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MG MGA - Ford Sierra Type 9 ratios

Has anyone who has a Ford Type 9 5-speed gearbox fitted to their MGA have any advice on the best gear ratios for it?

I have pretty much standard Sierra ratios in mine and I have noticed a bit of a gap between 2nd and 3rd especially when I am climbing long hill sections. I seem to be forever changing between 3rd and 2nd when the engine wont quite pull 3rd gear but seems to be revving too much in 2nd.

I could live with this but on the recent LE JoG I noticed that on some really steep descents when I was using engine braking in 1st gear, it was jumping out of first gear.
So there is some work to be done on the box and this may be a good opportunity to look at the ratios too.

1st gear seems ok as it went really well up the 1 in 3 Hardnott Pass in Cumbria last month but 2nd gear seems to be quite close to it.

Would appreciate any comments on this.

Thanks

Colyn
c firth

Colyn

What diff ratio are you running? I have the 3.9 which tends to make all the gears a bit longer.

Steve
Steve Gyles

Hi Steve
Im running a 4.3 diff with my 1850cc MGB engine, it pulls well but it doesnt really like the hills so much.

I am trying to get the ratios to be a bit more suitable for the longer hills where it is a little over geared in 3rd but under geared in second.

A taller diff (4.1 or a 3.9) would make 3rd gear even higher and so maybe not the answer.

Supercharger maybe? :-)

Colyn
c firth

Don't have the same issue at all, with or without Supercharger fitted. I have a 1622 fast road engine installed at the moment, standard 5 speed and standard diff 4.3:1

Is your engine out of tune? Or do you just need more pressure on the loud pedal?

But adding the Supercharger will make a world of difference, but the cheapJudson is not for you (I could have sold it twice today!). With your engine you have to use the Moss unit as to feed the 1850 engine you would be overdriving the Judson to get any effect.
dominic clancy

Im beginning to wonder if the problem may be the gearing?

I have a set of big Firestone Firehawk 185x65x15 tyres fitted on Racemettle alloy wheels and I wonder if they have a larger rolling diameter than the usual 155x15 size?

I suppose it could also simply be that I usually drive a 2.00 litre turbo-diesel and I am more used to the low end power it has.

Colyn


c firth

A quick calculation shows that the 186/65s are a fraction smaller than the 155s. Just over 1/4" in diameter.
Dave O'Neill 2

I have 165/80 R15 and the modern is also a 2L Turbodiesel - though the MGA sees much more use.
dominic clancy

Colyn
From memory the 2.8i 5 speed type 9 box had a higher 1st gear and 2nd and 3rd gears were correspondingly closer. I fitted this g'box to a Westfield and it was a dream of a box.
Mark
Mark Dollimore

Thanks for the info Dave and Dominic, so its not the tyres then.

It becoming obvious that I need more power and that is 1st on my to-do list for over the coming winter.

Mark, I knew that there was a Mk 9 gearbox with better ratios but I wasnt sure which one I needed.
I would imagine that the main problem is going to be getting hold of one!

Thanks again

Colyn
c firth

Colyn

I have some notes in my archives from Peter Gamble in 1999 when I was looking for a Type 9 gearbox. It says (underlined) do not use the 2.3 and 2.8 gearboxes as the primary shaft is too long..

Steve
Steve Gyles

These were Peter's notes to me.

Steve

Steve Gyles

Thanks Steve,
you have probably just saved me from wasting a lot of money.
It looks like I will have to get my present gearbox reconditioned and modified.

Apart from 1st gear jumping out occasionally and the large gap between 2nd and 3rd, I have noticed that 5th gear has a noticeable whine.

Hopefully I can get this done for less than the 1000 price I have seen listed for a "new" box with 2.8 ratios.

Colyn
c firth

Colyn

Probably a red herring, but I initially had my box jumping out of 1st, 3rd and 5th when I took my foot off the throttle. It turned out the the MGA rubber gaiter was acting like a retraction spring. As soon as the load was taken off the drive train the rubber gaiter would pull the stick back from those gear positions. Was I the first person to have a pre-selector gearbox in an MGA?! My interim solution of an MGB-type gaiter solved that one, and Peter Gamble later solved it once and for all by altering the geometry (throw) of his gear stick - now known as the short stick which is standard issue.

Steve
Steve Gyles

Don't have any problems with my standard MGA gearbox!
Lindsay Sampford

All the T-9 ratios are shown here:
http://hi-gearengineering.co.uk/content/view/17/32/
Gene Gillam

Thanks Gene

I have been studying the hi-gear sierra gearbox ratios and it does look like the T9 2.8 ratios are much more evenly spaced than the standard box ratios.

I was hoping to hear from someone who had actually had these ratios in their MGA (or MGB) and who could tell me what they thought of them.

I have listed the ratios below so you can see the differences.
......1st ... 2nd ... 3rd ....4th ....5th
MGA Box.. 3.636:1 2.214:1 1.374:1 1.00:1 n/a

Type 9... 3.65 1.97 1.37 1.00 0.82

T9 2.8.... 3.36 1.81 1.26 1.00 0.82

You can see that on the std sierra box, 1st is virtually the same as in MGA box, 2nd is a little higher (which is a slight improvement) but 3rd and 4th are almost the same ratios.

So you are correct Lindsay in that your gearbox has virtually identical ratios, but it is really handy to be ALWAYS able to select 1st gear without stopping the car and the overdrive 5th does make things a little less frantic if you are driving at 70 mph (or more).

Colyn
c firth

I tried to list the ratios like a graph but the forum set up defeated me. It keeps bunching everything up to save space I suppose.
I hope the ratios still make some sort of sense
Colyn
c firth

Colyn,
Strangely enough, the 5 speed topic will get a small mention in the December 2015 Safety Fast Twin Cam Group's spread.

regards
Colin
Colin Manley

Am I missing something here about the first gear ratio? After fitting my 5-speed I found I could comfortably use first to a higher road speed. However, looking at those figures that Colyn has copied from Peter Gamble's site it would appear that 1st gear is marginally lower than the standard MGA box. Or is it that the Type 9 is smoother in its power train and I am simply able to rev higher in 1st gear?

Steve
Steve Gyles

I will look out for that in Safety Fast thanks Colin.

Steve, just to make sure I had got this right, I have just doubled checked those 1st gear ratios on the MGA Guru and on Hi Gear Engineering websites and I have copied them correctly.

There is virtually no difference between the MGA box and the std Sierra box 1st gear ratios.
So I would think that the improvement you are experiencing is the effect of your 3.9 diff. I would think that you have the ideal 1st gear ratio with your set up.
Colyn
c firth

Colyn

The 3.9 swap came a year or two later. It was a direct comparison between the the two gearboxes, one out and one in over a few days. That said, it did also include the upgrade to the 5-bearing 1800, so maybe the smoothness of that engine also contributed.

Steve
Steve Gyles

Colyn,
It's nothing technical in the article, just a few words about how it improves the car.

regards
Colin
Colin Manley

Colin M

Have you fitted your 5-speed that you showed me?

Steve
Steve Gyles

Steve,
Yes, fitted it after taking it to the wire the night before going on a trip - let the car down onto its wheels at 9.20 p.m.

As you suggested, i did fit access panels in the transmission tunnel to both the filler/level plug and the reversing switch.

I'm really pleased with it. I do find the very first 'cold' gearchange from first to second a bit notchy, but it is loosening up.

Much smoother ride too. Await December's Safety Fast magazine.

regards
Colin

Colin Manley

Colin

I'd be interested in a photo or two of the inspection hatch for the oil filler - I have to remove my drip tray to get at mine and it's a PITA to do. I don't get any magazines....

Dominic

dominic clancy

You can also modify the 2.8 Gearbox suitably, see here

http://clancy.ch/Ford_T9_files/Type9.pdf
dominic clancy

Dominic,
is your oil drip tray a full length one that collects the drips from both the engine and the gearbox, or is it one of those small ones that just collects the drips from the rear engine plate jiggle pin?

Thanks also for the link to the Classic Ford Type 9 gearbox article. Lots of great info in there, especially useful is the mention of GBH Geartech who seem to have all the expertise and parts to sort my gearbox out.

I have been told that you can make a 2.8 Mk 9 box fit by simply cutting off a piece of the input shaft to make it fit my car but I must admit that I am a little wary of doing this myself.

Colyn
c firth

Colyn

Could you simply swap the input shaft over on a 2.8 for one of the correct length. Better than cutting.

Steve
Steve Gyles

This thread was discussed between 28/10/2015 and 31/10/2015

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