Jackshaft repairs and other modifications

[fussydave]

Hi All,

My jackshaft has seized and because the front of the engine will need to be stripped down to find out what has caused it (hopefully the water pump), I am considering carrying out some other works at the same time. The work will be carried out by my local garage. So this is what I am considering having done:

1 Replace the radiator:

Should I consider a standard rad, new or reconditioned or upgraded? The current rad seems to be the thicker, uprated one and is extremely close to the fan. I have read that the standard rad is actually more efficient than the uprated one due to allowing more air to pass through it.

2 Install an electric fan:

Should I do away with the viscous fan and if I do, do you remove just the blades or the viscous coupling as well? If you remove the coupling, is there any items that need to be altered, eg. the coupling retaining bolt, does it need to be shorter or can it be left off?

Which side of the rad does the fan go, how does it fix to the car and where does the thermostic control go?

3 Replace the timing chains:

Should I replace them (they do not rattle). They were replaced in 1991 at 72000 miles, now done 86000 miles. If I change them should I fit standard or German, should I replace all the sprockets?

Obviously when we get the jackshaft and pump out we will know what we are facing and this may put paid to any thoughts of modifications. Anyway, thanks in advance for any help.

Dave.

[Bassy]

If I were you I would keep the viscous fan. I found the temperature was erratic when I was just using an electric fan. My personal experience was that refitting the standard fan keeps the temp much more stable at speeds of 30 to 40 mph.
In fact my electric fan has not cut in since I refitted the viscous.

[StagJonno]

Hi Dave,

1 - Can't comment on the upgraded radiator, other than general consensus seems to be that the original is fine (though Tony Hart does an upgraded unit, and he does know much more than I do).

2 - I (my mechanic) swapped out the fan including VC for a Kenlowe 14" high output. Aim was to improve fuel consumption and to avoid the issue I'd heard of with the VC failing and getting the blades into the rad (probably pretty low risk). IMO there's not space on the engine side, but masses of space on the frontside. Make sure you get a unit that blows (rather than just sucks). At the same time, I swapped the original Temp guage for a combined Oil Press/ Water Temp. This has a capilliary sensor, so you can see engine temp (rear of LHS head) after switching off. I was quite alarmed to see it climb almost to 110C ~5min after stopping from the heat soak. I wasn't sure how much this temperature rise was due to the absence of the VC, or how much it was rising previously without realising (as the electric guage goes off with the ignition). I now run through a cooling down regime - engine rpm between tickover -1000 rpm alowing a couple of electric fan cycles. Currently planning to fit a manual override switch for the fan so I can switch it on constantly for the last 10min of a journey to get the water temp right down.

3 - Timing chains I leave to more knowledgable folk.

Good luck with your water pump investigations.

Jonno

Meant to say, the fan thermostat for the Kenlowe fits on the LHS of the rad, with the capiliary sensor inserted in the top hose. I had to play a bit with the setting, but it reliably switches on @92C, switching off @85C as seen on the Temp guage.

[flying farmer]

Temperature will be unstable in normal running with the viscous unit removed and an electric fan installed.
I tried this some years ago with a standard rad, then fitted an uprated one which made no difference whatsoever. The shape of the Stags front end panel work does not give an effective ram effect cooling unless a front spoiler is fitted.
This was my next effort, and the TR6 spoiler provides perfectly adequate cooling with only an electric fan, even with the standard rad and well over 200bhp on track days.

If going down the electric only route buy a decent fan, not some cheap ebay unit as I tried that idea and wasted my money! Both my Stags use Kenlowe 2 speed units.

If your jackshaft bearing is scored or badly worn you won't want to be spending money on upgrades as it will be a wallet emptying experience to fix anyway.
Neil

[StagJonno]

2nd ommission from post #3, got an LD Part "Secret Spoiler" for when the temperature rises a bit - maybe even this week

http://www.ldparts.co.uk/shop/shop.php?c=viewproduct&pid=922&cat=80&maincat=10&start=12&sid=sid8b19953e85f4ac27a56860d6260ea912

[Pete]

Hi Dave,

1 - Can't comment on the upgraded radiator, other than general consensus seems to be that the original is fine (though Tony Hart does an upgraded unit, and he does know much more than I do).

2 - I (my mechanic) swapped out the fan including VC for a Kenlowe 14" high output. Aim was to improve fuel consumption and to avoid the issue I'd heard of with the VC failing and getting the blades into the rad (probably pretty low risk). IMO there's not space on the engine side, but masses of space on the frontside. Make sure you get a unit that blows (rather than just sucks). At the same time, I swapped the original Temp guage for a combined Oil Press/ Water Temp. This has a capilliary sensor, so you can see engine temp (rear of LHS head) after switching off. I was quite alarmed to see it climb almost to 110C ~5min after stopping from the heat soak. I wasn't sure how much this temperature rise was due to the absence of the VC, or how much it was rising previously without realising (as the electric guage goes off with the ignition). I now run through a cooling down regime - engine rpm between tickover -1000 rpm alowing a couple of electric fan cycles. Currently planning to fit a manual override switch for the fan so I can switch it on constantly for the last 10min of a journey to get the water temp right down.

3 - Timing chains I leave to more knowledgable folk.

Good luck with your water pump investigations.

Jonno

Meant to say, the fan thermostat for the Kenlowe fits on the LHS of the rad, with the capiliary sensor inserted in the top hose. I had to play a bit with the setting, but it reliably switches on @92C, switching off @85C as seen on the Temp guage.

Jonno, why not fit a timer to the fan that keeps it running for a while after ignition off? More radical still, fit an electric pump that does likewise?

[ham204stag]

If your waterpump is knackered, throw it a mile away and invest almost the same amount of money into an external belt driven or electric pump. I put in an electric one but left the standard fan and VC. Never had it over the middle mark even when idling in 40c temperatures.

[mole42]

Mr. Hart recommended to keep the VC if adding an electric fan. Use a Kenlowe fitting kit, the others strap the fan to the radiator core with cable ties.....

Beware "German" timing chains, they might be no better than Indian or English. Buy German 'Iwis' brand chains from LD Part, best quality, a bit more expensive but you get what you pay for.

[StagJonno]

Jonno, why not fit a timer to the fan that keeps it running for a while after ignition off? More radical still, fit an electric pump that does likewise?

Yes, Pete, a timer is on my list - I'll try the manual operation first, but the problem is temp rise in the block from heat soak so the dog's b*ll*cks solution will be to add an electric pump with it and the fan running on a timer. On reflection, I wish I'd taken easy stages and fitted the capiliary temp guage first so I could observe how high the engine temp was normally getting to after switch-off.

Fitted the Secret Spoiler today and went for a run. Ambient only ~15C so not a real test - seems OK and the fan didn't seem to cut in as much, though was surprised that the fan came on a couple of times on a 6-mile dual carriageway @ 70mph (honest), mind this did include a 1.5 mile uphill incline section. Got a query with the fitting, so need to have a word with Peter at LD to make sure I've fitted it correctly.

[fussydave]

[Beware "German" timing chains, they might be no better than Indian or English. Buy German 'Iwis' brand chains from LD Part, best quality, a bit more expensive but you get what you pay for.[/QUOTE]

Hi Mole42 (sorry don't know your name) The LD Parts IWIS chains, tensioners and gaskets only add up to £6 more than the Rimmers offering so are not that dear. But my question was fundmentaly, should I change the chains or not as hopefully we may only need to replace the jackshaft and they have only done som 15000 miles.

Dave

[fussydave]

If your waterpump is knackered, throw it a mile away and invest almost the same amount of money into an external belt driven or electric pump. I put in an electric one but left the standard fan and VC. Never had it over the middle mark even when idling in 40c temperatures.

Hi, (Mario isn't it?), I have thought about this but is there a ready made kit to cover all aspects of the install, eg. pipework, electrics/stat, plugthe gap for the old pump position. The other question I have is does removing the pump from the jackshaft drive put an uneven load on the jackshaft with it driving the dizzy/oil pump at one end but not having any load at the front end. Can this increase wear on the jackshaft bearings?

Dave

[marshman]

[Beware "German" timing chains, they might be no better than Indian or English. Buy German 'Iwis' brand chains from LD Part, best quality, a bit more expensive but you get what you pay for.

Hi Mole42 (sorry don't know your name) The LD Parts IWIS chains, tensioners and gaskets only add up to £6 more than the Rimmers offering so are not that dear. But my question was fundmentaly, should I change the chains or not as hopefully we may only need to replace the jackshaft and they have only done som 15000 miles.

Dave[/QUOTE]

If you can afford the IWIS chains from LDParts then I would change the lot whilst you have it apart - especially as you don't know if the chains where overstressed when the jackshaft seized. If you don't want to pay for the IWIS chains then as Mole42 says you might just as well go for the "standard" Rolon ones as opposed to any other so called "German" chains.

With regards to your other "modifications" did the car have any cooling problems before the failure? If not why change the radiator or mess around with the fan arrangement. If it ain't broke don't fix it. A lot of Stag radiators run close to the fan with out problems, in fact in some ways it is good to have the fan as close to the rad as possible to ensure it draws air through the radiator core and doesn't pull in air from around the sides. Although others have removed the VC fan and just have an electric fan I would personally favour keeping the VC fan to keep air circulating around the engine bay at all times. In my opinion it can only help keep under bonnet temperatures down and reduce the risks of fuel vapour locks and coil and ignition failures doe to excessive heat.

Hope that helps

Roger

[mole42]

If your chains have done 15k miles, then I would change them. No question.
And especially after a catastrophic event, when you can only guess what stress the chains have suffered!

Richard

[ham204stag]

Hi, (Mario isn't it?), I have thought about this but is there a ready made kit to cover all aspects of the install, eg. pipework, electrics/stat, plugthe gap for the old pump position. The other question I have is does removing the pump from the jackshaft drive put an uneven load on the jackshaft with it driving the dizzy/oil pump at one end but not having any load at the front end. Can this increase wear on the jackshaft bearings?

Dave

Dave, Steve Hill (stagdad on here) used to have a belt driven kit for sale. Not sure if he has any left. For the electric pump you can do all your shopping at EJ Wards. I can pm you the list together with instructions if you're interested. Removal of the water mechanical pump reduces stress on the jack shaft and should make the engine rev more
freely even if slightly.

Cheers

Mario

[fussydave]

Dave, Steve Hill (stagdad on here) used to have a belt driven kit for sale. Not sure if he has any left. For the electric pump you can do all your shopping at EJ Wards. I can pm you the list together with instructions if you're interested. Removal of the water mechanical pump reduces stress on the jack shaft and should make the engine rev more
freely even if slightly.

Cheers

Mario

Hi Mario, I would appreciate the list and instructions for the EWP thanks, I may consider this if the repair to the jackshaft is not going to be too expensive.

Dave.