Jason,
Thanks – this is very helpful! We do plan to run it first on a test stand, then dyno it later once on the car. So, that will give us an opportunity to tweak it further. But, this is a good baseline starting point.
Regards,
Mark
From: JS Performance Motoring, LLC [mailto:jason at jsperformancemotoring.com]
Sent: Friday, October 24, 2025 9:32 AM
To: Mark Cook
Cc: Friends of Triumph
Subject: Re: [Fot] 123ingition distributor settings
Hi Mark,
For a racing setup, you spend most of your time in the upper RPM range that would be "all in" advance on a mechanical distributor. I'd recommend starting with an advance curve that mimics that, then fine tuning for small gains on the dyno if you have the chance.
My typical starting point for a curve is a very simple line that starts advancing at 2000 rpm, then maxes out advancing around 4000 rpm.
No added advance below 2000 rpm makes it easier to verify your idle advance with a timing light accurately.
I prefer to install the programmable distributors at 16 or so degrees static, NOT at TDC. This helps with starting, and also improves rotor phasing at max advance.
On the 123's, the rev limiter setting isn't always 100% accurate, sometimes you need to program the rev limit a few hundred RPM higher than intended.
I've attached a picture showing an example of a basic starting point for the advance curve.
Jason Sukey
JS Performance Motoring, LLC
440.984.7720
jason at jsperformancemotoring.com
www.jspmparts.com
https://www.facebook.com/JSPerformanceMotoring/
On Thu, Oct 23, 2025 at 3:18 PM Mark Cook via Fot <fot at autox.team.net> wrote:
All,
I am installing a 123ignition distributor (laptop programmable) into my "project" TR6 race car. Wondering if anyone has this installed on their TR6 (or 250) race car with triple weber 45 DCOEs. I thought about downloading the tuning curves from the 123 disti in my running #95 TR6 race car as a starting point:.
I realize the camshaft would make a difference in the settings, so my specs below. Both have 1.55 roller rockers. Thoughts?
The "project" car engine has a Racetorations race camshaft, triple Weber 45 DCOE and a CR of about 12.5:1. The camshaft specs are:
Peak Diff: Exh / Intake / LCA - 108.0 / 107.0 / 106.0
Duration: Intake / Exhaust - 336
Cam Lift: Intake / Exhaust - 370
Checking Clearance: Intake / Exhaust - 0.010"
Valve timing (at checking clearance) - Exhaust: Opens 96 BBDC / Closes 60 ATDC, Intake: Opens 62 BTDC / Closes 94 ABDC
The camshaft specs in my running TR6 are:
Peak Diff: Exh / Intake / LCA - 105.0 /103.0 / NA
Duration: Intake / Exhaust - 320
Cam Lift: Intake / Exhaust - 340
Checking Clearance: Intake / Exhaust - 0.010" (I think, but not certain)
Valve timing (at checking clearance) - Exhaust: Opens 87 BBDC / Closes 53 ATDC, Intake: Opens 57 BTDC / Closes 83 ABDC
Thanks,
Mark Cook
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