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MG TD TF 1500 - Checking the cam followers on a TD

I removed the rocker assy today and checked the Rocker shaft and rockers - all looks to be in order except for rocker No7.
It has a worn area about 7 thou deep and is the size of the valve head. About a 1/4" wide. All the other rockers have very small shiny areas that are 3/16" wide with no discernable pitting.

The cam followers look to me as if they have not been rotating? The Lobe wipe area on the follower is really only in one place?
I thought the cam lobs were offset some to help with rotation?
4 of the 8 look to have tried to rotate, as there is another wipe shiny area maybe 15 - 20 degrees off.

All the marking of the lobes seem to be almost in the center of the follower???
The offset must be very small - 1/8" at best - Is this enough to rotate the followers?
Is there something wrong with the cam installation that it is not in the right place? I cannot see how?
I measured all the lobe lifts several times - I used a dial indicator on the pushrod with the rockers removed and made sure the pushrod was in the center of the hole and the dial indicator was set up vertical to the push rod. Rotating the pushrod did not change the zero start point of the measurement.

I do not know if the Cam is OK. The lobes look OK through the lifter ports but some advice here would be appreciated.

From the front..
No1 0.235"
2 0.236
3 0.237
4 0.232
5 0.237
6 0.236
7 0.234
8 0.232

Would it be an idea to just fit a set of new STD flat lifters (which I believe these are) to all lobes and run them in correctly with cam lube.
The pushrods all look strait and the ends are firmly installed no looseness at all.
I did note some flat marks on some of the rods - as if they had been clamped in a vice? Kind of a flat spot but not very deep. All the pushrods are a hair under 8 3/8"

So the options are - fit new some new STD followers and run them in and see if they will rotate correctly. Maybe drive it this summer. ļ
OR
Remove the engine and replace the cam and followers & replace the No7 rocker.

Roller cam and roller rockers are expensive but remove a lot of worry on the follower side and don't have to worry about rockers going forward.
At my age it will be a push to do that and I will have to get hold of some tools to assist with the removal. Wife unfortunately will not be much help.
However I do respect those who are on this BBS and have done all this recently. Your words will be good council.
I have tried to photo the parts but it is very hard to see such small marks - I will post them on MEDIAFIRE and attach a link if you want to see what I found.

http://www.mediafire.com/download/h62jwrac2cler99/CAM.rar
use the download button at the TOP (1.68MB)

Any advice would be most helpful.
Rod
Rod Jones

General advice is to never install new lifters on a used cam. However some have done it with success. If you replace the cam, a better solution for similar money is to use a cam with a modern profile, not flat. Crane cams and the special Moss lifters will outperform the old flat stuff and can be had for about $600 for the camshaft and lifters.
Steve S

"Pushrods look straight"- put them on a table/flat surface and roll them to check. Obviously the valve with the worn rocker will clatter like crazy, especially when cold. While no expert, there seems to be very little difference in your cam lobe lift, so if they look fine they likely are. If the lifters are not grooved out, pitted, or otherwise trashed, I would put them back exactly where they came from, reface or replace the rocker and carry on. While technically they should rotate, again if not damaged it doesn't matter for average driving. What kind of driving are you going to do? If around town, parades and stuff, the cam/lifters may last for years. Different story if long distance, high RPM highway drives planned, even then things could last a long time. L-series Nissan engines use finger followers directly on the cam which of course don't rotate, the cams/followers go very high mileages with no problems. Why would a lifter not rotate? Too tight in the lifter bore, the core/bore in the block is centered rather than slightly offset from the cam lobe (or cam lobe not exactly positioned), etc. Seems many of the new lifters are really lousy metal, so I would reuse the old ones rather than replace unless changing the cam. George
George Butz


George
What do you consider too much wear on the lifters?
Here is what I found. There seems to be a little galling but the majority of metal is there and the depressions are only a thou or so deep.
Your right, the No7 rocker would have made a lot of noise. I use one of those clicker valve adjusters. Have had it since 1970 they are supposed to allow for the ware and not bridge the gap as per a feeler gauge when adjusting. Even with the ware it should have still been 12 thou - set not. That's the theory anyway :)

Still can't work out why the noise faded away after 1 min 53 sec's. Can the rocker or valve train change that much in that short of a time??? I would have sworn one of the followers was badly worn and rotating the bad spot - but was certainly proved wrong.

I checked the push rods and 4 have a very slight wobble on the end when rolled on the corner of a flat glass table - very small 5 to 10 thou at best? Is this enough to cause a problem?

Rod
Rod Jones

Forgot the picture of the lifters sorry.



Rod Jones

Rod, most of the time we don't know the life cycle or usage circumstances that the part we're trying to evaluate has been exposed too. I guess I've seen almost every type of wear condition possible with the TD cam and lifters in my 50 years of MG exposure. They wore out just as good 30 years ago as they do now, so I know it is not all oil related.
Since I've been in the exact situation your facing a few times in the past, I can only tell you what I did.
I did not put obviously worn or damaged lifters back in the engine. I checked them for wear on the face and on the sides and checked for fit in their bore. Acceptable ones were sent for regrind and bad ones discarded. Yes, some new ones might be less than desirable from a materials standpoint, but I doubt many are as poor as new MOWOG ones were in the 50s. Most original metal parts of the day were only as good as the bulk steel cast iron stock provided, and if you believe they were hardened and treated special, your one of the few optimists still around.

Obviously, it would be nice to be able to replace all of the worm cams and lifters with the latest roller/ high tech units advertised as the best , but I know I can't afford to do it, and if I did, I probable wouldn't want to run the engine because I'd be afraid I might hurt something valuable.

Finally, over the years, I have had some very good advice from the people at Delta Camshaft Company in Tacoma Washington--phone 800-562-5500. Give them a call and explain your situation, I'm sure they will answer your question for free, and recommend solutions that are reasonable because they have many years of actual first hand experience.
Richard Cameron

I have used Delta Cam many times and I am completely satisfied with their work.They also do a resurface on the lifters and I have never had a problem .
Sandy
ss sanders



Thanks Richard - Sandy.
I use the car for general trips and the odd charity show event. Not concourse events - No point. Being in Maine you have to get on the interstate to get anywhere so it will run at 65 or 70 for several hours. I have one of Steve Neal's gearboxes to help with that. But 4000 RPM is about it for cruising.
Your Delta Cam info is worth noting and I will give them a call and see about having the followers resurfaces and hardened.
The cam lobes I can see through the ports do look OK - Nice and shiny with no dark marks where the surface is pitting. But I am no expert either. As you say, the lift on each is very similar. Not sure what the tolerance is but I would think very close to all the same?
Both the TD's I have owned have never suffered from this issue in the past 50 years so it is all new to me.
One other thing I noted is the length of the pushrods??? In the Moss Catalog it says
----------------------
PUSHROD NOTE: Early TC-TD pushrods had an effective length (ball seat to ball end) of 8.681”.
While the later TD-TF pushrods had an effective length of 8.62”. This change occurred with the
change in adjusting screw lengths, as noted with #36. We stock the later specification pushrods,
which are suitable for all normal applications? Where a cam with oversized lobes or a cylinder
head with significantly reduced thickness are used, our short pushrod set with an overall length of
8.531” will suit.
-----------
Judging from that - My later TD (53) should be 8.62" long. But they are in fact only 8 and 3/8th or a hair shorter?? Which is nowhere near either?
I also noted that there is 4 older shorter adjusting screw. 29.8mm. Picture attached. Strangely one is on rocker that has all the ware? No7. 4 of the 8 are the longer 32.2mm? Just beggars my mind.
Rod.


Rod Jones

Rod, pictures tell a different story, those lifters are toast. The surface hardening is failing and those will just disintegrate. Most likely did not do the cam any good. Not sure about pushrods- the end/tip could be slightly off center and fine? Great advice to call the cam company.George
George Butz

I have used Effingham Regrinding, Inc. in Effingham, Illinois and was very satisfied with their work. Google the above name and give them a call. They have been around in the business for quite a long time.
Jim Merz

As George noted those lifters are done.

I went through this a while back on my TD. My previous-owner-installed Crane cam had a few lobes with some wear -- enough that something had to be done -- and a few bum lifters.

I like Moss but couldn't stomach paying $600 for their Crane cam + $350 for the lifters to go with it.

Instead, I sent it to Iskendarian where they checked it to make sure there was enough hardening left to grind (there was) and then reground it to one of their profiles. They recommended that, rather than buying new lifters of unknown quality, I find some good used ones that had been "field proven" and send them to be refaced. They suggested Rocker Arms Unlimited:
http://www.rockerarms.com/

RAU checked the hardness of the lifters (which were fine), then refaced them.

The bill was $90 to Isky and $3.50/per to RAU. I was happy. :-)

Isky also recommended Brad Penn oil FWIW.

Rob Edwards

Rob, you can buy the Crane cams elsewhere for about $385. And on sale, the Moss lifters are less than $300. While I do use many of Moss' parts, I do not recommend their pushrods. I use Smith Brothers to make mine to custom length for less money and top quality.
Steve Simmons

Rod,

In addition to Steve Neal's transmission install a 4.33 rear (mga) and you can cruise the Turnpike at 60mph at 3,000rpm. I got it, I do it. Love the peace of mind.

Jim
James Neel

Rod - your lifters have certainly not been rotating, and are junk - it looks as though the hardening has been compromised. Delta Cam can confirm. My guess is also that the cam is toast. Send it to Delta and they can tell about the cam and lifters.

When you check the pushrods for straightness, make sure the cup and other end are NOT rolling across the glass; they are usually not true. Study only the shaft of the pushrod.

Tom Lange
<MGT Repair
t lange

Thanks Guys - I am getting the message. The lifters are bad and would need at the least resurfacing. Talked to Delta Cam and they said to send them over and they would regrind them with a slight crown to help with rotation. I don't think I have a Crane Cam installed and these are flat tappets like STD, so not sure if crowning would be prudent?
Also of concern are the Pushrods.

Tom, I was rolling the rods on a glass table corner, so as not to involve the ends. 4 look to have some bend in them. I am concerned about the length. 8 3/8" is less than the Moss Crane Cam high lift ones?? Is the lift on my lobes at 0.237" High? Or is that the STD cam height? If so, you would think the valve geometry is wrong with really short push rods. Certainly the 4 short adjuster’s screws are on the end of their travel - as see in the photo above.

Looking down the lifter ports the cam lobs seem very near the center? How much off set is required to make the lifters rotate?
As you can see from the bottom of the lifters, ware is almost centered and they are not rotating.

Neal, I do have a new axel and diff coming from Dave Clark in September, so should enjoy the improved rev situation after that :)

Bottom line here it seems, is the engine has to come out and change the cam and lifters together. I really don't think my back will handle an "In car" replacement.

The question then is - rebuild what is in there - that failed after 15 years and 8000 fairly easy miles. Or replace and go with a roller cam and rockers and not worry about lot of this stuff again? I would use the TD much more if the engine was sound.

Need to think about that and if it is possible to do it before the winter gets here. It comes early in Maine.

I appreciate you comments and thank you for all and any information.

Rod





Rod Jones

Rod if you are replacing the cam it can be done quite easily with the engine in the car as hardly any time at all is spent under the car. Apart from dropping the sump, my removal & installation was done almost entirely from the front of the car sitting comfortably on an adjustable office chair, with the car on stands. Read "Replacing the camshaft" & if you plan on roller lifters read "Valve springs for roller lifters". Both are in the archive. Cheers
Peter TD 5801
P Hehir

Rod, can't offer anything of value regarding your cam and lifters but wonder what part of maine you hail from. I spent a year and a half (two winters) just south of Dover Foxcroft at a litle USAF station on Hwy. 15. What a georgeous State.

Jud
J K Chapin

I do not believe it's a good idea to run crowned lifters on a flat cam. They should both be flat, or not.
Steve S

A second for effingham. Great guys, great work, very competitive pricing, quick turn. Family business. Cannot say enough good things. No connection to the firm, just a very satisfied customer. Regards, tom
tm peterson

Well,
I got the followers reground flat by Delta and obtained a set of new strait pushrods form Smith Brothers. Fad the rocker No 7 also resurfaced by Delta. Got hold of some assembly lube and Tom’s rubber gaskets and put it all back together on the original cam.
Ran it in for 30 mins at 2000 to 3000 RPMs varying and speed occasionally.
As luck would have it, I had timed the dissy 180deg out and as it did not fire at once (which it has always done) took a look and saw the mistake. I had the mark on the pulley at TDC but it was for cyl No4 not cyl No1
I fooled myself looking at the piston on No1 and failed to check the valve positions - No 4 was on the firing stroke. Still it was a quick fix and it started right up.
At 3000 rpm I tweaked the position for best running but I need to go get a timing gun to double check degrees etc.
Because everything was cold after putting it back together and not wanting to turn the motor over unnecessarily. I set the tappets to 19 thou for the run in. Afterwards I set them all to 12thou hot and it purrs like a sewing machine again.
I guess I will have to wait and see if the cam and followers survive. It was very much the cheap fix so if it fails I can’t complain. I am amazed at just how robust these engines are - if you keep them lubricated right and don't abuse them too much.
Now all have to do is get the bonnet back on. Almost gave myself a hernia getting it off. Which I think is easier than putting it back on. Will have to get "her indoors” to lend a hand....

Thanks for all the advice gents. Appreciated the info and guidance.

Rod


Rod Jones

This thread was discussed between 12/08/2014 and 19/09/2014

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