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I'm back

Postby jmattox » December 5th, 2012, 11:30 am

Sebring Turkey Trot regionals, CFR finally got the grouping right (now, we need more Vees and FSTs to come play) put on DRE carburetor and pertronics ignition distributor NO OTHER changes to a really fine running engine. Could only get max 5000 rpm out of engine under load. Ran the whole weekend, thank goodness there were only 4 in class. Hoosiers were up to task, didn't see anybody else except when I got passed. My questions and dilemma. Could be main bearings are getting tired and need "refresh" (shipping time and $$$), Carb will get a complete rebuild (little bit of time and small amount of $)? Pertronix ignition and distributor, could old battery lead to underperformance? Other suggestions, other than buy another car with a competitve engine/transmission (my retirement can only afford so much)? Any help would be appreciated. Will be changing the oil and looking for shavings/ broken parts in the next couple of weeks. Cabin Fever Cure will be here mid February.

John
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Re: I'm back

Postby FV90 » December 5th, 2012, 11:33 am

John, did you check the throttle cable? I have had mine slip during racing and could not above 5K rpm.
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Re: I'm back

Postby brian » December 5th, 2012, 3:51 pm

I don't think it's likely that the engine is siezing up. If a dragging bearing caused a 1000 rpm reduction, it's likely to have gone up in smoke within seconds. Assuming the only changes you made were the carb and dist i would look there first. AS mentioned, make sure the throttle is opening to full stop. Then look in the carb and make sure the butterfly is fully opened when the linkage is on the stop. Make sure the dist. is advancing as rpm is increased. While we spend all our time at full advance it's still important that total advance be near or around 35 to 38 degrees. If you have battery or coil issues, most likely the engine would missfire. Lastly make sure the car rolls easily. If the alignment or brake adjustment is off it will slow you down.
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Re: I'm back

Postby tiagosantos » December 5th, 2012, 4:03 pm

I'd also check for air leaks around the carb to intake mating surface, and the manifold to heads surface.. It would probably sound nasty and you'd figure something else was up, but I've had that problem of having no power and low RPM when I messed up the installation of my intake manifold :oops: With the engine running, spray some WD40 or carb cleaner or.. Well, almost anything, really :D around the possible leak locations and if the idle changes at all, you have a problem :)
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Re: I'm back

Postby FV80 » December 5th, 2012, 6:31 pm

I'm betting you FORGOT to reset the timing after installing the Pertronix. Quick and easy error and VERY likely to cause the lack of high speed RPM.
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Re: I'm back

Postby jmattox » March 9th, 2013, 11:22 am

Sorry about taking so long to thank ya'll for the advice. Put in new "used but cheap" battery and engine with rebuilt carb and pertronix worked like a charm! Thanks for the assistance.

John
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Re: I'm back

Postby SR Racing » March 9th, 2013, 7:17 pm

jmattox wrote:Sorry about taking so long to thank ya'll for the advice. Put in new "used but cheap" battery and engine with rebuilt carb and pertronix worked like a charm! Thanks for the assistance.



Ok, but WHAT was the root cause? I suspect the carb or timing.
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Re: I'm back

Postby jmattox » March 9th, 2013, 8:02 pm

Jim,

Timing was dead on, has been since engine refresh. Carb may have been a part of the problem, but 8 volts and virtually 0 amps out of old used battery probably turned pertronix into a rev limiter. Was able to reach 6500 in 3rd with no problem. Takes a little long (see my "other" post). Putting an asthmatic carb and manifold on a really good autowerks engine may explain why I can only reach 5000 at Daytona. Thanks for your concern.

John
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