M-Series ideas

[Chris71]

I had a drive in a 1600M over the weekend and it got me thinking that if you could find one in need of restoration it'd be a great basis for a few minor tweaks.

The car felt light, nimble and impressively structurally rigid. The clarity of the steering was superb, with a sharp turn in and every minute change of texture in the road surface clearly telegraphed. It also rode well and seemed to be well screwed together. I didn't feel the crossflow had a huge amount of character, or indeed go, however. More worryingly the steering didn't really seem to be weighting up through the corners in the way that you'd hope. It also felt a bit vague on the front end - by the owner's admission (it's my dad's by the way) he's never played with the settings on the adjustable dampers, so that's almost certainly a contributing factor.

So, to the questions...

Does the above sound like a fair assessment of the 1600M? Are there any setup changes you can recommend for that car? Is it possible to engineer a bit more castor or change to different rubber to get the slip angles communicated a bit more dramatically?

Secondly - and more for fun - it strikes me as a great donor. What I'd love to do is put a somewhat tweaked 2.5 Alfa V6 in the front (not too far forward!) and possibly the GTV transaxle at the back. Re-engineer the front uprights to give it a bit more castor and look into some suitable modern rubber. Then hopefully those gorgeous retro looks would have the noise, the performance and the handling to suit. What do you think?

[Adrian@]

Nothing that has not already been done in your post...alloy rack mounts stop the steering issues and can be weighted for response...early wishbones on a late chassis give you more camber and I think that the alfa engine is already in 3 cars.
Adrian@
....may not the trans

Edited by Adrian@ on Tuesday 24th November 11:10

[Chris71]

Any idea how to address the steering feel? I think my dad's already changed the rack mounts and the one of the bearings in the column to a new design. The steering feels very precise and there's no obvious flex or play, it could just do with a bit more trail - whether pneumatic or kinematic, something needs to be done I reckon.

Some more ramblings on my blog if that's of interest to anyone: http://chriscarblog.blogspot.com/2009/11/driven-tv...

[FlipFlopGriff]

If you didn't feel the 1600 had much go try a 2500 or a 3000, or maybe a Taimar.
Adrian - no i'm not selling mine.
FFG

[Chris71]

FlipFlopGriff said:

If you didn't feel the 1600 had much go try a 2500 or a 3000, or maybe a Taimar.

True, there is that option. I've always been led to believe the Essex engine (let alone the Triumph lump) had a rather poor power to weight ratio though? A big heavy engine sat quite far forward not producing that much more power than the 4-cylinder. Admittedly that did come from a 1600 owner.

The Alfa idea was that it was a lighter engine, capable of plenty of tuning and equipped with a transaxle that would allow you to mount the engine itself well back as well as sticking the gearbox at the rear to maintain (or improve upon) the 1600's weight distribution.

My main objection to the Crossflow was it's lack of character to be honest. Even in mildly tuned (110hp) form it felt like it had been lifted straight from a Cortina. A massive flat spot didn't help, but to be fair that's just because that example needs a trip to the rollers.

I did love the pocket GT feel though - like a '60s Italian supercar in miniature (well, sort of). The Alfa V6 seemed like a good fit on those grounds.

[Adrian@]

Now I know the car ....early chassis..what shocks and springs is it running?...the steering can be weighted by adding a flat to each nut of the rack mounts..the ARB if standard is the 1st of 5 versions and has it got poly bushes on the front inner w/bones.
Adrian@

[Chris71]

Adrian@ said:

Now I know the car ....early chassis..what shocks and springs is it running?...the steering can be weighted by adding a flat to each nut of the rack mounts..the ARB if standard is the 1st of 5 versions and has it got poly bushes on the front inner w/bones.
Adrian@

It's running recent-ish springs at the original factory rates. The dampers are adjustables of some description, but what they're set to is anyone's guess (I realise this could be a major part of the problem!)

I'm not convinced the rack mounts will actually solve the issue with the steering? Although it is a tad on the light side that's not what I found disconcerting, it's the fact you got very little indication of the slip angle the tyres were working at. I'm not an expert, but I believe a bit more castor should produce more trail between the contact patch and the king pin axis - causing the light steering to weight up when you start to load the tyres and then unweight as they lose grip? Currently it doesn't really change - the light weighting is fine in the straight ahead position, but I'd expect it to weight up progressively as you approach the limit of adhesion and then go light again as the force generated by the tyre drops off.

As far as I'm aware the anti-roll bars and bushes are in the same situation as the springs; relatively recent items, but to original (1972) factory spec.

[Adrian@]

Chris71 said:

Adrian@ said:

Now I know the car ....early chassis..what shocks and springs is it running?...the steering can be weighted by adding a flat to each nut of the rack mounts..the ARB if standard is the 1st of 5 versions and has it got poly bushes on the front inner w/bones.
Adrian@

It's running recent-ish springs at the original factory rates. The dampers are adjustables of some description, but what they're set to is anyone's guess (I realise this could be a major part of the problem!)

I'm not convinced the rack mounts will actually solve the issue with the steering? Although it is a tad on the light side that's not what I found disconcerting, it's the fact you got very little indication of the slip angle the tyres were working at. I'm not an expert, but I believe a bit more castor should produce more trail between the contact patch and the king pin axis - causing the light steering to weight up when you start to load the tyres and then unweight as they lose grip? Currently it doesn't really change - the light weighting is fine in the straight ahead position, but I'd expect it to weight up progressively as you approach the limit of adhesion and then go light again as the force generated by the tyre drops off.

As far as I'm aware the anti-roll bars and bushes are in the same situation as the springs; relatively recent items, but to original (1972) factory spec.

Sorry, but are you over complicating this, the M has next to no vices esp as a 1600M...castor is not adjustable, but camber is, perhaps the profile/size/make of the tyre an issue here and as I mentioned inboard poly bushes on the front wishbone confines the front lower bushes to work as a rotational item rather than oscillating (affecting caster) under load, however using the OE spec springs even if new (I have not in 15 years) might give the car a inert feel.
Adrian@
Edited to say
A couple of mins with a 1/2 inch spanner... add a flat to all 4 nuts at a time and test.

Edited by Adrian@ on Tuesday 24th November 16:49

[Chris71]

Adrian@ said:

Perhaps the profile/size/make of the tyre an issue here.

Could well be - apparently it was a real struggle finding anything in the original size and it's ended up with something quite obscure.

I only mentioned the castor as my dad reckoned it was a known complaint with the M-Series when they were new and it seems to ring true with my initial impressions. You're right though - there's a huge number of other unknown quantities in there. Not least the damper rates. The tyre pressures could be out too for that matter, so it might be something basic.

I'll pass the ideas on, but sadly it's not my car to play with. However, I can't deny it got me thinking.

Something like this strikes me as quite a lot of car for the money: http://www.pistonheads.com/sales/1364572.htm