Comments on these chambers' burn pattern?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Comments on these chambers' burn pattern?

Post by BradH » Tue Apr 09, 2019 6:00 pm

Anyone have thoughts or comments on the burn pattern of these chambers? I don't really know enough to say anything one way or the other...

FWIW, this is the result of 25+ pulls on the dyno using a 50/50 blend of Sunoco 110 leaded and 93 E10 pump. Thanks - Brad
.
Burn pattern.jpg
You do not have the required permissions to view the files attached to this post.

JoePorting
Guru
Guru
Posts: 2667
Joined: Mon Jun 14, 2010 3:16 pm
Location: Lake Elizabeth, CA

Re: Comments on these chambers' burn pattern?

Post by JoePorting » Tue Apr 09, 2019 7:21 pm

What casting is that? I don't recognize it. The exhaust port shows a lot of pitting. We're you running a lean mixture or lots of nitrous?

I thought I was the only one who made SBC Chambers that big. lol
Joe Facciano

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Re: Comments on these chambers' burn pattern?

Post by BradH » Tue Apr 09, 2019 8:56 pm

It's the poor man's approach to building a 15*-head stroker small block... with an absurdly high bob weight... a stock 3.75"-stroke BB Mopar.

Edelbrock Victors with the chambers CNC'd by a small Mopar-oriented shop. CR is a hair under 11.5 with flat-top 4.380" pistons and .040" quench.

No N2O, but most of the carbs tested were lean. It's not pitting, but the carbon buildup looks kinda that way.

cgarb
Guru
Guru
Posts: 1706
Joined: Wed Jul 09, 2014 11:50 am
Location: Maryland

Re: Comments on these chambers' burn pattern?

Post by cgarb » Tue Apr 09, 2019 9:07 pm

Poor man!?! You did say Mopar correct?

cgarb
Guru
Guru
Posts: 1706
Joined: Wed Jul 09, 2014 11:50 am
Location: Maryland

Re: Comments on these chambers' burn pattern?

Post by cgarb » Tue Apr 09, 2019 9:08 pm

OK, nevermind...now I know why your poor...lol.

1972ho
Expert
Expert
Posts: 692
Joined: Thu Nov 21, 2013 12:52 am

Re: Comments on these chambers' burn pattern?

Post by 1972ho » Tue Apr 09, 2019 9:20 pm

Wouldn’t it be better to show the tops of the pistons.

mag2555
Guru
Guru
Posts: 2605
Joined: Sun Sep 18, 2011 11:31 am

Re: Comments on these chambers' burn pattern?

Post by mag2555 » Wed Apr 10, 2019 6:52 am

Please post up a picture of the plugs.

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Re: Comments on these chambers' burn pattern?

Post by BradH » Wed Apr 10, 2019 10:08 am

1972ho wrote:
Tue Apr 09, 2019 9:20 pm
Wouldn’t it be better to show the tops of the pistons.
"Better"? Not necessarily, since I believe the chambers may indicate things that aren't obvious w/ seeing only the tops of the pistons. I'll get pics of the corresponding pistons when I get a chance.

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Re: Comments on these chambers' burn pattern?

Post by BradH » Wed Apr 10, 2019 10:09 am

mag2555 wrote:
Wed Apr 10, 2019 6:52 am
Please post up a picture of the plugs.
I'll get pics of the plugs when I get pics of the pistons.

Newold1
Guru
Guru
Posts: 1844
Joined: Fri Apr 08, 2016 9:50 am

Re: Comments on these chambers' burn pattern?

Post by Newold1 » Wed Apr 10, 2019 10:54 am

Curious what leakdowns would measure on the cylinders if it was done before teardown?

What were air/fuels measured on dyno pulls?

Were any jet changes made between pulls?

As others here asked, what do piston tops and plugs look like?
The Older I Get, The Dumber I Get :wink:

Krooser
Guru
Guru
Posts: 1396
Joined: Wed Jul 31, 2013 10:14 pm
Location: Tropical Wisconsin

Re: Comments on these chambers' burn pattern?

Post by Krooser » Wed Apr 10, 2019 11:56 am

cgarb wrote:
Tue Apr 09, 2019 9:08 pm
OK, nevermind...now I know why your poor...lol.
When a 800hp fake Chevy dirt motor sells for less than $30,000 you will have a point.
Last place in the B-main is better than anyplace in the grandstands...

Powertrip
Pro
Pro
Posts: 260
Joined: Sat Feb 10, 2007 11:09 am
Location: North West Indiana

Re: Comments on these chambers' burn pattern?

Post by Powertrip » Thu Apr 11, 2019 4:49 am

What is the quench clearance?
The price of progress is trouble.

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Re: Comments on these chambers' burn pattern?

Post by BradH » Thu Apr 11, 2019 8:51 pm

Piston tops for 1 & 3 (same as chambers shown) and 8 & 6
.
Piston tops 1_3.jpg
.
Piston tops 8_6.jpg
You do not have the required permissions to view the files attached to this post.

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Re: Comments on these chambers' burn pattern?

Post by BradH » Thu Apr 11, 2019 8:52 pm

Plugs for 1/3/5/7 and 8/6/4/2
.
Plugs 1-3-5-7.jpg
.
Plugs 8-6-4-2.jpg
You do not have the required permissions to view the files attached to this post.

BradH
Expert
Expert
Posts: 686
Joined: Wed Apr 03, 2013 11:34 am

Re: Comments on these chambers' burn pattern?

Post by BradH » Thu Apr 11, 2019 9:03 pm

FWIW, we ran timing at 34 / 36 / 38; 34 wasn't that good, 36 was better, 38 was a tad better than 36 at peak HP. I was thinking it was going to "like" 35-ish like the old heads, but the additional timing made a significant improvement.

I brought a few 4150 carbs, but they weren't dialed in well at the time (new stuff I hadn't tested before). We spent some time working with two in particular (a 1.50" v downleg and a 1.58" v annular), but the AFRs were still in the high 13s. We then tested a smaller shop carb (1.40"? v downleg) that was in the high 12s to low 13s IIRC (don't have the printouts in front of me) that made as much power as the bigger carbs that needed additional tuning time.

Oh, no before or after leakdown tests. This was a re-hone & re-ring job on the shortblock, but with new heads, cam & intake.
Last edited by BradH on Thu Apr 11, 2019 9:59 pm, edited 1 time in total.

Post Reply