Cruising in my 79 which brings up a question

[Naomi]

Went cruising /ubbthreads/images/graemlins/driving.gif in my 79 MGB today which I purchased last week from a member of another forum. Wow, it is one tight MGB! The hubby finished the wiring woes, with a bunch of help from Tony, about 10 AM this morning and I talked him into riding along with me. Cruised around 150 miles round trip on the Blue Ridge Parkway and had a blast. Beautiful day for cruising here in the mountains.
Now for the question. This MGB does not turn as many RPMs as the my 64 or 80 MGBs in any gear. The hubby says the gearing in the 79 is probably higher since it does not have factory overdive like those two do. Is the hubby right?

Your turn,

Naomi from the Blue Ridge Mountains of Virginia
Owner of a 64 MGB, and an 80 MGB each repaired 4000 times and still loved. Now a 79 MGB, repaired just once, and instant love /ubbthreads/images/graemlins/smile.gif

 

[John Moore]

Happy New Year NA!

The gear box should have the same ratios as the others when your not using the OD.

I wonder if it has anything with him playing around with the coil? The tach gets it's pulse from the coil. I'm just guessing tho.

 

[Naomi]

John it actually feels as if it is in a 5th gear when in 4th. Very noticeable. Oh, the coil was fine and the correct one for the car. The wiring nightmare is now over.



Naomi from the Blue Ridge Mountains of Virginia
Owner of a 64 MGB, and an 80 MGB each repaired 4000 times and still loved. Now a 79 MGB, repaired just once, and instant love /ubbthreads/images/graemlins/smile.gif

 

[tony barnhill]

Na - glad you're enjoying MY car! hehehe

all MGB's have the same rear gears - the overdrive units have slightly different gears in them than doe the 4-speeds but if anything, it should feel like its revving higher than your cars with OD!

 

[Basil]

What a great way to start the new year!
/ubbthreads/images/graemlins/thumbsup.gif

 

[Naomi]

Wow I sure love that Jag of yours /ubbthreads/images/graemlins/smile.gif

 

[Joe Reed]

In all your cars (all MGBs, in fact) the rear end ratio would be the same, and 4th gear w/o overdrive is 1:1...so there shouldn't be any significant difference in the RPMs per MPH from one car to another. There are a couple of posibilities...

Sam's car could have had a MGC rear end put in it sometime in the past...

The tire size could differ from your other cars (the rolling circumference..which can even differ between two tires of the same size from different manufacurers). Unless the size is drastically different, it wouldn't be anywhere near the difference of having an extra gear...

Perhaps its a combination of two things. Maybe his tach is reading low. If that's the case, it could lead you to believe the engine is turning slower...especially if his car happens to be somewhat quieter than your others...

 

[Bruce74B]

or it might be a smogged up engine that doesn't run out like the ealier 18V's did before all the PC crap was added!

Bruce

 

[Mark Jones]

Naomi; I'm with you. I've driven in Bandit with Sam and the gearing did seem different. Maybe it does have a different rear-end ratio as Joe suggests.

 

[Joe Reed]

If it has the MGC rear end, she really got a deal!!

 

[Eric_C]

If you have different sized tires from your other cars, on you can see some difference in the RPMs as the engine will be running slightly more or less and the speed reading will also be a bit off. That's my guess.

 

[Nunyas]

different rear diff gears, and different sized tires would still yield the same RPM to Speedo ratios. The only time that would be different is if the speedo was recalibrated after the gears/tires were made taller