could play with your compression ratio, and you could detonate your engine and blow your HG again, if you put in too much boost.
Tks..I was wondering (after I take it back apart) if I could eliminate that damn shim altogether and use a thicker (maybe even metal) head gasket. Like a 2.0mm instead of a 1.4 thickness. Im not overly worried about horsepower or performance but I sick and tired of the over-heating issue. Does felpro or anybody make a "forgivable" thicker head gasket for the 7mge?? I thought about buying a used head with everything in tact but how would I know if it is out of spec or not. I dont want to invest a bunch more money to machine shop to clean yet another head. Hell at this point Im thinking of buying a 7mge rebuilt long block/engine. My compression right now is very low..like 95-100 psi in each cylinder because of the large gap (Im assuming) between the head and block!! So damn frustrated. Not sure what to do!! what do you think??
Well before taking everything apart why don't you just do a proper diagnostic on the cooling system. You can pick up an infrared thermometer from radio shack for like $20. Check across the radiator and see if it is passing coolant through it, if one side is hot and the other is not its not flowing. Also check the thermostat check temp before and after it to see if its passing coolant. I recently had a clogged radiator from the previous owner of my wifes supra, he put stop leak in it to try to fix the head gasket leak and only managed to clog the radiator.