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Posted

A lot of hidden work must have gone into making it fit that well, it looks great.  Does it fit under the standard bonnet, or is a gt6 type bulge required?

Posted

Fits comfortably under the standard bonnet, but yes, that has taken some effort to achieved. The bulkhead has had some attention though you might struggle to tell without a standard one to compare.

More pics of that about halfway down P13.

  • 3 weeks later...
Posted

It continues to resist. Had a session on it yesterday. 
 

First tried bleeding the clutch again. That just resulted in the new master cylinder sticking in the fully compressed position. So that had to be dismantled (took some serious beating on the bench to get the piston out). The guts from another new one with the wrong size outlet port were substituted. Reassembled and re-bled. Works. Bit of a long biting point but seems to be a feature not a fault….

It’s been randomly refusing to start. Will fire but not run. Seems to be the result of the 3D printed vacuum manifold being porous and more porous when hot. Temporarily (?) swapped for some fuel hose. Now starts and runs.

Wideband has been messing about, so we did a free-air calibration, which seems to have completely bolloxed it. Reads 18.7 (full scale high) always. Arse! Tried it again. Same….

Brand new prop vibrates horribly from 50mph. We’ve messed with Jubilee clips and it’s a bit better but needs more work.

We did drive it a bit and do some very crude mapping. Fumbling in the dark without wideband…..

Promising though. Very torquey low down even on strictly 2D ignition mapping and quite eager even on light throttle. More throttle doesn’t bring much gain at present due to mapping but makes an interesting growl from up front.  Still mostly sounds and drives like a Spitfire.

Gear shift is still a bit obstructive. Second going down the box especially so. No crunching but it sure can baulk!

Partly I think because the shift is still a bit over-geared (as it were).

Progress…. But slow!

  • Like 2
Posted

How brand new is the prop? I forgot what you did with it. UJs in good condition?

If it's shortened or chopped about did you get it balanced, or decided to DIY it with jubilees so were expecting a little vibration?

Posted
3 hours ago, BiTurbo228 said:

How brand new is the prop


Specially and specifically professionally built for this application. It fits fine but vibrates strongly at 50mph. It had been balanced as it’s got weights (quite a lot of weights) on it.  So far our fiddling has gained about 10mph….

The one I had built for the GT6 (which might actually fit the Spit also) by a different company is fine. That was the first and so far only time I’ve experienced a new/recon prop for a small chassis Triumph that didn’t vibrate as supplied….

  • 2 weeks later...
Posted

Well that's a disappointment. I used JW Engineering in Bexleyheath for the Jag's 2-piece propshaft and that worked perfectly, though they're quite a long shot from Somerset.

I assume you've checked silly things like the UJs being clocked correctly with each other.

I've recently gone down a bit of a rabbithole about making a DIY crankshaft balancer. Unlikely to come of anything just yet as I don't even have a garage I could put it in yet (let alone the coding that's way beyond my current non-existent expertise), but it seems like something that would be a Useful Tool.

Posted

Good point on the UJ clocking. Haven’t really looked as it’s not actually very accessible/visible with the exhaust on (centre silencer variety).

It’s also possible the operating angles are unfavourable, but can’t be very different from my GT6, which is fine.

  • Like 1
Posted

I wonder if there's a difference in UK clocking whether a prop is in the regular 'z' configuration and the 'broken back' configuration Triumphs seem to use. Apparently both can cancel out UJ phasing, though that's as much as I know about it!

Posted
3 hours ago, BiTurbo228 said:

I wonder if there's a difference in UK clocking whether a prop is in the regular 'z' configuration and the 'broken back' configuration Triumphs seem to use. Apparently both can cancel out UJ phasing, though that's as much as I know about it!

Nope, UJ phasing is the same whether it's Z or W (I knew there was another term for it).

682656.jpg 

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