Leakdown Testing - Finding TDC on Each Cylinder
#16
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and use a Snap-On compression guage as well:
Cheers,
Mike
#17
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Cheers,
Mike
#18
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I wonder if the Snap-On set uses the standard 0.040 orifice.
#19
Alex, Mike,
Thank you for the recommendations guys. I bought an inexpensive OTC 5609 Cylinder Leakage Tester Kit five or six months ago.
It has dual gauges similar to the Snap-On and Eastern Technologies units.
I used the distributor to find the top of the firing order and then used the marks on the crankshaft pulley for TDC for each cylinder.
Thank you for the recommendations guys. I bought an inexpensive OTC 5609 Cylinder Leakage Tester Kit five or six months ago.
It has dual gauges similar to the Snap-On and Eastern Technologies units.
I used the distributor to find the top of the firing order and then used the marks on the crankshaft pulley for TDC for each cylinder.
#20
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You are bang on -
Every 120 degrees clockwise on the engine moves to the next firing position. So just follow the firing order. You can double check your position by checking the rotor position on the cap - the rotor should be pointing to the cap wire that corresponds to the piston being tested.
Cheers
Mike
Every 120 degrees clockwise on the engine moves to the next firing position. So just follow the firing order. You can double check your position by checking the rotor position on the cap - the rotor should be pointing to the cap wire that corresponds to the piston being tested.
Cheers
Mike
Appreciate your help.
Craig
#21
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Probably a stupid question, but how do you manually rotate the motor? My dad and I were trying to think this through and couldnt figure it out. We tried turning the rear wheels while in gear but that didnt work. I was thinking maybe you can turn the fan pulley nut with a socket but I figured that might not be the right solution...
#22
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First thing, take out at least one plug per cylinder - it makes it much easier to turn over
Second, turn the engine clockwise only looking at the fan.
Third, you can use the large nut on the fan/alternator shaft to turn the engine over with the car in netural. If the belt slips, then push on the side of the belt to add tension so it grips - that is the way I have always done it and it seems to work fine.
Cheers,
Mike
Second, turn the engine clockwise only looking at the fan.
Third, you can use the large nut on the fan/alternator shaft to turn the engine over with the car in netural. If the belt slips, then push on the side of the belt to add tension so it grips - that is the way I have always done it and it seems to work fine.
Cheers,
Mike
#23
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I'll give the fan alt nut another try. The first time it spun pretty freely but the fan didn't move. Didn't want to break the grip of the nut against the bearings and end up with alternator problems, like stripping, that I've read on here.
#24
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sage advice.
I just did leak down test and removed all 6 prior to rotating.
I've also seen a few threads on Pelican where posters say to ensure you remove the "big wrench" from the nut prior to charging the system with compressed air......
ouch, that must have been a hard-learned lesson.
Craig
#25
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You can probably be ~5 degrees off on a street engine before filling the cylinder with compressed air will move a piston, and therefore the crankshaft and ultimately the fan.
#26
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Do enough of them, and most certainly you've been there. Guess it's more critical with the race cams of yesteryear where TDC alignment spot on is recommended.
You can probably be ~5 degrees off on a street engine before filling the cylinder with compressed air will move a piston, and therefore the crankshaft and ultimately the fan.
You can probably be ~5 degrees off on a street engine before filling the cylinder with compressed air will move a piston, and therefore the crankshaft and ultimately the fan.
Cheers,
Mike
#27
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And to clarify my comment on "race cams", it's all about being more TDC critical with the high overlap. Nothing like rolling the crank over to whatever cylinder you're testing, pressurizing, and finding 20-30-50% leakage........ Steve W or someone can correct me, but I think it was the original 906 sprint cam that had the intake open measurably at TDC.