99 EMS Primary gear ratio

[madwelshman]

Hi folks,

I know this isn't motorsport related, but can anyone tell me what ratio the primary gears (not chain and sprocket type) are on my 74 EMS?

The gearing is very low, 50mph at 3000rpm/70mph at 4000rpm and my Father changed the primary gears on his 74 EMS years ago for a set from a standard single carburettor 99 which raised the overall gearing slightly.

Eventually I will be changing the gearbox to a 5 speed, but for now, any increase I can get will be a bonus.

Thanks in advance

Will

[Crazyswede]

for reference my 75 99 with timing chains used to run 4000 rpm at 75 mph...but I don't know how the gearbox internal ratios on a chain box compare to a gear primary box.

[99Super]

My 73 carby ran 55mph @ 3K rpms, I just got used to it. It's not like you can break that motor as long as you keep some oil in it.
I don't think there were any options to change the gears.
Best bet is just a later trans, 4 or 5 sp.

John

[madwelshman]

Cheers for the replies guys.
I know my father swapped the gear type primaries on his 74 EMS for a set from a standard 99 many years ago and he said there was a difference in gearing afterwards.

John, what engine was in your 73, 1850 Triumph or a 1985 B series?

[99Super]

It was a B20. Later replaced w/ a BI20, but with the same trans. If there were different ratios in the gear drive trans, that's news to me. Every one I've driven had that same 55mph@3K rpm.

John

[madwelshman]

Ok thanks John.
I know that the EMS is lower geared than the standard car, though, so just trying to work out what year standard car I need a set of primaries from.

Will

[madwelshman]

Both my EMS and a friends one which is a 76, are both running 3000 @ 50mph/80kmh

[Crazyswede]

We had a couple of old 99 transmissions for a while but not sure if we still have them. If so could pull the primaries apart at some point in the future and see what ratio they are.

[madwelshman]

Crazyswede, were any of them EMS?

[Crazyswede]

There was one car that was an ems but we didnt pull the driveline out of it and it went on to someone else as a project. I think all the others were normal base models.

[madwelshman]

Ah right.
I would say that if they were 1972 or before they will have 0.95:1 ratio primary gears and 73 onwards, 1:1 primaries.
But as I say, EMS is the odd one as it's lower geared that the standard car and as you have said 55 @ 3000 and both ems I know of are 50 @ 3000 then the ems is definitely a different ration