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MG TD TF 1500 - Valve stem oil seals

Does anybody know if the 'improved' oil seals from Moss Europe require the valve guides to have retaining grooves machined in them.
Ray TF 2884
Ray Lee

Hi Ray,

I think they do. The seals are from a late BMC A Series engine and there is a lip inside the larger bore that locates in a narrow groove in the guide. This prevents the seal from lifting as the stem rises. I have recently fitted them to the TF's engine and they work a treat. There is absolutely no smoke from the exhaust at all. Previously I could see in the mirror a cloud folowing me! I removed my guides and turned a groove and had to reseat the valves but if yours are in good condition it would be easy to form the groove in situ with a needle file. I had considered using super glue but wondered about hot oil softening it. I bought my seals on line for £2.50.
Oh you will need to cut down the circular spash shields which fit in the springs and they are hardened so an angle grinder is needed.

Cheers

Jan
J Targosz

It doesn't sound like an easy job to me Jan- that is making a groove with a needle file, and making a tidy job of it at the same time. I bought some seals very cheaply as well and have put off doing the job. If a groove is needed I think I would be inclined to make a tool to do it. Something that could be hooked over the valve stem and pushed down against the top of the guide, with an extension piece to cut a groove.
Dave H
Dave Hill

Hi Dave,

Yes I had thought of making up a tool to cut the groove in situ. It doesn't need to be too accurate so you could pilot off the outside of the guide. Someone even suggested the job could be done without removing the head by either pressurising the cylinder with compressed air via a modified spark plug or by feeding a piece of string into the bore at BDC and raising the piston to TDC!

Fortunately I have access to a Serdi seat facing machine so pressed out the guides, modified them and recut the seats. I did make a mistake tough and pressed the guides back in from the top down. The groove does weaken them though and one of mine fractured. If I was to do the job again I would probably press them from the port side.

You do need to shorten the guide a little to prevent the collet retainer hitting the seal which does extend the length of the guide. You must also cut off the shank of the splash guard that fits into the inner spring. I think some people dispense with these all together but I still used the top part to locate the spring. Some people only modify the inlets but I did all eight. Without the splash shields there will be plenty of oil around the stems.

A friend has also similarly converted his TC engine again with absolute success.

Jan
J Targosz

I went with normal seals-the 'o'ring under the keepers mainly because of having sleeved guides which with the combo of stainless valves require a little drip of lube but rounded the top of the inlet guide to prevent excess oil pooling
Personal choice (old habits die hard) but it appears to be working ok
willy

William Revit

Here's a photo of the Peter Edney guides with the groove. You only really need them on the inlet valves as the outlet valves can do with lubrication.
Regards
Declan

Declan Burns

Yes I see, they also appear to be a bit shorter. I stayed with cast iron guides, rather than bronze, having had a problem with those in the past - fitted with insufficient clearance probably. Do the bronze guides leak more oil when fitted correctly, and therefore need the improved seals from day one?
Dave H
Dave Hill

Looking at that pic of the bronze guide, it has a large taper into the bore
With ordinary 'o' ring style seals,any oil splashed on the stem would be steered down the guide bore by that taper---It would definately need the mini style seals

willy
William Revit

In another thread I described how to fit Volvo B 18 umbrella shaped valve seals. Someone from Germany had used this for a long period with very god result. I put them on a shaft fixed in a lath and with a finger grinder ground them to a diameter to fit. Now after 500 km it still works fine and no smoke what so ever is produced.
Y Strom

Well for me - Cost and effectiveness - I use the original O Rings under the collets and have never had a problem It is now 64 years and it still works good. Replaced the O rings and they have been in there since 1974
The only time I have seen an issue with this system was way back in Gutersloh Germany, when a German friend with a TC was burning oil really well. We took the head off one afternoon and found the folks that had refurbished his engine had mounted the Oil deflectors upside down and put them under the springs instead of on top. We fixed that and he was all better.
I find it hard to believe excessive oil can get past this system if everything is in order.
Just my 2 C's worth.
Rod


Rod Jones

Sorry I can't agree with you Willy, but I have found that the standard O-Ring seal was simply inadequate.

I am using the Feldpro "hat-type" seal that goes over the top of the guide that prevents oil from getting down the guide as shown in the image attached.

Has always worked for me.

Gord Clark
Rockburn, Qué

Gord Clark

All good Gord
I went with the 'O' ring type but in my statement above----
"
Looking at that pic of the bronze guide, it has a large taper into the bore
With ordinary 'o' ring style seals,any oil splashed on the stem would be steered down the guide bore by that taper---It would definately need the mini style seals"

My use of the word mini probably wasn't the best choice of words as it could mean little or Morris Mini, --I was refering to the Late BMC A Series type seal which is the hat type seal that secures on the top of the guide

Sorry for the confusion there

The Felpro seal , Does that secure to the guide or is it an umbrella seal

With your picture ,where you have pointed out where the oil goes in is where I indicated that the pic of the Edney bronze guide had a fairly large chamfer on the inside which I would imagine would allow splashed oil to get down the valve stem if using original O ring style seals

Interested to know how that Felpro seal fits up

Cheers
willy
William Revit

Hi Willy

You are spot with your comment about the taper in the top of the bronze guides. My car was really smokey and I was advised by a contributor to this forum (sorry I have lost the name but thanks) to look at the tops of the collet retaining disks. These are hollowed in the centre and fill with splashed oil. The original seals stop oil leaking past the collets and trickling down the valve stems. I was told to look at the hollows about half an hour after the engine had been switched off. If there was no oil in them there was a problem with the seals. Mine were dry and as a belt and braces approach I fitted both original seals and ones from a late A Series engine. The oil now stays in the hollows even over night. Surely the taper in the bronze guides would exacerbate the problem and up graded seals would be essential.

I wonder why anyone would want to fit bronze guides. I had the engine in a TD I owned a few years ago reconditioned and the workshop fitted bronze guides. The car suffered from poor running which was eventually traced to sticking valves. We had to hone the guides to give extra clearance. The graphite in cast iron is an excellent lubricant so why do a change?

Jan
J Targosz

Hi Jan,
It was me that suggested looking for the oil pool on the valve caps. I have a spring compressor that I can use with the head in place.
The one I am working on had the pools but still burnt oil after idling or on acceleration after an overrun.
We took one valve off to see if the splash guards had been omitted and found the valve stem would wobble about 1/64" when just off the seat. This is on a head that was "professionally" fitted with hard seats and new guides under 3000 miles ago.
We now have the head off and will fit new guides and recut if necessary.
My own engine just has the original type seals fitted 30000 miles ago and no smoke even though I had to hone the sil/bronze guides after a sticking problem
Ray TF 2884
Ray Lee

Hi Ray,

I had pondered making up an "in situ" valve spring compressor, possibly pivoting from a scrap rocker shaft I have but I didn't know the best way of stopping the valve falling. I have been told to use compressed air or diesel in the bore and even to thread a long piece of string into the plug hole and then raise the piston.
Which method do you use?

I think that if the seats and guides are OK there is no need to disturb the guides and original "O" ring seals will be fine. If the seats need truing up or the guides are worn it makes sense to press the guides out and either fit new ones or machine grooves and fit up-rated seals.

Jan
J Targosz

the pyjama cord method does not work too well on the xpag you really need a hemi head like my BSA A7 SS bike,

The valve compressor loosely fastens to the rocker post tapping and will reach 2 valves at a time.
Drawing to follow
Ray

Ray Lee

fiddley but works
Ray

Ray Lee

the handle really needs to bent up at 45 degrees or it will foul on the carbs before the spring is compressed.
Ray
Ray Lee

My machinist has recommended fitting K-line sleeves to my original TF cast iron valve guides. His ideas about better wear resistance and less problems with the expansion of the bronze ‘gripping the valve stem are persuasive. Anyone else used them apart from Willy? I note that he rounded off the top of his guides to prevent pooling. Seems like a sensible plan to me so, unless anyone can suggest a good reason not to, I might just follow his lead. Also sounds like a lot less work than the newer type.
Chris
C I Twidle

Hi Chris,

By K-line do you mean reaming out the guides, pushing in sleeves and then sizing them by pressing a ball bearing through the bore? If this is so the machinist who has done many heads for me uses this technique and did so on a TC a few weeks ago.

Cheers

Jan
J Targosz

just finished the refurb on a friends cyl head. Noticed that #1 inlet valve stem end is level with or slightly below the valve spring retaining washer. Fitted new collets and still the same, I had a spare washer and fitted that, now all OK. I have seen slight differences in height before but this was enough to affect the spring closing pressure.
This head has been machined and has shims under the pedestals and as the rocker angles are compromised I think the rocker arm may have been hitting the washer.
Something else to look for on an old engine.
Ray TF 2884
Ray Lee

Thanks Ray, I’m picking my engine up from the machine shop tomorrow and that will now be on my list of things to check. I didn’t find any shims under the pedestals and the head is down to around stage two tuning thickness. I haven’t bought a gasket set yet, in case I need to look for a thicker one, so I don’t yet have any stem seals. Is the recommended plan to leave the pedestals alone and shorten the pushrods? (I have a dozen spares to practice on).
My plan is wait till after the Sydney MG club’s workshop day (5th Nov) on rebuilding the XPAG and pick some brains before deciding where to get bearings, rings etc. I will then check piston height to see if they come above the deck and check the chamber capacities to work out the CR before deciding on gaskets.
This is my first engine rebuild in 40 years so any comments greatly appreciated.
Chris
C I Twidle

Shorten the pushrods, or buy some shortened ones from B&G, etc. Doing so will maintain the correct geometry for the rockers.
Dave H
Dave Hill

Chris,
the head I am working on is 74.63mm,(2.12) shaved off.
The engine has been running quite happily on regular fuel (95 RON) with a stock head gasket, no pinking and pulls well.
The rockers are shimmed at the moment to get pushrod clearance.
If you google TKL707 you will see pictures of it back in its original Police configuration.
Ray TF 2884
Ray Lee

Ray, I spoke with a member of our car club recently, ex UK motorway police. Can’t remember what he had for breakfast but has clear memories of frequent trips to a place near Nottingham to have speedos calibrated. Didn’t drive MGs but clocked up a lot of very fast miles in Jags.
Your comments on that XPAG are very encouraging thanks.
Dave, I assume the rod reduction is in the order of the reduction in head height or is there something else to consider?
Chris
C I Twidle

Chris,
re police speedos.
I posted in August this year about this very subject, the car in question has a different speedo than stock TF's. see "54 TF speedo" in the archive.
The car was only 10 years old when he bought it (ex Kent Police) so we presume it was the original one.
Ray
Ray Lee

Chris. As I understand it, the push rod length is correct when the cam followers are on the base circle of the cam, the adjusters are mid thread, and the rocker arms are level. Later engines had shorter pushrods and longer adjusters, though even shorter pushrods are the way to go. First you have to find out what you have, and are they all the same. I think I shortened mine by a couple of mm or so.
Dave H
Dave Hill

Hi Chris,

The place near Nottingham was probably Edwin Richfields and they are still in business. I recently had my speedo reconditioned by them and recalibrated to suit my Ford gear box. I cannot recommend them highly enough. The cost was about £50 with a two week turn around. The needle is rock steady, the accuracy is spot on (tested with my sat nav) and it looks like a new instrument. I am going to send my tachometer to them for an overhaul over the winter.

Cheers

Jan T
J Targosz

Might also be Speedograph Richfield located near Nottingham, as I recall. I've been using them for 35+ years. Best in the business, IMHO.
Lew Palmer

Yes Lew it is the same company and I think the name you suggest is the correct one.

Jan
J Targosz

New valve guides, new seals valve seats ground in. Still smokes on acceleration after tickover. So it is engine out next to see what is going on inside.
If it had been a TD this would have been the first option but you don't take a TF lump out unless you really have to.
Ray TF 2884
Ray Lee

This thread was discussed between 10/10/2017 and 27/10/2017

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