2nd valve adjust rebuild backfiring like crazy

rgdtoo · 10-02-2013, 08:20 PM

Wondering if the backfiring is caused by incorrect valve adjustments or should I look elsewhere?

rgdtoo · 10-02-2013, 08:23 PM

Make that "2nd after rebuild"

snbush67 · snbush67's Garage

It is more likely an air leak, or you have plug wires mixed up.

moneymanager · 10-03-2013, 07:52 AM

Or you turned the crank in the wrong direction when you adjusted each cylinder. Car will run but sounds dreadful.

Ronnie's.930 · 10:35 AM

Quote:

Originally Posted by moneymanager

Or you turned the crank in the wrong direction when you adjusted each cylinder. Car will run but sounds dreadful.

I'm curious as to what this means - how could one turn the crank in the wrong direction in such a way that if affects running later on? Are you suggesting that he may have damaged the timing chains by turning the crank counter clockwise?

Eagledriver · 10-03-2013, 11:40 AM

I don't think there is anyway to adjust the valves so badly that it would cause backfiring.

moneymanager · 10-03-2013, 05:08 PM

Ronnie,
when you adjust the valves you turn the crank in a specific direction as you work from cylinder #1 onward. Go backwards and you have a disaster. The valve settings are completely wrong. Did it years ago on a Volkswagen. Jim

snbush67 · snbush67's Garage

I hear you, but it would be hard to mess it up by accident as over two-thirds of the cam surface is off the lobe. That means even if you rotate the engine with a blind spin you have a 66% chance of having the rocker face off the cam lobe, which is then in a perfect position to adjust the valves.

rgdtoo · 10-03-2013, 07:11 PM

Though I feel a bit like a

ya that's it "blockhead", I'm

for Joy.

I crossed wires 4nad5 or 5and4 however you want to look at it.

I love this place.

Thanks for the help...

moneymanager · 10-03-2013, 07:26 PM

Shane, you may well be right but just try it then start the motor. It will run, and sound like you put quarters thru all of the spark plug holes.

snbush67 · snbush67's Garage

Quote:

Originally Posted by rgdtoo

Though I feel a bit like a

ya that's it "blockhead", I'm

for Joy.

I crossed wires 4nad5 or 5and4 however you want to look at it.

I love this place.

Thanks for the help...

Great! Thanks for the follow up.

snbush67 · snbush67's Garage

Quote:

Originally Posted by moneymanager

Shane, you may well be right but just try it then start the motor. It will run, and sound like you put quarters thru all of the spark plug holes.

Nope, not gonna do it, even though the odds are good, I am not willing to take that gamble.

... Even if I did do it with a blind spin, and stopped on the lobe I would be able to tell because if the valves were even close before, then I would have to back the adjuster out all the way to release the spring tension. That would be an indicator that I was going down the wrong road. I do understand how it could happen to someone who had never done a valve adjust. Good point, thanks!