Twin Su idle high
Re: Twin Su idle high
you seem to be set on the idea that its the carbs causing fast idle, have you tried retarding the distributor slightly?
Some people are like Slinky's, they serve no real purpose in life but bring a smile to your face when you push them down the stairs.
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GrahamFountain
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Re: Twin Su idle high
Even with an unsafe amount of advance, I'd still expect to be able to get the idle down to a reasonable value. So, even if there's a bit of error in the timing, there's still a problem, probably with the carbs, their set-up, or the linkage.
And the first post said set to 10 degrees before TDC with no vacuum.
If the only problem is the idle won't set low enough, you got to eliminate the easy to find and fix problems with the linkage first and try the WD40 test for air leaks. Then look to the more difficult to find problems like the butterflies misaligned in their spindles, and the poppet valves being worn.
Graham
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.
Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
Re: Twin Su idle high
sorry I was just trying to be helpful based on personal experience of a problem I recently had where although the timing appeared to be correct it was running at higher revs and this was cured by moving the distributor back slightly.
Some people are like Slinky's, they serve no real purpose in life but bring a smile to your face when you push them down the stairs.
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GrahamFountain
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- Joined: Sun Sep 08, 2013 3:35 pm
- Location: St Annes on Sea, Lancs.
Re: Twin Su idle high
Why be sorry? It was a valid point that idle speed depends on advance, and I had no intention of suggesting otherwise.
Just that I think that if everything is as it should be the butterflies will shut well enough the engine shouldn't idle wherever the ignition timing is set. So even if backing the ignition timing off a bit fixed the problem with the idle, there must still be an underlying problem that's not been fixed.
Graham
Just that I think that if everything is as it should be the butterflies will shut well enough the engine shouldn't idle wherever the ignition timing is set. So even if backing the ignition timing off a bit fixed the problem with the idle, there must still be an underlying problem that's not been fixed.
Graham
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.
Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).
Re: Twin Su idle high
The O/P said that he had set it at 10*BTDC,I assume by lining up the notch on the pulley to the TDC markings but has he checked that the spark was on plug one, so maybe everything isn't as it should be?GrahamFountain wrote: ↑Tue Dec 01, 2020 9:50 pm Why be sorry? It was a valid point that idle speed depends on advance, and I had no intention of suggesting otherwise.
Just that I think that if everything is as it should be the butterflies will shut well enough the engine shouldn't idle wherever the ignition timing is set. So even if backing the ignition timing off a bit fixed the problem with the idle, there must still be an underlying problem that's not been fixed.
Graham
Its a very easy mistake to make
Some people are like Slinky's, they serve no real purpose in life but bring a smile to your face when you push them down the stairs.