carb fire

Go down

carb fire

Post  the great pumpkin on July 24th 2012, 6:57 pm

I have a 468 bbf dove-c heads,hypereutectic pistons,1150cfm dominator #80556-1,initial timing 10* total 35*,msd 6al box msd 8580 distributor,spark plugs autolite 45's,running 110 sunoco.I don't have the specs on the cam but the engine builder told me to set the valves at .025 and .023 i went with .024.
My problem is when i go to start the engine 9 out of 10 times i get a pop and fire thru the carb.car runs 10.30's without skipping a beat,only have this when trying to start the engine. scratch
Any info is appreciated and thank you for reading.
avatar
the great pumpkin

Posts : 6
Join date : 2012-07-24
Location : Illinois

View user profile

Back to top Go down

Re: carb fire

Post  racinghabbit on July 24th 2012, 7:22 pm

i would double check the firing order. maybe a really bad intake valve somewhere (easily checked by compression test). Just idea's
avatar
racinghabbit

Posts : 484
Join date : 2011-07-12

View user profile

Back to top Go down

Re: carb fire

Post  cool40 on July 24th 2012, 7:47 pm

do you run a starter retard of any kind? i use the msd multistep for mine and it takes 20*out at startup so i sometimes have the same problem with cold starts.it works fine after its warm.you could try more initial timing or lock it @ 32*.
avatar
cool40
BBF CONTRIBUTOR
BBF CONTRIBUTOR

Posts : 7161
Join date : 2009-08-31
Age : 47
Location : on the 1/8 mile dyno

View user profile

Back to top Go down

Re: carb fire

Post  the great pumpkin on July 24th 2012, 8:24 pm

wires are fine,engine don't miss at all going down the track.
no retard.use a 2 step for launch at 4400 and air shifter activation at 6600.
any chance this could be carb related,we are thinking of trying a friends 1050 this weekend.do you see any benefits with this combo to run a smaller carb? we were thinking we have to much with the 1150.
avatar
the great pumpkin

Posts : 6
Join date : 2012-07-24
Location : Illinois

View user profile

Back to top Go down

Re: carb fire

Post  cool40 on July 24th 2012, 9:01 pm

when i ran gas on my 526 it ran as good with a 1050 as it did with 1150. IMO a 1050 would work fine. your initial timing sounds a little low to me,have you thought about locking your timing? what kinda dist you run?
avatar
cool40
BBF CONTRIBUTOR
BBF CONTRIBUTOR

Posts : 7161
Join date : 2009-08-31
Age : 47
Location : on the 1/8 mile dyno

View user profile

Back to top Go down

Re: carb fire

Post  the great pumpkin on July 24th 2012, 10:45 pm

I was running 12* inital but back it down to 10* and tried that,made no change.i guess it don't do it as much as i thought warm but i don't like the idea of my carb on fire.
I have had another guy tell me he runs 34* total worked best on the dyno,but you say 32*?I will have to change my springs and stop?correct?
Dist. is a msd 8580
avatar
the great pumpkin

Posts : 6
Join date : 2012-07-24
Location : Illinois

View user profile

Back to top Go down

Re: carb fire

Post  kim on July 24th 2012, 11:11 pm

more initial timming, and pump the carb a few times before you crank it over. Its a lean pop, if it does cough back through the intake, just keep cranking, suck the fire back into the engine. No real big deal]

kim

Posts : 700
Join date : 2009-06-27
Location : Tucson AZ

View user profile

Back to top Go down

Re: carb fire

Post  cool40 on July 24th 2012, 11:48 pm

the great pumpkin wrote:I was running 12* inital but back it down to 10* and tried that,made no change.i guess it don't do it as much as i thought warm but i don't like the idea of my carb on fire.
I have had another guy tell me he runs 34* total worked best on the dyno,but you say 32*?I will have to change my springs and stop?correct?
Dist. is a msd 8580
i run 28-30*with methanol.i'd say if you lock the timing anywhere from 32-36*it'd work good.i'm not sure on the msd dist what you do to lock them,i have one but dont recall how i locked it,lol.
avatar
cool40
BBF CONTRIBUTOR
BBF CONTRIBUTOR

Posts : 7161
Join date : 2009-08-31
Age : 47
Location : on the 1/8 mile dyno

View user profile

Back to top Go down

Re: carb fire

Post  the great pumpkin on July 25th 2012, 12:04 am

Thanks for all your replys i will be trying this before saturday.
avatar
the great pumpkin

Posts : 6
Join date : 2012-07-24
Location : Illinois

View user profile

Back to top Go down

Re: carb fire

Post  Mark Miller on July 25th 2012, 12:30 am

I agree with the other guys,i would set the initial timing at 20-22 and total timing at 35 and see how that works.

Later Mark.

Mark Miller

Posts : 1338
Join date : 2009-09-01

View user profile

Back to top Go down

Re: carb fire

Post  bbf-falcon on July 25th 2012, 11:18 am

IMO,you are very close on the total adv. And alot of times a locked dizzy or Crank trigger w/o retard will always kick back to some xtent. I had that same issue w/my ct setup. I went back to a light spring dizzy and the kicking back has stopped along w/carb fires.

bbf-falcon

Posts : 8992
Join date : 2008-12-03
Location : Jackson, Ohio

View user profile

Back to top Go down

Re: carb fire

Post  the great pumpkin on July 31st 2012, 3:05 pm

Thank you for the info.
set it at 22* initial 40* total
The engine starts fine hot and cold also we picked up 2-3 M.P.H. at 1/8 mile.
again thank you all for your help.
avatar
the great pumpkin

Posts : 6
Join date : 2012-07-24
Location : Illinois

View user profile

Back to top Go down

Re: carb fire

Post  bbf-falcon on July 31st 2012, 9:15 pm

the great pumpkin wrote:Thank you for the info.
set it at 22* initial 40* total
The engine starts fine hot and cold also we picked up 2-3 M.P.H. at 1/8 mile.
again thank you all for your help.

WAY too much timing imo. Shocked

bbf-falcon

Posts : 8992
Join date : 2008-12-03
Location : Jackson, Ohio

View user profile

Back to top Go down

Re: carb fire

Post  Mark Miller on August 1st 2012, 12:50 am

Rick,i agree the 40 degrees total is a lot but the 22 degrees initial should be fine.

Later Mark.

Mark Miller

Posts : 1338
Join date : 2009-09-01

View user profile

Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum