The Ford Barn

Lawrie · 10-04-2022, 11:35 PM

Any one using the Mitchell and using the 3.54 rear end gears,
I have one coming for my 28 ccpu ,and would like to know how strong an engine you will need with the 3.54 rear end gears.
Lawrie

Synchro909 · 10-05-2022, 12:21 AM

Lawrie, I considered a 3.54 gear set with my Burtz engine and decided to wait. I'm happy I did. In fact, I am beginning to question whether I need the O/D at all with the new engine. It revs so freely and smoothly that if I were cruising at say, 55 mph in O/D, the car is now happy in ordinary 3rd gear and "singing" in a higher key at that speed. I have a virtually new 3.54 set on the shelf and if I don't use them in another of my cars, they will likely sit there for who knows how long.
How strong an engine? There have been a couple of times when I have forgotten to take the car out of O/D when I stopped and taken off in high first with the camper behind. Sure, it didn't make my cheeks go baggy when I pressed the accelerator but it did it. That engine was not as powerful as the one in your P/U but might have had more grunt t the bottom end.
A 3.54 diff and O/D is a pretty high ratio - about the same as using 5.25X21 tyres on the rear of a 3.78 diff. I run that on my tourer and it gallops along. Your engine will handle it easily.

Lawrie · 10-05-2022, 02:03 AM

Yes , no drama as I have a set of good original 3.78 gears.
I ment to tell you, you know you would be able to get .001 or .002 under bearings.

updraught · 10-05-2022, 07:14 AM

So how do you think a 3.27 diff would go with a Burtz?

I think it gives 15% taller in all gears.

dennis lumbert · 10-05-2022, 08:45 AM

I have a 30 Tudor with a AER touring engine with 5.5 head,V8 wheels 600-16 tires,3.54 gears..I like this combination very much.Not to many steep hills in my area but has no problem with them.I would have stayed with 3.78 gears with a stock engine.

nkaminar · 10-05-2022, 12:20 PM

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I am very happy with my Burtz engine, Mitchell overdrive, and 3.78 rear end. In overdrive it is like having a 3.0 rear end (about). I use second overdrive a lot in the hills were I live. I think 3.54 gears would be too tall.

Synchro909 · 10-05-2022, 04:36 PM

Quote:

Originally Posted by Lawrie

I ment to tell you, you know you would be able to get .001 or .002 under bearings.

L, I didn't know that but I'll keep it in mind for when the day comes that I need to do something. At the moment, it is going well.

Dale'45 · 10-05-2022, 05:29 PM

Lawrie,
Running 3.54 gears and a 26% overdrive gives you about a 2.60 final gear. I run a 3.78 gear with a 26% Mitchell and is a great combination with a stock engine. Mine would not like any taller gears. Cruises nice at 50 mph plus. Dale

ModelA29 · 10-09-2022, 01:48 PM

3.78 and the 26% OD gives you 66 mph at 2200 rpm. Direct is 53 mph.
1800 is 55 mph in OD.

Keith True · 10-09-2022, 01:59 PM

I went to put a Mitchell in my coupe,and found it had 3.54's.I put it in anyway,and it performs fine.I forget and drive it around a lot in high.I do find myself touching 60 quite a lot.Not sure how accurate my speedo is,at some point it will interest me enough to check it out.The previous owner thought it had a Brumfield head on it,at least that was what he was told when he bought it.It pulls fine.

MrBruce · 10-09-2022, 02:02 PM

Getting ready to do the Mitchell and have wondered about the 3:54 gears with a stock engine? I just picked up my engine and am debating putting the 6.0 head on it or just leave it stock? I have another rear end that I need to pickup this week and I think it's been gone through and is probably 3:78, so just need to decide if I need the HC head or just leave it stock with the overdrive and 3:78 gears?

walls · 10-09-2022, 02:59 PM

Quote:

Originally Posted by MrBruce

Getting ready to do the Mitchell and have wondered about the 3:54 gears with a stock engine? I just picked up my engine and am debating putting the 6.0 head on it or just leave it stock? I have another rear end that I need to pickup this week and I think it's been gone through and is probably 3:78, so just need to decide if I need the HC head or just leave it stock with the overdrive and 3:78 gears?

There’s no reason other than the cost of purchase to not use a high compression head.
Use a Snyder’s head and B carb if you want to look stock.
It’s a noticeable difference in performance.

Lawrie · 10-09-2022, 03:33 PM

OK , thanks for the info, I will take a chance and leave the 3.54 in and see how it goes, my engine is good, 6.2 head, 97 carb, and a stipe cam , its a Burtz engine .
Its only a few days work to change out the 3.54 gears for the 3.78 if I,m not happy with them
The Overdrive is a few months away , but will keep you posted how iy=t goes when it arrives.
Lawrie

Synchro909 · 10-09-2022, 06:56 PM

Quote:

Originally Posted by Lawrie

OK , thanks for the info, I will take a chance and leave the 3.54 in and see how it goes, my engine is good, 6.2 head, 97 carb, and a stipe cam , its a Burtz engine .
Its only a few days work to change out the 3.54 gears for the 3.78 if I,m not happy with them
The Overdrive is a few months away , but will keep you posted how iy=t goes when it arrives.
Lawrie

Lawrie, with that set up and on roads like that, please don't go past Mach 1.

TerryH · 10-09-2022, 10:10 PM

I have a 1930 Town Sedan, and had a Mitchell OD installed about 14 years ago, along with the 5.5 HC head, and it has the 3.78 rear end. The 4 doors are the heaviest Model A’s, and I would not recommend the 3.54 with the Mitchell, without some serious engine mods. Mine pulls the OD nicely…..very glad I did the 5.5 head too.

katy · 10-10-2022, 12:01 PM

Quote:

Originally Posted by Synchro909

Lawrie, with that set up and on roads like that, please don't go past Mach 1.

Do not lower windows at speeds in excess of 250kph.

Gene F · 10-10-2022, 06:32 PM

Quote:

Originally Posted by Synchro909

Lawrie, I considered a 3.54 gear set with my Burtz engine and decided to wait. I'm happy I did. In fact, I am beginning to question whether I need the O/D at all with the new engine. It revs so freely and smoothly that if I were cruising at say, 55 mph in O/D, the car is now happy in ordinary 3rd gear and "singing" in a higher key at that speed. I have a virtually new 3.54 set on the shelf and if I don't use them in another of my cars, they will likely sit there for who knows how long.
How strong an engine? There have been a couple of times when I have forgotten to take the car out of O/D when I stopped and taken off in high first with the camper behind. Sure, it didn't make my cheeks go baggy when I pressed the accelerator but it did it. That engine was not as powerful as the one in your P/U but might have had more grunt t the bottom end.
A 3.54 diff and O/D is a pretty high ratio - about the same as using 5.25X21 tyres on the rear of a 3.78 diff. I run that on my tourer and it gallops along. Your engine will handle it easily.

So can I ask....what if you never had an overdrive in the car behind your Burtz? Do you think you would eventaully snap a rod? With pressurized oiling on a scat crank don't you take the dipper tray out, and the rod caps have no dipper?

Synchro909 · 10-10-2022, 07:41 PM

Quote:

Originally Posted by Gene F

So can I ask....what if you never had an overdrive in the car behind your Burtz? Do you think you would eventaully snap a rod? I don't think snapping one of these rods is going to happen under about 6,000 revs. With pressurized oiling on a scat crank don't you take the dipper tray out, and the rod caps have no dipper? It depends which rods you are using. Unless the crankshaft were drilled for oil to the rods, the dipper tray would stay in there and the dippers on the rods would supply the oil to the big ends. In the Burtz engine, the crank is drilled so the rods are pressure fed While the dipper tray in theory would not be required, it is recommended that it be left there so that the rods will throw up a good oil mist to help lubricate other things like bores and valve gear.

My response is in red.

Gene F · 10-11-2022, 05:02 PM

Thanks Syncro.

ModelA29 · 10-11-2022, 05:14 PM

I would think the dipper tray acts as a windage tray in an engine with pressurized rod bearings.

https://www.enginelabs.com/engine-te...o-we-fight-it/

The idea behind a windage tray is that they provide a physical barrier between the violently moving crank with the oil it's throwing everywhere, and the oil supply, while still allowing oil to move back into the oil supply in a smoother, calmer manner.

10-04-2022, 11:35 PM	#1
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,221	Mitchell overdrive Any one using the Mitchell and using the 3.54 rear end gears, I have one coming for my 28 ccpu ,and would like to know how strong an engine you will need with the 3.54 rear end gears. Lawrie

10-05-2022, 12:21 AM	#2
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 7,496	Re: Mitchell overdrive Lawrie, I considered a 3.54 gear set with my Burtz engine and decided to wait. I'm happy I did. In fact, I am beginning to question whether I need the O/D at all with the new engine. It revs so freely and smoothly that if I were cruising at say, 55 mph in O/D, the car is now happy in ordinary 3rd gear and "singing" in a higher key at that speed. I have a virtually new 3.54 set on the shelf and if I don't use them in another of my cars, they will likely sit there for who knows how long. How strong an engine? There have been a couple of times when I have forgotten to take the car out of O/D when I stopped and taken off in high first with the camper behind. Sure, it didn't make my cheeks go baggy when I pressed the accelerator but it did it. That engine was not as powerful as the one in your P/U but might have had more grunt t the bottom end. A 3.54 diff and O/D is a pretty high ratio - about the same as using 5.25X21 tyres on the rear of a 3.78 diff. I run that on my tourer and it gallops along. Your engine will handle it easily. __________________ I'm part of the only ever generation with an analogue childhood and a digital adulthood.

10-05-2022, 02:03 AM	#3
Lawrie Senior Member Join Date: May 2010 Location: Qld, Australia Posts: 4,221	Re: Mitchell overdrive Yes , no drama as I have a set of good original 3.78 gears. I ment to tell you, you know you would be able to get .001 or .002 under bearings.

10-05-2022, 07:14 AM	#4
updraught Senior Member Join Date: Feb 2015 Location: Australia Posts: 1,971	Re: Mitchell overdrive So how do you think a 3.27 diff would go with a Burtz? I think it gives 15% taller in all gears.

10-05-2022, 08:45 AM	#5
dennis lumbert Senior Member Join Date: Feb 2011 Location: central Arkansas Posts: 150	Re: Mitchell overdrive I have a 30 Tudor with a AER touring engine with 5.5 head,V8 wheels 600-16 tires,3.54 gears..I like this combination very much.Not to many steep hills in my area but has no problem with them.I would have stayed with 3.78 gears with a stock engine.

10-05-2022, 12:20 PM	#6
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,903	Re: Mitchell overdrive Sponsored Links (Register now to hide all advertisements) I am very happy with my Burtz engine, Mitchell overdrive, and 3.78 rear end. In overdrive it is like having a 3.0 rear end (about). I use second overdrive a lot in the hills were I live. I think 3.54 gears would be too tall. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

10-05-2022, 05:29 PM	#8
Dale'45 Junior Member Join Date: Aug 2018 Location: Rubicon, Wi Posts: 19	Re: Mitchell overdrive Lawrie, Running 3.54 gears and a 26% overdrive gives you about a 2.60 final gear. I run a 3.78 gear with a 26% Mitchell and is a great combination with a stock engine. Mine would not like any taller gears. Cruises nice at 50 mph plus. Dale

10-09-2022, 01:48 PM	#9
ModelA29 Senior Member Join Date: Sep 2022 Location: SoCal Posts: 591	Re: Mitchell overdrive 3.78 and the 26% OD gives you 66 mph at 2200 rpm. Direct is 53 mph. 1800 is 55 mph in OD.

10-09-2022, 01:59 PM	#10
Keith True Senior Member Join Date: May 2010 Location: Epping N.H. Posts: 2,990	Re: Mitchell overdrive I went to put a Mitchell in my coupe,and found it had 3.54's.I put it in anyway,and it performs fine.I forget and drive it around a lot in high.I do find myself touching 60 quite a lot.Not sure how accurate my speedo is,at some point it will interest me enough to check it out.The previous owner thought it had a Brumfield head on it,at least that was what he was told when he bought it.It pulls fine.

10-09-2022, 02:02 PM	#11
MrBruce Senior Member Join Date: Oct 2014 Location: Charlotte, NC Posts: 310	Re: Mitchell overdrive Getting ready to do the Mitchell and have wondered about the 3:54 gears with a stock engine? I just picked up my engine and am debating putting the 6.0 head on it or just leave it stock? I have another rear end that I need to pickup this week and I think it's been gone through and is probably 3:78, so just need to decide if I need the HC head or just leave it stock with the overdrive and 3:78 gears?

10-09-2022, 10:10 PM	#15
TerryH Senior Member Join Date: May 2010 Location: Fountain Valley, Calif. Posts: 937	Re: Mitchell overdrive I have a 1930 Town Sedan, and had a Mitchell OD installed about 14 years ago, along with the 5.5 HC head, and it has the 3.78 rear end. The 4 doors are the heaviest Model A’s, and I would not recommend the 3.54 with the Mitchell, without some serious engine mods. Mine pulls the OD nicely…..very glad I did the 5.5 head too.

10-11-2022, 05:02 PM	#19
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 1,975	Re: Mitchell overdrive Thanks Syncro.

10-11-2022, 05:14 PM	#20
ModelA29 Senior Member Join Date: Sep 2022 Location: SoCal Posts: 591	Re: Mitchell overdrive I would think the dipper tray acts as a windage tray in an engine with pressurized rod bearings. https://www.enginelabs.com/engine-te...o-we-fight-it/ The idea behind a windage tray is that they provide a physical barrier between the violently moving crank with the oil it's throwing everywhere, and the oil supply, while still allowing oil to move back into the oil supply in a smoother, calmer manner.