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MG MG Y Type - fitting an hs4 or hs6 carb...

hi-im in upstate ny, a lot like the english lake district, gentle terrain and quiet back roads for my ya.
i have thought for a while about finding an old td intake manifold and going to 2 hs2 carbs, but thats just so expensive (40 years ago i had a box of them in my basement!) so i was thinking-one hs4 or hs6 carb, which i still do have a box of-any hints on a near fit manifold that wouldnt be too hard to modify?
like an after market 1275 mini manifold?
i sure whould like a bit more power-i'll rebuild the head to stage one specs while im at it i guess-thanks-jim moody,ithaca ny.
jim moody

Hey Jim

Cannot comment on the carburettors but I'll ask Neil to have a look at the thread and give his comments. Meanwhile we don't have your car on the Ys on Parade section of the website www.mgytypes.org yet. Better send us something quick - you can be the first of 2004!

Paul
Paul Barrow

There was a thread on the TD-TF BBS within the last two or three months on various ways of increasing power. Havn't gone to the archives to recheck it but my recolection of the consensus of the knowledgeable was that increasing the size of the carburator didn't do much for power but increased your gas consumption considerably.The thread had something to do with fitting Weber carbs. I think the best way to increase the engines BHP is to go to TC/YT and TD specifications by fitting twin carbs and the camshaft used in those models. Joe Curto in NY state could certainly help you with the twin carb set up. Terry
Terry O'Brien

Jim

I seem to remember Dick Jacobs got more power from his Y simply increasing the size of the existing standard SU carburettor by 1/4 inch. This would have the advantage of not looking too out of place in the engine bay. You can also add a blower or supercharger too. Both mods would be in keeping with the style of the Y and substantially increase the power too.

Paul
Paul Barrow

It is actually better to fit a larger single carburetter than a twin set up, as the only real advantage of the twin carb is at high rpm. I would suggest getting hold of a SU from a M.G. Metro. This is a large carb fitted to a 1275cc engine, not much bigger than our 1250cc. BUT you need to improve the passage through to the valve, as just fitting a bigger carb increases fuel consumption for no real gain. The inlet manifold needs smoothing off inside, and the divider between the ports in the head need slimming a little, ( see the book by Phillip H. Smith, sold by MG Octagon CC for how much you can remove.)
The M.G. Metro uses a SU HIF 44, ( a 1 1/2 inch carb, with a concentric float chamber, temperature compensated mixture control.)

If you go for fitting a twin 'TC'-'TD' set up, you will need the camshaft and distributor weights, or little will be gained.

OR you could gas-flow your current carburetter, as this makes it flow like the next size up. You must follow the instructions given in David Vizzards book on tuning the 'A' series, ( get it from the library, photo-copy the pages on gas-flowing the SU.) This improvement, along with smoothing out the inlet manifold and ports, will lead you to need a richer needle. Follow his advice for tuning the 1275cc 'A' series here. This way, nothing looks out of place under the bonnet. You might try having the bigger 'TF' valves fitted to your head, as this improves power.

In the end it all boils down to how much you can get into the cylinder. Just fitting a big carb is not the answer. Jacobs car had a very tuned up cylinder head fitted, all gas-flowed and balanced combustion chambers. It was specially built for the job, almost a blue-printed car.

Neil.
Neil Cairns

Hi Jim

Neil has fairly comprehensively covered the options there I think! Thank you Neil.

I have tried to email you several times but your isp has rejected all my email accounts but in response to your email to me regarding registering and posting to Ys on Parade, I know exactly the horrendous weather conditions you are currently experiencing so I appreciate the car may be snowed in the garage now. We would certainly love to have your registration and entry for Ys on Parade and a combined form is available under Registration and Register your Y. Look forward to hearing from you in due course.

Paul

Paul Barrow

thanks all for taking the time to reply to my query. i think ill go with the tf valves and an su h4(inch and one half)carb, use the existing manifold, just ream it out to fit the larger carb.
my car is a gently restored almond green 1951 ya which i bought in little dunmow,essex, about 6 years ago, and id like to keep it as original as possible, and certainly i dont need a large hp increase to enjoy it-just enough to get me up the long hill home. our hills are a little hillier here than in essex...jim moody, ithaca,ny
jim moody

Jim; as the owner of another (formerly) almond green 51 YA which has not strayed so far from home, I read this thread with interest. I guess every Y owner dreams of a bit more power - just be careful of the critical link in getting all those extra horses on to the tarmac, which is the axle half shafts! The axle was designed for the 8hp Morris and Wolseley cars of 1938-48, and even standard Ys break their shafts (which is why I have a spare in the car and another in the garage!). Good luck anyway.
Tim Griggs

Tim,

You say the axle was for the Morris 8, I thought it was the Morris 10? I was offered a Morris 8 rearaxle and declined, thinking it was not a suitable halfshaft-donor.

Are the Morris 8 and 10 rearaxles the same, and are their half-shafts suitable for the YA?

I would like to be sure because it has to be excavated from the end of a sea-container full of filthy old Land Rover parts!

Greetings,

Willem
Willem van der Veer

Willem/all:
Perhaps Neil Cairns can be the final and most knowledgeable adviser here, but I have had the impression for some years that the Morris 8 axle is the source for the Y component... principally because the body tub is shared and this governs the width of the car, and hence of the chassis and the rear wheel track. Possibly the Morris 10 axle is simply a wider version of the same diff, with a wider banjo and longer halfshafts?

My point was really that the Y's appetite for half shafts has been known since the late 1940s, and adding bhp can only lead to a higher risk of that dreaded "clonk" from the rear of the car, followed by a mysterious rise in engine revs, followed by a conversation with the AA (or local equivalent)!
Tim Griggs

Looks like I'm out of luck with an Morris 8 axle, the link is to an article about MG rear-axles:

http://www.mgcars.org.uk/mgcc/sf/sf100104.htm
Willem van der Veer

Or maybe I should first read carefully, and see the axle is also used in the Morris 8?

I think an expedition over Land Rover parts is called for....
Willem van der Veer

Interesting how the thread has changed from carbs to half shafts. Third time for half shafts within a year.
I don't know and I suspect few if any know now whether Morris 8/10 or whatever half shafts are interchangeable. Forty years ago or so it may have been usefull info but in this part of the world the Morris 8/10s are long gone. If they were in fact the same I would want to know someone who had actualy done the the switch. But even that is irrelevant. The shafts are old; they will break from time to time, and new ones are not available. For TCs new shafts are available made from up to date steel. That is what is needed to keep YA/Ts on the road.
I am going to throw out a suggestion. I have a spare set of shafts and a friend who is a machinist and who knows all the local machine shops. I will take him one of the spares and ask him to get quotes on making new ones; 50-100-200-300. If someone in the UK, Australia and the US can do the same then we compare prices and figure out how to pay for them. I am not an engineer but I think we would need to determine the grade of steel for the shafts so that we are comparing apples with apples. Terry
Terry O'Brien

Terry,

Of course you are right and your ideas are very good. Please ask your friend for good quality, the spares market is flooded with poor quality reproductions that are no good at all.

A Dutch TD-driver told me a story about TD-halfshafts. He bought a pair in England and they where twisted after a couple of thousand miles. Somehow he discovered that the parts where made in Germany and he asked the manufacturer why he used such an poor grade of steel (it wasn't even steel).
His answer was simple: he also made a batch in a high grade of steel (of which my friend bought a pair immediately) but the English client thought them too expensive and ordered a poorer grade.....

In my view both the parts-specialist and manufacturer did wrong to order/make the poor quality.

Greetings,

Willem
Willem van der Veer

I have never had an axle break. Can those who have broken axles, what were the circumstances?. I know of two that were broken reversing out of a driveway.

What I'm wondering is, did the axle break dur to the diff not operating as it should, or the engine torque being too much for just one axle.

If you fit indestructable axles, what will break next?

The remanufacture idea is great, but I have only one Y-Type on the road (again soon) and six spare axles, so I'm hoping this supply will outlast me.
Tony SLATTERY


The performance of my YA was improved by raising the compression ratio to 8.6:1 as advised by W.E.BLOWER in his MG Tuning Manual. I reasoned that the car was designed to run on Pool Petrol and so could benefit from the better fuels available. Even with a standard carb the top speed is now over 80MPH with an improved fuel economy.
On the problem regarding 1/2 shafts, I found that it is very important to prevent snatch loading particulaly when over rough ground when the car tends to surge. I have towed a caravan over many miles and countries in the 1970-80s without any trouble.

Bryan Mellem

This thread was discussed between 03/01/2004 and 22/01/2004

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