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MG MG Y Type - How many valve springs

Hi Y Typers

Having taken the head off my 1953 YB I was surprised to find double springs only on the exhaust valves with single springs on the inlets. Is this usual, as I can find no reference to such a layout.
I know single springs were sometimes used on unstressed engines to lighten the camshaft load.
It seems it was intended to be like this as special shrouds were used at the bottom of the single (large) springs to locate them.
I am wondering whether to add the inner springs or leave it as it is.
Any thoughts chaps.

Regards
Brian
B R HOUGH

No expert on dismantling heads and it has been a while - arent they double on both? Moss catalog is not clear on this.

Paul
Paul Barrow

Hi Brian,

the Spare Parts Catalogue for the 1953 MG YB lists 8 Inner and 8 Outer Spring Valves - so it seems someone has dismissed for unknown reasons the springs for the inlet valves.

On some MGB engines single springs have been used, but only for a while - so it is up to you.

Regards
Manfred
M. G. Schulz

When I bought our YT back in 2007, the previous owner (a retired motor mechanic) had removed all the inner valve springs to reduce the load on the camshaft followers. In his opinion, the inner springs only stopped valve bounce over 5000 rpm.

I drove that engine for over 30,000miles like that, around SE Australia towing a teardrop trailer with no ill effects.

About a year ago I re-installed the inner springs when replacing the valve seals, but there has been no change in performance or economy, but I suspect there is more load on the cam followers now !.

So don't be too concerned about having just the outer spring - it will be fine in my experience.

Tony
A L SLATTERY

I have two YA engines one of which is in the car and they both have only single valve springs. Long ago in my motorcycling days I read that in high revving performance engines the valve spring could at a particular speed go into its natural resonance so not closing the valve [called valve float], a second smaller spring would have a different period and so not coincide. Otherwise if the object was just to return the valve to its seat then a single larger poundage spring could have been used. I understand that this so called valve float can be used to prevent an engine over revving, But I'm not sure manufacturers do that now. In view of the paucity of performance in a Y engine I would prefer to save the poor tired camshaft the extra loading, also save the crankshaft. Bryan
B Mellem

I would add as a post script that it is wise to check the unloaded springs during an overhaul that they are all the same length. better still replace them. Bryan
B Mellem

I'm getting heavily involved with valve springs on the TD site as I'm installing a Fanelli cam. I would also add to B Mellam's comment that the springs should be tested on a valve spring tester, enabling a comparison of loads @ predetermined lengths. A simple, quick, cheap test on a Rimac will show if any, some, all have fatigued & need replacing. Cheers
Peter TD 5801
P Hehir

I concur with those who have commented that single valve springs are fine in an XPAG engine. Before the YT went on the road I covered thousands of miles and competed in numerous motorkhanas and regularity trials in our TD with slightly stronger single valve springs. At a minor rebuild a few years ago (bearings & rings) cam & follower wear was negligible.
Cheers
Richo YT3208
R A Prior

This thread was discussed between 30/03/2014 and 02/05/2014

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