Compression test results - process and request for feedback

[ferrellmedia]

I took a chance when purchasing this engine.

- No idea on it's history
- No idea what the guy did when he rebuilt it

I literally took a chance in hopes this was a good engine, from a guys family where the guy who owned the shop died suddendly and he had a few rebuilds complete and in stock, so I paid 1500.00 for one of them.

I'm trying to attempt to see if I got taken or not...

 

[jcarr]

I bought mine from cornwell tools (truck comes by work, but they are in most decent sized cities). the kit is made by star incorporated and is decent. The same kit is on the snap on truck for twice the price. I live by most of my snap on tools, but I am finding out the hard way that not all things snap on ,come from snap on (and thereby can be had for much less)

punk

punk i'm pretty sure i got the same kit. bought it off the snap off truck though. love the kit though it works on the idi's as well as the tractors i see everyday at work. only prob i found was i think it cost me about $200-$300 but at least that was less than half the price of a snap off kit.

 

[Shadetreemechanic]

"leak down fast" - meaning when I stop running it over, the pressure reads at 250, then after approx 1:00 it leaks down to 100 or so....

I actually expected it to peak and hold....

I bought this as a rebuild, did I get taken?

Or will it work?

I have the same Harbor freight compression tester (US General) and have had no problems with it. You didn't have it assembled correctly if it leaked down. I tested my idi using the glowplug adapter provided which has an integrated schrader valve so that it holds the pressure. If you use the injector adapters you have to use the provided intermediate shrader valve attachement so that it will hold pressure.

 

[ferrellmedia]

That is the same kit I have, "US General" and I used the injector hole adapter, (cause that was the only one which would fit) and the short shrader valve "air hose" like connector top to the compression gauge end.

I've tried EVERY glowplug adapter in this kit and NONE fit the glowplug holes.

Everyone on here use the glowplug holes for compression tests, I'm using the injector holes and not sure if this is leading me to these low compression numbers.

In this kit, each piece is numbered and lettered, do you still have this instruction booklet and can you tell me what IDI you have and what numbered/lettered piece you used when doing your compression test?

 

[dave186]

I bought mine from cornwell tools (truck comes by work, but they are in most decent sized cities). the kit is made by star incorporated and is decent. The same kit is on the snap on truck for twice the price. I live by most of my snap on tools, but I am finding out the hard way that not all things snap on ,come from snap on (and thereby can be had for much less)

punk

MOST things snap on dont come from snap on! you will find a lot of the same stuff on all the tool trucks now. unfortunately my mac and cornwell dealers went out of business so im left with matco and a snap on guy that nevers comes around.

back on the topic, I have a diesel comp tester from cornwell that is a pretty nice unit, i forget who makes it but it is USA and a lot cheaper than snap on.

 

[f-two-fiddy]

I have the HF tester. IMO, it's a POS. I never could get decent numbers. They were all over the place.

 

[Shadetreemechanic]

That is the same kit I have, "US General" and I used the injector hole adapter, (cause that was the only one which would fit) and the short shrader valve "air hose" like connector top to the compression gauge end.

I've tried EVERY glowplug adapter in this kit and NONE fit the glowplug holes.

Everyone on here use the glowplug holes for compression tests, I'm using the injector holes and not sure if this is leading me to these low compression numbers.

In this kit, each piece is numbered and lettered, do you still have this instruction booklet and can you tell me what IDI you have and what numbered/lettered piece you used when doing your compression test?

Instructions say use adapter #17 which is the glowplug piece all the way to the left when the plastic handle is pointing down. I scanned all the instructions,but for some reason all but this page were too big to upload. I'll try to get the rest up after work.

 

[ferrellmedia]

Yes, I have the instructions it's a brand new set, I tried to follow them and your correct, it says to use the glowplug adapter #17 in the instructions, but that adapter does not have the correct threads to run into the hole, so the injector adapter was the only one which would fit.

this is why I started this thread, not sure if that adapter would prove the same readings as the glow plug adapter.

The instructions say for a "ford/navistar" which is what I have, 1993 7.3 IDI, to use the glow plug adapter, #17 in the kit, I've ran thru all the glow plug adapters in this stupid kit and NONE fit the glow plug holes in the head, only the injector adapter with the schrader valve threaded into the top.

 

[Shadetreemechanic]

Yes, I have the instructions it's a brand new set, I tried to follow them and your correct, it says to use the glowplug adapter #17 in the instructions, but that adapter does not have the correct threads to run into the hole, so the injector adapter was the only one which would fit.

this is why I started this thread, not sure if that adapter would prove the same readings as the glow plug adapter.

The instructions say for a "ford/navistar" which is what I have, 1993 7.3 IDI, to use the glow plug adapter, #17 in the kit, I've ran thru all the glow plug adapters in this stupid kit and NONE fit the glow plug holes in the head, only the injector adapter with the schrader valve threaded into the top.

My kit was used on the 6.9 that is for sale in the marketplace, but I wasn't there. I thought they used adapter #17, maybe they had another and didn't mention it to me. I have used it personally only on my Izuzu and Mercedes motors.

 

[Alex S]

shoild be the same one used for GMs 6.2/6.5