The Triumph Dolomite Club - Discussion Forum

Will a sprint rear axle bolt straight to a 1500hl body? Can't seem to find any info on this at the moment.

Yes but you also need to change the prop I suspect. The nose may not coincide with the prop you have.
The 3.45 ratio is also wrong for 1500 mechanics....but I suspect you know all this.

Jonners

In fact everything Sprint fits. After I wrote off my race car bodyshell, I used a 1500 shell and moved everything across. It was even drilled for the brake bias mechanism. As Jonners says, if you try to mix and match, then you might have the odd issue connecting 1500 to Sprint parts.

Geoff

The OP fitted an MX5 engine in his Dolly. He has a thread in the "resto" sction HERE.

Just wanted to make sure that I didn't have to change any brackets on the body. Will try and source axle and prop when I have some funds unless anyone's got one going for free.

The nose of the Sprint diff is about 1" longer than the 1500s. When I put the Sprint axle in the Carledo, I got away with the Toledo propshaft, but only just! However, the Toledo prop has its sliding joint at the very back, next to the diff and the plunge movement is what i used most of up making it fit. I suspect your 1500 prop will have its slider at the front (or has been replaced with a slider into the back of the Mazda gearbox) That being the case, you may have to shorten the rear section of the prop by an inch or so to make it work out.

Steve

I am in the middle of such a conversion, got a rear axle and prop from wins.

Just out of interest could you swap a Sprint diff into a 1500 axle?

No to diff swap. Completely different axles. One is made of cheese and the other is proper pig iron

Tony

Something to consider.....
the MX5's like to rev, and the long fatio 3.45 sprint axle is a long way off what is fitted to the MX5.

What should be possible is to put a 4.1 or 3.7 diff (or at least CWP) into a sprint axle.

Nothing worse than an over-geared car with the engine constantly dropping out of the power band. I had that on my spit, and have since fitted a 3.9 ratio diff (that means I can stay in the power band, before wit a 3.63 is was driopping out when changing from 2>3 and 3>4, and would do 100 in 3rd, which is daft....

cliftyhanger wrote:Something to consider.....
the MX5's like to rev, and the long fatio 3.45 sprint axle is a long way off what is fitted to the MX5.

What should be possible is to put a 4.1 or 3.7 diff (or at least CWP) into a sprint axle.

Nothing worse than an over-geared car with the engine constantly dropping out of the power band. I had that on my spit, and have since fitted a 3.9 ratio diff (that means I can stay in the power band, before wit a 3.63 is was driopping out when changing from 2>3 and 3>4, and would do 100 in 3rd, which is daft....

What ratio does an 1850 have? Also I've fiddled with the engine a little so that its got more torque at lower revs. Will quite happily poodle along at 1500rpm in 5th gear now.

3.63, but I doubt it would last long...
(saying that I know a herald with an MX5 engine and 3.63 diff, prior to that the 4.11 lasted for over a year of being driven hard, which amazed me)

Have a look at teh minty lamb speed comparison thingy, try different diffs and so on. Trundling around is all very well, but I bet it needs 4-5k to get into the real powerband! My zetec springs into life at 5-7K, with the old diff when I changed at 7k the next gear left me at about 4.5k, too big a gap.

Early Triumph 2000 models had either 3.7 or 4.1 diffs and the crown wheel and pinion can be fitted into the Sprint diff housing, along with an LSD if you wish. I think the 4.1 was in the manual and 3.7 in the auto. Be careful as a lot of those cars were retro fitted with later diff units with the 3.45. If you do get the correct ratio (counting teeth is the best way to be sure) it isn't the easiest of job to change and set up correctly.
Geoff

cliftyhanger wrote:Something to consider.....
the MX5's like to rev, and the long fatio 3.45 sprint axle is a long way off what is fitted to the MX5.

What should be possible is to put a 4.1 or 3.7 diff (or at least CWP) into a sprint axle.

Nothing worse than an over-geared car with the engine constantly dropping out of the power band. I had that on my spit, and have since fitted a 3.9 ratio diff (that means I can stay in the power band, before wit a 3.63 is was driopping out when changing from 2>3 and 3>4, and would do 100 in 3rd, which is daft....

Hmm. Having recently found a Sprint axle for my own MX-5 project that wasn't what I wanted to read :p

Steve

It may be OK, but many people seem to think you want a relaxed, low-revving engine, so a "long" diff is best.

Fine for a torquey engine, sot so good for one where you want max performance. Manufactureres tend to get ratios correct, so I would be trying to copy the MX5 ratio.
On my spit the downside is that it now does 20mph/1000prm, so cruise is at 3500 (maybe 4K!) which is a tad noisy. However, I have a larger diameter set of tyres for things like CLM where it is a long drive (with no track time at the end)

Or it may be you just use gears 4/5 less often.....but that has downsides too if you want a track orientated car type of thing.

I've been winging it from start to finish, so it'll probably be awful I have no real purpose for the car (track/race etc) so as long as it drives at the end of it I'm not too fussy. As for noise/gear changes - I drive a 1959 Morris Oxford - I'm used to a racket and effort lol.

Steve