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Spit 4 1150cc timing


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For 97//99 ron fuel , as close to factory spec as you can , if it pinks under load retard just a little till it stops pinking

If you dont have a lamp, strobe or any setting equipment , raise the idle to about 1500 and rotate the dizzy to get the best running position

And retard it from best,   a run up the road it should pull at 30mph in top without pinking its head off

If it does just keep backing off till the tin can rattle of pinking disappears

pete

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Its just in their hey day they were designed to run on 100+ fuel, you used 95 ** in mowers and some low compression side valves

Of you have run on 95 unleaded then you must retard a good few degrees  to stop pinking, you loose a good chunk of performance and 

The combustion becomes overheated,  not a good place to be ,  

Dont waste money on any afddatives   just stick with a ultimate or similar fuel, 

6There is lots of lead memory in the head casting so no need for lead supplements either , 

If you do ever get a valve problem then its the time to have exhaust inserts fitted , till then , buy  decent fuel,   use car , no worries 

Maintain settings close to spec and the car does what it was intended

Use low grade fuel and you loose performance, over heat valves, and  gives less smiles

Pete

 

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Thanks. Yes will run on premium fuel so will use the original settings. Working through things to find out what's causing the 4k rev limit. New plugs ordered and will look at the Dizzy next and so on. 

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Item 11 on this diagram is described as a crankshaft pulley and damper

https://www.canleyclassics.com/triumph-gt6-mki/ii-mki-crankshaft-and-camshaft

However, on this diagram, for my car, item 154380 is simply a crankshaft pulley. 

https://www.canleyclassics.com/triumph-gt6-mkiii-crankshaft-flywheel-connecting-rod-piston

So, do I actually have a damper?  :o

 

Worried of Twyford.

 

 

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Doug the rear ring with the timing marks on on both these pullies is rubber bonded to the main pulley

It has a possibility the bond fails and the ring/damper weight with its marks actually rotates out of position 

To check it the flywheel has a tdc line but you cant see it with the clutch  hsg on.

Next time you take the head off you, could make a piston stop and halve the arrest point to get tdc

Or grannies knitting needle down a plug hole , but hard to detect crank tdc whith a piston at top

as the crank can turn a good bit without the piston moving

 

Pete

 

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9 hours ago, dougbgt6 said:

Grant,

No! :lol: Original settings won't work, my GT6 is supposed to be 13 degrees BTDC, but these days, with the best fuel I can get, it's at 7 BTDC. 

Doug

Mine runs happily around 10 degrees irrespective of fuel according to the timing light. But mine is the earlier spec of engine to yours.

Gully

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Gully,

I read elsewhere my engine is the least desirable of all! :(

I set my timing by the Pete Lewis ear method, or if I'm feeling technical the vacuum gauge eye method. Eye is more or less the same as ear, turn dizzy for maximum vacuum/revs and back 1 bar. So actually I don't really look at the BTDC, last time I looked, a long long time ago (in a galaxy far far away) it was 7. Better fuel does allow further dizzy adjustment, on mine anyway.

Doug

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1 hour ago, Pete Lewis said:

Doug the rear ring with the timing marks on on both these pullies is rubber bonded to the main pulley

It has a possibility the bond fails and the ring/damper weight with its marks actually rotates out of position 

To check it the flywheel has a tdc line but you cant see it with the clutch  hsg on.

Next time you take the head off you, could make a piston stop and halve the arrest point to get tdc

Or grannies knitting needle down a plug hole , but hard to detect crank tdc whith a piston at top

as the crank can turn a good bit without the piston moving

 

Pete

 

Could also drop the cam cover off and find TDC based on the cam position - No 1 inlet valve at highest point should be 110' ATDC (If other 6 cylinder engines are anything to go by) 

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I stand by the "ear" method every time. I have said it before, but when my car was on the rolling road the chap (VERY experienced with carbs and dizzys) could not improve on what my ears had set the dizzy at. And I am hopeless at setting stuff up.

Doug, it may be you have tired dizzy springs? I discovered mine were on my Toledo (TR7 engine/distributor, spawn of the devil himself) and gave full advance from about 1500rpm. I managed to get some new springs of different strengths/lengths and played until the curve was within the factory limits. Seems to have improved economy! Still doesn't like to rev over 3K, but that may be needles/filters....

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