86 4 Runner timing chain bent valves?
08-21-2016, 03:03 PM
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86 4 Runner timing chain bent valves?
Was driving down Highway at 60 mph and all of a sudden lost power and I heard loud clanking knocking noise and pulled over immediately and engine stalled. I told the truck home and when I try cranking it it will start when I give it gas and loud knocking is coming from the top back of the engine. When I took the valve cover off I do have a broken timing chain guide and timing chain is extremely loose. Is it possible I jumped the link and when that happens do the valves hit the cylinders and bend? I'm wondering if that is possible and the engine would still run if I give it gas or is it something else? Also before this happened the truck was running good and quiet no ticking. Here is a video
08-21-2016, 03:19 PM
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Yes it's an interference engine
Gonna have to pull head and timing cover and check out extent of damage don't keep starting it or it will get worse
whether it jumped a link or not all the slack will throw off cam timing and that can really mess stuff up
good luck!
heres what happened to mine...
https://www.yotatech.com/forums/f116...arnage-296318/
Gonna have to pull head and timing cover and check out extent of damage don't keep starting it or it will get worse
whether it jumped a link or not all the slack will throw off cam timing and that can really mess stuff up
good luck!
heres what happened to mine...
https://www.yotatech.com/forums/f116...arnage-296318/
Last edited by 4RunnerFreak12; 08-21-2016 at 03:21 PM.
08-21-2016, 03:31 PM
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Thanks for the quick response. Yes I've only tried to start it twice since I brought it home. Wants to diagnose what was happening and wants to make the video so I don't have to start it anymore to show people. I guess what I'm asking also is this a problem that would happen all of a sudden or does it start and then get worse because there were no problems prior
08-21-2016, 03:38 PM
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It kinda depends. The drivers side guide breaks (very common since its plastic) but can usually still be ran for sometime which causes chain to eat thro timing cover into a coolant passage which than causes coolant to get into the oil
In your case seems like maybe the chain tensioner may have failed also so allowed it to either jump a tooth or throw the cam timing off enough to let the valves hit the piston
same thing happened to another member that posted in that "Epic fails" thread only it didn't cause valve damage just started to melt a piston
when you fix it I highly recommend ENGNBLDR he has replacement heads and more importantly a HD timing set that features a steel drivers side guide rail and an OSK (OEM) tensioner.
In your case seems like maybe the chain tensioner may have failed also so allowed it to either jump a tooth or throw the cam timing off enough to let the valves hit the piston
same thing happened to another member that posted in that "Epic fails" thread only it didn't cause valve damage just started to melt a piston
when you fix it I highly recommend ENGNBLDR he has replacement heads and more importantly a HD timing set that features a steel drivers side guide rail and an OSK (OEM) tensioner.
Last edited by 4RunnerFreak12; 08-21-2016 at 03:43 PM.
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