Tune it or Upgrade it ?

Post by **PSL184** » Mon Apr 13, 2009 7:43 pm

I have both a 948 and a 1275 engine available to go into the Traveller. I like the idea of keeping the engine "standard" in terms of capacity so was thinking what gains can be had from the 948 to make it more sprightly or should I just not waste time on it and drop the 1275 in?

Post by **d_harris** » Mon Apr 13, 2009 7:47 pm

Put the 948 in with a decent carb & manifold.

Then give the 1275 to me

Depends what you are looking for. You will never get the same performance from a 948 as you will from a 1275. Depends what you want from the car really

Post by **PSL184** » Mon Apr 13, 2009 7:58 pm

Well I don't want a tarmac burner as the other one is going that way so I want something different. If I go 1275 it would be totally standard but I was just wondering if I could squeeze 50 - 60 bhp from the 948 or not?

Post by **bmcecosse** » Mon Apr 13, 2009 8:47 pm

If you want decent economy - use the 948 and modify it. Main problem is - the block has only one cam bearing - so cam choice (and valve spring choice) is limited. MG Metro cam and the 940 head from the 1275 engine - it will be good for ~ 55/60 bhp at considerable revs - so best get a crankshaft damper too. But should still be ok for economy if driven sensibly (but where's the fun in that!). Larger carb and half decent exhaust will be needed of course.

Post by **Peetee** » Mon Apr 13, 2009 9:35 pm

I've gone this way with a 948 and can say that if you start with a good engine the results can be very pleasing. I fitted a mildly ported 12G295 head, alloy inlet, HIF38 and standard sized stainless exhaust. With 1098 gearbox, Ford disc conversion, 20W oil in the dampers and front anti roll bar it was a very nice balance between power and handling. I've always found that modified cars have a habit of feeling quicker even when they arn't so just to be sure I timed the old boy. 0-60 was down from 29 seconds to 18. It revved very freely with no noticable power band. it would easily hold 70 uphill on a motorway and 3rd gear would give you uphill acceleration to pass traffic at 35-40mph.
Basically it had more power that a standard 1098 and keeping in the higher rev band was far more rewarding and much less thrashy.
It certaily felt quicker than it really was but was a good example of how limited power can still provide a lot of fun if it's in a good package. My present 1275 convertible is still a long way off being as well sorted as that little 948 was.

Post by **bmcecosse** » Mon Apr 13, 2009 9:45 pm

Yes - because of the short stroke, the 948 is 'smooth' where the long stroke 1275 can be 'harsh'.

linearaudio · Post by **linearaudio** » Mon Apr 13, 2009 10:14 pm

Yes- you would get much more fun with 60hp from a 948 than 65hp from a 1275

Post by **PSL184** » Mon Apr 13, 2009 10:39 pm

Hmmmm, I'm liking the sound of this. I've already put a 4.22 axle in the back end and have a 1098 box so i think I'll tune the old 948 and rebuild the 1275 for a supercharger

Thanks all

Post by **Peetee** » Tue Apr 14, 2009 10:10 am

Sourcing that head is the important thing. Without a larger valve head of one type or another you are wasting your time with the other performance bits. I'd be like asking Chris Hoy to lap the velodrome breathing through a couple of straws.

Post by **PSL184** » Tue Apr 14, 2009 10:25 am

Peetee wrote:I'd be like asking Chris Hoy to lap the velodrome breathing through a couple of straws.

???

linearaudio · Post by **linearaudio** » Tue Apr 14, 2009 11:15 am

Something to do with bicycling??

Silly sport using your legs when you could strap an engine on

Post by **Peetee** » Tue Apr 14, 2009 11:31 am

Oh dear. So most of the olympic medals, the BBC sports personality of the year and cereal adverts passed you by then?
http://news.bbc.co.uk/sport1/hi/tv_and_ ... 782818.stm

Post by **PSL184** » Tue Apr 14, 2009 11:34 am

The only sport I watch is motor racing or rugby and I don't like cereal

linearaudio · Post by **linearaudio** » Tue Apr 14, 2009 11:44 am

Peetee wrote:Oh dear. So most of the olympic medals, the BBC sports personality of the year and cereal adverts passed you by then?
http://news.bbc.co.uk/sport1/hi/tv_and_ ... 782818.stm

When you are REALLY dedicated to a moggy, you don't have time for telly!

Post by **d_harris** » Tue Apr 14, 2009 12:22 pm

If you need a 295 let me know.

Post by **PSL184** » Tue Apr 14, 2009 12:45 pm

Thanks Dan - I've got an old midget engine in the back of the garage. I'll check it and if no good I'll get back to you - How much you wanting, just out of interest?

Post by **d_harris** » Tue Apr 14, 2009 1:45 pm

Seventy quid posted?

Post by **PSL184** » Tue Apr 14, 2009 1:48 pm

OK - will let you know, cheers