Not enough gear

[norville]

Rootes also had other ratios available to, at least 5.22:1.

Starting from 4.22:1, possible ratios are;

4.44:1, 4.55:1, 4.78:1, 4.86:1, and 5.22:1.

There may be more but these ARE listed in my Hillman service manual. BTW, they are all spiral bevel gear sets EXCEPT 4.22:1 and 4.44:1 which are hypoid gear sets.

I would agree that the tach is probably out of calibration due to the known tendency for electronic component degeneration. There is a possibility the rear gears could be the real problem.

I think I would check the tach reading against a garage's inspection or tune up analyzer machine before getting more involved mechanically.

Just a few thoughts,

did you have only one wheel off the ground ?

4.44:1
???

bob

 

[Stevesass]

Yes , 1 wheel off the ground. It was probably closer to 2 1/8 rev. I did some more checking on the internet and my guess is I have 4.22 ratio. In another post it said 4.22 are Hypoid gear sets. If I change it to 3.70 which are spiral bevel gear sets will this still work because of the different types of gears ???

 

[RootesRacer]

Yes , 1 wheel off the ground. It was probably closer to 2 1/8 rev. I did some more checking on the internet and my guess is I have 4.22 ratio. In another post it said 4.22 are Hypoid gear sets. If I change it to 3.70 which are spiral bevel gear sets will this still work because of the different types of gears ???

3.70, 3.89, 4.22, 4.44 are all hypoid.

Only the earlier higher numerical ratios (not listed above) are spiral bevel.

The spiral bevel gear sets are incompatible with hypoid third member cases, but the entire functional third member can be installed provided you have the proper axle splines for the diff gears.

 

[Stevesass]

COOL !! Then it sounds to me my choice will be to get the 3.70 gear set and have my local rear shop ( who is Very good) to do the swap. I will let everyone know how it turns out.
THANKS TO EVERYONE FOR ALL THE HELP !!!!!!!!!

 

[old grumpy]

Tell him the secret!

 

[old grumpy]

Well guys , now I'm really confused.
I jacked up 1 side of the rear and counted the rev's of the drive shaft when I turned the tire 1 rev. I got about 2 1/4 revs ?????????
This made no sense so I tried it on the other side with same result. Then I tried turning the drive shaft instead with same result ?????????
Does this make sense to anyone or am I doing something wrong

OK!
Turn the wheel two revs.

The differential is the answer
1. If both wheel is turning one rev. at the same time you will see (I guess) 4,22 rev. (2,11 x 2)

2. And now, one wheel is turning and other not, you have to turn 2 revs. You will se 4,22 revs

3. If one wheel is turning 1 rev. forward and the other 1 rev. backward at the same time the drive shaft will not move at all.

Do you see the mechanical logic in this ?

 

[Stevesass]

That makes sense to me. Sounds like I'm going to change the gears