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Hello everyone.. been a while since I've posted. While performing a timing check operation, I noticed that the fan pulley on my 64 TR4 has a good amount of play/wobble in it. Probably the Fan Hub needs to be replaced. Has anyone been through this before? Am I looking at just the Fan Hub (and chain tensioner while I'm in there)... OR .. it it possible I have Crankshaft damage as well?? I probably will not dig into this until spring but just so I know what I am in for ahead of time.. Thanks
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TR4/4A TR4 - Fan Pulley wobble question
- Thread starter MrAlex
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There are bushings between the fan and the hub extension, a pulley hub and two pulley halves with bolts. You can have anything from worm bushings to broken/worn bolts. You may not know till you have it apart. If you have cooling concerns a trick to consider (since you'll have it apart)would be to use the curved/multi bladed TR6 fan (shame it's a yellow plastic one), but to do this you'll need to replace the fan extension with one from a TR3 (it's shorter than the TR4 one and thereby gives you the clearance needed).
Good luck,
Bob Muzio
Good luck,
Bob Muzio
Alex, If you mean everything is moving: fan,pedestal, pulley assembly, then maybe just the big bolt holding the whole mess on the crank has worked loose. If there's a balance weight mark it and remove the four fan bolts, pull the fan and check it out (the big bolt that is). Interestingly, I don't think I've ever seen a torque for it and for bolts like that I usually use an impact wrench.
Tom Lains
Tom Lains
Alan_Myers
Luke Skywalker
Offline
Hi MrAlex,
Let me be sure I'm understanding correctly...
You are seeing just the belt pulley wobble, right? Not the entire extension? Or the fan out on the end of the extension?
In any case, it's not likely you have a crankshaft problem.
If just the belt pulley is wobbling, well it's rather cheesy, made of two halves of pressed steel. Likely it got bent somehow. It also might just be loose, there are a series of bolts around that hold it to the extension hub. If loose, they can be tightened without much disassembly. They should have Nylock nuts to prevent loosening, though.
If the pulley is bent, it is probably best replaced since it can be hard to straighten accurately. The major vendors all supply the parts.
Unfortunately, you'll need to remove a number of things to bolt on a new pulley, since it attaches to the *back* of the flange on the extension. Start by removing the radiator shroud, then drain the coolant system, then remove the radiator. Next the large bolt in the end of the extension needs to come out, then the extension can be pulled forward and off the end of the crankshaft. Some folks drop the steering rack out of the way, but don't remove it entirely. I've been able to get by without doing that, but that's with the early type rack.
When you remove the extension by pulling it toward the front of the car, be careful of the Woodruff key between the end of the crankshaft and the extension. Try to avoid it dropping down into the front engine cover, which would probably need to be removed to retrieve it. Also watch out to not damage the lip seal in the front engine cover, that rides on the rear of the extension. Inspect the rear of the extension, for any gouging or damage that might effect that lip seal, too. (If rough, it might damage the seal... a Speedee Sleeve can be put on the extension, if necessary.)
These warnings may not be all that important if you are planning to remove the front engine cover and replace the chain tensioner, too. If you do that, try to get the silver replacement tensioner, not the black one. The black ones have been known to break pretty frequently. Many folks reuse the old, original tensioners without much concern, so it might not need replacing. But a good inspection might be a good idea, depending upon the history of the car. If the tensioner has little wear and isn't cracked or broken anywhere, it's likely safe to keep using. The original ones seem to last a long time and never lose their springiness. The spring tensioner often gouges the front plate of the engine, but that's a major job to remove and correct, requiring a lot more disassembly to get the plate out, have it brazed and then grind it back down smooth.
If you take the front cover off to replace the chain tensioner, you should plan to replace that lip seal in the front cover. It's just worth doing while it's apart, rather than redo the whole job later if a re-used seal starts to leak. You'll need a new gasket for the front cover, too, unless you make your own.
A couple things to watch if you remove the front cover. There are usually a few shims behind the extension, that serve to help line up the pulley with the ones on the water pump and the generator. There is also an oil spinner on there, to help prevent leaks at the lip seal. Just be sure to note how it's installed and put it back on the right way, if you remove it.
This can all be done without removing the fan from the extension. However, if you do want to remove it for any reason, watch the balance weights on it and mark their location. There should be a hole drilled through the weight marking it, about 1/16" diameter, but that's not always the case. Usually there is just one weight.
If the entire front hub/extension/fan assembly is wobbling, that's most likely just the large bolt at the end of the extension is loose. This might indicate an imbalance, though, that has caused vibration and loosened things over time. Again, check to see if there are any weights (sort of crescent shaped piece under one of the bolts) or if it might have been removed in the past. More rarely, I've also seen balance weights on the bolts at the pulley.
Unfortunately, no one seems to know how to re-balance this assembly. There are no instructions for balancing in the service manual.
If it's only the fan that is wobbling, Bob is correct and new bushings and bolts are a good idea. The Roadster Factory sells a complete kit with all the pieces included except for the balance weight. If the fan has a wobble, again it might just be loose, perhaps Nylock nuts weren't used (or were re-used, they should always be replaced with new). Again, a fan might gradually loosen due to vibration if balance weights were omitted. Another thing to check is if the blades are bent or cracked. The 4-blade, metal fans are notorious for this (similar fans put two out of three TR3s out of LeMans, the first time Triumph went racing there... which is especially silly since fans are useless at 114 mph). Could be time to install the yellow plastic fan that Bob mentions. As far as I know, no one ever uses balance weights with the plastic fans.
The fan bolts can be tightened or removed, and the fan can be replaced without removing the radiator, although clearances are tight. Just be careful about the radiator fins.
While in the area, check the pulley and extension clearance to the steering rack, frame cross-member, etc. If you have trouble getting the belt on and off the pulley, it's a sign that the two front engine mounts are getting old and the engine has settled a little bit under it's own weight. Jacking up under the oil pan (with a wide piece of wood to protect it) is a temporary solution to get the belt off. The engine mounts really should be replaced, if the engine has settled like this.
I recommend a little caution replacing the front extension. It also serves as a dampener for the crankshaft. This might not be an issue with a well-balanced engine or one that's not driven very hard, but harmonics can make a mess of the gearbox and/or the crankshaft, if not dampened. The TR3 extension Bob mentions seems okay, as far as I know. I've converted my TR4 to fanless (electric instead), an alternator and a thin belt, so am using a proper harmonic balancer/pulley.
Hope this helps!
/ubbthreads/images/graemlins/cheers.gif
Let me be sure I'm understanding correctly...
You are seeing just the belt pulley wobble, right? Not the entire extension? Or the fan out on the end of the extension?
In any case, it's not likely you have a crankshaft problem.
If just the belt pulley is wobbling, well it's rather cheesy, made of two halves of pressed steel. Likely it got bent somehow. It also might just be loose, there are a series of bolts around that hold it to the extension hub. If loose, they can be tightened without much disassembly. They should have Nylock nuts to prevent loosening, though.
If the pulley is bent, it is probably best replaced since it can be hard to straighten accurately. The major vendors all supply the parts.
Unfortunately, you'll need to remove a number of things to bolt on a new pulley, since it attaches to the *back* of the flange on the extension. Start by removing the radiator shroud, then drain the coolant system, then remove the radiator. Next the large bolt in the end of the extension needs to come out, then the extension can be pulled forward and off the end of the crankshaft. Some folks drop the steering rack out of the way, but don't remove it entirely. I've been able to get by without doing that, but that's with the early type rack.
When you remove the extension by pulling it toward the front of the car, be careful of the Woodruff key between the end of the crankshaft and the extension. Try to avoid it dropping down into the front engine cover, which would probably need to be removed to retrieve it. Also watch out to not damage the lip seal in the front engine cover, that rides on the rear of the extension. Inspect the rear of the extension, for any gouging or damage that might effect that lip seal, too. (If rough, it might damage the seal... a Speedee Sleeve can be put on the extension, if necessary.)
These warnings may not be all that important if you are planning to remove the front engine cover and replace the chain tensioner, too. If you do that, try to get the silver replacement tensioner, not the black one. The black ones have been known to break pretty frequently. Many folks reuse the old, original tensioners without much concern, so it might not need replacing. But a good inspection might be a good idea, depending upon the history of the car. If the tensioner has little wear and isn't cracked or broken anywhere, it's likely safe to keep using. The original ones seem to last a long time and never lose their springiness. The spring tensioner often gouges the front plate of the engine, but that's a major job to remove and correct, requiring a lot more disassembly to get the plate out, have it brazed and then grind it back down smooth.
If you take the front cover off to replace the chain tensioner, you should plan to replace that lip seal in the front cover. It's just worth doing while it's apart, rather than redo the whole job later if a re-used seal starts to leak. You'll need a new gasket for the front cover, too, unless you make your own.
A couple things to watch if you remove the front cover. There are usually a few shims behind the extension, that serve to help line up the pulley with the ones on the water pump and the generator. There is also an oil spinner on there, to help prevent leaks at the lip seal. Just be sure to note how it's installed and put it back on the right way, if you remove it.
This can all be done without removing the fan from the extension. However, if you do want to remove it for any reason, watch the balance weights on it and mark their location. There should be a hole drilled through the weight marking it, about 1/16" diameter, but that's not always the case. Usually there is just one weight.
If the entire front hub/extension/fan assembly is wobbling, that's most likely just the large bolt at the end of the extension is loose. This might indicate an imbalance, though, that has caused vibration and loosened things over time. Again, check to see if there are any weights (sort of crescent shaped piece under one of the bolts) or if it might have been removed in the past. More rarely, I've also seen balance weights on the bolts at the pulley.
Unfortunately, no one seems to know how to re-balance this assembly. There are no instructions for balancing in the service manual.
If it's only the fan that is wobbling, Bob is correct and new bushings and bolts are a good idea. The Roadster Factory sells a complete kit with all the pieces included except for the balance weight. If the fan has a wobble, again it might just be loose, perhaps Nylock nuts weren't used (or were re-used, they should always be replaced with new). Again, a fan might gradually loosen due to vibration if balance weights were omitted. Another thing to check is if the blades are bent or cracked. The 4-blade, metal fans are notorious for this (similar fans put two out of three TR3s out of LeMans, the first time Triumph went racing there... which is especially silly since fans are useless at 114 mph). Could be time to install the yellow plastic fan that Bob mentions. As far as I know, no one ever uses balance weights with the plastic fans.
The fan bolts can be tightened or removed, and the fan can be replaced without removing the radiator, although clearances are tight. Just be careful about the radiator fins.
While in the area, check the pulley and extension clearance to the steering rack, frame cross-member, etc. If you have trouble getting the belt on and off the pulley, it's a sign that the two front engine mounts are getting old and the engine has settled a little bit under it's own weight. Jacking up under the oil pan (with a wide piece of wood to protect it) is a temporary solution to get the belt off. The engine mounts really should be replaced, if the engine has settled like this.
I recommend a little caution replacing the front extension. It also serves as a dampener for the crankshaft. This might not be an issue with a well-balanced engine or one that's not driven very hard, but harmonics can make a mess of the gearbox and/or the crankshaft, if not dampened. The TR3 extension Bob mentions seems okay, as far as I know. I've converted my TR4 to fanless (electric instead), an alternator and a thin belt, so am using a proper harmonic balancer/pulley.
Hope this helps!
/ubbthreads/images/graemlins/cheers.gif
Yes.. the whole assembly is wobbling (I can wiggle it). That is why i thought it was the hub on the crank. Gee.. Thank you for all of the insight and detail. You guys are great. Now I can't wait to see what's there.. Will post on this at a later date with whay I find.. Alex
Alan_Myers
Luke Skywalker
Offline
[ QUOTE ]
Yes.. the whole assembly is wobbling (I can wiggle it). That is why i thought it was the hub on the crank.
[/ QUOTE ]
Hi again Alex,
In a way, that's good news! If you don't want to go too deep into the other projects right away, repair might be pretty simple.
I'm guessing you may be able to just remove the fan and tighten that big bolt to snug it back up (this is the bolt that has the strange end, into which the handcrank fits). Hopefully it's not so loose that the Woodruff key on the end of the crankshaft is out of place. The slot in the extension is pretty long, so it's unlikely the Woodruff has dropped out. Depending upon how long it's been loose and how much wobble there has been, I suppose there is a possiblity the slot in the extension or the end of the crankshaft or the keyway in the crankshaft could be beat up or worn. Short of disassembling everything, I think you'll just have to see if you can tighten it up, to decide for yourself.
After removing it, you may need a new fan mounting kit unless yours is relatively new, and will need to watch out for any balancing weights currently installed on the fan (probably just one under one of the mounting bolts). Maybe it would be wise to mark everything before disassembly, so it can go back in exactly the same orientation (even though it may not be in very good balance already, depending upon what has been done in the past). Mark the front side of the fan, too, before removing it.... more than one has been reinstalled backward... it still works, just not as well.
If you do opt to simply tighten things up for now, after doing so keep an eye on the lip seal in the front cover, right behind the crankshaft belt pulley. Wobbling of the whole extension might have damaged that seal and you might see more of a tendency to leak oil there.
I'm wondering why it all loosened in the first place. It's not a common thing to happen. I suppose if the balance weights were left off during previous work or the whole thing were re-assembled in a way that causes some vibration, that might explain it. Another thing you might want to check is the lower/front mount for the generator. The part that bolts to the front engine plate, to which the generator is in turn bolted, often loosens a bit and then grinds away and wears inside its mounting hole (i.e., enlarging the hole in the front engine plate itself). That might cause a lot of fluctuation in belt tension even though it appears to be adjusted correctly in the engine's usual "stop" position. If that mount is worn and loose, the belt might alternatively slacken and tighten on the two other pulleys, possibly setting up a situation that eventually vibrates the extension hub, fan and pulley assembly loose. This would be hard on the water pump bearings, too, I'm sure, and you might check that the water pump pulley is snug, as well.
After tightening or making any other repairs, you should probably keep an eye on it to see if it again loosens. Usually I'd not suggest it, but some Locktight on that long bolt might help keep it secure. The problems are that this can make engine disassembly harder in the future, plus the only way to pull that bolt out far enough to get to the threads with Locktite is to remove the radiator from the car.
It sounds like it might be a relatively simple fix, I hope so, and just a bit of a red flag to check out a few other things.
Yes, keep us posted on what you find!
Happy New Year!
/ubbthreads/images/graemlins/cheers.gif
Yes.. the whole assembly is wobbling (I can wiggle it). That is why i thought it was the hub on the crank.
[/ QUOTE ]
Hi again Alex,
In a way, that's good news! If you don't want to go too deep into the other projects right away, repair might be pretty simple.
I'm guessing you may be able to just remove the fan and tighten that big bolt to snug it back up (this is the bolt that has the strange end, into which the handcrank fits). Hopefully it's not so loose that the Woodruff key on the end of the crankshaft is out of place. The slot in the extension is pretty long, so it's unlikely the Woodruff has dropped out. Depending upon how long it's been loose and how much wobble there has been, I suppose there is a possiblity the slot in the extension or the end of the crankshaft or the keyway in the crankshaft could be beat up or worn. Short of disassembling everything, I think you'll just have to see if you can tighten it up, to decide for yourself.
After removing it, you may need a new fan mounting kit unless yours is relatively new, and will need to watch out for any balancing weights currently installed on the fan (probably just one under one of the mounting bolts). Maybe it would be wise to mark everything before disassembly, so it can go back in exactly the same orientation (even though it may not be in very good balance already, depending upon what has been done in the past). Mark the front side of the fan, too, before removing it.... more than one has been reinstalled backward... it still works, just not as well.
If you do opt to simply tighten things up for now, after doing so keep an eye on the lip seal in the front cover, right behind the crankshaft belt pulley. Wobbling of the whole extension might have damaged that seal and you might see more of a tendency to leak oil there.
I'm wondering why it all loosened in the first place. It's not a common thing to happen. I suppose if the balance weights were left off during previous work or the whole thing were re-assembled in a way that causes some vibration, that might explain it. Another thing you might want to check is the lower/front mount for the generator. The part that bolts to the front engine plate, to which the generator is in turn bolted, often loosens a bit and then grinds away and wears inside its mounting hole (i.e., enlarging the hole in the front engine plate itself). That might cause a lot of fluctuation in belt tension even though it appears to be adjusted correctly in the engine's usual "stop" position. If that mount is worn and loose, the belt might alternatively slacken and tighten on the two other pulleys, possibly setting up a situation that eventually vibrates the extension hub, fan and pulley assembly loose. This would be hard on the water pump bearings, too, I'm sure, and you might check that the water pump pulley is snug, as well.
After tightening or making any other repairs, you should probably keep an eye on it to see if it again loosens. Usually I'd not suggest it, but some Locktight on that long bolt might help keep it secure. The problems are that this can make engine disassembly harder in the future, plus the only way to pull that bolt out far enough to get to the threads with Locktite is to remove the radiator from the car.
It sounds like it might be a relatively simple fix, I hope so, and just a bit of a red flag to check out a few other things.
Yes, keep us posted on what you find!
Happy New Year!
/ubbthreads/images/graemlins/cheers.gif