I have a 1980 Toyota corona. It has a 20r obviously. I recently replaced the headgasket. Installed a engine bildr 261c cam, a 32/36 weber, and replaced the headgasket and all top end gaskets.

The problem I'm having is I am having to run the distributor as advanced as i can go to get the car to idle and run ok. My problem is: when I drive the car it is fine in first and most of the way through second. However in second at probably around 2500 rpm and over half throttle it will lose all power and backfire. If you let off the gas and give it throttle again it will have power again. Now I'm pretty certain it has no vacuum leaks. I know when I put the timing chain and cam and crank sprockets on everything was lined up properly at 0 degrees. So I am out of ideas. Any help would be apreciated. The car is not driveable in this condition.

Thanks in advance.

 

The fact that there are two new variables to consider makes this a tricky one. However, the fact that it will run right at first and then degrade suggests to me that it is not a problem with the cam installation. I'm no Click and Clack over here but the first thing I would suspect is a fuel issue. It sounds like it could be running out of it as you row through the gears and maybe even experiencing a lean issue at idle, since you need so much advance.

Give a good, hard look at that carburetor. Check your float level. Make sure it's getting enough fuel to it. Make sure you've tuned it properly. To me it sounds like you're way lean.

It might be helpful to swap the original carb back on and see how it runs. That way you'll be isolating the two new variables and getting a clearer picture.

 

Well I have it running a eleteric fuel pump. It puts out 5 to 6 psi. I have it running straight from the pump to a fuel filter to the carb. I can adjust it so it seems like its getting enough fuel but it runs too rich. I can't find that middle ground. The original carb isn't an option because I no longer have it. It's crazy to think that the carb isn't getting enough fuel because the webers are supposed to run just 3.5 to 4 psi. And the pump putting out 5 to 6 it should be getting plenty of gas.

 

You may not have the distributer in correctly. Could be off be a few degrees. In fact it's almost definitely off by a few degrees, if you're having to advance it that far. But with as much work as you just did, it could be a few things...that's the first thing I'd check, though. If you can't tell for sure, a shop would probably be able to let you know, and fix it, for pretty cheap if that's all it is.

 

Distributor is my guess as well. The dot was pointing straight up right? Quick an easy to check. Also check distributor advance, make sure that it is getting good vacuum, might have something to do with that since it seems to be getting worse at speeds. Possibly need a richer jet in the Weber with that crawler cam as well.

 

I pulled the distributor out and lined everything up again and it runs 10x better. I was still running to rich so I put the regulator back on. Set it at 4 psi. No more backfire and no more bogging. Thanks for the help guys. I would have never thought of the distributor being a few degrees off.