Leak down test - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 8 (permalink) Old 11-09-2017, 12:33 PM Thread Starter
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Leak down test

Hello Alfisti,

As I was getting ready to put manifolds back on the engine, remembered #6 cylinder that had a clean spark plug when I got the car. After running couple bottles of Motul fuel system cleaner, testing injector (it clicks) and installing new spark plugs, all 6 plugs look the same. But still want to do a leak down test on cylinders to get to know the 3.0 bit better. Also it's easier to hear leaks with manifolds off.

I know firing order is 1-4-2-5-3-6 and need to bring each cylinder to TDC to be tested. Whats a best way to do that, getting TDC on each cylinder without removing the covers off the heads? I have a 1 5/8 (41mm) socket on the pulley to turn the engine and spark plugs are out, what's next?

Any guidance is much appreciated, as I could not find anything on V6 leak down test on here

P.S. I can't remember what is the correct way to install manifold gaskets? Flat side to the engine head, ribbed side toward manifold?

Zaza

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Last edited by Nakagtv; 11-09-2017 at 01:29 PM.
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post #2 of 8 (permalink) Old 11-09-2017, 01:50 PM Thread Starter
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Ok, gonna try looking at the rotor's orientation vs distributor cap. Should tell me which cylinder is on compression cycle right?

Zaza

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post #3 of 8 (permalink) Old 11-09-2017, 02:09 PM
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I stick a chopstick down the spark plug hole and watch it as I rotate the crank.

Tom

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post #4 of 8 (permalink) Old 11-09-2017, 02:20 PM
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Both valid methods. The dowel down the plug opening is more accurate, but the rotor will tell you if you are in the compression stroke. Combining both is not a bad idea.

Whatever you do, don't turn a Busso v6 backwards! You can jump the timing belt. And/or mess up the tensioner.

Al

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post #5 of 8 (permalink) Old 11-09-2017, 02:35 PM Thread Starter
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TDC V6 engine

Quote:
Originally Posted by Gubi View Post
I stick a chopstick down the spark plug hole and watch it as I rotate the crank.
Thanks Tom, got that too.

Quote:
Originally Posted by radioal View Post
Both valid methods. The dowel down the plug opening is more accurate, but the rotor will tell you if you are in the compression stroke. Combining both is not a bad idea.

Whatever you do, don't turn a Busso v6 backwards! You can jump the timing belt. And/or mess up the tensioner.

Al
I will do just that Al and thanks. I'm having nightmares of engine turning backwards... don't even look at it backwards, just in case...

Zaza

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post #6 of 8 (permalink) Old 11-09-2017, 02:39 PM Thread Starter
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Manifold Gasket V6

Correct orientation for this?
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Zaza

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2018 Stelvio Ti Sport
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1970 Euro-spec GTV 1750

Refreshing 1750 GTV
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post #7 of 8 (permalink) Old 11-09-2017, 02:41 PM
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Quote:
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P.S. I can't remember what is the correct way to install manifold gaskets? Flat side to the engine head, ribbed side toward manifold?
Yup, your intuition is correct.

If you suspect the mating surface may not yield you the best seal to the manifold, I've seen folks coat a thin layer of ultra copper on the manifold gaskets too (should be able to get this at your local auto parts store).
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post #8 of 8 (permalink) Old 11-09-2017, 02:59 PM Thread Starter
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Originally Posted by nizam View Post
Yup, your intuition is correct.

If you suspect the mating surface may not yield you the best seal to the manifold, I've seen folks coat a thin layer of ultra copper on the manifold gaskets too (should be able to get this at your local auto parts store).
Mating surfaces looked good, I'll clean up and take a closer look. Thanks

Zaza

Current Alfas:

2018 Stelvio Ti Sport
1987 Milano Verde
1970 Euro-spec GTV 1750

Refreshing 1750 GTV
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