If it runs on starting fluid, it sure seems like a carburetion / fuel
issue. Did you "degree" the cam when assembling? Having it off in
timing by a tooth can make it run like crap and be hard to start too.
If you've got SU carb's, with the piston removed you should be able
to see a little fuel in the jet tube. A little bit of debris can
clog the passage from the float bowl to the jet.
- Tony
At 02:23 PM 4/25/2010, George Harmuth wrote:
>Time query the collective again. My son and I just finished a rebuild of
>his 72 Spitfire (1296, large journal) and I can't get it to run. The car
>will start up on starting fluid but won't even fire on it's own. Confirmed
>fresh gas to carb, gas in fuel bowl, disassembled carb, cleaned and
>inspected, looks OK and was working (rebuilt last summer) before engine
>rebuild.
>
>Think I've tracked it down to no vacuum, either from the vacuum port (flat
>0 reading on gauge, no fluctuations ) on the carb or gross check, putting
>my hand (or carb sync gauge) over the mouth of the carb. I've removed the
>carb and intake manifold, gaskets etc all look good. Removed the valve
>cover and plugs, verified ( multiple times) cam to TDC on cylinder 1
>positions. The valves open in the correct sequence with respect to the
>piston position, rechecked the valve clearance, are all set to .015.
>Compression is a little low (1-4, 110.115,118,115) but the engine has less
>than a minute of run time, I expect it will rise a bit as it breaks in.
>
>The engine was working before the rebuild but it had low (ave 70Lbs)
>compression on 3 cylinders. I found 3 broken top rings, I suspect the PO,
>who had the car sitting for years, didn't do a proper job when he re fired
>the motor before he put it up for sale and the rings broke. The block was
>clean, looked like a recent (milage wise) rebuild on it but we replaced
>rings, bearings, new valves and springs etc.. The cylinder bore was
>inspected, measured and honed. The only parts not stock were a little
>hotter grind on the cam, nothing radical and a Maniflow header to replace
>the stock manifold.
>
>Any idea where I screwed up or what I can check before I do a teardown?
>
>thanks
>mike
>
>
>
>G. Michael Harmuth
>_______________________________________________
>fot@autox.team.net
>
>http://www.fot-racing.com
>
>Donate: http://www.team.net/donate.html
>Archive: http://www.team.net/archive
>Forums: http://www.team.net/forums
>Unsubscribe: http://autox.team.net/mailman/options/fot/tony@tonydrews.com
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|