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Horrible rattle in the front after ALT conversion ...

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Well, I did the Dyno swap and all was running well until the other day at a red light I noticed a horrible "clatter" coming from the front end.  Checked the water pulley and it was nice and tight.   Took the alternator off and disassembled and reassembled.  That said, I noticed the fan on the alternator does not "lock" on the key on the shaft?  It is actually below.   Wondering if under tension it is vibrating/spinning and causing the rattle?  Has anyone else had an issue with the fan not reaching the key on the shaft?

The only other thing I can isolate is some "clatter" from the passenger (rt) top of the chain cover behind the fan?  Timing tensioner possibly?  That will not be a fun 2 days of pulling the front end apart.

Don

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The alternator fan, as you say, is not keyed, it relies on the pulley clamping it tight. so suggest you check the tightness of the pulley nut.

Bob.

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Attaching a pic as I just pulled the Alt again.  Despite not being in the key slot, the fan seemed "tight" from the impact gun attaching the nut on the outside of the pulley.

Alt.jpeg

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So I am afraid it is the chain tensioner - just moved the water pump pulley and ran the motor briefly - still clattering.  Maybe it's time to upgrade to the skinny belt set up?  Of course, that means an electric fan as well?

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Found a kit from BPNorthwest that will retain the fan hub extension and plastic fan.

What all do I need to buy if I attempt to make this repair on my own?  Obviously the best chain I can find and tensioner, but as far as seals/gaskets/locking tabs, etc?  Hoping the gears are OK but won't know that until I get it tore down.

 

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Any 'witness marks' on that alt fan? is one blade hitting something (maybe the tensioner bolt/bracket) in the installed setup?

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Unfortunately no.  Even after taking the belt off, still getting rattling.  Given the history of the previous owner and what has (or hasn't been done correctly) I am tempted to pull it and do a complete do over.  BUT, a few hundred in bits and pieces and a couple of days is appealing as well.....

 

Don

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Have you contemplated a "skinny" belt conversion with a harmonic balancer, deleting the hub extension and fitting a thermo fan.

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9 hours ago, Malbaby said:

Have you contemplated a "skinny" belt conversion with a harmonic balancer, deleting the hub extension and fitting a thermo fan.

Yes, but is the $600 in parts worth it?  Moss carries the belt conversion for $320, and the fan, sensors, mounts is about another $200, plus the tensioner, chain, seals, gaskets, etc.

 

Don

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Don, I installed the “undamped” narrow pulley kit from Rimmer Bros ($156), and kept the stock fan/extension on my TR4a . I guess I’m just a “fan” of that old industrial look (sorry, couldn’t resist:D).

BTW, the metric fan belt they included in the kit didn’t quite fit snug enough with my alternator setup. I found that NAPA belt 25-7395 worked better.

Jim

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Could it be a simple as the crank bolt being loose and the pulley/fan extension rattling on the woodruff key?   I am always thinking that todays problem is the result of what we did yesterday...and since you have changed the Alt/Dyn that must be somehow the cause...weird that a timing chain tensioner would suddenly fail...did you turn the engine backwards?? that can kill the spring if its on its last legs... 

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Easy check, tighten the crankshaft dog bolt up to 120 lb ft.

I've had to replace 3 or 4 front pulleys on engine rebuilds where the dog bolt has not been tightened enough and the woodruff key has "machined" a 3 mm slot into the pulley side allowing it to rattle. Because there isn't a torque specified on the 4 cylinder engine, owners think maybe 80 lbs ft is enough...it isn't. This size fastening and thread will take plenty, 5/8 th UNF from memory is good for 150 lb ft at 120 the pulleys don't come loose. 

Maybe worth pulling the pulley to check the key way isn't damaged as above, needs replacing if it is. At least it's quicker than pulling the timing cover for the tensioner, and you're part way there if you have to go in further. The pulley might need " wiggling" either way if damaged to be able to remove.

Mick Richards

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11 hours ago, ctc77965o said:

Could it be a simple as the crank bolt being loose and the pulley/fan extension rattling on the woodruff key?   I am always thinking that todays problem is the result of what we did yesterday...and since you have changed the Alt/Dyn that must be somehow the cause...weird that a timing chain tensioner would suddenly fail...did you turn the engine backwards?? that can kill the spring if its on its last legs... 

It's odd b/c I drove it around for a few hundred miles post new belt/alternator with no issue.  It wasn't until the other day after a hot warm up and then idle at a light I heard the clacking noise from the front end.  Removed the water pump pulley thinking it was rubbing, even swapped it with another one I had, but no luck, and as mentioned there are no fan blade marks on the alternator.  Will try to see if I can attempt to secure all but the crank nut with radiator removal and "hope" for something loose.  From the sounds of it, I'll order one of the skinny belt kits that preserve the fan as well.  My new belt got chewed momentarily when I first started it up and didn't notice it wasn't quite right on the crank on start up.  Urgh ...  And no, haven't turned the engine backwards.  But if I have to pull it all to check the crank bolt for the extension, guess it will be time order parts.  I know I'll need a new tensioner, cover/plate seal, and chain, but is it worth pre-ordering a set of crank/cam gears as well?  Is there anything else?  I read something about "locking tabs"?  Local British car shop quoted me close to $1200-1500 for the swap, but can't work me in for a couple of months.  Don't think I have that kind of patience anymore to wait that long.  Thanks.


Don

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"clacking noise from the front end."

If it walks like a duck, has a bill, and quacks...it's a front pulley working back and forwards against the woodruff key because the "dog bolt" holding it onto the crank isn't tight enough...and making a "clacking" noise.

Mick Richards

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LOL.  I just walked in.  Put the old engine stethoscope on and "wagged" the fan back and forth and could definitely here a metal clang/click from where the tensioner is fitted.  When I put it on the fan extension hub at the base by the pulley, the sound dissipated.   That said, I have to strip it down to get to the crank bolt anyway and as you say work my way back into the engine.

Going to convert to a skinny belt.  Just have to decide on OEM set up or harmonic balancer and electric fan since I'll have it all apart any way.

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Hi Don,

when you turn the fan left and right with a broken chain tensioner or a worn timing chain you can realize an "empty way".

I have some clips about that on my  YouTube channel.

Ciao, TR4A-Driver

Old timing chain and broken tensioner:

New timing chain:

(bolts locked with "Nord-Lock" washers)

Nord-Lock

Edited by Z320

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If removing the engine-driven fan, fitting an electric fan, and converting to narrow belt drive for alternator, you don't have to fit a harmonic damper, you can run bare, as recommended by Revington.  His engines (and mine) run that way.

Why spend money on an unnecessary piece of kit?

Ian Cornish

 

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Hi Don, if your engine clutch and flywheel have been balanced then a fixed damper should be fine but if your not sure then I would play safe and go for the damped pulley. Better to be safe than sorry and not much diff in cost. Also def get rid of the existing fan extension as these frequently don't run true and serve no useful purpose with either a balanced engine or a damped pulley. 

If you decide to go the whole hog and fit an alternator then OK, but the pulley in the narrow belt kit will fit a dynamo and work fine. I don't do much night time driving and have been running with damped conversion electric fan and dynamo for over 15 years. 

Chris

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Thanks.  Z320, that first clip sounds like what I heard in rocking the crank which apparently the loose slack in the chain.

As long as I set the crank to TDC before unbolting everything, I should just be able to simply "reinstall" as stopped and not have timing issues with the CAM or do I have to re-degree the CAM?

 

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At least I would mark the sprockets and count the number of chain links on tension side, just in case anything slips. 

Chris

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9 hours ago, ChrisR-4A said:

At least I would mark the sprockets and count the number of chain links on tension side, just in case anything slips. 

Chris

Of course that assumes the previous owner, who has cut corners I am finding out, degree'd it correctly.  LOL. Getting pretty quick at disassembling the front end and engine bay.

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If the generator pulley from a narrow belt kit is fitted to a dynamo, the dynamo will spin faster than before.  This might not prove a problem in a car which seldom exceeds 3500-4000 rpm, but if the car is driven at higher engine speeds, the dynamo is likely to give problems.

Alternators are designed to spin faster than dynamos, hence the smaller pulley.

Ian Cornish

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Good point Ian, and 100% correct, although I am in the rarely exceeding 4000 rpm group I still had problems as after about 5 years use the alloy pulley wore away and the belt bottomed out and started slipping. I managed to find a couple of original steel pulleys which fit the 1/2 ins belt and are larger as used on Ford Anglias, Cortinas and Minis back in the 60s.  They show little sign of wear apart from a few rust pitts. Not all innovation is progress! 

The smaller pulley may also result in errors when setting the regulator box as you will be setting the dynamo output voltage at  higher revolutions  than the workshop manual states. 

Chris

Edited by ChrisR-4A

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Won't make any difference to the reg setting, just don't over rev it - it may fly apart.

Bob.

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Already have alternator in place, so no generator issues.

So I see Racetorations sells an uprated tensioner that is "15%" thicker - is it worth it over what Moss sales?  Only issue is, I am across the pond so shipping is nearly double what the part costs?  Just don't want to "repeat" this swap out process of the sprockets, chain and tensioner again if and until I have a major internal melt down requiring the engine to be pulled. ;)

 

 - Don

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