MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MG Y Type - Crankshaft Pulley

Hi All, It's been a while since I posted, but rest assured that YT4825 has been in regular use. It is now time for some TLC, primarily to attempt to cure the engine's chronic incontinence! The primary culprit was the front pulley seal. So the engine is out and now completely disassembled ready for checking, cleaning, repainting and reassembly.
As an aside, there was also a leak from the head area, which was traced to a crack in one of the pushrod tubes. This was cured with some Devcon aluminium epoxy which lasted for some time. Now the head is off, I have removed the offending tube and pressed in a new one.
I intend to make a new front pulley with a double groove to enable fitment of a supercharger. I intend to make the pulley to fit two BX v-belts as per the original single pulley. I intend to make the boss OD the same as the original and fit a speedi-sleeve and lip oil seal. From my original and spare, the boss OD is 35.9mm, which will take a 99146 speedi-sleeve and use of a 36x47x7mm oil seal.
I have 3 pulleys as reference for the pulley OD. Two are close at 95mm and 96mm OD respectively, but the other measures 106mm OD. I realise that this is somewhat nominal as the only impact is to change the water pump/fan and generator speed a bit; but I am curious to see what the "correct" size should be.
I have read the thread on XPAG oil leaks and cures, but if anyone has some additional advice it would be greatly appreciated. And if you could measure your pulley OD and let me know that would also be appreciated. Thanks, Ewan
E.J. Ward

Hi Ewan,
difficult to measure but it seems to be the case that the lower (crankshaft ) pulley on mine is 95mm.

The upper (water pump) is 106mm.


cheers KG (YT3470)
K G Mills

Well, I went for an OD of 95mm as that was the consensus and happened to match the material I had on hand. Here is a before and after picture of the raw material and the finished pulley. Thanks, Ewan




E.J. Ward

Hello E.J. This should help you. The drawing is for a Wade supercharger crank pulley. Other superchargers used different diameters for the front two sheaves. I have used this drawing to make a pulley for mine. Be sure to use a good steel or cast iron. The first ones I made were out of 7075 aluminum and it took me a couple of years to figure out that when the aluminum got hot it expanded enough that the groove for the water pump and generator opened up the belt ran further down in the pulley(smaller diameter)and gave higher tach reading.

Butch


R Taras

Ewan. I have just noticed this thread and as I am enjoying a well deserved rest in the sun in the garden with the garage doors open I have just measured two of my spares, crank & pump, and can confirm that these two are 96mm and 106 mmm so made the right call. Nice bit of turning there.

Ian
ian thomson

For completeness, here is a picture of the crank pulley bolt that I also made. The old one was all chewed up and the threads distorted. I made a new one from 4140 high strength steel and decided to incorporate the washer to make a flanged bolt. Thanks, Ewan

E.J. Ward

Don't forget to shim under the flange to get the crank handle position correct.

Handle should be at 12 o'clock at TDC or thereabouts.

Cheers

Tony
A L SLATTERY

Great reminder Tony.
K G Mills

Thanks Tony. I was indeed wondering why there were shims shown on the parts illustration. I have never used the crank handle - other than to rotate the engine to set the valve clearance. But worth setting up correctly just in case it needs to be used in anger.
Regards, Ewan
E.J. Ward

I loaned a Y-Saloon to a good friend to do a family tour of Tasmania back in 2012. When they went to drive on to the ferry the starter died, so with the help of all in the line behind him, they push started it to get on the ferry. He rang me in Qld to ask how to fix the starter - don't bother I said, try the crank handle. Sure enough when it came time to leave the ferry the hand crank worked first try.

He spent the next week driving around Tassie and entertaining the locals by crank starting where he could not find a suitable hill. In the end it was one of those things that made the trip a lot different than they expected.

We did fit a new starter when he got to Hobart, but missed the crank start show some days on the way back home to the big island.

You just never know with old cars........

Tony
A L SLATTERY

This thread was discussed between 12/05/2021 and 25/06/2021

MG MG Y Type index

This thread is from the archives. Join the live MG MG Y Type BBS now