Next Step Carb

6

66Sprinter

Famous Member
VIP
Well I have been driving my car for about a week now and after the engine rebuild some of the momentary excitement has worn off and now I am not sure the 1100 was the best fit for my new engine. Originally it had a fuel overflow problem, but a rebuild by PONY helped. But not quite all the way. Sometimes I still see gas on the manifold or smell it. My fittings are tight, good clean fuel at 5psi and good vacuum at 1000 rpms but jumpy when I am lower. I am running a 1.5" reducer to the 1.75" intake.

What gets me is that I dont have the jump from idle that I thought I would have gotten. Once into first and above 1500 rpms...I am pulling good, but its tough to down shift smoothly and I think she is bogging some. My idle is closer to 1000 then 750. The cam is partly the cause of this..but still what is the next step for me in carbs. I am throwing mileage out and want performance and driveability from idle...

Here are my specs: 1.39EX/1.65INT 450 lift with 268 duration cam with 216@50deg. Timing is just right with the DUI (by ear). I have had some discussions about a Weber 38DGES with a guy at Clifford and also a Holley 2100. Both require some work...to fit..but OK..it does. Another guy suggested I tame the cam some and drop back to a single pattern cam at 264?

Again, the champagne and caviar are long gone and now its ready to face reality and I think the 1100 is not going to make it?

David, Addo?? Anybody with thoughts on this! Take your shots.

Jim in MO (Headed to the Cotton Bowl Jan 2!)
 
Hey you're heading to the Cotton Bowl on the 2nd? You going to be in town for a while? If you're up for it, I've just put my engine in, and I'd be happy to look at yours. Not sure if I can help a whole lot, but it's worth a shot
 
Wow,

I am moving to Mesquite/Garland and will be towing my truck. My mustang will come down later in 08.

Did you build your engine...what carb are you runnin.
 
Yea it's an all new 66 block, 70 head, with C4 trans, and a H/W 5200 with a DSII. But, it's still not been started. I'm hoping tomorrow.
 
did you get your stuff from Langdons in utica, MI?

Looks familiar I was wondering how stable is the engine whit larger parts aroudn it!
 
Good point. 5psi is factory and thats what my pump is doing.

PONY says that this is not the issue. They tested the carb on a stock engine. (There was no way to mock up a build one!)

I was considering using a Holley regulator to bring down the pressure to 2.5-3psi...and see if that will hold. If so, then I have another problem, the engine will probably starve on the high end when I need more fuel in the bowl?

Does anyone want to compaire the Holley 2100, the Weber 38DGES and the H/W 5200 maybe give me a hint which would fit my specs better?

Jim (in Muskogee tonite - and Dallas on Sunday!)
 
Howdy Jim and All:

Nice problem!!

To begin with the stock '66 1100 is not going to be completely compatible with your MSD distributor if it still has a SCV. With that cam, it probably will do better, regardless of what non-SCV carb you go to, with a full manifold vacuum source for the vacuum advance, because of the duration of the cam.

You didn't say what CR your new engine is running? With that cam you will need to get it up in the 9.2 to 9.5:1 CR to make up for the loss to bottom end torque. At least try to maximize your initial advance to help to build low rpm cylinder pressures

The good news is that you have upgraded to a 3.25:1 rear axle ratio. Did you loosen the torque converter on the rebuild?

Your combo is begging to be put to work at a higher rpm range than your 1100 is capable of. You might try adjusting the accelerator pump circuit for a bigger shot at take-off.

A small Holley/Weber 5200 will only be a half a step toward your engines potential. Many here like this carb for mild upgrades and economy. The Weber DGESs are pretty pricey, but a better performance choice than a Holley/Weber progressive two barrel. IIRC these are rated @ 360 cfm.

A two barrel 2300 Holley #7448 @ 350 cfm or an Autolite 2100, 1.21 @351 cfm will get you into the neighborhood you want to roam. The Holley will require a little more fine tuning but may have a little better top end. The Autolite will be simpler to tune and rebuild, and may have better driveability due to the Annular discharge boosters. Either should be mounted directly to the log- NO ADAPTER!!!

Both will have a source for full manifold vacuum as well as a ported vacuum source, for experimentation. Most often, and engine with this much cam will not produce enough ported vacuum signal to get a correct response in vacuum advance. You will need to try both to see what works best in your situation.

What do you think?

Happy New Year.

Adios, David
 
Thank you David,

Happy New Year to all the FSPP members. I hope you all get as much fun from your 6's as you can.

On the 2100, David, am I correct in interpreting that you want to modify the log to bolt the 2100 on directly, so we are not using a 2-1 adaptor.

I am investigating a purchase or swap for my 1100 as we speak.

I have the 9.5:1 ratio for CR. Unless there is something called a torque converter on the rear, I have a T5 so no torque converter is needed. The 1100 has no SCV.
 
Howdy back:

Q- "am I correct in interpreting that you want to modify the log to bolt the 2100 on directly, so we are not using a 2-1 adaptor?"

A- Yes. Again your engine parts are past what a funnel adapter will be able to support. To get the full potential of a 350 CFm 2 barrel carb you will need to mount it directly to a modified log.

FYI- a 2100 is an Autolite 2 barrel designation. A Holley 2 barrel is a 2300 series. While they share many qualities and dimensions they are very distinct and different.

YOur 1100 Pony carb should be quite a popular item by many on this forum. If the trade doesn't work out, list it in the classified section.

Keep us posted.

Adios, David
 
Dave, this is a real learning process for me and hopefull for others here too!

To make this mod, I will need to remove the log/head and get the facing done at a good machine shop. (Sorta wish I had the money for the FSPP head now!) I can use my son for some of the leg work while he is at home from college right now. (BTW...the Cotton Bowl was awesome!!)

Meanwhile, I wonder if adding a fuel regulator will at least allow the carb to run the engine, even without the top end. There seems to be some really 'HOT STOVE" opinions about this problem of mine.

A certain tech at PONY says that 4-6psi is OK and the problem has to be dirt in the needle or sticking float. He refuses to sell me a 2100!

Another at Clifford says my cam is all wrong and the engine will never run right without using his 224 cam and his Weber 38 plus his fuel regulator. (Convient that he sells this kit with the linkeage)

A third from Stovebolt says the 2100 two bbl, progressive. with an adaptor is the only way to control the small amount of fuel at idle and low rpms, until the secondary comes in to allow the top end to run at its potential.

Yet another tech at Gateway says the fuel pressure is too high, (considering its not a bad needle/seat or a bad float) so a regulator at 2.5 - 3pis will be best. (But I will have to give up the top end.)

Lastly, a nod was given to getting an RBS carb or similar from the 70;s which was the original 1/75" intake bore for that log head.

I did my research and from what I determined, the engine is on spec for what I asked for. The cam, headers, everything is exactly what I wanted, with the right HP and mated with the DUI, it should flat out run. I did not really give the carb a second thought until now. I figured it would run for a year or less until I could get the FSPP head and a real 2bbl like the 2100.

So I am just tossing this out and wondering what you guys think!

Jim - Dallas is home now.
 
I think we are all living proof here that pony is wrong when they say a 6 can never run correctly with a 2bbl. I have a holley 2300 350cfm right out of the box no mods. The motor has stock cam pistons and head with the carb adapter and dual exhaust out dual headers. With you higher lift cam and larger valves you should be able to take even more advantage of the carb than i can. My car has the best power and runs much smoother with this carb than any 1bbl.
 
My nature is to follow rather than lead. I initially trust everyone..until burned. When I originally talked with this guy, he assured me that he knew everything there ever was to know about carbs and the ones he builds.

When I mentioned that my motor was different and had more HP because of the mods, cam , decking etc,....he stated that I really didnt get what I asked for...there was no real HP gain>>>>>? At that point, I was already in for a carb and rebuild, but it stock with me about the attitude. When I called around to Clifford I seemed to have gotten the a guy from the same school..."Listen to me...those other guys dont know anything"..

Thats why the forum is more valuable than it gets credit for!
 
You're obviously willing to commit some more money.

I also think your wife is a "keeper" because she worked hard to get the car ready while you were busy. If you go changing stuff, won't it grate with her?

What about a little data acquisition... Some dyno runs that also log manifold pressure (vacuum) besides A/F ratio. Then we can all throw in our 2¢ worth based on facts!
 
Yes....my wife is a keeper (for 0ver 30yrs). Since I travel alot, she does get in the middle of things that I have started and keeps them going..or in this case finishes them off..while I am gone.

Some more money is required, dependant upon my money back guarantee from Pony! At the moment, I have ordered a Holley 1-4 psi regulator, just to see what happens with the 1100 with reduced pressure. Since I am not home, I have time to run the test and get more data.

Since the car wont run, cant be driven, I cant get it to a dyno. If the regulator gets me to idle, then I am there for the testing.
 
Timing is just right with the DUI (by ear).
Click to expand...

I think you need to spend some time and verify the timing and the advance that you are getting. A bigger carb is not going to help your low rpm drivability and could easily induce more bog in the engine.

Since you have a new cam, I would assume that the TDC timing mark on the balancer was verified when the cam was installed and that the indicated TDC is truly at TDC. Was the balancer replaced? Maybe it has slipped since the cam was installed.

Your low performance may very well be that you do not have enough ignition advance. Map your ignition advance. As David mentioned, I would use manifold vacuum for the ignition advance. Disconnect the vac line and plug it and get a dial back timing light to see how much advance you have at 500 rpm increments. Reconnect the vac advance line and repeat the procedure. Also get a vacuum gauge and look to see when the vacuum motor on the distributor starts advancing the timing and when it finishes. If you have a vaccum can that requires more vacuum to operate than what your engine generates, then you will have insufficient vacuum advance and inconsistent idle.
Doug
 
I do not have a vacuum can on the motor. I do have a booster unit for the dual M/C so I am sharing some there.

I will try to get setup for the weekend, so I can be on the phone while my son runs the car. By then I will be in Dubai..or at least Jordan...should be interesting.
 
I was referring to the vacuum operated motor or cannister that attaches to the distributor. The vacuum cannister motors are available with different operating ranges of vacuum. For instance, one for an engine with low vacuum may start operating at 3" of vac and be all in or fully deployed at 8". More commonly the range will be higher up to 15 or 16" of vac.
Doug
 
You must log in or register to reply here.

Similar threads

xavier296
All Small Six Ignition Timing Map
Replies
5
Views
386
xavier296
xavier296
A
All Small Six Low throttle fuel flow
Replies
11
Views
582
drag-200stang
drag-200stang
S
All Small Six Holley EFI and Ignition in 200
Replies
4
Views
643
xavier296
xavier296
S
All Small Six EFI with Duraspark ignition
Replies
0
Views
303
Stuffsarebeast
S
F
All Small Six Cam Advice (2nd try)
Replies
14
Views
996
awasson
awasson
Back
Top