-72 1641cc turbo build log

[villemil]

Was a lot longer than 20min Had to make a mount for the oil cooler. Haven't even started it yet. After some wiring and somehow finding a way to do my throttle cable I can finally start her up!

[villemil]

So a question regarding my ignition base map...
Will 30° advance maxing out at 3500rpm with vacuum advance set to 0° and under full boost at 24° be a good starting point? At 1000rpm I would have 10° of advance and from there going linear to the max 30° @ 3500rpm.

[madmike]

when them guys wake up they will help you I'm just running a Mallory CDI Box & a MSD dizzy Locked at 24* so I can't help,sorry

[Schweg]

What fuel type are you running?

24 degrees seems pretty advanced to me.

I started at 18 and have been adding timing.

[villemil]

I use 98 RON fuel.

[buguy]

24 degrees under moderate boost is pretty much the norm. I'd say you will be fine with 30 and 24 at boost. If your adjustable, you could always start lower and sneak up on it while listening for detonation.

[Schweg]

So without knowing your AFR is good I would start conservative and add timing in slowly.

Better to not blow a hole in a piston or get detonation.

I’ll look at mine later today. I’m pretty sure I ramp up to 30+ degrees up to 100kPa.


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[villemil]

I haven't even started my engine yet
I got AFR gauge and just wanting to know a safe starting point for ignition timing when I do the cam breaking in.
Also yes, I got adjustable ignition. Tried to start multiple times yesterday but seems like something is off. Engine spins fine, gets fuel but just does not want to start, not even trying to.
I got 123Tune+ dizzy that I installed by the manual. Coil and dizzy are getting power but nothing happens :/
Really don't know what could be the issue

[madmike]

pull a spark plug and see if it's wet? , you may have just fouled them?,as it too much fuel? for cam break in u can use an advance up to 32* because you won't be 'Boosting' without a load on it

[Schweg]

Have you verified base timing?

And the above that madmike mentioned?


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[villemil]

Now it runs, kinda. Does not respond to throttle, exhaust leaks and maybe have a intake leak. Does not run without choke. I will get a strobo light this saturday so will continue then.

[madmike]

well how'd it go?

[villemil]

She is running now. But I am a little worried about my rocker sound... I got stock retainers, stock valve plates, logmech hd-1017 springs, engle TCS-20 cam, CB superduty aluminium pushrods and stock rocker assembly.
Here is the valve specs and a video of the sound

53 kg / 42,1 mm
62 kg / 39,1 mm
109 kg / 27,3 mm
119 kg / 25,4 mm

https://youtu.be/YfXcKQys_8M

[villemil]

Okay so I got everything fixed now. Now I really need advice on tuning my carb. I have Solex ADDHE 40 carb, very similar to Weber DCOE.
I got my idle around 13 on my wideband gauge, also changed my main jet to 200, less than that it was way too lean. So when I go pass half throttle my car acts like a kangaroo. If I floor it it simply stalls and my wideband is going past 18 even slightly above half throttle.
So full advice on carb tuning is needed. I have zero experience of carb jetting.

[Coyotemutt]

Okay so I got everything fixed now. Now I really need advice on tuning my carb. I have Solex ADDHE 40 carb, very similar to Weber DCOE.
I got my idle around 13 on my wideband gauge, also changed my main jet to 200, less than that it was way too lean. So when I go pass half throttle my car acts like a kangaroo. If I floor it it simply stalls and my wideband is going past 18 even slightly above half throttle.
So full advice on carb tuning is needed. I have zero experience of carb jetting.

I've never messed with a dcoe but carbs are all generally the same in that they respond to throttle position moreso than RPM.
The way the car acts while the throttle butterfly is in motion (during the push of the pedal) is largely the responsibility of the accelerator pump squirt. I like to tu e this part last, personally.

The way the car responds below approximately half throttle is controlled by the idle jet (or in some carbs called the low speed circuit, pilot jets, and a few other names).

As you go above half throttle the mains slowly take over. Larger air jets and the overall design of the emulsion tube controls how soon and how strong the main comes in. I like to tune this area by using a WAY oversized main jet so I can watch the AFR gauge shoot dead rich when the main takes over. This can reveal if you have a lean spot between the idle jets and the main jets.if you DO have such a lean spot but the low speed performance is otherwise okay, the air jet needs to be bigger to bring the main in sooner. If you have a nice clean running low speed that gets too rich too early, a smaller air jet can delay the mains coming on.

The idle (low speed) jets are the easiest to tune in my opinion. Just get it to cruise smoothly on the leanest idle you can. Done. If you have a good vacuum advance, you can get away with much leaner cruise AFRs. Without vacuum advance I end up cruising around 13.5:1 give or take. I usually start tuning here, btw. With any solex I've used it's the easiest circuit to manage.

Last thing first, try to report all your results in terms of steady-state throttle positions and AFR values. Makes tuning easier.