Itinerant Air-Cooled

Idles now. Set the timing at zero statically, and it was right there with the timing light. Valves were fine. Took her for a spin up and down the road mostly in second, and backfires. Shifting fine, ran fine, brought her back and timing had slipped to almost 6 degrees before TDC or zero, brought her back to TDC. Might have a slight exhaust leak. Will go over it with the wrench before any more running. But so far so good.

neal

ruckman101 wrote:Idles now. Set the timing at zero statically, and it was right there with the timing light. Valves were fine. Took her for a spin up and down the road mostly in second, and backfires. Shifting fine, ran fine, brought her back and timing had slipped to almost 6 degrees before TDC or zero, brought her back to TDC. Might have a slight exhaust leak. Will go over it with the wrench before any more running. But so far so good.

neal

Do I get to drive her later this summer . . . . . . pleeeeze? Pleeeeeze? Pleeeeeze?

( ) FINE! I didn't want to ANYWAY
( ) Thank-you!

Colin

Amskeptic wrote:Do I get to drive her later this summer . . . . . . pleeeeze? Pleeeeeze? Pleeeeeze?

( ) FINE! I didn't want to ANYWAY
( X ) Thank-you!

Colin

But of course. No need to ask. A given.

neal

Just an update. As I had to take the rebuilt transaxle back to the builder (still popping out of fourth), and I had 300 miles of break-in run time on the engine, I took the opportunity to re-torque the nuts on the head bolts. I went all out, removing fan, tin, intake manifold etc. to get to the top four on each side. The bolts on the cylinder one/two side took very little if not none at all, the three/four side was another story. All of them snugged up quite a bit. I probably got 60 degrees of rotation out of most of them. Glad I made the effort. Exhaust tightened a smidge, but otherwise things were good. Hopefully the transaxle will be ready Monday.


neal

hmmm hes making me envious, head retorquing...

good call there while you had it out!

ruckman101 wrote:I took the opportunity to re-torque the nuts on the head bolts. All of them snugged up quite a bit. Exhaust tightened a smidge,
neal

Neal,

Do you think the backfire was from the exhaust or another source? I'm asking because I have an occasional backfire during deceleration that I'm trying to figure out.

Dave

It's an occasional pop on decel. I think it's at the exhaust. The old engine did the same thing. I'm starting to think I might be running rich, and getting an incomplete burn that ignites in the exhaust. The popping ceases if I give it a touch of accelerator pedal during decel. Entirely speculation at this point. I did nothing with the carburetor beyond taking it off, wiping it clean and putting it back on. I have a friend with an oxygen sensor, EM3 or something that I would like to borrow and apply to the task of adjusting the carb. The engine does run cool, which also makes me suspect a rich mixture.


neal