71' 911 2.2T Troubleshooting Engine
 

I'm having issues getting my 2.2T running. Recent acquired unknown on when it last ran, probably 25 years ago. I rebuilt carbs, adjusted valves and did leakdown test with no issues. However Cylinder 4-6 are bouncing around on the synchrometer and I can't get them to balance with any carb adjustments, currently running Zenith 40 TIN. The Synchrometer is practically pegged and bouncing on 4 and 6. On Cylinder 5 it's about 2-3 kg/hr.

Any recommendations? Please let me know if any other info would be helpful. I'd love to get the motor running soon so I can work the rest of the car.

In addition to leakdown, do a compression test. I don't remember if you can swap carbs from one bank to the other on that engine. If you can, see if the problem follows the carbs.

I swapped carbs between sides and cylinders 5 & 6 were not going crazy pegged out on the synchrometer like before. Additionally, that problem oddly didn't move over to cylinders 1&3, cylinder 2 was fine as well. However, I was getting no intake reading on the synchrometer for cylinder 5. I manually pumped the accelerator pump for cylinder 5 just to see if I could get a jump, and instead got some flames from under the engine fan shroud cover.

So a lot of weird stuff happening. Open to additional recommendations.

Yeah, that's weird. Did you do the compression test yet?

Flames under the shroud: Could be fuel pooled there that got ignited. I would check the gaskets between the carbs/manifolds and manifolds/heads first --that also would cause uneven synchrometer readings. Check for fuel leaks that could have leaked fuel to cause the flame.

If the gaskets seal well and you have good compression, then about the only other place to examine is the carbs themselves. While you have the carbs off to make sure the gaskets are good, take them apart and inspect again.

Have you driven the car yet, or does it run too poorly to drive?

Since you are new here, we don't know your level of experience. Are you sure you adjusted the valves correctly?

Was able to do the compression test. Compression on #5 after cranking for about 3 seconds is 145psi and held.

When I removed the carbs I did notice that the gasket between the intake manifold and carbs was partially missing, this happened once before too.

I've got years of self taught experience working on cars, but when it comes to air cooled P cars and engine work, especially carbs this is all new. With that said though I feel pretty confident I adjusted the valves right.

What was the compression on the other cylinders? 160 or so? If so, then 145 is not bad.

Have you driven it? If so, how does it run? Unless there is a serous problem with driving it, I recommend that you refill the tank with fresh gas (I assume you drained the old stuff out, right?), and pour a can of Chevron Techron in the tank. Then go drive it for a few hundred miles.