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MG TD TF 1500 - XPAG Crank cracking
|Has anyone experienced stress cracking at the front and rear journals on an XPAG Crank? Engine shop found two while checking the crank. Since cranks are almost non-existant,and new is cost prohibitive , the crank is going out for repair. I will have to wait to find out how deep the cracks are.|
|They all seem to crack eventually. I have two two-part cranks in my attic, both broke between the #1 main and rod. If you hit the big piece of one of them, it thunks instead of rings- meaning another very, very deep crack present. George|
|Thanks for the tip George. Good thing the engine shop was right on top of it. Fortunately they have a lot of experience with this. I waiting for the next phone call....|
|IMHO, I would not put a crank in the car that has a crack or was repaired. Yes the cost new is overwhelming but if you throw a rod, the cost of a new block, crankcase and other related items will be cheap in comparison. I had a crank go and the new one was very expensive but I sleep better and run much calmer knowing that the new one is in there and not some 50 plus year old piece of metal that has spun around millions of times and is cracked to boot. I would bite the bullet and go with a new one.|
|Tom Maine (TD8105)|
|C.R. i second tom's opinion..these cranks are 60+ plus years old..your has cracks that formed WITHOUT the added stress of welded repairs. it is SCRAP. for ALL the reasons tom stated buy a new one. much cheaper than a new block and a new crank in the future. i would be VERY surprised if you found any long time MG owner/mechanic/enthusiast who would weld one of these original cranks.|
that front journal is a very common crack location. regards, tom
|Tom, Is there anyway to identify the new cranks from the originals with out pulling the pan? Where are the identifying marks, if any? PJ|
|I dont know how to identify the new crank, I got mine from Dave Zipp, think that it is a Moldex, maybe Phoenix. My builder said it was really nice, did not need balancing or anything.|
|Tom Maine (TD8105)|
|Who sells and has competitive pricing for new nice quality XPAG cranks besides Moss? It is a pricey item upfront but I agree with the piece of mind and much less $$$ and headaches down the road if the stock crank ever fails.|
I come from the Harley world having built my motor several times with a disease I have with no cure called "dyno-nitits" chasing more HP and TQ. (Started as a 88 cubic inches and now 124".) All parts were not from the HD factory but from other sources with better quality, made in the USA, and more competitive $$$. HD by the way stands for Hundred Dollars because you end up spending that much every time you go to the dealership and parts are made in China.
There has to be other venders out there besides Moss and Abington Spares for these cranks.
From what I've been reading in archives, this is a weak link.
|Moldex is in Redford, MI. You can get a billet crank from them for around $2100 (quoted a few months ago). They might have one on the shelf (they weren't sure). I thought about snatching it up. They're only a couple of miles from our NEMGTR MI Chapter meetings so I'm going to set up a tech session there next year, hopefully.|
You can get a Moss forged crank through Little British Car Co. for about the same money.
Manley Ford can provide a billet crank for approx. the price.
You might procure a spare cast iron crank from a forum member cheap, but it may not be any better than yours.
I can ask a TD owner who upgraded to one of Manley Ford's, if you would like.
|Crower Rod of CA indicated to me that they could build a crank. the price at the time was same as what I was going to pay for mine. Dave Zipp might still have one on hand, he had a number built a few years ago.|
|Tom Maine (TD8105)|
|All good opinions. I see comments that these are cast cranks. The one in my engine is a forged steel crank. Wonder if it had been changed before.|
|There were two early cranks. The original, produced for the first TDs in 1949, up to the TF, were of nodular iron. While homogeneous, they were crystalline in structure and subject to cracking. I replaced two on my TDs, but in those days, a new crank was $120. The last crank I broke in my TD was replaced (believe it or not, under warranty - Nuffield had a great policy on parts in those days). |
That crank was of cast steel, not iron. and it was noticably better. If I had to buy it, it was $160 in 1953!
Like Geo Butz, I saved the "remainders" of my broken crank and have threatened to make some sort of a trophy out of it, But that, like so many other of my projects , has been relegared to the mañana file.
|Gordon A Clark|
|Manleys' website is: |
The Manley Ford/John Targett billet crank is built a bit heavier by design. If you get new rods, he recommends sizing to the MGB dimension to get quality bearings. Manley dispenses advice freely and I think quite a few of us have ended up with the "Ford" Engine: crank, header, Saenz rods, Brown and Gammons lightweight flywheel, Cortina diaphragm clutch. It's an investment, to be sure, but like the old guys around here used to say: Go for Broke!
|Good stuff guys!!|
|Well, not to be a contrarian, but I run with a very slight crack in my crank. If the crank does break it is HIGHLY unlikely that it will take out the engine. It will simply separate at its broken point and the ends will no longer work in harmony. A broken rod is a different story. That's the kind of break that can destroy an engine as the rod flails about.|
So, no plans to race my engine, add a supercharger or dwell in the 4400 RPM harmonic. Maybe I'm on borrowed time, but it has been a fantastic 18,000 miles since I finished the car in 2008 and I'm looking forward to many more miles. I routinely cruise at 70 mph with the 4.3:1 gear set turning about 4200 RPM. I do spend more time at 65 at about 4000 RPM.
|My crank is a billet type. My broken crank did not cause any other problems, as it broke right behind the first journal. drove it for almost a mile with the crank broken. When I shut it off however, no start again. no other damage to engine, rods or anything. just sheared right off like someone took a saw and cut it in half..|
|Tom Maine (TD8105)|
|I also recommend the John Targett forged crank. Cheaper than Moss when I bought mine.|
Where/how does one find John Targett.
|I have a Targett crank in my racing TD. Have two seasons on the engine and about 10 race weekends. So far so good. The engine lives most of the time between 4500-7000 rpm while on track and it has been rock solid. John T. can be reached at firstname.lastname@example.org |
I have a forged Moss crank available that is at standard and in excellent shape. One rod journal was damaged by a faulty bearing but was welded and ground back to standard by a specialty crank shop. The other journals are untouched. I would have no hesitation putting this back in my race engine if I needed to. Contact me off line if interested.
|I am going to have the crank redone and welded. The Machinist has done cranks for 40 years and they have investigated the cracks and are preparing the crank for refinishing. The cracks are not bad and he is confident that they will be repaired and the crank will be as good as new...maybe better as he will have it balanced. He is curious to see how much weight has to come off it to balance. He seems to think that the crank was not close enough balanced and this is what is the major contributor to the cracking. He does race engines and says that he has repaired worse than what he sees in my crank in some race engines and has never had a repaired one fail.|
I know the metallurgy is different but it is good to hear that if the crank does fail it won't take the whole engine with it.
Onward and upward!
Who is doing your crank? What is the cost? I want to take the journals back to standard and repair a small stress crack in the extra crank I have. I have one that is in need of the same service and have not been able to find any one that can do this in Cincinnati.
|Did the XPEG 1500s have a different crank as far as physical make up than the XPAGs? PJ|
the crank is the same on the xpag and the xpeg but the original mg workshop manual says, that it must not have a regrid on the xpeg but has to be changed for a new one on the 1500 engine.
May be the Morris engine gurus were not sure about the quality of the crankshafts in the mid 1950's but I think a well grid crank that has been nitrated and dynamically balanced shout outlast the stock quality used many decades ago.
|R.S. Ralph Siebenhaar|
|The only problem I see with our cranks being welded/repaired is that the XPAG is a 3 main crank and there is no harmonic balancer and this is one of the reasons they bust. Good luck, i know David is running a cracked one so hope you have the same luck.|
|Tom Maine (TD8105)|
|The early cranks (TC/early TD) were marked 168628 or 22528. The later, better, cranks which used better steel were marked 168557.|
|<<The later, better, cranks which used better steel were marked 168557.>>|
Question to everyone: Are the crankshafts in the TF's more reliable than in the TD which are more prone to cracking due to the change in the steel?
Anyone out there with a TF that the crank failed?
|My TF had a failed crankshaft.|
|Not sure if it was a broken crank or a connecting rod but our TF 1500 engine blew up fresh out of warranty, and an XPAG TD engine was sourced from a low mileage wreck. |
|Rick Taylor; I will talk to my engine guy and see if he can give me any leads for crank work in your area or if he is willing to do the work himself.|
Best I can do.
|I replaced my original crank with the Manley Ford/John Targett billet crank last winter and called it "insurance." I don't need a broken crank 1000 miles from home bringing my vacation tour to a sudden end. |
My stock crank checked out fine by the machine shop and I would sell it, if someone is interested. Let me know.
|I had been planning on getting a new crank and after reading this thread checked the numbers on my old crank and it is 22528 so I am definately getting a new crank now.|
|Richard Taylor TD3983|
|Frank Cronin, please contact me|
|Broke my TF crank many years ago at the front. I thought it was some other problem like a valve failure as it was still running on three cylinders. Parked it and drove it onto the trailer. Replaced with a billet crank.|
|According to Neil Cairns, in his book Living with the XPAG The Morris 'X' Series Engine at engine # TD2/27551 the crankshaft was forged out of E.N. 100 ton carbon steel, and went to P/N 168537. I had one of those crankshafts in the engine in our TD when I threw a rod at 4200 rpm an destroyed the engine. When I rebuilt the new engine I purchased from a friend, I had the crank in the destroyed engine checked for any cracks or other problems. In spite of having been beating all to hell, the crank had no cracks in it and it presently is being used in a TC somewhere here in Washington State. Cheers - Dave|
|I got my TD from my uncle and he claimed when he redid the motor in 1969 he used a '100 ton crank'. never really knew what he meant by that until reading this post. Don't know for sure but I hope it is.|
|Mort; Here's the crank numbers from a discussion last year. Dan|
|Hmmmmm....My crank is stamped 22716(or 8)...Wonder what that means (replaced by PO, perhaps?)?|
Incidentally, before someone notices, cotter pins have been replaced with safety wire.
The numbers aren't stamped in the crank, they're raised.
|edward, i see those numbers on your main bearing cap...are they also on your crankshaft? regards, tom|
Sorry, for the mis-que....They are obviously raised in the photo...(look closely)...
Anyway, what do these numbers mean, about the crank...?
Newer, older, replacement????
Rather than tie up this thread, I am going to re-post in a new thread.
|I have the Manley / Targett crank with MGB journals sanez rods, forged fully floating pistons, cortina finger pressure plate clutch, brown and gammons spoked flywheel. As extra I have the Manley extractor and the fanelli roller litter cam shaft. I LOVE the piece of mind and the performance of the new build.|
I have a numbers matching TF 1500 that belong to my grandfather. When my crank broke, the thought of having to replace the irreplacable made the unobtainable cost CHEAP in comparison. I am still paying of my build but would not do it another way if given the chance to do it again.
To each their own, but I'd replace that crank with the Manley / Targett version. Same price as moss but better, improved engineering.
|Why do we don't get our heads togther and make a bulk order for 15 cranks or so . I'll bet you get for under|
1350,-- or even less.
|All this broken crank talk is making me nervous. I run a totally stock 1951 TD and never continuously operate it at over 3500 RPM, maybe 4000 in short momentary bursts. Am I less likely to be running on borrowed time?|
|John Quilter (TD8986)|
I don't know that you should be concerned. This topic (and others like it) are usually posted as the result of something dumb by a PO. It could have been done innocently but erroneously buy the previous owner or by a re-builder not familiar with this engine(or looking for money/time saving shortcuts).
|Mort (50 TD "Mobius")|
|Don't be in a hurry for a Targett crank...I gave mine away in September to another racer who needed it sooner than I did (his was supposed to arrive around Thanksgiving) and I'm STILL waiting for the replacement thru John.|
|It must be the oddest sight to see an engine with a snapped crankshaft still running on 3 cylinders. If it lost the front piston then non of the pullies or fan would be spinning. Kinda reminds me of the headless chicken. On the other hand, I hope I never do see it. Sandman|
|A snapped crankshaft won't run on three cylinders because the camshaft is driven from the front of the engine?|
A broken crankshaft may run on four cylinders, but will be noisy?
|Willem vd Veer|
|A broken crank will almost certainly not do any major damage to any other part of the engine. Everytime this question of a broken crank comes up there are numerous posts warning about total disaster with a broken crank. Think about it for a minute. If the crank breaks the two pieces are still held in place by the main bearings and are not free to fly about and do any damage to the block. I would like to know if anyone has had block damage associated with a broken crank.|
Over the years I have disassembled a couple of dozen engines that were good runners. At least a quarter of the cranks were cracked. So with this thought there are probably thousands of XPAG and XPEG engines happily running with a cracked crank. Therefore if you are worried about breakage either have the crank checked every 6 months or so or lash out and purchase a new one. Personally I'm with Dave and would not hesitate to use a cracked crank for my driver. In the event of breakage it would be inconvenient but after the car was home it would take only a day or so to replace it. To me a broken crank is not much more of a PIA than a broken half-shaft.
Just my 2-bits worth.
|Many decades ago I had a friend who bought a 948cc Morris Minor for dirt cheap money. It had a huge engine knock but did run. I drove it at a slow speed of 30 MPH for about 8 miles to my friend's driveway and he and I removed the engine and when we got down to the crank removal it came out in two pieces. There was no other damage to the engine. We got another crank, fitted it, and freshened up the engine. and we were good to go.|
|John Quilter (TD8986)|
|When I broke my crankshaft the fracture ran abliquely across the crank between the front web and #1 big end. Because of the diagonal crack the motor kept running although I lost a lot of oil pressure but was able to get home without any other damage at all.|
This thread was discussed between 07/12/2011 and 27/01/2013
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