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

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.

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.

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.

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.

Re: Mitchell overdrive
 

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.

Re: Mitchell overdrive
 

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.

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

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.

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.

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?

Re: Mitchell overdrive
 

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.

Re: Mitchell overdrive
 

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

Re: Mitchell overdrive
 

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

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.

Re: Mitchell overdrive
 

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

Re: Mitchell overdrive
 

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?

Re: Mitchell overdrive
 

My response is in red.

Re: Mitchell overdrive
 

Thanks Syncro.

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.