Engine Backfire Diagnosis Led to Wiped cam Lobes

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350runner

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Trying to diagnose engine issues is hard over the internet. I woulda fixed leaking head gaskets b4 you took it apart.

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Skweegle89

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My head gaskets aren't leaking that I know of. I did find this vent push rod though. At least, I think it's bent: https://vimeo.com/116426558


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Skweegle89

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I also have some gnarly surface rust on a couple of other push rods. Does that mean anything or is that normal?


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Skweegle89

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So being as how push rods just don't bend on their own, I'm going to try a couple of things on that link and continue with my tear down. I'm wondering if my timing chain didn't slip and that's what's causing all this.


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Skweegle89

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I have found several other forums where somebody had all the same symptoms, even the super low vacuum. Problem is, they are all several years old and they didn't bother coming back and posting the solution to the problem. I have found 6 or 8 different threads that nobody ever posted the solution to.


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HotRodPC

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I wouldn't be afraid to cheap out on any of that stuff you need either. The Summit brand cams are not so bad and several to choose from as well as lifters to go with them and a $20 double roller chain kit. The double chain is an import I'm sure but works well for everyone that has used one that I know of. I forget who grinds their cams, but most of them spec out very very close to Comp Cam #'s. I do agree Comp Cams has done the leg work so you can simply plug it in straight up and not need to worry about dialing it in. It's a bit complicated for a Novice and even time consuming for those who do know their doing. It's not a full race motor so a couple hundred thousandths on the lobe lift isn't even going to be noticed.
 

Skweegle89

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I wouldn't be afraid to cheap out on any of that stuff you need either. The Summit brand cams are not so bad and several to choose from as well as lifters to go with them and a $20 double roller chain kit. The double chain is an import I'm sure but works well for everyone that has used one that I know of. I forget who grinds their cams, but most of them spec out very very close to Comp Cam #'s. I do agree Comp Cams has done the leg work so you can simply plug it in straight up and not need to worry about dialing it in. It's a bit complicated for a Novice and even time consuming for those who do know their doing. It's not a full race motor so a couple hundred thousandths on the lobe lift isn't even going to be noticed.


I will shop around before I buy anything. Gatta find the problem first. 35 pages on the same topic is getting a bit excessive lol.


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Skweegle89

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Water pump is off. I have decided to replace it and the alternator and the fuel pump. I initially thought the motor had been rebuilt fairly recently, but I think I was mistaken. Waiting on a guy to bring me a balancer puller so I can check out the t chain.


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Skweegle89

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Being as how I have to pretty much drop the oil pan anyway, and with all the gas that went through the crank case, would it be wise to go ahead and completely drop the pan and replace the oil pump?


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Being as how I have to pretty much drop the oil pan anyway, and with all the gas that went through the crank case, would it be wise to go ahead and completely drop the pan and replace the oil pump?


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If your dropping the pan do the rear main seal if its 2 piece. Also I kept my oil pump as it looked to be in good shape but I did replace the distributor shaft with a metal one.

And get a 1 piece oil pan gasket too.
 

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If your dropping the pan do the rear main seal if its 2 piece. Also I kept my oil pump as it looked to be in good shape but I did replace the distributor shaft with a metal one.



And get a 1 piece oil pan gasket too.


Already replaced the entire distributor the other day. The oil pump still works, but with all the gas that was in the oil pan, I'm thinking about going ahead and replacing it. My oil pressure gauge isn't working at the moment and I just think it would be negligence not to go ahead and replace it to be on the safe side. Another question. My timing cover has the timing tab in the 12 o'clock position. It's a huge pain in the ass to get a timing light pointed behind the water pump to time it and with the carb backfiring, I lost most of a sideburn the other day lol. Can I just buy a dofferent balancer and timing cover or does it not work like that?


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firebane

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Already replaced the entire distributor the other day. The oil pump still works, but with all the gas that was in the oil pan, I'm thinking about going ahead and replacing it. My oil pressure gauge isn't working at the moment and I just think it would be negligence not to go ahead and replace it to be on the safe side. Another question. My timing cover has the timing tab in the 12 o'clock position. It's a huge pain in the ass to get a timing light pointed behind the water pump to time it and with the carb backfiring, I lost most of a sideburn the other day lol. Can I just buy a dofferent balancer and timing cover or does it not work like that?


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The shaft I am talking about attaches to the oil pump and the distributor shaft afttaches to this. Standard OEM equipment is a metal rod with a plastic bushing on the end. Aftermarket pieces are metal with a metal bushing and these are better as they don't deteriorate and breakdown. The plastic on my old one when I took it out literally fell part in 3 pieces.

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Regarding the timing cover and harmonic balancer you have to just make sure you buy the appropriate harmonic balancer for the timing cover. I purchased a new harmonic balancer which placed the 0 mark at the 2 position then just purchased a bolt on timing tab. The old timing tab I just cut off with my grinder and flattened out.
 

Skweegle89

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The shaft I am talking about attaches to the oil pump and the distributor shaft afttaches to this. Standard OEM equipment is a metal rod with a plastic bushing on the end. Aftermarket pieces are metal with a metal bushing and these are better as they don't deteriorate and breakdown. The plastic on my old one when I took it out literally fell part in 3 pieces.



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Regarding the timing cover and harmonic balancer you have to just make sure you buy the appropriate harmonic balancer for the timing cover. I purchased a new harmonic balancer which placed the 0 mark at the 2 position then just purchased a bolt on timing tab. The old timing tab I just cut off with my grinder and flattened out.


I gotcha on the shaft. I will get the pan dropped tomorrow and go from there. Just trying to get a parts list together to see how much this is all going to cost me.


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