Compression test

[ward cleaver]

Harbor freight: for those who like to buy tools twice or thrice!

 

[BJS]

Harbor freight: for those who like to buy tools twice or thrice!

Hey don't knock all of the tools, I picked up some welding magnets for 86¢ that actually work better than the ones I paid $5 for, oh and a great source of tools used for beating and prying, not to mention an excellent source for raw materials for producing custom service tools.

 

[DaveBen]

Just don't hurt yourself.

Dave

 

[strokin'_tatsch]

i'm actually pretty dang happy with the pittsburg ratchet wrenches from HF and the pittsburg swivel headed ratchets or as a buddy and i call 'em the double reverse left handed with a right handed option swivel headed ratchet. haha. they actually are very handy on our engines for all the hard to reach areas such as the rear oil galley plugs and such. some of their stuff is junk, but the pittsburg tools are alright in my book.

 

[arrowstrap]

ok i found an adapter to use the HF tester... here were my first results. i turned the motor over 4 times, recorded the PSI, turned it over 4x's again and then a third for a total of 12 strokes of built up pressure:

1) 350-380-400
2) 360-390-400
3) 350-370-380
5) 390-400-420
6) 350-390-400
7) 380-390-400
8) 350-380-390

ran a seccond test on 3 & 5

3) 320-350-380
5) 340-400-400

i was concerned with the reading of #3 and suspected i may be loosing compresion through the injector so i swapped #3 & #5 injectors and tested the left side again. my first reading on #3 was 550... i think i had some oil in the cylinder so i cranked the motor over for 30 seconds to blow it out and pulled the following results:

1) 350-380-400
3) 360-400-400
5) 350-400-400
7) 350-390-400

I am so confused... also, i have a considerable amount of blow-by when i remove the oil fill cap.

how do i get a true reading of compression? i run the truck and burn out the oil in the cylinders. when i pull the GP's some oil runs down in the hole... so my first reading will have oil and by the time i get to the last cylinder it'd pretty much spit out.

also, my batteries (new and fully charged) dont turn the motor over as strong by the time i get to the last cylinder....

can someone tell me the porceedure for checking compression so i can know that i'm doing this right... how many cranks etc?

 

[DaveBen]

I think you are sweating the little stuff here. The numbers look good and even. You are at 400 pounds and that is good. Blow by is going to happen in any engine that has more than ZERO hours. Does the truck start and run? It has been a few weeks since you started this post, and I don't recall.

Dave

 

[Zookie400]

cold engines have excessive blowby, the ring gaps and piston clearances tighten up when its hot.

 

[BJS]

if you're really compulsive about the small things, then for the batteries you will need a commercial/shop type charger that you can use to provide help even out the power, disconnect the GPR trigger wires, and do this on a hot engine too.

For the oil crack the glow plug so that it is a vent to the cylinder and then turn the motor over, volia all the oil is blown out of the glow plug depression or blow it out with a blow gun or can of compressed air.

 

[trackspeeder]

ok i found an adapter to use the HF tester... here were my first results. i turned the motor over 4 times, recorded the PSI, turned it over 4x's again and then a third for a total of 12 strokes of built up pressure:

1) 350-380-400
2) 360-390-400
3) 350-370-380
5) 390-400-420
6) 350-390-400
7) 380-390-400
8) 350-380-390

ran a seccond test on 3 & 5

3) 320-350-380
5) 340-400-400

i was concerned with the reading of #3 and suspected i may be loosing compresion through the injector so i swapped #3 & #5 injectors and tested the left side again. my first reading on #3 was 550... i think i had some oil in the cylinder so i cranked the motor over for 30 seconds to blow it out and pulled the following results:

1) 350-380-400
3) 360-400-400
5) 350-400-400
7) 350-390-400

I am so confused... also, i have a considerable amount of blow-by when i remove the oil fill cap.

how do i get a true reading of compression? i run the truck and burn out the oil in the cylinders. when i pull the GP's some oil runs down in the hole... so my first reading will have oil and by the time i get to the last cylinder it'd pretty much spit out.

also, my batteries (new and fully charged) dont turn the motor over as strong by the time i get to the last cylinder....

can someone tell me the porceedure for checking compression so i can know that i'm doing this right... how many cranks etc?

Those numbers are fine. Drive it. Better yet drive it like you stole it.

 

[DOC-MX]

ok i found an adapter to use the HF tester...

I have the HF tester and havent used it, so I didnt know that it doesnt work, were did you find the adapter, part number and cost? please.

Thanks in advance.