Intake Valves Clearance Adjustment question

donkey · 09-11-2009, 09:06 PM

Reposting cause this question was buried in an old thread:

I just brought my 1990 NA into a shop for a leaky valve cover gasket replacement and valve clearance adjustment. After measuring the clearance, the mechanic found 3 intake valves out of adjustment (two on one cylinder). All were too tight, and the worst was 1/2 the minimum spec. He says these intake valves are always out of adjustment b/c of carbon deposits built up under the valve. He says the only way to solve it is to try fuel injector cleaner (Redline) or remove the head. Is he right? Is the whole Toyota recommended shim measurement and replacement procedure to adjust intake valve clearances just a crock of shit when it comes to these engines (7M-GE)? I've been running my car on E85 (with modified injector pulses to richen the mixture) for the last 6000 miles, so I find it hard to believe I would have carbon deposits under my valves. The head has 136000 miles on it, and the short block about 36000.
thanks in advance.

mikeoc1 · 09-14-2009, 02:45 AM

Just fix the clearance with new shims and not worry about what the mechanic says. I just did my valve clearances last week. I had 18 of them totally out of whack. Easily fixed by following the toyota method in the service manual. Made a huge difference in how my supra ran. Nice and quiet now and running well. Some of mine had no clearance some were over a mm to much. your mechanic probably just doesnt want to bother with doing the calculations and such and order the new shims. A little time consuming but neccesary.

09-11-2009, 09:06 PM	#1
donkey Stock Join Date: Sep 2009 Location: Berkeley, CA Posts: 2	Intake Valves Clearance Adjustment question Reposting cause this question was buried in an old thread: I just brought my 1990 NA into a shop for a leaky valve cover gasket replacement and valve clearance adjustment. After measuring the clearance, the mechanic found 3 intake valves out of adjustment (two on one cylinder). All were too tight, and the worst was 1/2 the minimum spec. He says these intake valves are always out of adjustment b/c of carbon deposits built up under the valve. He says the only way to solve it is to try fuel injector cleaner (Redline) or remove the head. Is he right? Is the whole Toyota recommended shim measurement and replacement procedure to adjust intake valve clearances just a crock of shit when it comes to these engines (7M-GE)? I've been running my car on E85 (with modified injector pulses to richen the mixture) for the last 6000 miles, so I find it hard to believe I would have carbon deposits under my valves. The head has 136000 miles on it, and the short block about 36000. thanks in advance. __________________ 1990 Toyota Supra, NA, 7MGE, Automatic

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09-14-2009, 02:45 AM	#2
mikeoc1 Stock Join Date: Jun 2009 Location: tn Posts: 20	Just fix the clearance with new shims and not worry about what the mechanic says. I just did my valve clearances last week. I had 18 of them totally out of whack. Easily fixed by following the toyota method in the service manual. Made a huge difference in how my supra ran. Nice and quiet now and running well. Some of mine had no clearance some were over a mm to much. your mechanic probably just doesnt want to bother with doing the calculations and such and order the new shims. A little time consuming but neccesary.