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MG MG Y Type - 60mph crusing?

In the March issue of MG Enthusiasts, the mag we get with the MGCC Safety Fast newsletter now,Andrew Roberts has an article on the Y Type. In it he quotes " Drivers were impressed by the ability to cruise at 60mph or more,..."

As the Y has a max speed of 70mph on a good day, I think this a bit high. How many of you cruise your Y Type at 60mph on motorways, etc? I would suggest that 50-55mph is more normal if the engine is not to blow up.

Comment please, I talk of standard Ys, not those with MGB engines, or five speed gearboxes, or higher diffs.

Neil.
Neil Cairns

Neil,
I agree, I was surprised but maybe the reference was to when the cars were new. Even so for me it's too close to the maximum and if nothing else the fuel and oil consumption would be rather higher.
My standard YB will indicate 70mph but checked with a GPS this is more like 66. I avoid motorways but on a good road will cruise as you say at an indicated 50 to 55 and at that speed it handles nicely even with cross ply's and just sings. ( Or is that the back axle? )
Ted Gardner

Whilst I dobt that I get beyond 50mph (my speedo swings so wildly it could be 30 or 70)I thought that the XPAG had a reputation for being un-burstable. Now you've disillusioned me!
I'm just reding Dick Jacobs book, and he currently has the YB achieving over 90mph.
Michael Nicholson

Neil,

You're right. My '49 Y Type is quite comfortable at 50 to 55 mph, but starts to sound rather stressed at 60. Like Ted, I think that the comment referred to new cars, so cruising at 60 mph was probably ok (and relatively fast in those days).
Bill Bennett

Y5888 frequently drives 60 mph (+/- indicated), but she does that herself; I must really watch out not to drive too fast. She crawls unnoticed to 60! A speeding ticket is forthcoming I'm afraid...

She really sings and sounds and feels more happy at that speed than 50 mph but that's because I still have an irritating vibration from the engine/clutch at 50 mph.

But CRUISING at 60 mph with a standard Y seems a little overdone.
Willem van der Veer

Maybe I'm tempting fate or maybe my speedometer is way off, but my YB easily cruises at 65MPH and if I'm not careful will creep up over 70 if I'm not careful. Not much power in that engine for acceleration, but once I'm up to speed it has no problems whatsoever holding it.
Steve Simmons

Wow Steve, it must be our youth that we like driving that fast!

Why don't you check with GPS to see how far you really are from destruction? If you have those new fangled "low profile" 165R15's on your YB the speedometer-reading might be a bit optimistic?
Willem van der Veer

We all have our views on what some words mean. But to me "cruising" at 60 MPH in a Y is a misnomer. The same applies to all the pre 56 T series. In my part of the world distances are of some significance and the pre 56 MG bunch calculate that for a journey of about 300 miles per day we should average 45MPH, which means travelling for the most part at 50-55 with the occaisonal burst over 60. That is fairly comfortable. We try as best we can to avoid motorways and the like and thus far that works quite well. Terry
Terry O'Brien

G'day Neil, I have not received my March issue yet all the way down here in OZ but look forward to reading the article. Although you were not looking for responses from those of us with modified cars I could not resist. Obviously I have no drama with my YT with B engine and OD but I also have a TD and one of the first things I did back in the early '70s was up grade to 4.55. It now runs a 3.9. Yes a standard car can cruise at 60mph but for how long is the question? I suggest this would be measured in minutes rather than hours! Cheers Richard
Richard Prior

I do run Dayton 165R15 tires. I was going to look up the rolling radius but it appears they have recently discontinued the tire.
Steve Simmons

Interesting thread. Personally, like many here I find 60mph too fast for comfort, and 50-55mph much more suitable for the car. But one statistic that I observe in many roadtests of the 'forties and 'fifties is interesting here: the key number is the piston speed of 2,500ft/min, which seemed to be regarded as some kind of par performance level, and was widely quoted in tests. Does anyone know why this parameter was regarded as important?

For the XPAG engine and the YA's gearing, such a piston speed corresponds to 61.8mph, according to Autocar's test. So even then, such a speed was not outrageous, though achievable very rarely I imagine, given the roads of that period. In 2006 and on a crank nearly at final undersize, I'll take it easier, I think!
Tim Griggs

I'm sure that Neil will weigh in on the 2500fpm piston speed, but my understanding is that this is the piston speed, at or below which, there is no accelerated wear. One can exceed that speed without harm to the engine, but there is acelerated wear on the engine (primarily the bores) in that area. On the XPAG engines (and suprisingly on the B seires engines) 2500fpm of piston speed is right around 4300 RPM. We run our TD at 4200 RPM, which is just a bit over 60mph with the tires that are on it. We just got back from a weekend event with our local register that was some 70 miles from our home and since it it was open road for most of the trip, it was done at 4200 rpm all the way. We have taken two 5000 mile trips through the western US in the TD, running both times at 4200 rpm most of the time and the worst thing that happened to the engine was a fouled plug on one cylinder. Cheers - Dave
David DuBois

We haven't had the YT on a run of more than 50 miles yet but driving into town which is only 10 miles she sounds fine at 4000 rpm which is 60 mph (12.5 mph/1000 revs) naturally after a warming up couple of miles. Obviously this is not sustained but we have excellent and even compression in all cylinders and an almost 60 psi oil pressure. The engine has only done 91,000 miles and was well looked after.

When I had the TF 1250 engine rebuilt I had the fly wheel lightened and balanced and a thorough balancing throughout and a line bore to ensure that the crankshaft was where it should be. With this simple work the improvement has been remarkable. Cruising at 4000 rpm is fine which represents 68 mph at 17 mph to the 1000 revs.

Thus my suggestion when you come to an engine rebuild is to balance the engine components and lighten the fly wheel and at 4000 rpm a Y should do 60 mph comfortably. Now lower the windscreen, fit a full tonneau cover, wear some goggles and cruise even faster!

Rob Dunsterville

This thread was discussed between 15/02/2006 and 20/02/2006

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