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 Post subject: Carbs and gears
PostPosted: Tue Sep 27, 2016 3:55 pm 
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Future Club member hopefully!

Joined: Tue Sep 06, 2016 2:54 pm
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Building my first Dolomite for historic rallying plus the odd autosolo/sprint/hillclimb etc

First question is which carb to use on a 1500 engine? As the car will need to change direction quickly I need something responsive.
Thoughts are:
28/36 Weber, is there a manifold available? I have experience of these on Formula Ford engines and they work well.
Weber 40/45 DCOE, I know that there is a manifold available for these but as I can only use a single twin choke carb, does this work with the Siamese`d manifold?
Twin SU`s, balancing, needles, throttle response?

Second question, final drive and gearbox ratios. What is the lowest FD available across the range and which is the closest ratio box that bolts up to the 1500


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 Post subject: Re: Carbs and gears
PostPosted: Thu Sep 29, 2016 1:48 am 
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Joined: Fri Oct 06, 2006 8:57 am
Posts: 478
Location: Auckland, New Zealand
I don't believe there are many (any?) people on here who are using the 1500 as a powerplant in motorsport, most are like me with a Sprint engine. I wonder whether you would be better off finding a forum for the Spitfire? I know many people have developed very fast Spitfires for racing based on that very engine and they may be a better source of information. Here a lot of 1500 Dolomites were broken to supply engine replacements for Spitfires!

JIGSAW seem to quite a bit of work on ADU 7B, the only surviving ex Triumph Works Rally Spitfire, so they should have a very good idea of what was used in period as I imagine that would also be important to you. That may be a 1296cc though.
http://www.jigsawracingservices.co.uk/7bintro.htm

I would be interested to hear how you get on and more about historic rallying as you get into it.

Geoff


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 Post subject: Re: Carbs and gears
PostPosted: Thu Sep 29, 2016 6:29 pm 
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Joined: Sun Aug 21, 2011 4:12 pm
Posts: 4277
Location: Highley, Shropshire
I've not seen a 28/36 manifold but that doesn't mean there isn't one out there somewhere! Or an adaptor to go with a single carb Toledo or 1500FWD manifold. But I have seen, quite recently, a manifold to take a single 40DCOE/DHLA, I think Jod Clark or Richard Brigstock had it for sale.

With regard to final drives, the lowest practically available one is the 4.11 fitted to Heralds/Spitfires1-3/Toledo/Dolomite 1300. There is (or was) a lower one at 4.875 (IIRC) that was used on 948cc Heralds but a) very rare, b) made of cheese, c) not sure the half shaft spline is the same as on a Dolly axle. I hear rumours of a 4.11 LSD, which would be the holy grail of diffs for such a beast, but I think this is borrowed from the Compo Triumph 2000/TR cars,(if it does exist) so would need to be in a Sprint case.
The ordinary 4.11 is not terribly strong either being only designed to cope with 60odd bhp, but it will go straight into a 1500 case and second hand ones are plentiful and quite cheap (which is handy if you are going to break a few)

Other choices are 3.89 (early 1500/1850 Dolly/SpitIV1300/Vitesse 2000/GT6 with O/D)
3.63 (late 1500/1850 Dolly/Spit1500)
3.45 (Sprint, has to have a Sprint case, I believe a 3.7 from a T2000 can also fit this case)
3.27 (Dolly 1850 auto/GT6 non O/D)

Of these, the toughest one to use in the 1500 case is the 3.63 which is not very low but can be built with uprated bearings and will cope with up to about 120bhp.

If I was doing this, I would be inclined towards the Sprint axle, which is strong enough to take the punishment and get the gearing advantage with an overdrive gearbox modded to give overdrive in 2nd gear too. Maybe try for the 3.7 conversion but this would need to be custom built into a Sprint case as it's not an "off the shelf" choice.

HTH Steve

PS, there is not a lot of choice in the gearbox department, though there are several boxes that can be MADE to fit from the Triumph range, they are all much of a muchness as far as intermediate ratios go. Or If your regs permit, you could consider a Ford type 9 conversion.

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2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.


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 Post subject: Re: Carbs and gears
PostPosted: Thu Sep 29, 2016 10:17 pm 
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Joined: Thu Oct 06, 2011 12:13 am
Posts: 2388
Location: The continent
It would be historic regularity rallying. You won't need much power and other final drives. A good tripmeter, stopwatch and navigator will be fine. Low ratio diff ads only noise and unnecessary revs. If you are planning stage rallying only the four door sprint is homologated.

Jeroen

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 Post subject: Re: Carbs and gears
PostPosted: Fri Sep 30, 2016 4:01 pm 
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Joined: Sun Oct 26, 2008 7:26 am
Posts: 1757
My toledo had a 1500 engine and 4.11 diff. In fact, if you want the axle, you are welcome to it. It had no issues at all.
The 1500 engine has a weak bottom end. After 4 or 5 cranks, I changed to a TR7 engine/sprint box and axle. Rather stronger, a bit quicker etc. I used the car for clubman level 12 car rallies, autosolos, autotests, regularities and some PCT's, as well as a few trackdays.

On a 1500 the twin SU's are good and perfectly adequate. You will gain very very little by any of the alternatives.

You really need to do your research on building a good reliable 1500. It can be done, but will take a fair amount of effort and probably cash.

In all honesty, you would be much better off starting with a sprint!

_________________
Clive Senior
Brighton
Driving Toledo fitted with slant 4, sprint OD box and axle. Needs fettling!


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 Post subject: Re: Carbs and gears
PostPosted: Wed Oct 05, 2016 3:02 pm 
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Joined: Fri Aug 13, 2010 7:50 pm
Posts: 535
Location: newton abbot, south devon
Just came across this and remembered that someone wanted one similar. Let the pictures scroll through.
http://baituofei.com/triumph/triumph-sp ... crankshaft


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 Post subject: Re: Carbs and gears
PostPosted: Sun Oct 09, 2016 7:54 pm 
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Joined: Fri Aug 13, 2010 7:50 pm
Posts: 535
Location: newton abbot, south devon
More Weber stuff for our classics, not triumph but getting closer for the member who wanted one on his 1500? Engined project.

Look at this on eBay  http://www.ebay.co.uk/itm/191988959231


Sent from my HTC


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 Post subject: Re: Carbs and gears
PostPosted: Sun Oct 09, 2016 8:53 pm 
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Joined: Fri Aug 13, 2010 7:50 pm
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Location: newton abbot, south devon
Actually, here's one for the 1500.
www.ebay.com/itm/331263414221


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 Post subject: Re: Carbs and gears
PostPosted: Thu Oct 27, 2016 3:03 pm 
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Future Club member hopefully!
Future Club member hopefully!

Joined: Tue Sep 06, 2016 2:54 pm
Posts: 15
Thanks guys, very useful. The 28/36 in the states looks to be a good price (shame about the exchange rate!)
First event for the car on Sunday so lets see how it goes and then I can decide on a carb.
Will report back.


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