Seized Jackshaft

[flying farmer]

It has taken a while to get round to posting these pictures (it all went wrong back in March), but since it is cold outside and I am waiting for new bits to arrive I thought now is as good a time as any. http://s740.photobucket.com/albums/x...aft%20seizure/



The engine has now been completely stripped, the block and crank are away for machining, andnew fast road camshafts should be delivered some time this week.

The heads have been ported and rebuilt with new valves, valve guides, springs and cam buckets. I will start a new thread shortly, with photos, as I put it back together and show all the various performance enhancing modifications I am doing while I am about it.

Neil

[peter f]

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Very informative Neil - keep em coming!!

cheers bud,

Peter f

[Rubce]

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Fascinating stuff

Bruce

[RogerP]

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Neil

What are you doing about replacement water pump?



Roger

[NickA]

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RogerP wrote:

Neil

What are you doing about replacement water pump?

 

Roger

And are you having the jackshaft bearing machined then sleeved?

[flying farmer]

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RogerP wrote:

Neil

What are you doing about replacement water pump?



Roger

I have fitted one of Stagdads belt drive conversions as I have had three water pump failures on three different engines in the last 12 months. The one in the Stag stripped its teeth, the one in the estate had a rust flake cut through the seal below the impeller. This one was rebuilt again as I last did it 15 years/ 60,000 miles ago and the teeth on the jackshaft and pump are still perfect

The last one was on the TR, wich despite only being done 3 years ago had suffered corrosion pitting of the impeller causing it to leak. This one has been fitted with an electric water pump as I had one left over from another project. I shall probably rebuild this one with an LD Parts ceramic seal kit as the teeth are perfect on this one as well, and keep it as a spare.

Neil

[flying farmer]

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Jackshaft bearing is being fitted with a bronze bush, and the crank is being ground and hardened by the same people. Must give them a ring and see how they are getting on.

Neil

[RogerP]

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flying farmer wrote:

Roger


I have fitted one of Stagdads belt drive conversions as I have had three water pump failures on three different engines in the last 12 months. The one in the Stag stripped its teeth, the one in the estate had a rust flake cut through the seal below the impeller. This one was rebuilt again as I last did it 15 years/ 60,000 miles ago and the teeth on the jackshaft and pump are still perfect

The last one was on the TR, wich despite only being done 3 years ago had suffered corrosion pitting of the impeller causing it to leak. This one has been fitted with an electric water pump as I had one left over from another project. I shall probably rebuild this one with an LD Parts ceramic seal kit as the teeth are perfect on this one as well, and keep it as a spare.

Neil

Just wondered we had the same problem 5 engines in 3 months. Fitted EWP no problem.

Rogerp

[surreyone]

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Neil,

Where do you get the fast road camshaftsfrom, Faversham Classics?Do you get more power over the rev band or just at high revs?

Thanks

Colin

[flying farmer]

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surreyone wrote:

Neil,

Where do you get the fast road camshaftsfrom, Faversham Classics?Do you get more power over the rev band or just at high revs?

Thanks

Colin

Camshafts are from Faversham, it is difficult to tell about bottom end power. The fast road cams are fitted to an engine with bigger bore primary pipes on the tubular exhaust manifolds, different inlet manifold and more compression.

Comparing the fast road cammed engine with the standard cammed engine, there is very little difference up to 3500rpm then the fast road cams start gaining.

It is significant though, that the standard cammed engine produces far more torque with the stag tubular manifolds at low revs than with the big bore pipes on the TR, and this is the same engine that is now on strombergs and before it was on efi. There should be no difference between the two sorts of fueling as the mixture was correct on both, and a near standard stag inlet manifold was being used for the efi.

I am almost certain that the big bore pipes are holding down bottom end torque, which would suggest that the fast road cams and stag tubular manifolds could gain at low revs compared to standard cams and tubular manifolds. The ignition will need to be advanced somewhat at low revs to make the fast road cams give the best results. To achieve this I used the weakest springs I could find on the advance weights in the distributor, that would still pull the weights back to the stop.

The big bore pipes on the TR lift the peak torque from 3500 to 4100rpm on standard cams. The engine exhaust note clearly changes at 3300rpm which is probably the point where the manifolds start working properly.When I first fitted the fast road cams to the TR I was using a heavily modified Stag inlet manifold, which quite honestly is a complete waste of time as it destroyed bottom end torque. The peak torque moved up to 4600rpm with the fast road cams. I would suggest that the fast road cams move the torque curve up the rev band by 500 rpm, but with a better inlet manifold the torque keeps building and actually peaked at 5250rpm on the TR, with torque above 190lbft from 3000 to 6000 rpm

There is nothing simple in this life:?.If I had only changed one component at a time, I would have a far clearer idea of what works best, but as I had to fabricate my own manifolds for the TR I have started from a different base than everyone else, but it is all coming right in the end

Neil