[dsimm91602]

I have an 86 Spider which was converted to Dellorto's. All of the FI components have been removed and the engine is now a bare 2L. I replaced and rings, (jugs were good) resurfaced the valves and installed new Euro cams. The valves are set at .018 and .021, the valve timing is right on at 102 and the distributor is set at the mark on TDC (P). Everything seems right but when I try to start it it will only pop and backfire through the exhaust. It is getting good fire and fuel and I checked the seating of the valves by running some air into the cylinders with a differential pressure tester (good). There is a lot of blowby into the block but I am guessing that is because the rings have not been seated yet. I am now to the carbs but am not sure they would cause this problem.

Does anyone have any ideas, I'm all out.

Thanks,

Dave

 

[BEAR WABBIT]

Two items to check, first make sure that you are at TDC firing #1 not #4 it will look the same except the rotor will be on #4 not #1 . Take the distributor cap off when you check this.
Second you should be static timing the engine with the distributer at firing #1 and the crank pulley at "F" for fixed which is 5 degrees before top dead center.

 

[dsimm91602]

Thanks Jim.

When I set the distributor to align the reference mark with the rotor at P I thought that was correct. What is the correct way to statically time it.

Dave

 

[Tifosi]

Off the wall question:

When this carb conversion took place, the orginal fuel supply system was replaced with a low pressure setup was it not?

Also, what are you actually using for ignition?

 

[dsimm91602]

Yeah, the fuel pump is a solid state low pressure (2-3.5 PSI).

It has a Marelli single point distributor with a Bosch coil. I am going to change it to Pertronix as soon as I have some more spare cash.

Ok, I feel a bit stupid saying this but I wired the plugs by the distributor cap numbers and not by the firing order. After I read Jim message and went out and looked at it again I saw it right away. Stupid huh.

It fired right up after that and runs really well, even at idle. Can't wait to see how it does when it is timed and I tune the carbs. Boy do those Dellorto's make a racket on acceleration, pretty cool actually.

Thanks for the help.

 

[180OUT]

Comments removed because I _didn't_ read the entire thread.

Glad you got the problem fixed. I had an even more frustrating problem with my Lancia. After I'd carefully installed new plug wires, the motor wouldn't start. I was certain I'd done everything right until someone finally let me in on a little Lancia factoid: Although the distributor caps are neatly numbered 1-6 the numbers mean absolutely nothing in terms of their relatiionship to the motor's firing order. This piece of information was not written in anything I could find. If you work on Lancia Flaminias you're just supposed to know it.

 

[dsimm91602]

That was the problem, when I had everything set and the distributor rotor was set it was pointing to what was #2 on the distributor cap. Clockwise it then went #1, #4 and #3. This is the way I wired it. I do not know why I didn't realize this at first but I should have know it was supposed to fire on #1 in that position. I ended up making #2 on the cap #1 and then following the firing order the rest of the way around. Worked great then.

Dave

 

[180OUT]

That was the problem, when I had everything set and the distributor rotor was set it was pointing to what was #2 on the distributor cap. Clockwise it then went #1, #4 and #3. This is the way I wired it. I do not know why I didn't realize this at first but I should have know it was supposed to fire on #1 in that position. I ended up making #2 on the cap #1 and then following the firing order the rest of the way around. Worked great then.

Dave: That'll work OK. However, there is one thing you sould check. The key that connects the dizzy shaft to the oil pump shaft is very slightly offset.
It's very easy to get this wrong and, if you do, driving the car this way will put too much of a load on the dizzy shaft and cause it to break.

Rotate the dizzy shaft. If you can feel some slop, you probably have the dizzy in backwards. When it's in right, it feels solid.