How to tune a 2lt

[Mick A]

So how did you go with the comp test?

[joestram]

So how did you go with the comp test?

I wouldn't even know how to do that! The car needs to be running for that so I'm not sure how that will go


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[Mick A]

Google how to do it. Engine just needs to be able to crank.

I am trying to help by giving the right advice to you and helping you diagnose a fault.

It's a process of elimination. You need to eliminate all possible causes.

A comp test should have been done before you even touched the carbies.

Cheers.

[bonno]

Joe
That black gunk definitely would be causing your car problems. Your carbs definitely need a complete strip and thorough clean and then tune and balance as described in an earlier thread PS : make sure there are no air leaks between carby and manifold.  Hopefully this might fix the problem.
bonno

[joestram]

Thanks for your reply Mick. I have just watched a video and the testing looks simple enough.

I just have a few questions

1. My car has an electric fuel pump. Does this need to be disconnected?

2. Do I need to remove the carbs or will air box removed be enough?

3. What compression is normal for the 2lr?

Thanks

Joe


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[joestram]

Joe
That black gunk definitely would be causing your car problems. Your carbs definitely need a complete strip and thorough clean and then tune and balance as described in an earlier thread PS : make sure there are no air leaks between carby and manifold.  Hopefully this might fix the problem.
bonno

Thanks Bonno.

What would be causing the black deposits?

I did a "rebuild" on them recently using a rebuild kit from Thornbury Carbs.

I must have messed it up some how

Joe


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[Neil Choi]

Comp test, you need one of these.
Take plugs out, screw in comp tester into cylinder 1, probably good to pull coil to distributor lead.  Crank engine for 10 sec until pressurised and record measurement.  Repeat on other cylinders, all should be same or close to each other.
In terms of tuning, I am having some issues of my own to figure out too.  Mainly misfire.

[joestram]

Thanks Neil.

Just to confirm - Do I still need to have the throttle all the way down?

Thanks

Joe

[bonno]

Joe
Check the fuel filter for signs of contamination  and or drain/flush  fuel tank.
bonno

[bazzbazz]

Thanks Neil.

Just to confirm - Do I still need to have the throttle all the way down?

Thanks

Joe

Yes, throttle should be fully open when doing compression test, and as advised, pull the main lead on distributor so engine does not fire.

Baz

[joestram]

Thanks Neil.

Just to confirm - Do I still need to have the throttle all the way down?

Thanks

Joe

Yes, throttle should be fully open when doing compression test, and as advised, pull the main lead on distributor so engine does not fire.

Baz

Thanks Baz.

What do I do about the electric fuel pump? Obviously if I have my foot down the car will be pumping petrol into the carb/cylinder.
Will I flood the engine?

Joe


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[Mick A]

It will be fine.

It doesn't work that way. Once the floats in the fuel chamber are up they will close the needle & seat valves. Fuel doesn't just pour into the engine. One pump of the throttle is one squirt of fuel into the combustion chamber from the pump jets. It will all be displaced out the exhaust valve as you perform the test.

All comp gauges are different so not all accurate, but what you are looking for is consistent readings from all cylinders. Hopefully you have somewhere around 175-200psi, that would be good from an old motor.

MICK.

[Colin Edwards]

Hi  Joe,
That black goo is a worry.  The Dellorto's air supply to the air correctors is unfiltered.  All that gunk may be restricting airflow through the idle and main air correctors.  This will make the carby run rich.  Very dificult to tune. 
Need to clean the idle and main air correctors as a priority.  Next job will be to ascertain how they got that dirty and prevent it from reoccurring. 
I prefer the Dellorto over the Weber, however the lack filtering to the air correctors in the DHLA carby is a pill.

[joestram]

Hi Everyone,

Firstly, I'd like to thank Neil for coming to explain and show me a thing or 2 about maintenance.

Neil was able to connect his compression tester and we found cylinder 1 & 2 had 220 and 3 & 4 had 200.

Neil also checked a few other things out and seems to think the issue might be isolated to the carbs.

When we started the test, fuel started to pour out of cylinder 1 & 2 trumpets so we disconnected the electric fuel pump.

All the spark plugs were black as well.

Thanks again everyone

Joe





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[carlo rossi]

so you have a needl;e and seat issue
when you clean the stack can you tell
me what is the number on the air corrector thats the black end
cheers