Engine troubles
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Engine troubles
My camshaft timing gear completely shredded the other day. I tore the engine apart today, as i figured it's a good time for a minor rebuild. From what i understand, and I might be wrong here, is that if the cam spins independently of the crank, the valves can bend. Well, before I realized this was a timing gear issue, I thought that this was a fuel pump issue. As a result, the engine was turned over quite a few times. The crank and cam spun out of time with each other. What are my chances that my valves are bent? I really don't want to tear apart the head if at all possible. Also, what else should I knock out while the engine is torn apart? I'm already doing new gaskets, timing gears, front/rear main seal, and cleaning off some of those deposits on the cylinder walls. Keep in mind this is my daily driver and I dont have time or money for machine work such as a port and polish. Any help and guidance will be appreciated. Thanks.
This is a 300I6 out of a 75.
This is a 300I6 out of a 75.
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As far as I know, the 300 does not bend valves when the cam gear goes. Even with the valves fully open, the piston can reach TDC without hitting. You should be OK, but if you want to check to be sure, I suggest the following:
Pull the valve cover. First, look for bent push rods, bent rockers, or rocker studs pulled out. If all is OK, turn the camshaft around one full turn and make sure all of the valves go up and down the proper amount without any rocker arms getting loose and without any valves hanging open.
It is pretty common for the factory 300 cam gear to shred. Happens all the time. Never heard of anyone having valve damage (With stock cam and pistons, that is). However I have heard of a few cases of guys who replaced the timing gears and fired up the engine, only to have it loose oil pressure after a few minutes of running. Upon inspection, they found the oil pickup screen plugged with all of the shredded cam gear fibers. I would suggest that you pull the oil pan and clean all of the old cam gear out.
Pull the valve cover. First, look for bent push rods, bent rockers, or rocker studs pulled out. If all is OK, turn the camshaft around one full turn and make sure all of the valves go up and down the proper amount without any rocker arms getting loose and without any valves hanging open.
It is pretty common for the factory 300 cam gear to shred. Happens all the time. Never heard of anyone having valve damage (With stock cam and pistons, that is). However I have heard of a few cases of guys who replaced the timing gears and fired up the engine, only to have it loose oil pressure after a few minutes of running. Upon inspection, they found the oil pickup screen plugged with all of the shredded cam gear fibers. I would suggest that you pull the oil pan and clean all of the old cam gear out.
Last edited by f100jim; Mar 30, 2011 at 09:02 AM. Reason: clarification of one point
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Yeah, the engine is tore down to the block. I wanted to make sure I got all the pieces of the gear out. So you feel pretty confident that my valves are ok? U can't really tell anything with the head off.
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With the head off you can check the valves, you can look for marks on the tops of the pistons (if a piston hits a valve, it will not go away unscathed). You can tell everything with the head off. It is with the head still on that you have to look for other "tell tale" signs.
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That's not really an option unless it is absolutely necessary. This is my only vehicle, and I don't have the extra money/cash to do that. It would be nice though.
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Fleet Owner
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From: Blue Hill Township
Suit yourself but if I had a vehicle where I think there may have been P-T-V contact I would have the head looked at just to be safe.
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Thanks for all the replies, everyone. Puts me at ease on the heads condition.
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