Outer Limits 4x4 Board

I was at a 4WD training session this weekend, and one of the things we did was a stall start. I drove up the hill, stalled the car with the brakes, put it into reverse, and let go of the brakes. It was in low range. Now, the instructor told me that the compression of the engine should hold the car back, but mine was "ticking" backwards. They attributed this too poor compression.

And by ticking, I mean that when I had the car pointing up this hill, with foot and hand brake off, and ignition off, just in the reverse gear low range, it would tick backwards down the hill again. It was like it went through a cog or something, took a 2 second long rest, tick through another cog and go a few more cm backwards, and so on. I can best describe it like the second indicator on a clock, it would tick backwards, each tick it would roll a few more cm.

What does this mean? Do I have to do anything about it? Should I be
concerned? Im going to tassie for easter, and Cape York in July, I need my engine to be up for it.

The car is a HJ47 Troopcarrier with a 2H with 340000km on it.

Jo

yea, your compression may bit down, however that is expected on a car with that many kilometers, i would expect most cars other than newer ones would roll back..

i have never tryed to stay still in reverse on a slope, normally in 1st as it has lower gearing will be harder for the car to roll, and genrally i would just flick the key with a small amount of throttle to get going, not using the clutch at all.

it may be worth getting a compression test, which is done using either a compression tester or a leak down tester (generally wound into the glow plug holes) which any mechanic can perform. it will tell you what cylinders are bad, and how bad they are. Will give you much more confidence in the veichle on the trip, if you know its ok.

BeZeRK wrote:it may be worth getting a compression test, which is done using either a compression tester or a leak down tester (generally wound into the glow plug holes) which any mechanic can perform. it will tell you what cylinders are bad, and how bad they are. Will give you much more confidence in the veichle on the trip, if you know its ok.

Ill get a compression test done, and post the results back here for a second opinion. Thanks!

Jo

If it doesnt feel down on power I would just continue to run the motor into the ground, it is over $3k for one of them to be fixed up, so yeah, you don't wanna get to into it..

I got the compression test done today, these are the results:

Davoe gave me the desired numbers:
Desirable- 2746kpa
minimum- 1961kpa
maximum variation between cylinders 196kpa

And these are what came from the compression test today:
Cylinder 1: 1708kpa (350psi) 88% leakage to sump
Cylinder 2: 1611kpa (330psi) 90% leakage to sump
Cylinder 3: 1806kpa (370psi) 86% leakage to sump
Cylinder 4: 1806kpa (370psi) 84% leakage to sump & inlet
Cylinder 5: 1855kpa (380psi) 76% leakage to sump
Cylinder 6: 1855kpa (380psi) 44% leakage to sump & inlet

So the engine is beyond the recovery stage, and almost within the maximum variation. Any opinions? Im going to tassie for easter, and Cape York in June. I shouldnt have any problems doing that, should I?

Jo

If you didn't do the stall test during the training exercise you'd be none the wiser on the engine cond - right?. Go on the trip and then worry about it.

Even if you did break down on your hols, which I doubt, have the vehicle transported home then decide what to do with the engine.