Engine Backfire Diagnosis Led to Wiped cam Lobes

[Skweegle89]

85swb "Fancy"

Save some money and roast them with a torch if you have one

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I have already done that twice with this set of plugs. Works for a few mins and then they are toast again. And these are the ngk plugs.


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[350runner]

In this case it won't matter what brand you have because the a/f ratio is too far off :-(

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[Skweegle89]

85swb "Fancy"

In this case it won't matter what brand you have because the a/f ratio is too far off :-(

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Just out of curiosity, where are your a/f screws set? I know everybody's are different, but I have tried everything from 1 to 2 1/2 out and nothing has ever improved. The holly that's on now was pulled right off a running truck and put on mine 10 minutes later. I'm about to pull my hair out.


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[firebane]

Just out of curiosity, where are your a/f screws set? I know everybody's are different, but I have tried everything from 1 to 2 1/2 out and nothing has ever improved. The holly that's on now was pulled right off a running truck and put on mine 10 minutes later. I'm about to pull my hair out.


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Every carb and every motor will be completely different when it comes to A/F ratios. The only way to ever dial it in properly is with a vacuum guage and a wideband o2.

 

[350runner]

My A/F screws are approx 3 turns out in cold weather approx 2.5 in warm hot weather.

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[HotRodPC]

I was told the engine needed to be up to temp to do the test. It won't run unless I put new plugs in. It will idle ****** enough with new plugs to get the temp up before the new plugs foul out. I thought my timing chain might have jumped, but wouldn't I get erratic readings with a timing light?


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Not true. You can do a compression test and find the obvious issues at any temp even cold. Only thing bringing it up to temp will do, is if you have a cracked head, then the crack should be opened up once warmed up and easier to detect, but even a small crack can show it's face on a cold motor with a compession test. You need to start somewhere with a preliminary test. Just be sure to pull all your plugs then do the test. This way the motor turns over freely and if compression is leaking to another cylinder it will show ZERO compression.

 

[Skweegle89]

85swb "Fancy"

Not true. You can do a compression test and find the obvious issues at any temp even cold. Only thing bringing it up to temp will do, is if you have a cracked head, then the crack should be opened up once warmed up and easier to detect, but even a small crack can show it's face on a cold motor with a compession test. You need to start somewhere with a preliminary test. Just be sure to pull all your plugs then do the test. This way the motor turns over freely and if compression is leaking to another cylinder it will show ZERO compression.

10-4 I will do that when I get off work And see what happens.


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[Skweegle89]

85swb "Fancy"

Can anybody tell what what heads these are? Numbers Iv found are 333892. Under that looks like J 4 0? 7 1


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[Skweegle89]

85swb "Fancy"

I pulled the drivers side valve cover off. Everything, and I mean everything under there is absolutely covered in gas. Puddles of it everywhere.


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[350runner]

Pcv on the passengers side right?

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[HotRodPC]

Can anybody tell what what heads these are? Numbers Iv found are 333892. Under that looks like J 4 0? 7 1


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Pretty much junk ass run of the mill heads. 76CC chambers.

 

[Skweegle89]

85swb "Fancy"

Pcv on the passengers side right?

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No the pcv is drivers side. But pulled the other one and its full of gas too. I assume is from all the gas that was in the oil before I changed it and it hasn't run enough to get it all out. That should explain all my big backfires right? After I get it running I will change the oil again. Cranked it and everything is moving as it should, so it doesn't show a bad spot in the cam. Decided I should take a break from it and hang out with my wife for the night so I put the compression test off until tomorrow.


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[Skweegle89]

85swb "Fancy"

Pretty much junk ass run of the mill heads. 76CC chambers.

That's good to know. My main concern is that they weren't 305 heads.


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[350runner]

If you got flat tops they will raise the compression a bit . Still aren't the best but it'll run

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That compression test tho?

 

[Skweegle89]

85swb "Fancy"

If you got flat tops they will raise the compression a bit . Still aren't the best but it'll run

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That compression test tho?

I will do it tomorrow. My wife has been pretty cool about me spending every night working on the truck, and taking up her parking spot in the garage, so I thought I would take a night off. The suspense is killing me though.


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