Bugpack 4061-10 and 34 PICT-3 idle issues

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E4ODnut
Posts: 38
Joined: Sat Aug 31, 2013 3:36 pm

Bugpack 4061-10 and 34 PICT-3 idle issues

Post by E4ODnut »

Has anyone used a Bugpack 4061-10 with a 34 PICT34-3 and gotten it to idle well?
We have fresh build 1641 with this combination, no other exotic stuff, and can't seem to get it to idle dependably. Idle at ~900 is very lumpy and AFR is ~ 17: 1 increasing the revs it smooths out about 1500 at or so at ~12.5: 1 AFR and runs reasonably well. Timing changes don't help. We've tried 2 other 34s and they all behave the same way. We are wondering if this combination is just too much for the idle circuit.

Cam specs @0.050" lift are:
IO 14 BTDC
IC 40 ABDC
EO 50 BBDC
EC 4 ATDC
Lobe lift 0.338"
Dur 234 degrees
I C/L 103 degrees
E C/L 113 degrees
Lobe separation 108 cam degrees
Overlap 18 degrees
Built in advance 5 degrees

Any opinions?
Robert
2001 Dodge 2500, 4x4, extended cab, long box, 8.0L V10, NV4500 5 spd manual, Custom EFI
Bruce.m
Posts: 980
Joined: Sun Aug 11, 2013 1:44 pm

Re: Bugpack 4061-10 and 34 PICT-3 idle issues

Post by Bruce.m »

Weak vacuum at idle so doesn’t pull fuel from the carb.
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AdminSteve
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Posts: 264
Joined: Mon Dec 04, 2006 8:46 am

Re: Bugpack 4061-10 and 34 PICT-3 idle issues

Post by AdminSteve »

Like Bruce said not enough vacuum at idle you need a cam with a wider LSA to help increase the idle vac.

AdminSteve 8)
S&S Aircooled Parts and Accessories
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E4ODnut
Posts: 38
Joined: Sat Aug 31, 2013 3:36 pm

Re: Bugpack 4061-10 and 34 PICT-3 idle issues

Post by E4ODnut »

The engine will be converted to EFI but we were hoping to get it running well on the carb before commiting.
Robert
2001 Dodge 2500, 4x4, extended cab, long box, 8.0L V10, NV4500 5 spd manual, Custom EFI
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V8Nate
Posts: 840
Joined: Mon Sep 03, 2018 12:34 pm

Re: Bugpack 4061-10 and 34 PICT-3 idle issues

Post by V8Nate »

Give a bigger idle jet a shot, also make sure your throttle plate is adjusted properly and you only use the air bleed screw to adjust your idle speed. Have you tried messing with the timing when you are trying to get it to idle lower. Also double check fuel pressure and float level
E4ODnut
Posts: 38
Joined: Sat Aug 31, 2013 3:36 pm

Re: Bugpack 4061-10 and 34 PICT-3 idle issues

Post by E4ODnut »

V8Nate: All done.
Robert
2001 Dodge 2500, 4x4, extended cab, long box, 8.0L V10, NV4500 5 spd manual, Custom EFI
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