Anyone Running Earl Edgerton mild grind and stock 1BBL ?

[James_Douglas]

Hi All,

 

I am dropping off a cam for Earl to regrind.  I run the fluid couplings in my cars.

 

In stop and go driving with the fluid drive you MUST use the dashpot or if you start off from a stop sign and then have to pull your foot off of the pedal in a hurry you will kill the engine.  It is worse in a heavy car than a lighter one.

 

The original electronic dashpot is not adjustable.  In the big Desoto Suburban when I put in the 3-speed (with fluid coupling) and OD the problem was worse.  I found a later carb that had a mechanical dashpot that I could adjust to dial it in.  Now works just fine.

 

I am rebuilding an engine for the '49 Convertible, that one having the block issue, and I have to regrind a cam.

 

This car is engine wise dead stock.  Fluid Coupling and M6 trans.  I do not want to use a different carb.

 

So, my issue is this.  Earl's stock grind and his mild grind:

 

Stock grind;  250 Dur @ Lash; 200 Dur @ .050; .375 Lift

Mild Grind:  260 Dur @ Lash; 220Dur @ .050; .410 lift

 

If I go with the mild grind, will the vacuum change at low RPM COUPLED WITH THE FLUID COUPLING cause more revision and make the off idle go-stop on the throttle issue rear its ugly head?

 

All you guys with regular clutch and trans without fluid drive...this will never effect you. 

 

So, I am looking for someone out there that has Earl's mild grind in his car and is using the single Carter 1BBL. What I would like to ask is for that person, if it exists on the board, to take an at idle vacuum reading for me and tell me what that is with that cam.

 

I am assuming you have a newer strong engine.

 

If anyone has a fluid drive car with Earls mild grind in it and can do the same...that would be great.

 

Thanks, James.

[Jeff Balazs]

James;

You might be able to tell something about this from someone ....anyone who has one of these cams and a single carb setup. I believe what you are looking for is a steady vacuum reading at idle. At least that is what the fluid drive in my 52 3/4 ton wants and responds well to. It weighs a shade over 4000#.......so fairly heavy. The fluid drive feature did not work well at all until I got a good steady vacuum reading at idle. Anything between 18" and 21" works fine .......as long as it is steady. My feeling about this is they function poorly if the needle is bouncing at all. When I first got this thing running I had about a 1" or less bounce on the gauge and it did not work worth a darn.

 

Jeff

[greg g]

Does any one have the stock cam specs?

[mopar_earl]

I believe I saw in the carb kit that the dashpot can be adjusted mechanically. The solenoid just activates the dashpot passage in the carb. I don't recall how it said to adjust it. I believe you adjust it to a certain height. Which you could probably play with different height adjustments.

Earl

[James_Douglas]

Jeff & Earl,

 

Thanks.  My M5/M6 Semi automatics work fine.  The issue is not one with the shifting.

 

 

"Vehicles, particularly those employing automatic transmissions, use a dashpot to arrest or time delay the final closing movement of the engine throttle valve located in the carburetor of the engine to prevent stalling during deceleration.

 

This stalling is caused by the sudden decrease in the intake manifold pressure when the throttle is closed, which vaporizes condensed fuel collected on the inner surface of the manifold during normal engine operation.

 

This vaporized fuel, together with the decrease in the air supply, creates a fuel mixture which is far too rich to burn properly. The above described dashpot arrangement, which causes a time delay in the final closing movement of the engine throttle, produces an air-fuel mixture that may be properly burned by the internal combustion engine, thereby preventing the stalling action."

 

What causes the stall off a stop on a fluid drive car, or any modern carb automatic, is that drop in pressure.  What I am concerned about is that the non-adjustable electric dashpot will not be able to delay the closing of the butterfly enough to compensate for a non-stock cam pressure drop which may well be a lot more of a "spread" than a stock one on closing.

 

I have an adjustable dashpot on the big Desoto with the 3-speed and fluid drive.  Only on Dodge was used for a year on their fluid drive with 3-speed set up. On the convertible everything is stock and I cannot change it over as I am still using the M5/M6.

 

Hence why I am looking for someone with one of EE's mild cams and a fluid drive with M5/M6 car...

 

 

[James_Douglas]

Does any one have the stock cam specs?

Look at my first post.

[greg g]

duh I read that as mild V less mild.  It would seem that you wouldn't notice much difference with those numbers.  The increase in duration moves the power slightly up the rpm band and will slightly drop manifold vacuum a couple of inches at idle. Seems you would see that reduced signal sooner.  Does that suggest the dash pot would come into effect earlier and stay in play longer? 

[Jeff Balazs]

James;

I didn't think you were worried about shifting. The question is how is the fluid drive going to behave when at idle. My feeling is it will work OK as long as you don't get a fluctuating vacuum reading.at idle with this cam. If you don't have a steady vacuum reading of 18" or above at idle then I believe you won't be able to get it to work properly.

Good luck finding some one with this exact combination.

 

Jeff. 

[55 Fargo]

16" -21" at idle for a stock engine, or a mild cam performance change, should yield a steady reading of 16"-21".

radical high perf cam profiles will result ina lower somewhat unsteady vacuum reading at idle...... I would think Mr Edgy shall be able to confirm what's to be expected  vaccum and idle readings after this stock cam has been altered....