VCU data

I refitted my VCU and props in readiness for my WoF [your MoT] test and out of interest took it for a test drive. About 19km in total.

The FL drove well, no noises out of the ordinary... Course was highway, then small rural sealed road up a gentle hill, about 2km then a 3km decent on a gravel [metalled/dirt] road. Before rejoining the highway I pulled over and felt the VCU. At the top of the hill it was cool to the touch. At the bottom of the hill I did some circle driving in an open area on cropped grass. I can easily idle around both left and right turns on lock in 1st gear. I can also do them in reverse but it is stiffer. If I try to start off on lock [L or R] the motor will stall. But if I begin with the wheels straight then apply full lock in reverse no problems. After this the VCU was only warm to touch.

From there I drove on the highway toward home and pulled over and explored some short but steepish slopes beside the lake there. When in 2WD I couldn't get up, but can with 4WD no problems. I did about eight of these up and down cycles in first gear then felt the VCU again, well it was warmer but not hot and I could easily keep my hand on it quite comfortably.

Later today I'll do the one wheel up test. Cold first then after the same drive I'll repeat it. I'll put my findings on this thread later to day.

Well I did a series of one wheel up tests, five essentially when cold, I had driven about 2km and none over 50kmh and it had sat for about 45 minutes. I did another five after driving the course I did yesterday 19km or so.

Weather, high overcast, some light rail showers, very little wind and about 12ºC.

I used a 1255mm piece of square aluminium tube as my bar, a 32mm socket, my 1/2" ratchet drive and 3 plastic bottles with just under 8L of water. I put a screw in at the 1200mm point to hang the bottles on.

Timed from the 45º mark to horizontal rest [90º]

Results - COLD
#1 - 2.00
#1 - 2.02
#2 - 2.08
#3 - 2.09
#4 - 2.00

Averages out at 2.03 rounded.

Results - Warm
#1 - 1.29
#2 - 1.35
#3 - 1.41
#4 - 1.46
#5 - 1.51

Averages out at 1.40.

Interesting in the second set of tests the time got longer as the VCU cooled.

Interesting stuff Alan - I was wondering if the VCU wasn't getting hot because its so tight there's not a lot of movement inside it to generate any heat.

Could your new Bridgestones have added to the ability of the car to climb that slope?

GrumpyGel said:

Interesting stuff Alan - I was wondering if the VCU wasn't getting hot because its so tight there's not a lot of movement inside it to generate any heat.

Could your new Bridgestones have added to the ability of the car to climb that slope?

Click to expand...

Tyres, noooo, I tried it with them in 2WD and could only get part way up. My stiff VCU was put on for my WoF - passed! Have now taken prop' shaft assembly off again.

It may be that the timings in the hot test got longer as the warm oil was moved around all the plates, therefore giving more surface contact and more friction.

I've been keeping a close eye on my VCU for a while now because of a few of the various symptoms occurring. Now, I know mine is knackered, but not once as it ever felt hot to the touch. Barely even warm to be honest. It has had to go though, for peace of mind if nothing else.

Look up the sheering effect and what happens inside a vcu and this will answer yer questions.