Little Black smoke from the new Crate 350 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Daubs** · 07-31-2006, 05:08 PM

Brother drove the K-20 and I was following. Noticed some black smoke from tailpipes at times. Put new Edelbrock carb on and haven't touched it or checked the plugs. Thinking it's running a little rich. Or could be something else?

Thoughts. Thanks, D.

bryanw1968 · 07-31-2006, 05:12 PM

Sounds rich. Especially if you haven't adjusted it.
Tune the carb for the highest vacuum through the air/fuel mixture screws.
I'd check the gap on the plugs as well. What cam do you have and where is your initial timing?

**68350** · 07-31-2006, 05:25 PM

I agree, I would say just running rich and needs some adjustment.

**Daubs** · 07-31-2006, 07:35 PM

Plugs gap is .60 and timing is by feel. Advanced until ping under load, then back off a little.

**special-K** · 08-01-2006, 07:50 AM

Definately a fuel mix issue,you`ll get it right.How`s that motor feel,though?Pretty nice.

1969 BRUCE · 08-01-2006, 08:37 AM

Could very well be a combination of both especially if timing is retarded.

bryanw1968 · 08-01-2006, 11:33 AM

.60 sounds like a pretty big gap even for a hot ignition. Might try closing it a little. I run a full MSD 6AL with a blaster coil and only run about .45
Any more and it runs goofy.

Nothing wrong with timing by feel. When you retard it remember a sharpy mark is about 2 degrees.

How big is your motor and how big is the carb?

Thanks,
Bryan

bryanw1968 · 08-01-2006, 01:50 PM

Duh....

You're original post said you had a new crate 350 and I asked what size your motor was. Doh!

*wolfthing2000* · 08-01-2006, 02:02 PM

Please guys, .060 and .045

**Daubs** · 08-01-2006, 02:13 PM

Quote:

Originally Posted by wolfthing2000

Please guys, .060 and .045

Yes, .60 would be...well, HUGE gap. I stand corrected.

Love the engine. It is just the base level 260 HP crate 350. Ran like crap after installing, backfiring, etc. But pulled the old Holley and put on the Edelbrock 600 CFM manual choke and she runs like a top! Haven't touched the new carb save for a little idle speed adjustment. I'll check plug gaps and work on idle mixture soon.

Thanks for replies.

*wolfthing2000* · 08-01-2006, 04:32 PM

The .060 sounds right for the HEI

bryanw1968 · 08-02-2006, 11:14 AM

Here is a similar motor to yours and they recommend .045.

http://www.sallee-chevrolet.com/fram...90hp350gm.html

You might try .060 to see what happens though. However, if you don't have enough charge going to that plug you might not properly fill the gap and misfire.

Good luck
B

JAKES 68GMC · 08-02-2006, 04:17 PM

My truck black smokes when you rev it, like its too rich. I've done everything there is to do to try and fix it. Timing, carb adjustments, plugs. I've got it running almost perfect and it still smokes when you rev it. So I just live with it.

07-31-2006, 05:08 PM	#1
Daubs Registered User Join Date: Jan 2005 Location: Eastern Nebraska Posts: 611	Little Black smoke from the new Crate 350 Brother drove the K-20 and I was following. Noticed some black smoke from tailpipes at times. Put new Edelbrock carb on and haven't touched it or checked the plugs. Thinking it's running a little rich. Or could be something else? Thoughts. Thanks, D. __________________ '72 Chevy K-20 Crate 350, SM465, 4.10's

07-31-2006, 05:12 PM	#2
bryanw1968 Senior Member Join Date: Jul 2006 Location: Leander, Texas Posts: 850	Re: Little Black smoke from the new Crate 350 Sounds rich. Especially if you haven't adjusted it. Tune the carb for the highest vacuum through the air/fuel mixture screws. I'd check the gap on the plugs as well. What cam do you have and where is your initial timing?

07-31-2006, 05:25 PM	#3
68350 Senior Member Join Date: Jan 2002 Location: Williston, ND Posts: 2,999	Re: Little Black smoke from the new Crate 350 I agree, I would say just running rich and needs some adjustment. __________________ 68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi

07-31-2006, 07:35 PM	#4
Daubs Registered User Join Date: Jan 2005 Location: Eastern Nebraska Posts: 611	Re: Little Black smoke from the new Crate 350 Plugs gap is .60 and timing is by feel. Advanced until ping under load, then back off a little. __________________ '72 Chevy K-20 Crate 350, SM465, 4.10's

08-01-2006, 07:50 AM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,859	Re: Little Black smoke from the new Crate 350 Definately a fuel mix issue,you`ll get it right.How`s that motor feel,though?Pretty nice. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

08-01-2006, 08:37 AM	#6
1969 BRUCE Registered User Join Date: Sep 2005 Location: charlotte Posts: 23	Re: Little Black smoke from the new Crate 350 Could very well be a combination of both especially if timing is retarded.

08-01-2006, 11:33 AM	#7
bryanw1968 Senior Member Join Date: Jul 2006 Location: Leander, Texas Posts: 850	Re: Little Black smoke from the new Crate 350 .60 sounds like a pretty big gap even for a hot ignition. Might try closing it a little. I run a full MSD 6AL with a blaster coil and only run about .45 Any more and it runs goofy. Nothing wrong with timing by feel. When you retard it remember a sharpy mark is about 2 degrees. How big is your motor and how big is the carb? Thanks, Bryan

08-01-2006, 01:50 PM	#8
bryanw1968 Senior Member Join Date: Jul 2006 Location: Leander, Texas Posts: 850	Re: Little Black smoke from the new Crate 350 Duh.... You're original post said you had a new crate 350 and I asked what size your motor was. Doh!

08-01-2006, 02:02 PM	#9
wolfthing2000 Account Suspended Join Date: Oct 2004 Posts: 1,276	Re: Little Black smoke from the new Crate 350 Please guys, .060 and .045

08-01-2006, 04:32 PM	#11
wolfthing2000 Account Suspended Join Date: Oct 2004 Posts: 1,276	Re: Little Black smoke from the new Crate 350 The .060 sounds right for the HEI

08-02-2006, 11:14 AM	#12
bryanw1968 Senior Member Join Date: Jul 2006 Location: Leander, Texas Posts: 850	Re: Little Black smoke from the new Crate 350 Here is a similar motor to yours and they recommend .045. http://www.sallee-chevrolet.com/fram...90hp350gm.html You might try .060 to see what happens though. However, if you don't have enough charge going to that plug you might not properly fill the gap and misfire. Good luck B

08-02-2006, 04:17 PM	#13
JAKES 68GMC Aluminum slot wheels rule... Join Date: Jan 2006 Location: Maine Posts: 6,212	Re: Little Black smoke from the new Crate 350 My truck black smokes when you rev it, like its too rich. I've done everything there is to do to try and fix it. Timing, carb adjustments, plugs. I've got it running almost perfect and it still smokes when you rev it. So I just live with it.



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