1275 engine and 5 speed ?????

Post by **PAULJ** » Fri Nov 27, 2009 8:20 pm

Hi all, at the moment I'm driving around with no interior which as you can imagine is loud. I have a 1275 engine and 5 speed box. To say I am disappointed with it would be an understatement or was I expecting too much. unfortunately l have only got the old speedo which I know is wrong.
What is a realistic top speed in 5th with these mods. It may well be that its the noise that is making me feel the revs are higher than they are.
The interior will go in once I'm happy with the running and I wax oil.
Thanks

Post by **mike.perry** » Fri Nov 27, 2009 8:58 pm

Have you changed the diff as well? 5th gear gives you the equivalent of a higher diff whilst 1 to 4 retain the gear spacings, more or less, of a 4 speed box. In this respect it is a better, though far more expensive option, than just upgrading the diff. Changing the diff as well would give you too high a top gear (in my opinion).
I would recommend checking your speedo against a sat nav before making any decisions

Post by **PAULJ** » Fri Nov 27, 2009 9:25 pm

As far as I know its a 4.2 diff. I will borrow a sat nav and see what it is doing. What do pepole do about the speedo? once I know how far out it is can they be re callibrated.

Post by **mike.perry** » Sat Nov 28, 2009 1:34 am

On the Series MM website, http://seriesmm.mmoc.org.uk click on car identification and scroll down to a table of speedometers.

Post by **alzax3** » Sat Nov 28, 2009 9:25 am

Our van came with those mods, and a very noisy home-brew exhaust. The 1275 didn't seem to offer any exciting advantage (and was just using more fuel) so we swapped it back for a 1098 and kept the 5 speed. Happy!

Sat Nov 28, 2009 5:36 pm

There are several companies that will recalibrate your speedo, i used these people a few years ago

http://www.speedograph-richfield.com/

I did the calcs a few months ago and the ford 5 speed box has very similar gear ratio all the way to 4th obviously 5th is great for motorway work. I ran a 1275 with an overdrive box effectivly 5 speed and was very happy with both acceleration and top end cruise.

I would fit your interior back in and then pass judgement on the mods.

Post by **Mogwai** » Sat Nov 28, 2009 6:15 pm

I run a 1275 with the ford box & a 4.22 diff. At 70 it will be around 3500rpm & 80 around 4000rpm.
as for top speed it will do more but this will depend on the power output of the engine to pull max revs in 5th etc.
Just making sure all the grommets & holes that cables etc on the bulkhead no matter how small are sealed can make a big difference to noise

this is a handy program to calculate rpm to speed http://www.locost7.info/gearcalc.php

Post by **PAULJ** » Sat Nov 28, 2009 6:26 pm

Thanks for the speedo link. So the people that are happy with 1340 and 5 speed what diff do you have

Post by **PSL184** » Sat Nov 28, 2009 7:14 pm

I'd stick with the 4.22 diff as the gear ratio's (1st - 4th) will allow you to accelerate swiftly enough and the 5th (effectively overdrive) will do fine for motorway cruising. My 1275 is noisy too but I haven't gone to any truble to soundproof it yet, however, 0-70mph comes up quite quickly

Post by **bmcecosse** » Wed Dec 02, 2009 11:41 pm

Some of the 'cooking' 1275 engines are only rated at 55 bhp - they have a very soft camshaft and small carb. If you only have the standard 1098 carb and exhaust fitted - you will have even less power - possibly no more than the original 1098. Although even a 'cooking' 1275 should 'lug' rather better than a 1098 - the performance is not going to be startling - especially in an overdrive 5th gear. Decide what speed you are actually doing - when the speedo says 50 mph - if no Sat Nav then follow some trucks on the Mway - they can only do 56 mph, and note your speedo reading. Look closely at the speedo in the car and note the 'tpm' figure. There are a range of speedos with different 'tpm's - probably one will suit - and will certainly be MUCH cheaper than getting your speedo re-calibrated.

Thu Dec 03, 2009 8:33 pm

to be honest did not think about looking for a different speedo..

this might help ( can not vouch if this is correct )..

http://www.guess-works.com/Gearbox/Technical/speedo.htm

Post by **Kevin** » Mon Dec 07, 2009 1:00 pm

Hi all, at the moment I'm driving around with no interior which as you can imagine is loud. I have a 1275 engine and 5 speed box. To say I am disappointed with it would be an understatement or was I expecting too much.

Right what did the engine come from and what did you do to when fitting it (did you change anything) which carb and exhaust did you use, and what condition was the engine in.

Post by **PAULJ** » Thu Dec 10, 2009 8:04 pm

engine is an Itel with new rings and shels. The carb is off a metro and I have the large bore stainless exhaust. I havent tried the car with the new sat nav because the seats have been away getting upholstered. I rearly just whan to know what top end to expect in 5th at what revs. I will shoot myself in the foot now by saying I ran the engine with a 4 speed moggy box with the same carb and exhaust with no problem. Im just thinking all the expence and trouble. was it worth it?

Post by **bmcecosse** » Thu Dec 10, 2009 8:07 pm

It won't go any faster - just maybe slightly quieter when in 5th gear.

Thu Dec 10, 2009 10:04 pm

why will it not go any faster?

when i had an O/D unit on my ital box it would certainly go faster in O/D fourth than in fourth.. ok acceleration in O/D 4th was not as good as 4th. so why would 5th be slower than 4th because ford type 9 4th and moggy 4th are the same at 1:1

Post by **PSL184** » Thu Dec 10, 2009 10:09 pm

It will all depend on if you reach max engine rpm before you run out of gearing or vice versa.

Post by **bmcecosse** » Thu Dec 10, 2009 11:48 pm

So - it will likely be fastest in 4th gear! It's highly unlikely to reach max revs even in 4th gear - even if you take it to Bonneville! So it will certainly not make it in 5th gear - unless 'downhill with a tail wind'! My warmed up 1098 with 3.7 diff will do 80 in 3rd gear - with the engine screaming near valve bounce - yes - it will likely go faster in 4th - but will never get up to the valve bounce point - not that I would try it anyway on our restricted highways!