No power, popping on intake, HELP!!!

[jwldane]

Hi everyone,

Bought a second Spider that was close to completion on a restore/build. Can't seem to get it running right, not sure what to do or check next without starting to tear the engine down. First let me say that I am not a mechanic. I can do some basics but that's where my knowledge ends. I have had the car at my mechanic (not an expert on Fiat, but builds competitive drag cars and know his stuff), and he believes the car has cam or valve issues.

This is what I know about the car. I can't swear to it but this is what I was told.

The car has a 2.0 liter block and 1.8 liter head. The block has supposedly been re-honed with new bearings, high compression pistons and rings. The head was supposedly resurfaced and valves adjusted. Single plane intake manifold with Weber 32dfev carb, entirely new header exhaust system, rebuilt dizzy converted to electronic, new mechanical fuel pump and oil pump.

Timing was set at TDC at the crank, aux shaft at 1-2 o'clock position, cams at the respective marks on the cam housing, dizzy set to fire on #4.

Current condition and issues:

The car will start and idle after air cleaner removed. Carb makes popping sounds and will occasionally spit fuel up out of the carb. The car produces no power at anything over 1200 rpm. Really anything above idle is terrible. We perfomed a compression test with all 4 plugs removed and we got consistent results on all four but only between 70-75 psi. I would expect a minimum of 120psi and up to 190psi on a high compression engine.

Short of starting disassembly of engine, what are we missing? My mechanic is convinced it is in the cams or valves. Could the intake and exhaust cams be reversed? Since I bought the car in this condition I have no idea exactly what was done, by whom, or whether it was done properly. Any suggestions would be greatly appreciated.

Also, on a side note, the transmission on our 1980 has reverse as push down, to the right and rear. Reverse on the problematic car is lift up, then to the right and rear. Is this normal and what year ranges was this transmission from?

Thanks in advance.

[azruss]

It would be hard to switch the cams. The exhaust cam couldn't drive the dizzy with the intake cam. It is possible to have switched the cam pulleys. there has been lots of discussion here about such matters. Do a search and you will see how to identify each pulley.

[So Cal Mark]

compression that low on all 4 cylinders indicates incorrect cam timing as the most likely culprit. What is the manifold vacuum reading at idle?

[jwldane]

Thanks for the responses so far.

Have not checked vacuum as of yet. My mechanic agrees with you that it is a matter of the cams (timing) or a possibly a deeper valve issue. According to him, regardless of vacuum advance, air intake leaks, or even fuel pressure issues, we should be getting better results (or power output) when we apply throttle. Even the slightest increase in throttle results in sputtering and spitting.

We have adjusted the timing at the dizzy so that the car will at least idle, although roughly with the carb popping and spitting fuel back up through the butterfly. There are no immediate signs of air leakage at the carb or intake, no popping from the exhaust side. Plugs were cleaned, gapped and reinstalled. Rotor, cap and wires are new. New fuel tank and lines with new glass fuel filter. The previous owner said that that carb has sat for a while during the restoration but mechanic doesn't seem to think there is a bad float or gummed up situation.

We agree that the fuel pressure and vacuum, carb jetting, etc., will still all need to be looked at and adjusted, if necessary, but he feels we should have a much better baseline than where we are now and I am not knowledgeable enough to disagree. From what I have read here so far, I suspect the cam gears might be reversed as suggested. They were removed and painted prior to reinstallation of the timing belt.

I will check for any identification marks and report back.

Thanks again.

[So Cal Mark]

you're wasting your time trying to tune it if your compression readings are accurate. 70lbs of compression is not enough

[2ndwind]

I agree, sounds like cam timing issue or grossly mis-adjusted valves.