12WWGSR91

iTrader: (51)

Hey guys i wanted to do a leak down test to see how my car is performing. I know the general concept of how to do it but, im unfamiliar of how to get each cylinder to TDC top dead center. I know the screw driver trick, where you rotate the crank and when the screw driver is at its highest point thats where its tdc for that cylinder.

I was wondering if there is a more accurate way on doing this? Like reading the markings on the cam gear or crank?

Thanks in advance!

TommiM

iTrader: (19)

Thats the way Ive done it, with a long extension that is.

jason42003

iTrader: (18)

Yeah same here, it's accurate enough. If you're off my a couple of degrees the pressure from the airline will push the piston down and you will know.

12WWGSR91

iTrader: (51)

Thanks guys for the response. But for cylinders 1 and 4 to get it really top dead center i can match up the marks on the valve cover and the cam gears right?

And for 2 and 3 i would have to use the extension trick. But its possible that you can be tdc and and the exhaust valve is open. If thats the case i just rotate it one more time until the extension comes back up again right?

bbyevo8u

iTrader: (14)

with the cam gear cover off put the car in 3rd gear rock the car forward until the notches on the cam gears line up with the notches on the valve cover.. done

jason42003

iTrader: (18)

I went off the marks on the cam gears and for that only cyl 1 was lined up after that each cyl is 90 degrees off that in 1-3-2-4 order if I remember correctly. But yes if the valves are still open when your extension is at tdc and it won't hold any air at all then give it one rotation till the extension come back up to tdc.

jason42003

iTrader: (18)

As long as you leave the transmission in neutral you can just turn the crank with a 1/2" ratchet and extension till the marks line up and thru the whole cycle. A lot easier than rocking the whole car thru the cycle.

12WWGSR91

iTrader: (51)

I thought if cylinder 1 is tdc then cylinder 4 should be as we'll?

jason42003

iTrader: (18)

Yup I got my numbers a lil mixed up and I was in class so I couldn't check them right away but you're correct. Fire order is 1-3-4-2