Hi Ratio Crown Wheel and pinion

Trevor J

I am looking at purchasing a hi ratio Crown Wheel and pinion for my 35 Hudson 8. Has anyone got experience with these apparently about 25 were made and sent to the US from the UK. What are they like to fit and what road speed could I expect once fitted.
Thanks Trevor
NewZealand

Jon B

Pat McDonald of England was responsible for reproducing them, and used to have a new batch made up when the built-up quantity of orders would justify it. I believe it fits Hudson products made from approximately 1934 to 1939. I think he is no longer making them but I could be wrong. Possibly, if enough people needed them, he might consider doing yet another production run. The price at the time was about $600US as I recall.

Trevor J

Hi John. I have one sorted if I want it I was just interested before I finally commit to see what increase I could expect from it.
Thanks Trevor

bob ward

Trevor, is another batch being made or are you managing to score one from an earlier batch. 35 H8s typically had a 4.11 back axle, it would be interesting to know what the ratio of the English gear sets is.

ESSX28-1

From Patrick McDonald in 2008:
Hi David, ratio is 3.5:1. fit all Hudsons 1933 to 1939,similar to fitting an overdrive unit.

Patrick McDonald -- HETjasmcdonald@fsmail.net (Drop the HET etc)

Jon B

A word of caution: when installing the ring gear (crown wheel), you may discover that it will not quite fit into the differential case. (This is true of some Hudsons but I don't know the year). In this event, do not panic, as I understand that one must grind away a bit of the lip (at the large round opening in the case) in order to get the crown wheel in. As I understand it, you don't have to grind it away all the way around, just at one place around the opening (since the crown wheel is inserted while perpendicular to the plane of the opening, not "flat" against the opening).

I know at least one Hudson guy who, when he was unable to insert the crown wheel in the case, concluded that it did not fit, and returned it to the seller.

Trevor J

Dave is correct with the ratio. I have been told not to expect an increase in road speed just a reduction in engine revs I thought that an increase would have been expected otherwise no point in the exercise

Jon B

Not sure I understand. Would you NOT get an increase in speed, at the same rpm? (I guess "a reduction in engine speed" at the same road speed, would be another way of saying the same thing.) The net result is that you CAN drive these older cars at greater speeds with the 3.5 gearset.

Another way around the issue: install an early 1950's differential from a Ford with automatic transmission. I spoke to a fellow from Ohio with a '35 Terraplane who had done this, and the pumpkin bolted right into the Hudson rear axle housing using the existing studs (or threads). Some sort of simple modification had to be made in the pumpkin but nothing big. And I think the drive shaft might have been shortened but then again, it might have remained the same.

MikeWA

Look like about 17% increase, "doing the math". Or 15%, if I didn't do the math correctly (there are only two possible answers, and those are them).

Trevor J

Hi John.
I have made some further inquires regarding this and have been told that I would probably be disappointed in the performance of the higher ratio given that I live in an area with a lot of hills and would probably be in 2nd gear a lot. I am also aware that some early Ford diffs bolt almost without alteration into 35 hudsons however to do that you would have to convert to juice brakes and I don't know that I want to go there. I may give it a miss and stick with what I have got.

bob ward

That's interesting info about the Ford diff centres Jon. According to this article, the 54 Fords with Fordomatic had a 3.31 diff centre. http://www.hemmings.com/hcc/stories/2007/01/01/hmn_feature22.html

ivanz62

Trevor,
I was the one who held Pat McDonald's gear sets here in California and I sold about 15 of them and kept two for myself. Everything said here about ratio and fitting is essentially correct. A number of people have told me how happy they were with the change--most recently Richard Esparza with his 36 Terraplane. If there is a set available, the owner should make it available to someone here on the forum. At least a dozen have asked since there were no more..........
Ivan

PAULARGETYPE

I WENT WITH A 358 GREAR SET WHEN I BUILT MY 50 PACEMAKER I WAS NOT HAPPY WITH IT AS THE ENGINE REVED TO HIGH AT AROUND 60/65 MPH I WENT WITH A 307 53 AUTOMATIC DIFF OUT OF A STEP DOWN I JUST LOVE IT I DID NOT INSTALL OD I DID USE A 48/9 8 CLY TRANSMISSION ( THE 8 CYL'S HAD A DEEPER 1ST GEAR ) SO NO DAMAGE WILL HAPPEN TO THE CLUTCH PULLING OUT THE CAR NOW HAS OVER 20,000 MILES EVERY THING STILL WORKING FINE

Trevor J

Hi
As I said I was keen but you have to remember I was looking at putting it in my 35 Hudson 8 coupe and have been told not to expect an increase in speed. I am concerned given that I live in a very hilly area and don't want to be in a lower gear all the time if I make the switch. Thoughts ????????????

Jon B

I would agree. Most people who install high-speed rearend gears, do so because they travel on highways that are flat or have moderate grades. They are worried about damaging their engines by prolonged use at high speed. This would not seem to be your problem.

Do you know what the present ratio is, in your car's differential gears? I believe the standard ratio was 4.11, installed from the factory. But some cars and many trucks had the 4.5 (give or take) fitted, which might be ''overkill'' in your area. The Hudson engines were able to "lug" up hills pretty well. They had plenty of low-end torque. So, if you have the 4.5 (or whatever it is), you might be well advised to switch back to a 4.11, if a gearset can be found.

bob ward

To me the main benefit of a lower ratio rear end is to keep the revs down on an 80 year old engine. Going from a 4.11 to a 3.5, at 60mph/100kph you will go from 2600RPM down to 2200RPM (assuming tyres with a 32" rolling radius)

As to the hills, if they are that bad I imagine you will be spending time in second gear whichever ratio you go for. You are near Dunedin if memory serves?

jjbubaboy

Hey Trevor,
I put a Ford 8.8 out of an 89 Mustang in my 36T. I put a 3.55 gear set in it and had it set up.
I cut off all the old mounting brackets, had the correct width ones welded on that I got from Currie enterprises, and used the flat mounting flange that was on it. Changed the u joint to match the rear and the driveshaft and bolted it in. No driveshaft work was needed and it works great.
Jeff

Jon B

The Mustang and also 1960 MoPar complete rear axles can certainly be used in the older Hudsons. The advantage of the Ford-O-Matic rear from the early 50's, is that just the pumpkin can be transplanted....leaving the original Hudson axle housing intact with all its brake parts, etc.

jjbubaboy

Oh yea,
I did also have to 'modify' the backing plates to accept the e brake cables, which I got off a 90 Ranger that are 10 inch brakes and drums. Also got 2 Ranger right side axles so the bolt pattern of the wheel is the same.
Jeff

terraplane8

I wonder whether it is possible for someone to take over this work from Pat, as he also made the free-flow exhaust manifolds which are sold out now (he made 100 of these). I understand that he does not intend making any more as he told me last year that there was no more demand for the manifolds. Hopefully he has the patterns still or someone does?

bob ward

FWIW the diameter of an old style 16" cross ply measures more like 28" rather than the 32" I assumed in my last post, this bumps up engine revs by 14% at any given speed.

This means that at 60mph with a 4.11 diff the engine is turning at 2960 RPM and with a retrofitted 3.5 diff the engine is turning at 2520 RPM.

A big improvement for sure, but I think I'll be looking for something like a 3.08 (2220 RPM @ 60mph) for my 35 H8 project.

Rocket

I have a set of these gears and I find myself needing another set of these for another 36 Hudson I just bought so if there would be enough people interested in them I will look into having them made here in the US if Pat dose not do another run just let me know.