DCOE's - Out of my depth!

[iani]

I have just about had enough of this project, 2 blocks, 3 cylinder heads, 2 camshafts, 3 sets of pistons & an unknown number of man-hours & ££ spent. Today I have yet another go at setting the triple DCOE's up, Colourtune used on all 6 cylinders, burning nice & blue, AFR reading mostly ok, some fluctuation but towards rich in the main, then I noticed the exhaust manifold pipes were glowing where they mate with the head on Nos 2-5, I assumed they were lean and enriched the mixture, they stopped glowing but the collector for these pipes was still glowing, as per the pic.

The engine has +20 county pistons, balanced crank, maxpeeding rods, the cylinder head is from Tony Lindsey-Dean, it should be c. 11.5:1 CR I believe, the Camshaft is one of his 3R cams, this is a 300 degree with 40-80 80-40. 

I have had a bit of a saga with this build, after the original head sprung a leak I fitted what was effectively a race head from Tony, that led to lean running and melted pistons, hence that head being replaced with this, slightly tamer one.

The carbs are configured with:

To those that know, does anything look way off here? When the manifold was glowing, the car was idling c.1k RPM with 10 degrees of advance kicking in at 1k

[john.r.davies]

In my experience, glowing exhaust headers indicate grossly retarded ignition.  

What is yours set at?

And are you sure that the timing marks on the crank pulley are correct?  If you have been re-using the same crank pulley through all your other part replacements, then that would explain your problems   As many as 20% are faulty.     Find TDC by a piston stop method and check.   If it does not coincide, then the outer inertia ring on the crank damper pulley has shifted, and it is either scrap, or needs a rebuild.

If you're unsure, send it to me to be tested on my engine rig.

John

[iani]

12 minutes ago, john.r.davies said:

In my experience, glowing exhaust headers indicate grossly retarded ignition.  

What is yours set at?

And are you sure that the timing marks on the crank pulley are correct?  If you have been re-using the same crank pulley through all your other part replacements, then that would explain your problems   As many as 20% are faulty.     Find TDC by a piston stop method and check.   If it does not coincide, then the outer inertia ring on the crank damper pulley has shifted, and it is either scrap, or needs a rebuild.

If you're unsure, send it to me to be tested on my engine rig.

John

I have a 123 Tune+ dizzy John, you set it at TDC. The pulley is from Moss, one of the ones without any timing marks other than TDC.

[Keith Wigglesworth]

I had a plague of red hot exhaust headers on my old TR2 sprint engine. The car had a Triumph Tune sprint cam which in combination with slightly retarded ignition seemed to be the cause. It exhibited at around 1000 revs and it seemed to be a higher static advance was the solution. I also had very bad run on. Rich mixture may also be an element in this. It took an age to adjust things to avoid the problem.  I have now rebuilt the engine and changed the cam. Also I use a distributor doctor dizzy. 
I would recommend a careful check on the ignition timing as a first step. 
Hope this helps. 
Keith

[Icarus60]

iani

If you are setting your 123 tune at TDC then you need to add the static advance degrees to the 123 curve setting . What is the total advance set into the 123?         I would be tempted to slacken the distributor and rototate it to find the peak RPM at a happy idle and see what that told you.

Rog

[john.r.davies]

Ian,

 having never used 123 ignition, I didn't offer further advice, but Icarus and Keith have supported the diagnosis.   That's the problem with 'black boxes', they don't explain their results!    I suggest using a strobe to find the actual ignition timing should be your next step.

John

[iani]

7 hours ago, Icarus60 said:

iani

If you are setting your 123 tune at TDC then you need to add the static advance degrees to the 123 curve setting . What is the total advance set into the 123?         I would be tempted to slacken the distributor and rototate it to find the peak RPM at a happy idle and see what that told you.

Rog

Did this today Rog, installed the 123 as per its instructions then rotated it to give 12 degrees advance with nothing being added in the curve, it was much happier at this point. Had engine running steadily for 15 mins or so without issue, seems to be much happier now, still an odd noise though, will check valve clearances again but have done so twice already.

https://youtube.com/shorts/MvWHLTMulPc?feature=share

[iani]

5 hours ago, john.r.davies said:

Ian,

 having never used 123 ignition, I didn't offer further advice, but Icarus and Keith have supported the diagnosis.   That's the problem with 'black boxes', they don't explain their results!    I suggest using a strobe to find the actual ignition timing should be your next step.

John

very true, the instructions for earlier 123 units do tell you to install at the static timing whereas the Tune+ tells you to install at TDC but no mention of compensating in the map. Read two online articles on how to set it up and you'll get three opinions, it is certainly happier for now. The odd thing is that I didn't have any issues with how I'd set it up on this car when it had the 2l engine & twin SU's, I think the whole setup is much more temperamental now.

[JochemsTR]

9 minutes ago, iani said:

the instructions for earlier 123 units do tell you to install at the static timing whereas the Tune+ tells you to install at TDC

Because the “normal” 123 has preconfigured curves and depends on the static value as the 123Tune does not. So setting at TDC is sufficient and program your 1 and 2 curves accordingly. 

[iani]

28 minutes ago, JochemsTR said:

Because the “normal” 123 has preconfigured curves and depends on the static value as the 123Tune does not. So setting at TDC is sufficient and program your 1 and 2 curves accordingly. 

I'm not sure what you mean by "1 and 2 curves" Jochem? I have the BT version and am using a curve posted by yourself some time ago

[JochemsTR]

Ian, the BT and Tune use the TDC. 
With a Stroboskop you can verify the values, if they are off, you may have an issue with your damper. If they match, you need to look somewhere else. 

[iani]

6 minutes ago, JochemsTR said:

Ian, the BT and Tune use the TDC. 
With a Stroboskop you can verify the values, if they are off, you may have an issue with your damper. If they match, you need to look somewhere else. 

Dizzy is now set at 12 degrees showing on strobe, 0 advance on 123 curve, that appears to be correct. As the RPM increases, the advance follows the map curve.

[Tim D.]

Sounds like you are making progress. Having set up (or rather attempted to setup) Webber and dellortos i would recommend a trip to a rolling road run by someone who knows these beasts well.. the only real way to get them set up is using the variable load on the dyno and an AFR so you can see mixture at different loads and rpm. Otherwise you are in the dark to some extent. Believe me it is well worth the investment. 
tim

[roy53]

4 hours ago, Tim D. said:

Sounds like you are making progress. Having set up (or rather attempted to setup) Webber and dellortos i would recommend a trip to a rolling road run by someone who knows these beasts well.. the only real way to get them set up is using the variable load on the dyno and an AFR so you can see mixture at different loads and rpm. Otherwise you are in the dark to some extent. Believe me it is well worth the investment. 
tim

+1

123 with bluetooth , they can then adjust as revs require

Roy

[Lo100469]

i can confirm what Roy and Tim said.  My mechanic has very good reputation and only does vintage British cars. The only work he will not do himself is tuning my Weber DCOE.  They came with the car so i will keep them and go through the pain of getting them right alongside an engine rebuild.  There is only one guy in Belgium who does the tuning properly, that means he needs to know what cam/pistons you use, then he will refurb the carbs completely, optimise the inlet manifold, put the engine on an Dyno and tune it there and he will only use a 123 ignition with BT.   There is no shortcut on those carbs i'm afraid and the challenge is to find the right guy to do the job....

[Tim D.]

There is a guy called Keith Franck online who is probably the world guru on DCOEs. If you look at some of his work you will realise these should be set up by an expert. Unfortunately he is in california 

Tim

[iani]

I discovered I had an exhaust leak from the manifold, I have replaced the gasket and gone through the fuel mixture settings again. The car now idles well once warmed through, there is some hesitation on initial acceleration but the engine seems to pull strongly. I would be happy to drive this the 25 miles to its rolling road session next month, I doubt I will tweak much more before then.

 

 

[Tim D.]

Great. Sounds like progress. Getting rid of hesitation is probably the hardest thing to do on DCOEs as it is all about smoothing the transition to main jets. There are lots of things you can change to get it to work which makes it complex. 

Tim