I just finished putting a new Z Head on my T and it runs poorly. I've checked the plugs for spark and timing an all seems good. What carb setting do most of you that run these heads use. Thanks Steve.
If you have any other ideas let me know.
Every car is different. How is it running poorly? Check for vacuum leaks. What carb are you running? What is the compression? Did you do a valve job, what cam?
How did it run before you installed the Z head? Did you change anything else other than the head?
Have you checked the torque on the head bolts after the initial warm up? If the bolts loosen up it could be losing compression, or coolant seeping into the cylinders.
Re-torqueing of Z heads should be done when the engine is cold.
Steve, Do you have the tools to do a compression test?
I remember this many years ago here. It was determined that plugs needed to be reset to 25g.
I ran a compression test and the were all about 70 psi and I think that is normal for the Z.
1. I have a Stipe 250 cam and valve adjustment is OK
2. I have retorqued the head to 45 after running when it's cold I'll recheck.
3 I can throw a spark about 3/4 in.
4. Starts easy with the hand crank and idles fine. It seems to have low power going up hills or with a load.
5 I checked the timing with a light about 5 degrees atdc and plenty of advance with the lever.
Sorry for these rambling notes but it's late,Steve.
Steve, do you have a filter in the fuel line, other than the one in the tank outlet? Your symptoms are typical of fuel starvation.
Hope this helps.
.Allan from down under,
George has a good idea changing plug gap. Remember that a great spark at atmospheric pressure may be a poor spark under higher compression. When I installed a Z head years back on my 1919 I had to change the spark plug gap for better performance but I cannot remember what the numbers were. I assume it might be slightly different on different units depending on if the block was decked etc.
Recheck the gap on the plugs.
The higher compression requires a fat spark, a short one is better, so gap needs to be tighter.
'Z' head on my '27 with Stipe 280, Anderson timer, coils and hot magneto, and Champion 'X' plugs required the normal .025" gap, worked fine. Any larger gap and noticed power drop off.