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Pinto vacuum advance take off point ?
Derbyboy - 21/5/19 at 10:10 PM

Evening all, I'm new to the world of kit cars and have just bought one with a 2.0 pinto engine which I believe is completely standard as it came out of the 1986 Sierra diner car. The engine seems in good condition, but isn't running very well so I'm doing some investigation work. The first thing I've noticed it that the vacuum advance on the dizzy isn't connected to anything.

I've found a pipe from the manifold that was cable tied under the manifold it's shown in the photo below


This looks like it's supposed to be the vacuum pipe for the dizzy. Looking in the Sierra Haynes manual it's in a different place to the original location, does anyone know if this will work ok ? I'm wondering if it didn't work well and that's why it was disconnected.


cliftyhanger - 22/5/19 at 05:49 AM

That should work fine.

However, the vacuum advance is unlikely to make any difference to the running, it is there to give better fuel consumption and torque under "light cruise" conditions.

If running poorly, do the usual stuff. Check the timing, and that the distributor is advancing correctly (timing gun needed)
Check for air leaks on the inlet side. And that if carbs everything is clean/moving etc. Spark plugs can be a problem, it seems some never recover from being flooded.

A few pointers to describe the symptoms would be useful so pointers can be given.


Derbyboy - 22/5/19 at 06:52 AM

Thanks for the reply, here's a few more details on what the engine is doing.

Poor starter often on 2 or 3 cylinders from cold
Very rough idle when cold
Feels like it's lacking power
Popping in the exhaust when off the throttle
Very heavy on petrol

So far I've cleaned the air filter, next was to check the timing and this is where I found the vacuum advance disconnected. So my next step is to set the static timing correctly and test the mechanical advance. Then I'll try re connecting the vacuum line and see how it runs.

[Edited on 22/5/19 by Derbyboy]


rusty nuts - 22/5/19 at 07:12 AM

First thing to check and adjust would be the valve clearances ,done with a cold engine. All of the symptoms you have can be caused by tight clearances. Iíve also had the auto advance mechanism seize on Bosch distributors especially when they have not been used regularly. The vacuum advance take off is likely to be below the throttle butterfly on the carb


Derbyboy - 22/5/19 at 07:53 AM

Thanks for that, I'll get those checked too. The engine doesn't have any tapping from the tappets thinking about it, so maybe they are too tight.


mcerd1 - 22/5/19 at 08:05 AM

quote:
Originally posted by Derbyboy
The engine doesn't have any tapping from the tappets thinking about it, so maybe they are too tight.
^^ always worth a check


also for a totally unknown engine it wouldn't hurt to check the cam timing too (it not impossible to have slipped a tooth or have been assembled wrong at a previous belt change....)
Just pop the cam belt cover off (4 bolts), turn it over by hand until the cam timing mark is aligned and then just check the crank and dizzy are lined up too

a stock 2.0 pinto is a non-interference engine, so the pistons shouldn't touch the valves even if the belt snapped - so they can run with the timing out by a surprising amount (but not run very well obviously)
BTW any mods like head skimming, high lift valves etc and it becomes an interference engine quite quickly


next on my list after all the above would be a compression or leakdown test

the good thing about pinto's is that they are very simple / easy to work on and pretty bombproof too



[Edited on 22/5/2019 by mcerd1]


chillis - 22/5/19 at 11:57 AM

The Distributor vacuum advance pipe should go to a tapping on the carburetor not the manifold, if you use the manifold it may prove hard to start as you will have too much advance on cranking.