I know it’s been discussed before but I couldn’t find much.

511 BBC with hilborn stacks and a 110 pump. Parked near the gate at Huntsville I used 1.75 gallons if I had it leaned out on the way up. Pretty close to 2 gallons round trip with the fuel full open. It’s a longish drive back from the turnoff but not terrible.


I was thinking I should be closer to 1.5 gallons per pass but everything is working good so not sure how much I should mess with it.

I know the blades are too far open because I can lean it out to about 3-4K but the blade gap is inconsistent so I set them where it will hit on all 8 at idle.

One other note. The temp gauge is in the block and it’s pretty easy to maintain 160-180. If I was measuring in the head I don’t how much different it might be.

blade gap is inconsistent.
????? what? why?

quote:

Originally posted by Dave Koehler:
blade gap is inconsistent.
????? what? why?

It’s a 50 year old Hilborn setup. I talked to the guy that built it, did the reset twice just like he said. He told me, ya, we weren’t very good at making shafts back then. I then did the “other” procedure he recommended which involves two really big pry bars. It seemed to help at the time but I think they “crept” back to their original postitions.

It sounds like you already know the answer to your question...

If you tighten the blade gap some and lean the barrel valve you’ll use less fuel. You’ll also raise the engine temperature.

We burn about a gallon per run, terminator injected big blocks in dragsters going 7.40s. Drive up on gas back on alcohol.

quote:

Originally posted by BJs Wild Ride:

quote:

Originally posted by Dave Koehler:
blade gap is inconsistent.
????? what? why?

It’s a 50 year old Hilborn setup. I talked to the guy that built it, did the reset twice just like he said. He told me, ya, we weren’t very good at making shafts back then. I then did the “other” procedure he recommended which involves two really big pry bars. It seemed to help at the time but I think they “crept” back to their original postitions.

I still don't understand your problem.
Are the shafts or shaft bores worn out?
Is the BF clearance different or changing from side to side?
Do you have stops on all 4 corners?

Ship injection to Dave, problem solved.

Dave, the shafts aren’t straight. That’s right from the horses mouth. Stops on the back of the shafts only. 1,2,3,5,7 are pretty close. If I get those right, 4,6, and 8 are closed and won’t fire.

Mostly just looking to see how much fuel I could save if I got real serious about fixing it. If the best injected bbc out there takes 1.5 for a round trip, not much to be gained. If I should be closer to 1 gallon per run maybe I’d be more motivated.

quote:

Originally posted by 183N:
...
If you tighten the blade gap some and lean the barrel valve you’ll use less fuel. You’ll also raise the engine temperature.

We burn about a gallon per run, terminator injected big blocks in dragsters going 7.40s. Drive up on gas back on alcohol.

If I tighten up the blade gap it runs ALOT cooler because it only idles on 5 cylinders

Have you ever run yours without the primer to know how much more alky you burn?

I've run 2 cars with Terminators

Old car had just a gas primer and I would bring 24 gallons of alcohol with me to a Lucas Series race...

Warm ups each day and 3 time runs....and make 7 runs to win the race. I was basically out of alcohol....So 10 runs to burn about 22-23 gallons...That is actual fuel used for those 10 runs...

The Second car I had a Terminator and a Primer Plus and I am sure I used no more than 1-1/2 gals per run and usually less....Very easy to warm up and head to the lanes on gasoline.....Make the run and drive back on methanol....

Bracket 565 with Rons terminator I would use about 1.5 gallons driving to the lanes and back to the pits after the run. On the TD I use 5 gallons towing too and from on a 1/4 mile pass lol

What about drilling small holes in the butterflies on 4,6 and 8? If you don't know a reason not to do this make sure people who know a lot more than me say it's OK.

quote:

Originally posted by BJs Wild Ride:
Dave, the shafts aren’t straight. That’s right from the horses mouth. Stops on the back of the shafts only. 1,2,3,5,7 are pretty close. If I get those right, 4,6, and 8 are closed and won’t fire.

Mostly just looking to see how much fuel I could save if I got real serious about fixing it. If the best injected bbc out there takes 1.5 for a round trip, not much to be gained. If I should be closer to 1 gallon per run maybe I’d be more motivated.

Seems to me you have 3 options.
1: Get new shafts by any means possible
2: Put this "seasoned" "nostalgia" mess up on Ebay
3: Crutch it like you are and quit worrying about fuel mileage. You don't race at idle.

Just a thought.
The problem is on one bank.
You don't by chance have 4,6 and 8 BFs in backwards?

quote:

Originally posted by Dave Koehler:
Just a thought.
The problem is on one bank.
You don't by chance have 4,6 and 8 BFs in backwards?

The whole car is kind of a “seasoned mess” so I hate to break up the party.

I would think I would have noticed butterfly’s in backwards but it’s definetely worth a second look. The stacks are a complete pain in the rear to R&R but you have me curious enough to want to give it a look before next race.

quote:

Originally posted by BJs Wild Ride:

quote:

Originally posted by Dave Koehler:
Just a thought.
The problem is on one bank.
You don't by chance have 4,6 and 8 BFs in backwards?

The whole car is kind of a “seasoned mess” so I hate to break up the party.

I would think I would have noticed butterfly’s in backwards but it’s definetely worth a second look. The stacks are a complete pain in the rear to R&R but you have me curious enough to want to give it a look before next race.

Backward BFs happen more than one would think. Likely because most folks don't realize the edges are cut on an angle but it sure throws things off if backwards.

have 586 with DSR injection, running 730s uses about 2 1/2 gall a run, but drive it up run and drive back...still cheaper than gas lol

Something else to look at while investigating your issue.
I haven't touched one of those 1960s-1970s stack units in about 20 years but I seem to recall the blades were not real thick.
A good engine backfire could bend those.

If you find it is a shaft only problem will you order up a new shaft?

Can you carefully file the edge down on the BF that are not open at the correct settings?

quote:

Originally posted by RyanNorton1:
Can you carefully file the edge down on the BF that are not open at the correct settings?

That would be a No.
It would then wind up with an oval plate in a round hole leading to a worse idle leak on those cylinders than he has now.

If they are not upside down/backwards/bent as mentioned earlier then new parts are the only course of action.

We’re running the blower car this weekend so haven’t gotten to work on the injected car yet. I’m not sure if it would be worth it to change shafts to save ~1/4 a 1/2 gallon per pass. It’s the wife’s setup, I’ll let her decide.