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MG TD TF 1500 - TD/TF Camshaft Life

I know most people aren't driving their old cars enough to regularly wear out camshafts anymore, but does anyone have an idea of the life expectancy of a camshaft in a TF1500? I don't recall if the springs are heavier in the XPEG but if not then should be similar to TD I suppose.

Thoughts?
Steve Simmons

I wore out a camshaft on a TF 1250 in 3000 miles, it's not the spring pressure it's the condition of the cam followers that take the top of the lobes. My TD eat 3 camshafts so I have change both my TD and TF to roller cams.
B W Wood

I'd reckon you have more knowledge than I Steve when it comes to these engines so I can only give my experience with my XPAG and I doubt the XPEG would be much different. I run the engine hard and my experience was the tappets were failing at around 10,000 miles. New set of tappets with the same cam first time...reground second time with same cam and what you see after 30,000 miles. Would it go another 10,000 ? I didn't think so, so it got a new cam and tappets on the last build. Will things be any different? Probably not but I'm not putting the mileage on it I once did.





L E D LaVerne

One of my customers with a S/C TB drives it on the long distance "Hero" Rally's in the UK ond or other parts of Europe, He was tired of XXX brand cams from the UK wearing out,multiple times. Steve Baker recommended one of my Roller cams and he has been very happy!
TB TC TD springs are 93pounds closed and 123 pounds open
TF 114 -135 pounds closed and 150 pounds open.
Len

Len Fanelli

Thanks LaVerne, exactly the kind of info I was looking for. I had a regrind fail after about 9K miles. Before the regrind it went 17K miles, but to be fair it wasn't well taken care of by the previous owner.

I'm aware of roller cams, and I have an engine with one. But this isn't for my engine so I'm just trying to give some data to him.
Steve Simmons

Curiosity question here......

How do you know when you've got an issue with a camshaft/tappets? I had my engine rebuilt a long time ago, and it still seems to run fine. A Crane cam was installed (standard lift) along with new tappets, pushrods, pistons, springs, valves, etc.

I don't drive it a lot, but what are tell-tale signs a camshaft/valve train is not up to par....short of it breaking?

Jim
Jim Rice

Reduced performance or new knocking sounds could be a sign. One way to investigate is to measure the valve lift and see if it has changed. In my experience, when a cam fails, one or two lobes will usually be far worse than the others, so you have to measure them all. I'd say the best way to know the health of your cam is to remove the tappet cover, rocker assembly and push rods. Then pull and inspect each tappet and lobe visually. Not a bad thing to do every 10K miles or so.
Steve Simmons

If you are having to close up one or two rocker adjusters regularly that is a good (bad) sign that those lobes are losing their tops. Mine for some reason on two totally different cars was always No3 cylinder.
B W Wood

Have you noticed that it's usually an exhaust lobe that goes first--I've got a theory
When the engine is on it's power stroke the exhaust valve opens before the piston gets anywhere near the bottom of it's travel and there's still combustion pressure in the cylinder that the exhaust valve has to fight against to open putting extra load on the cam/follower--same with rocker bushes ,it's the exhausts that cop it first
The inlet gets an easy ride as the exh. valve is still open when the inlet opens and no cylinder pressure to fight against
Aftermarket cams like Crane for example usually last longer as they have the lobes ground very slightly conical which encourages the cam follower to rotate better than the std 'flat' grind
William Revit

Good point, although I have a cam here that just went bad and it was an intake (#6). But there are a lot of variables that can lead to a tappet or lobe failing.
Steve Simmons

For anyone interested, as a Comp Cams dealer I can supply any Comp Cams cam at the BEST price, period!
For the XPAG /XPEG engines I can also supply the proper tappets for a Comp Cam, push rods & valve springs. But for a few hundred dollars more you can get one of my Roller tappet cam kits > "Whem only the best will do"
Rolleer cams and tappets have been known to last over 300,000 miles.
Stock T type "Blue printed" Roller cams back in stock
Safety Faster
Len
Len Fanelli

As noted above, the valve springs used on TD/C, TF and TF1500 engines are stronger than those used in TB, TC, and TD engines. (I call them 150# and 125# springs, for convenience.)

The stronger springs are necessary when an engine will be driven hard, and when revs will regularly approach 5500. But most drivers do not use that rev range often - if at all - so the 150# springs are quite unnecessary in an engine that will turn no more than 5300RPM, occasionally. Logic tells me that heavier springs cause increased valve train wear, so I don't use them.

I have put the lighter valve springs in the dozen or so engines I have built in the last 10 years, and have had not a single complaint about reduced power. I have no empirical data to prove that the lighter springs cause less wear, but I still believe it.

Tom Lange
MGT Repair
t lange

Agreed Tom, and easier on rocker shafts etc as well
The TF springs usually run around 120-125 lb seat pressure std. which is fairly high for such a little valve and lightweight valve train
William Revit

My 2 cents on the issue of spring pressuresfor any solid lifter cam >
https://help.summitracing.com/app/answers/detail/a_id/4786/~/valve-spring-pressure---solid-flat-tappet
(It states 130 # seat pressure AND 300-325# open
pressure)
Len
Len Fanelli

I don’t think the premature wearing out cause is fully understood. Back in the day, the cam/lifters did not wear out like today. I think the cam/lifters in my engine had 30k miles on it when the crank broke and were in decent shape. This engine had been driven hard- worn cylinders with big time ridges at top, eaten up and worn rod/main bearings and sludge- but cam fine. Most of the guys that seriously drove and raced the cars are long gone, so can’t ask them. As long as I’m not adjusting valves all the time, I’m not going to look at mine! George
George Butz III

Len, that's not a very good 2 cents worth
how long do you think an XPAG/XPEG std flat tappet cam would last with pressures like that--not long I don't think--even a std LS chev roller engine only runs90/280
William Revit

When I bought my TC in the 50s, I was told by old timers there were 2 things you should never do with a TC or TD.
One was never stick a screwdriver in the doorpost to see if the wood was rotten. It probably would be. The other thing was never check your cam followers for wear , because they will be worn and the car will continue to run good if you ignore the wear , until the cam is really bad. Worn cams were always an issue.
When I rebuilt my car in the late 80s and put it back into daily use, I found many things on the car start to wear out around 8 or 10,000 miles. A daily use car using the standard valve springs will have a lot of follower wear and often cam wear at this mileage.
Keep in mind this was a daily year round driver and took a lot more wear than a hobby car.
Charlie
c mac quarrie

William my post was to show that, most but not all, replacement parts are not as good as the original ones to say the least! > Most Cams not copper coated for a much deeper heat treating, Most tappets very poor quality & rocker shaft most likely not as good as the original.
The rocker shaft wears much more than the rocker bushings.
The spring pressures you mentioned are for a hydraulic roller lifter cam.
The 300-325 # open pressure is for a modern solid lifter cam valve lift of 4.00"-.500" vs the original cams of .315"
Solid tappet Roller cams & tappets have been known to last 300,000 miles with 340# open valve spring pressures.
Safety Faster
Len
Len Fanelli

Exactly--my point is----absolutely nothing to do with a std XPAG
William Revit

Lets not forget, the oil no longer has ZDDP.

Today's oils give cams the shaft!
JIM N

All oils still have ZDDP.
These tappets were removed from a car BEFORE levels of ZDDP were reduced.
Regards, Tom


tm peterson

I bought a Y-Tourer in 2006 and the previous owner had removed the inner valve springs saying - "they are not needed if your revs are kept below 5,000rpm". He was a retired professional mechanic from the era when these cars were brand new.

I drove the car around urban areas and on long trips interstate for a year before re-fitting the inner springs. I noticed no change in performance, but no doubt the load on the camshaft lobes is now higher than it was before.

One day when my lucky numbers come in, I will invest in a roller cam & followers from the USA.

I will be removing the inner springs soon to extend the cam and follower life. My car has a 4.55 diff ratio to reduce highway rpm by around 600 at 60MPH.

The cylinder head has not been off this car in 16 years in my ownership and around 25,000miles of travel.

Safety Fast!

Tony Slattery
The Classic Workshop
Black Mountain
Australia





A L SLATTERY

Another couple of things to look for:





PJ Jennings

This thread was discussed between 07/03/2023 and 22/03/2023

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