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Discussion Starter #1
Has anybody had any experience with them causing a problem with individual cylinder flow?
I have a friend / customer who has a SBF built by Mike Janis with BT 4.3 heads and nitrous. No matter how much attention is paid to #5 cylinder, the plug keeps getting hot. Timing is all out and a bunch of nitrous also pulled. Nozzles are clear and flow fine. New piston with rings was just installed and still having an issue.
The only opinion I have is that the intake is causing a problem. It seems to be a real nice piece with a beautiful port job. The customer is considering going to sheet metal but really doesn't want to. The engine is built right with nothing spared so far. It's starting to get very discouraging for him.
Any thoughts?
 

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Discussion Starter #2
Chambers are softened, 12.5:1 compression, coated diamond pistons. We thought it may be the forward facing scoop but it happened once last year without it.
 

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Has the intake been on a flow bench.I would think that would help with the troubleshooting.Also,how the cooling system flow?
 

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We ran bt 4.3s and their intake with no issues. The corner 4 cyls had to be tweaked i think we had 2 deg max out on those 4.What firing order are u running we ended up with the stock 351 windsor order tried the early 302 with a 2-8 swap aka 4-7.The 351stock order worked best in our case
 

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I ran one earlier this year. It had a dry plate on it w/ EFI. The corners were terrible. It was like the 4 center cylinders were getting all the nitrous and doing all the work. Are you guys using a plate or fogger?

As for what Steve touched on, I was pulling as much as 20% of fuel out the corner cyl's and those plugs were still pig rich.
 

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Discussion Starter #7 (Edited)
Bykr, I wasn't involved in the engine build so I don't have any flow data from the intake. I know it was purchased from AJ Powell so I assume it was taken care of. The cooling system works flawlessly.

10inchbuick, it has the standard 351W firing order.

Steve, # 5 had been knocked down to 28n 22f on both systems. I want to say there is a 34N in the 1st and a 30N in the 2nd. I haven't been to the track with him nearly as much this year as I have been buried with work.

Joshgn, the car has 2 IS foggers.
 

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Discussion Starter #8
1 degree of timing left in #5 lol
34N corners 36N centers on the 1st stage.
30N on the 2nd.
 

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Discussion Starter #9
Just talked to another member with the exact same issue. Run and data look perfect, no sign of any problems and does his due diligence to keep the tune in check. Same combo, same intake, same cylinder.
The only difference between them is he is EFI, my buddies is carbed. Both cars are running lexan scoops as well.
 

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I learned this the hard way as didnt catch on to it at first, but on the MSD software you have:

#1= 1cyl
#2= 3cyl
#3= 7cyl
#4= 2cyl
#5= 6cyl
#6= 5cyl
#7= 4cyl
#8= 8cyl

so #6 in software where you make changes is actually #6 on the list. also providing you have the correct firing order programed into the box.

mine is different as I run the A fire firing order. like the poster above said 2-8 swap on the old 302 firing order, which is same as 1-6 swap on late model firing order
 

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Discussion Starter #11
Hey Sam, the firing order in the MSD is one thing we make sure is correct. I did that with my car 1st time out until a local tuner said "hey, double check this.". LOL
 

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Discussion Starter #13
I guess the safest thing to do is have the intake flowed and see if there is any turbulence or something going on. I wonder if they could duplicate air flow with the carb and lexan scoop on it.
 

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Having the same issue on #6 on our new motor with the sc1. Very discouraging. Took a 4.80 motor apart and sold it to buy better shit and it eats plugs like a 5 yield eats pez.Please pass the hammer!
 

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Discussion Starter #15
That sucks Kent. What intake are you using?
 

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Eddy 2868 with 2 IS foggers. Gonna test tonight in hi 90 deg. weather but we gotta test. Made some adj. Just hope they work.
 

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I think you guys are focusing too hard, on the wrong area. EVERY motor, regardless of brand, favors a certain hole and many times, it is a corner. Not just a FORD thing, it's ANY motor. While the intake MIGHT be part of it, I highly doubt it. Seen many guys go to sheetmetal and two carbs, only to have the same EXACT issue, on the same EXACT hole. The problem is generally limited to a few things. One is a mechanical thing, like piston sealing, valve sealing, water circulation, etc..........or, just the fact that motors have hot holes, which is usually related to flame front speed. How to fix it varies. Less timing, less nitrous are obvious choices, but there are other ways as well. The following is things I have done, to various motors..............more head gasket on one bank (ie, less compression) chamber mods, spark plug mods.........basically just whatever it takes, to get a problem hole in line.

In a perfect world, an 800hp motor, would make 100hp per hole...........problem is, this is NOT a perfect world and it rarely if ever works out that way, so you do what you have to do to fix it. Don't get too caught up in the fact that you have to soften a hole up...........most everyone else does to. If you have to take power from that hole, timing from that hole, or compression from that hole, so be it. Are you more worried about things being all equal, or the motor living.

Monte
 

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Agree with Monte, I see guys spend so much time testing chasing down one hole and when/if they ever get it right the net result is a pretty set of spark plugs and not much more. The net results in performance will be minimal if any..

ever considered throwing a colder plug in the cylinder if your out of timing?
 

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Lol, I don't care about a pretty set of plugs but I would be able to look at the strap ! What's the most you guys have handicapped a cylinder? Ours looks like it will need to be significant. Hopefully we make some headway tonight.
 

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Discussion Starter #20
I was trying to find a common theme between that intake and the #5 hole. There seems to be a couple people experiencing the Exact same issue with the exact same hole. That cylinder is more than a little handicapped, it's a huge problem an wont take anything more than 2 28N jets. The plugs are NGK -11 with a .026 gap.
 
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