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TDC for Carburetor Cars (Read 1,481 times)
FlorinG
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TDC for Carburetor Cars
Sep 20th, 2020 at 5:41pm
 
Hello
Is there any way to "catch" the TDC for cylinder 1 with PicoScope on a classic engine with no ECU, carburetor, one coil, and distributor?
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StitchB
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Re: TDC for Carburetor Cars
Reply #1 - Sep 21st, 2020 at 4:22am
 
FloringG, don't think it would be exact but would see it with compression wave form, JMO, again don't think it would be exact but close.

Larry
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Tom Roberts
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Re: TDC for Carburetor Cars
Reply #2 - Sep 21st, 2020 at 8:20am
 

X2

The peak pressures will be nearly exactly TDC as long as you are working with a good well sealed cylinder.  If the cylinder has leakage, peak pressures will be before TDC.

You must also use a quality transducer like the Pico WPS for reliable results.
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Spence
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Re: TDC for Carburetor Cars
Reply #3 - Sep 21st, 2020 at 8:46am
 
FlorinG wrote on Sep 20th, 2020 at 5:41pm:
Hello
Is there any way to "catch" the TDC for cylinder 1 with PicoScope on a classic engine with no ECU, carburetor, one coil, and distributor?


Do you own a timing light?
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FlorinG
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Re: TDC for Carburetor Cars
Reply #4 - Sep 22nd, 2020 at 3:01pm
 
Thank you for your answers.
The only reference I have is a notch in the flywheel that can be seen through a small window in the clutch housing.
Spence wrote on Sep 21st, 2020 at 8:46am:
Do you own a timing light?

Unfortunately I don't. What are you thinking at?
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StitchB
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Re: TDC for Carburetor Cars
Reply #5 - Sep 23rd, 2020 at 6:59am
 
Spence, you have my attention. I suppose one could pull a plug, rotate till TDC physically with a rod. Then mark the Ba-lancer or what ever? Struggle to see relevance as do we know the exact time of timing fire.

Have always wondered in this case if there is a stick on CPS one could create once you have found the TDC physically, then use Pico from there. Is there an optic CPS?
I suppose the question is what is his end attempt and how accurate does it have to be in light of what Tom said.

All this said am doing some testing on motorcycles and using the Transducer for gaining experience. These are old school but the in cylinder images are powerful to look at valve timing and the question of TDC which we are presently talking could also be relevant as older units have no CPS.

Also a question to Tom. I am presently working with a Fluke 350 which I never used as considered it inferior although thought I bought it from Tom when I bought the Pico unit, could be mistaken. Have been doing some captures and seems to work fine, but again have no long term usage. I have a WPS 500 on back order and of course consider it the best, but the Fluke does not seem like a marginal unit at this point and having 2 will be nice.

Larry
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Tom Roberts
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Re: TDC for Carburetor Cars
Reply #6 - Sep 23rd, 2020 at 9:03am
 
StitchB wrote on Sep 23rd, 2020 at 6:59am:
Also a question to Tom.


The old production Fluke PV350 did a good job of in cylinder testing.  It was the industry standard for many years.  The ones currently available by the same name are garbage.
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FlorinG
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Re: TDC for Carburetor Cars
Reply #7 - Sep 24th, 2020 at 12:16pm
 
I have found out that the 'hole' I see through the notch on the flywheel could accommodate a crankshaft position sensor given there is a 5V power supply applied too. I will give it a try.
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Re: TDC for Carburetor Cars
Reply #8 - Sep 25th, 2020 at 3:21am
 
Are you looking to apply this to a specific application or all carbureted engines?
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FlorinG
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Re: TDC for Carburetor Cars
Reply #9 - Sep 26th, 2020 at 12:06pm
 
So far on a specific car. It is a Skoda Felicia, first Czech car made under VAG patent.
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