1998 3.4 engine sheared cam gear bolt
04-13-2017, 10:44 AM
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1998 3.4 engine sheared cam gear bolt
1998 4Runner 3.4 engine 2wd. I am buying a 98 4runner in good shape except the engine has some problems. Not sure what is causing this but the timing gear on the cam has sheared the bolt holding it on. My neighbor replaced the bolt and it ran good, for a while, but he said he could hear the engine chirping when they fired it up. He drove it around for a while and it quit again. He hasn't gone back in it to see what is wrong again. That is where I come in, I am buying it cheap enough that if I have to replace the engine I still won't be hurt. Any suggestions what may be the problem.
04-13-2017, 01:54 PM
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He did find the rest of the pin and bolt head, I guess I will just have to wait until I can get into the cams to see what is going on. I appreciate your response.
There is an older thread here but they got off topic and never addressed the end results, when I find out what is wrong, I will post what it is.
There is an older thread here but they got off topic and never addressed the end results, when I find out what is wrong, I will post what it is.
Last edited by jiju1943; 04-13-2017 at 01:56 PM.
04-21-2017, 08:25 PM
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Well so much for the cam problem, I have other problems also. I have a blown head gasket on the opposite side of the engine which has nothing to do with the cam gear bolt and pin shearing. I would guess the gear bolt wasn't torqued correctly which caused the pin to shear and over tighten the bolt which popped the bolt head off.
Now to my other dilemma, I have the engine torn down to the short block now. I noticed all of the cylinders still have the hone cross thatches still visible, not like when fresh honed but still there. The pistons are stock as there are no over size stamp on them.
The heads are in need of resurfacing as I think that is the reason the gasket blew. Another reason I think the head is warped is the the rear head bolt (allen head bolt) is broken off even with the block. I think someone didn't know that bolt was there and pryed on the head hard enough to break the bolt off even with the block.
I am at the point now wondering if I should do a rebuild or check the main and rod bearing clearance to see if they are worn too much If they are within specs, replace the heads and cams, go back with a new timing belt and all that goes with it. The head cam journals aren't that bad, no discoloration at all, so not over heated. Maybe I can find a place to regrind the cams or just buy another set.
Any suggestions?
Now to my other dilemma, I have the engine torn down to the short block now. I noticed all of the cylinders still have the hone cross thatches still visible, not like when fresh honed but still there. The pistons are stock as there are no over size stamp on them.
The heads are in need of resurfacing as I think that is the reason the gasket blew. Another reason I think the head is warped is the the rear head bolt (allen head bolt) is broken off even with the block. I think someone didn't know that bolt was there and pryed on the head hard enough to break the bolt off even with the block.
I am at the point now wondering if I should do a rebuild or check the main and rod bearing clearance to see if they are worn too much If they are within specs, replace the heads and cams, go back with a new timing belt and all that goes with it. The head cam journals aren't that bad, no discoloration at all, so not over heated. Maybe I can find a place to regrind the cams or just buy another set.
Any suggestions?
