1983 Triumph T140W 750 TSS; 8 valves & electric start!

[Sea Dog]

Sealing the four head studs located inside the rocker voids has had me scratching my head, as the O rings on the studs which seal on the stud threads were totally destroyed by excessive crush when I removed the head. The TSS uses two sealing rings and not a head gasket so the head studs need to be sealed independently.



This is the original set up, where the o ring sits in the counter sink taper in the head. When assembled the o ring is crushed into the threads. The over crushing (destruction) of the o ring will eventually allow oil to pass down the stud.



The copper washer that fits around the o ring is half the o ring's thickness. This allows the o ring to compress into the stud threads and counter sink in the head without being destroyed. Being a viton high temperature o ring, it will survive the high temperatures and continuous movement of expansion and contraction of the surrounding parts when the engine heats up and cools down. With the o ring retaining its original shape and density, it will have enough elasticity to take up the movement. I am expecting this to work better in the long term than the original set up.

 

[Sea Dog]

Copper Cooper rings arrived today. Now I can work on setting the correct crush on the push rod tube o rings.

 

[otherwise]

Interesting, your solution looks good to me. Keep us updated.

 

[otherwise]

The 4 valve head looks in good nick.
Many Honda 4 valves at that time suffered from cracking between spark plug thread and valve seats.

 

[Sea Dog]

Four valves from the eyes of a piston crown roaring up the bore.

 

[otherwise]

That's art!

No, it's motorcycle porn.

 

[DaveM]

That is COOL

 

[mikechev]

Great post SD, love your work...

 

[Sea Dog]

An interesting discovery with the push rod tubes (PRT)



The PRT diameter where the upper o ring seats is 25.15mm



The tappet block diameter where the lower o ring seats is 23.4mm

The upper and lower o rings are the same dimensions with a cross section diameter of 2.5mm
The upper o ring which seats in the head is the correct fit. The lower o ring is not. See next photo.



The head is on with the copper head gasket rings in place and the upper PRT o ring in place. As can be seen, the lower o ring is flush with the tappet block shoulder and PRT flange. The retaining ring above, slides easily over the o ring. It should be an interference fit.
The crush of the PRT and upper and lower o rings is only 0.014". It should be 0.040"
To fix the crush and the o ring expansion onto the retaining ring, I will replace the lower 2.5mm cross section o ring with a 3.0mm o ring.
That will give me close to the 0.040" crush required and the interferece fit with the retaining ring. This should solve the oil leaks from the bottom of the PRTs.
Another voyage of discovery with the TSS.

 

[CarlS]

Great work and great posts. I am eager to know how your solution works.

 

[otherwise]

Looks like the people who packed up the gasket / o ring kit had no idea what's going on.
Surely it can't be an old stock factory kit?

 

[Sea Dog]

Looks like the people who packed up the gasket / o ring kit had no idea what's going on.
Surely it can't be an old stock factory kit?

Yeh, good point Kev. They are certainly not old factory stock. Still something wasn't right from the factory, as the part numbers are the same for the upper and lower O rings. With the diameters of the tappet block and upper push rod tube being close to 2mm different, I would expect that the factory would have listed two different O rings.

The TSS being the last effort for the Meriden factory to make it, I think money was tight and attention to detail lacking. The poor quality of the aluminium castings for the head and barrels certainly indicates a build for price situation. Still, at least they had a go.

 

[mikechev]

This stuff is better than the TV can’t wait for the next episode....

 

[Sea Dog]

This stuff is better than the TV can’t wait for the next episode....

Next episode should be TSS purring sweetly, free of weeping oil, headed for the twisties.

Back up script could be.........

TSS owner ranting naked under the full moon, at a bonfire fueled by a blazing TSS as his unhinged mind disintegrates at the sight of an oil weep. Last heard shouting at the Harley God "Take me....Vibrate me with your V twin goodness...I am yours...free me from the evil of weeping hydrocarbons."

 

[devo]

 

[mikechev]

Next episode should be TSS purring sweetly, free of weeping oil, headed for the twisties.

Back up script could be.........

TSS owner ranting naked under the full moon, at a bonfire fueled by a blazing TSS as his unhinged mind disintegrates at the sight of an oil weep. Last heard shouting at the Harley God "Take me....Vibrate me with your V twin goodness...I am yours...free me from the evil of weeping hydrocarbons."

Scary! but true...

 

[grandpaul]

Such drama! My TSS is totally original and suffers none of the typically noted issues.

I also now have an OEM exhaust system on the shelf from Big D Cycle.

 

[Sea Dog]

Such drama! My TSS is totally original and suffers none of the typically noted issues.

I also now have an OEM exhaust system on the shelf from Big D Cycle.

Hi Paul,

Do Big D Cycle have another OEM exhaust system?

SD

 

[mikechev]

Such drama! My TSS is totally original and suffers none of the typically noted issues.

I also now have an OEM exhaust system on the shelf from Big D Cycle.

SHOW OFF!

 

[Sea Dog]

Spent a couple of hours searching the industrial area of my town for the Viton O rings I needed for the push rod tubes. Thought my chances would be good as the industrial area services a huge coal mining industry. I visited 5 hydraulic and bearing companies before I struck gold ........and met some characters on the way. All part of the fun.

Anyway, just completed a dummy assembly to measure the O ring crush and all is good.



Feeler blades in place



Managed 0.037 " crush which is close enough to the 0.040" recommended.
The great advantage of the copper head gasket rings, is there will not be the somewhere about 1mm crush the OEM compressible steel head gasket rings, so the push rod tube O ring crush can be measured accurately.

Next step....put it all together.