Moss Motors, Ltd

I'm going with an electric fan conversion for cooling and in eliminating the fan assembly and crankshaft extension I noted there is no damper.  The fan extension is heavy though.  I've installed an aluminium crank pully.  Is there a requirement for a damper on the TR3 like on the TR6?

Thanks,

Glenn

Glenn,

There is no specific requiremment, but hard won knowledge has taught us that they are a pretty good idea, especially if you're going to use some pretty good Revs. I believe they are available, though I don't recall which specialty maker does them. That means it's Google time, I guess. ANY of the earlier four cylinder engines in our sports cars, especially if they are equipped with only three main bearings, will benefit from a true damper. A damper will help to eliminate the "nodes" of twist (crankshaft whip) and will contribute significantly to crankshaft and bearing longevity.

I'm not trying to push your hand here, though. The number of attatchments and improvements we could make to any one of these engines is endless, to the point where you'd wonder if you shouldn't just buy some modern engine and clamp it in. In fact, plenty of folks do just that. In our shop we've done a bunch of this kind of thing, from MGB engines into TDs to a Nissan 280Z fuel injected motor and automatic transmission into an old Austin Princess. Actually, that one came out really nice, and I'll bet it's the quickest Princess out there!

I guess what I'm trying to say is, do what you can afford to improve things, but more importantly, whatever you do, do it with great attention to detail and the result will be satisfying, I'm sure.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

Motorbill,

My TR3A will be a driver and probably not too spirited at that.  I saw a "racing" engine on eBay that has a damper, but after looking at it I would be concerned about the clearance with the cross member.  I'll take your suggestion and Google for one.

Thanks for your response,

Glenn

I fitted one of Moss's kits including the narrow belt conversion and it went in like a dream. One word of advice - mark top dead centre or a relative position to top dead centre if you rotate the crankshaft as I did so the key is up top and wont fall out. Then you can work back to TDC on the new unmarked pulley. The narrow belt is a decided advantage (but not original of course). But my real reason was I had an electric fan and lightened flywheel and having removed the crank extension (which is a "harmonic balancer") left me worrying about engine vibration.

David B

I've been worrying about this harmonic balancing question ever since I'v gotten  back on the road with my 62 TR4. I like to drive the car but see no need to wind it past 4 grand or so. Is it really the case that the crank extention serves as a harmonic balancer on the stock setup? I can find no referance to this in shop manuals. Also, I have a question regarding fans. Has anyone ever installed an after market flex type fan on the TR4? I would really like to get rid of the stock fan. It strikes me as a totaly over enginered   inefficient  relic from the past. Thanks KSD

KSD,

I have never heard that the extension acted as a damper in my forty years doing this either. That doesn't mean somebody smarter than I has figured this out. I just don't see how it would work.

I don't think the aftermarket flex fan is such a hot idea. First, My opinion is that some flex fans are dangerous. Secondly, the pitch of this fan must take into account the fact that it will only be turning at crankshaft speed, not water pump speed, like most fans. Hmm. I dunno. This car is an awfully good candidate for a thermostatically controlled electric fan...

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

I am also wrestling with the harmonic damper question.  The narrow-belt pulley kit I am considering purchasing for my TR3A includes a damped pulley.  I worry that the damped pulley may fail in the distant future and the future owner (one of my sons by that time) may not be able to fix it. 

Concerning the stock fan extension, it could well be that the extension coupled with the stock rubber-mounted fan was intended to be a harmonic damper.   The fan is rather hefty.  Why else would Triumph originally have mounted the fan using rubber bushings?

Concerning using a flex fan, I mounted a 15" flex fan in my 67 TR4A, and it works very well.  It is sharp (dangerous) as mentioned above.  The combination of using the flex ban, blocking the bypass, and fixing the overflow reservior fixed my summer overheating problems in the Mojave desert of California.

In mounting the flex fan, however, I removed the harmonic damper effect (if it is indeed real), since I hard-mounted the flex fan.  I have noticed a pronounced rattle from the timing chain at a rather narrow range of RPMs.  I suppose this could be from harmonic vibrations (I read somewhere that timing chains can be beat up by harmonic vibrations).  The rattle could also be due to the fact that I foolishly scraped off the vibration deadening goop on the front of the timing chain cover.  I don't know if the timing chain rattle started when I changed to the flex fan.

At this time I'm leaning towards proceeding with the harmonic dampening pulley assembly.

                             West K.

 

TRWest,

Go for it! In that distant future, assuming we are still allowed to drive, there are a couple of firms that rebuild dampers that have started to delaminate. So, not to worry.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

A a matter of info.

We have in the UK used for years the early MGB front crank harmonic damper assy on the 4 Cyl TR engines.  The only challenge is turning up on the lathe a suitable diameter spacer to fit over the MGB oil seal surface area to ensure the front timing cover seal works and position the V belt in the right plane. 

I would guess Moss make this and other bits all part of their kit.

Cheers

Peter W