Triple Stromberg 97 drivability problem

[Henry Floored]

Guys I’m getting a car in that’s powered by a 276” Flathead I built a year or so ago. It’s got a Max 1 cam, fully ported but not relieved. It’s topped off by Offy heads and an Offy three carb intake with Stromberg 97’s and a progressive linkage.

Also the engine is backed by a modern AOD transmission with a 2200 stall speed converter I’m told. (I didn’t have any part in the transmission installation)

The owner loves the way it runs and drives (channeled ‘32 pickup) right up until he pedals it enough to open the secondary carbs.

His description was that it immediately starts “pinging and banging and obviously doesn’t perform properly”

Forgot to mention it has a Mallory distributor.

My initial thought was as the secondary carbs are opening the thing is going dead lean and causing all these problems. I’ll know more when I actually get the truck home.

My question is what are your thoughts and have any of you run into this problem yourself? Anything is appreciated.

Also have a very happy and blessed Easter gang. Thank you.

[glennpm]

I'd disconnect the progressive linkage and check how it runs with just the center carb. It could also be an issue with the distributor advance. You may get help with this thread too.

https://www.fordbarn.com/forum/showt...essive+linkage

[Henry Floored]

Originally Posted by glennpm

I'd disconnect the progressive linkage and check how it runs with just the center carb. It could also be an issue with the distributor advance. You may get help with this thread too.

https://www.fordbarn.com/forum/showt...essive+linkage

Thanks Glen will take your advice. Also thanks for the link. I appreciate it!

[glennpm]

I also agree that with the pinging, it is lean. I bet the Mallory is over-advanced or the curve is wrong. Could be a large vacuum leak too.

[Bored&Stroked]

Hopefully you're running accel pumps on the outer two carbs . . . as you need the squirt of fuel when the throttle-plates open to prevent a lean condition.

I'd also check the position of the accel-pump push-rod mount at the bottom. I usually end up with the outer position- adds more fuel earlier and in a higher volume.

After checking the timing (I'd set it to about 24 degrees TOTAL advance), you might also consider running all three carbs in a straight linkage.

[Henry Floored]

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Thanks guys! I’ll be checking these things.

[Tim Ayers]

Originally Posted by Bored&Stroked

Hopefully you're running accel pumps on the outer two carbs . . . as you need the squirt of fuel when the throttle-plates open to prevent a lean condition.

I'd also check the position of the accel-pump push-rod mount at the bottom. I usually end up with the outer position- adds more fuel earlier and in a higher volume.

After checking the timing (I'd set it to about 24 degrees TOTAL advance), you might also consider running all three carbs in a straight linkage.

I agree with all of the above posts by B&S and Glenpm. I also agree with getting rid of the progressive linkage. It's not needed IMHO.

[aussie merc]

first find out if its a 2barrel idle or a 6 barrel idle it may be as simple as the outers are just gummed up from sitting Lots of luck 3x2 looks cool until they arnt One of the best ive seen was 2x2 primary [front and back] topped up by a1x2 in the center different but it worked and didn't mess with the intake flows also a lot of 3x2 dont have a lot of runner length so often carb spacers work wonders

[tubman]

To expand on this, why not block off the center carb and run it like a "Super" dual with straight linkage.

[Henry Floored]

Thanks guys. Lots of food for thought here.