94 4Runner 3.0 head gasket repair
#1
94 4Runner 3.0 head gasket repair
Finally getting around to repairing blown head gasket in 3.0 VZE. It was done by the previous owner, and it appears that I’m gonna get to do it again! Got the heads off, and much like everyone said it would, gasket had failed at number six cylinder by crossover pipe. The disassembly went fairly smoothly, however I should make it clear that I am a pipe welder, not an auto mechanic. I have a couple of questions, and any guidance would be greatly appreciated. First, I didn’t realize that the buckets, or caps, under the camshafts had different thicknesses.Therefore, I did not denote position when they came off. I’m assuming this doesn’t matter, as I will have to check valve clearance on reassembly anyway? Also, I broke some sort of fitting at the back of the plenum upon removal. I have no idea what It is, or where the vacuum line reattach.
I found one of the hoses with broken nipple under the truck. I have no idea where the other one is.
Last question……I was going to replace knock sensor and wire while I had access to it. Dang… pretty expensive. Will I be sorry if I don’t replace?
I found one of the hoses with broken nipple under the truck. I have no idea where the other one is.
Last question……I was going to replace knock sensor and wire while I had access to it. Dang… pretty expensive. Will I be sorry if I don’t replace?
#2
Registered User
iTrader: (1)
First you should make sure the Head or heads are not cracked
Clean and clean some more before putting things back together
You should be able to find a valve Shim kit pretty easy. Most times one puts all the parts from one valve in a separate container and notes the location
You have a job ahead of you. Kinda like doing 20"' pipe with no helper in 120 degree temperature with your umbrella no where to be found
Clean and clean some more before putting things back together
You should be able to find a valve Shim kit pretty easy. Most times one puts all the parts from one valve in a separate container and notes the location
You have a job ahead of you. Kinda like doing 20"' pipe with no helper in 120 degree temperature with your umbrella no where to be found
#4
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The broken part is the TVV (Thermal Vacuum Valve) or BMSV (Bi-Metal Switching Valve). https://parts.lakelandtoyota.com/p/T...092505047.html They are often broken at your vintage; they live in a hellish environment and the plastic is doing pretty well to last 15 years. There are several on this forum who have successfully repaired them, but for the money, I went with a new replacement. They connect the Evap Canister to throttle body; when the engine is warm the throttle body sucks the stored fuel vapors out of the evap canister. Yes, you want to fix that.
Yeah, the metal shims you mixed up set the valve clearance. I assume you're getting the valves ground, in which case you do need to re-do the timing shims. Personally, I've never been able to find an entire valve shim kit (when adjusting valves, I'm very careful to compute whether I can swap shims to meet spec on some valves, reducing the number of shims I need to buy). But your machine shop may have access to them, and they can do the valve adjustment for you. Even if it's an extra cost item, it is probably worth it.
Yeah, the metal shims you mixed up set the valve clearance. I assume you're getting the valves ground, in which case you do need to re-do the timing shims. Personally, I've never been able to find an entire valve shim kit (when adjusting valves, I'm very careful to compute whether I can swap shims to meet spec on some valves, reducing the number of shims I need to buy). But your machine shop may have access to them, and they can do the valve adjustment for you. Even if it's an extra cost item, it is probably worth it.
#5
YT Community Team
Replacing the knock sensor and wire would be a good idea at this point. Taking everything apart a second time isn’t fun.
That vacuum valve looks like it has been broken for awhile. The breaks don’t appear fresh
That vacuum valve looks like it has been broken for awhile. The breaks don’t appear fresh
#6
Thanks to everyone for getting back to me. I really appreciate the information. I’m annoyed with myself for not labeling the valve caps upon disassembly…I just didn’t know. I’m assuming there’s some sort of specialty tool that allows the valve to be depressed so that the shims can be changed out? Also, I seem to remember reading that intake valve clearances are .007-.011 and exhaust clearance is .009-.013? Is this correct? Thanks in advance to anyone who takes the time to help a welder navigate an engine.
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old87yota (08-18-2021)
#7
YT Community Team
Odds are the shims were too thick/thin at their respective buckets, so no harm. Here’s your chance to dial it in.
It’s a special tool, but readily available. and fairly priced.
It’s a special tool, but readily available. and fairly priced.
Last edited by Jimkola; 08-17-2021 at 06:59 PM.
The following users liked this post:
old87yota (08-18-2021)
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