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Author Topic:   missing
AC156
Dirt Freak

Total posts: 295
posted April 20, 2002 09:49 AM
guys
i run a 355, with a holley 500 2 bar, and a stock hei dist. about halfway down the straightaways the car starts missing and popping real bad. it does it till i let off going into the turn. i think it is a problem with the carb. what do you all think? it idles and runs to about 5000 rpm fine, but after that it cuts out. thanks.

racer17j
Dirt Forum Champ
Total posts: 1565
posted April 20, 2002 01:46 PM UIN: 54865418
if you have a stock coil and modual in your hei it will strart to fall off about there

redneck racing
Dirt Freak

Total posts: 276
posted April 20, 2002 06:43 PM
Ac156 are you running roller rockers?

AC156
Dirt Freak

Total posts: 295
posted April 20, 2002 06:58 PM
No, i am not running roller rockers. I have heard people say that if the motor back fires out of the carb, you need to change the power valve. When we first started the engine it did back fire out the carb. Would that cause my problem?
Also, we changed engines. The engine we are running now is a lot higher compression than the one we were running. The old engine would run fine up to about 6,000 rpm, which is the most i ever turned it, with the same distributor.

CUSTOMPERFORMANCE
Dirt Forum Champ
Total posts: 639
posted April 20, 2002 07:18 PM
I had a similar problem in my mod once with a engine it would only turn about 6,000 rpm and then start popping. Turned out to be weak valve springs something you may want to check.

jammin
Dirt Administrator

Total posts: 5556
posted April 20, 2002 08:33 PM UIN: 16262997
Yup, thats what I told him.....springs are probably weak.

jammin

racer2
Dirt Maniac

Total posts: 166
posted April 21, 2002 09:18 AM
Pick up coil in the distributar

AC156
Dirt Freak

Total posts: 295
posted April 21, 2002 01:20 PM
thanks guys

Donnie Ross
Dirt Maniac

Total posts: 109
posted April 21, 2002 03:27 PM
check the wires to the module from the pick up coil sometimes they get pinched and cause this problem also check where the 3 wires from the module to the coil they some times break about 1/2 in two will still run but will miss at high rpm. make sure your primary wire is at least 14 gauge, a hei has a very high instantanios amp draw.

doug
Dirt Full Roller

Total posts: 28
posted April 21, 2002 08:39 PM
could be a intake gasket sucking air at hi rpm just another thing to check the buzzard7

45cent
Dirt Roller

Total posts: 18
posted April 22, 2002 03:14 AM
What size of air filter are you running and what is the power in your carb I ran into the same thing once I had too small air filter and wrong power valve small things can play an huge part in performance

c21
Dirt Freak

Total posts: 346
posted April 22, 2002 11:43 AM
Is your fuel pressure good at the end of the straight?(you may want to pressure test your fuel supply line from the tank).
Is your needle and seat large enough? (you may be emptying out your fuel bowl) What do your plugs look like?

Moroso makes an inexpensive valve spring tester ($59 from summit I think) that lets you check your springs on the car. The calibration on this unit is pretty poor, however, so check a spring on another head that has been verified on a quality tester to get a feel for the reading you are looking for.
Good Luck

EVANSRACING24E
Dirt Forum Racer

Total posts: 80
posted April 22, 2002 10:32 PM
also check your fuel needle valve setting. had same problem and turned out the one for the fuel and it solved it.

[This message has been edited by EVANSRACING24E (edited April 22, 2002).]

AC156
Dirt Freak

Total posts: 295
posted April 25, 2002 03:53 PM
thanks for all the help guys. i got a accel module and put in it and it runs like a top now.

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