Price of SU Carbs?

[stripyt6]

Just wondering if anyone can tell me what these might cost to buy and get fitted?

I've sourced a close ratio type 9 box (picking up on Saturday, exciting!) and a stage 2 Jigsaw engine (which I'm even more excited about :) ).

I've been told to get the best out of it my Strombergs won't cut it!

I've seen a few 1 3/4" sets which look good on ebay but they seem to vary a lot in price!

(webers might be a bit fuel thirsty and expensive from what I've read on here)

[Clive]

What engine??
Recent stuff has indicated that the strombergs are actually good. If you are looking at 1.75 inch carbs, I am guessing a 2 litre? No reason a set of non-emission strombergs will not be ideal if it is a fast road engine, or go to SU's off a dolly sprint, they have the short dashpots. Again, best to get a set with the circular springs arouund teh spindles rather than the ones with "normal" springs, as they wear the bodies a lot less and are usually in better condition. And then dump the waxstat jets.

How much?? £25-150 depending on the seller for a secondhand set. A bit or opening up of the inlets to match, and opening the carb mountings up so they will bolt on. Jigsaw should be able to advise on suitable needles to get you started.

[Royboy66]

Stage 2 ?  What's that mean then?

I mean you may be ok with the strombergs depending on the BHP  :)

[stripyt6]

lol - I know, 'stage 2' doesn't really mean anything does it?

It's a 2ltr, and has had the following work:

• Surface grind engine block face
• Re-grind crankshaft, tuft ride crank and micro polish
• Lighten flywheel and fit new ring gear
• Balance con rods end to end and match all four weights
• Match weights on pistons to balance, and height to deck of block
• Balance crankshaft, flywheel, clutch and pulley together
• Skim head to raise compression ratio
• Front alloy engine block to be re-heli coiled
• Port head, gas flow, measure and equalise combustion chambers. Equalise inlet ports
• Match inlet manifolds and gaskets and dowel to head

I'll be combining that with a decent exhaust & manifold. I'm hoping to make upwards of 140hp and I'm expecting it to rev nice and freely - only the RR will tell however once its all fitted.

I'm not sure what cam the head currently has in it but I'm thinking of fitting something like a TR5 cam for road manners as I've read on here its a nice cam.

[stripyt6]

If I can get the most out of the engine from my current carbs - possibly once they've been fettled a little I'll just keep those :)

[stripyt6]

Um, am I in the right ballpark HP wise? Most of my experience is in fettling K series so I'm just going by other threads on here ...

[Sheepy]

If you have a good roading road chapie, he should be able to tweak the best from your carbs and set up,

Then he will say if it's better to go for this carb or that one etc.

I would use what you have to start with, get it set up, use it for a while to see how it feels, then if needed update the carbs.

Yes you can buy cheap sets on flea bay, but what are you buying? Why are they selling them? Do they need re building etc etc.

it's probably better to wait (hence use it with your carbs) until a fellow member here converts to injection and sells his carbs! Just a thought.

[Clive]

140 may be a bit optimistic, bear in mind the PI TR5's  produced about that  that, and they have some extra CC's too. But yours will rev better. A TR5 cam may run out of puff at the top end, worth investigating. And again jigsaw should advise what the rev limit will be.

You REALLY need that cam profile before you choose carbs, but I suspect you may need the larger ones. Indeed RR man can let you know. Which is a good idea to start with.

[stripyt6]

Excellent :) thanks for the advice, in which case I'll hold fire, drop it off with Jigsaw and get them to advise and set up, suck it and see as it were!

[Richard B]

From another thread

570 wrote:

Don't ignore twin 175 Strombies either

[Sorry, link no longer available]



Dazzer rallys a MkI 2000

[stripyt6]

Thanks Richard! Having a good read through now :)

[stripyt6]

.. interesting, very interesting, from what I've read (there and elsewhere) I'm starting to lean towards 175 stromburgs. They sound from what I've heard that they'll need less on going maintenance - if I can source some and get them rebuilt nicely. Does anyone on here run 175's on a modified 2ltr? Thoughts?

such as http://www.ebay.co.uk/itm/Twin-SU-HS6-1-3-4-Triumph-Carbs-and-manifold-2500-TR6-TR5-/330823241579?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4d069a0f6b

[stripyt6]

.. I know I could just ask the garage ... however, I like the research - learning process!

[Richard B]

4953 wrote:

Does anyone on here run 175's on a modified 2ltr? Thoughts?

PM Dazzer he rallys a MkI 2000 with twin 175's. He tends to post in the 2000/2.5 section

[stripyt6]

.. well, after all that I went to see the engine at the weekend, and the guy selling it had a pair of rebuilt SU barbs and manifold etc all ready to roll with the engine! .. so - it seems crazy not to jsut snap it all up and get it fitted :) he'd also fitted a TR6 cam to it .. should be just the job!

[GT6boy]

How anyone could think about using the excellent, and very reliable, but limited in needle selection Stromberg carbs, for a go-faster engine which is possibly a (no disrespect intended) mish-mash of after market parts and specs- i will never know. Unless you are an absolute expert in such things, as compared to someone selling stuff to people and professing to be an expert, the selection of a carb with a severely limited selection of needles to match to a 'tuned' engine seems a no-brainer? :-/
It would be interesting to know the intended ignition system and what thought had been given to matching this to the cam timing and CR here, or the expected actual combustion chamber value the 'gas-flowing' work will leave you with.
I hope I don't come across as grumpy, it's just that it frustrates me that decent people pay out hard earned money for work which sometimes ends up as poorly matched hotch-potch of 'go-faster' bin parts.

If the people doing this work for you can't or are unwilling to provide the detail on things like optimising the ignition system (i.e. tuning the dizzy springs/weights to what the engine needs, not some fancy dan 'high-spec coil), the combustion chamber values before and after and why they think they will work- that disappoints me.
Moral of the story is ask 'em, ask 'em and then ask 'em some more! :)

[stripyt6]

Ah no worries, all very fair comments. Yes, it's true - a mish-mash. But I'm enjoying learning more about the GT6 engine and fine tuning it as part of the mish-mash assembly process, and after all isn't enjoyment what it's all about? :)

I was only looking at the 175 Stromberg carbs after reading a few threads on here from people who seemed to find them good - altho I had read that the lack of needles was an issue.

After viewing the engine at the weekend and seeing that they also had a set of rebuilt SU carbs (rebuilt by Andrew Turner) .. and looking at my old Stromburgs which look tired I thought what the hell (especially as they offered the carbs at a very low cost). I'll give them a go (esp after what I'd read about the needle issue).

So the mish mash now =

Balanced engine with flowed head (very recently rebuilt)
6-3-1 manifold mated to Phoenix Stainless Twin Sports Exhausts (which is already on the car)
SU carbs (also rebuilt)
TR6 cam
Type 9 CR box


Which I believe from my research thus far should be good starting ingredients?

I do still need to find however someone to put all these bits together and advise on the fine tuning, I was going to Jigsaw but I think it would be better on reflection to try and find an expert closer to home in Surrey. I don't need a posh garage who recomend high-spec oil ... just someone who really knows their stuff and is a passionate enthusiast would do! ... basically I'm looking for the equivelant of DVA in the K series tuning world!

[stripyt6]

I am VERY open to advice and knowledge on the ignition system - in fact I'll scour the forum for some :)

[thebrookster]

Seeing as your engine is anything but standard, you will have to tailor your ignition somewhat.

This is possible with a dizzy, by changing weights and so forth, but this is a lot of work, and so to be perfectly honest my recommendation (for what it is worth) is a fully map-able electronic ignition. Exactly which one you go for is up to you and your wallet, there are a few out there, from the 123 system (pricey I understand, but more in keeping with the classic look, if that is what you want) to Megajolt, a build it yourself system.

The basic electronic ignition systems are no use to you, as they use the dizzy timing (which is the issue in the first place!), it is a map-able system you would be looking for.

[stripyt6]

Thanks Philip! I'll take a look into those in more detail.

[GT6boy]

You're buying or have bought a recently reconditioned engine: what evidence do you have to support the info you been given about it's consituent parts? :)
If it was recent, i'd imagine there would be a spec list or reciept of parts purchased to complete the work and where they came from?

Strange as it may seem, some people have bought engines believing they have cam A in them, when they actually have cam B which turns out to be far from ideal! This is usually only discovered months down the line after much wasted expenditure on trying to work out why it wont pull the skin off the rice pudding. :B

It would also be useful to know the current compression of the engine too- dead easy to check. Again, sometimes gas flowing work turns the compact and bejou combustion chamber into an aircraft hanger with resultant fart like performance gains...


The moral of the story being find out exactly what you have, so you can propely identify what does need doing and how  :)

[Richard B]

IIRC You can fit SU needles to Strombergs with a bit of effort.  :-/

[junkuser]

"IIRC You can fit SU needles to Strombergs with a bit of effort."
       2nd that.  
Brass shim is all that is required.  Have forgotten the thickness now but easy to calculate.
Stays in position at subsequent needle changes so its only the original fitting that is a bit of a fiddle.
  

[Richard B]

6 thou shim?   :-/

[stripyt6]

The seller has the reciept from Jigsaw for all the work, the head was off when I went over so I could peer at it ... not that I know what I'm looking at really, but it did look like an assembly of new components and I did goggle at the forged pistons. However, it is very clear they are a real enthusiast and not a rip off merchant (well I thought it was :) a bit of a leap of faith I know. Maybe I shouldn't be so trusting :o

After chatting with the seller it seems he also has a modified dizzy he had modified for the cam profile which he's throwing in :) He has a load of bits and bobs he was collecting to build his own GT6 Mk2 a while back before he went and bought a heavily modified spitfire which a friend was selling (in his garage, tripple stomburgs, custom manifold ... sounded like thunder and SERIOUSLY mint). So all the components look top notch as they were intended for his project - not for resale ...