Don't adjust your valves in the cold

[Brewmaster]

As said in the title, don't adjust your valves in the cold.

I had my heads off and in the garage. So I figured a nice warm place to work on them would be much better.

So I set up a work bench in the dining room and brought the heads in and started to check the valves.

I did all the measurements while the heads were still pretty cold (~5 C). I then had some dinner and double checked my measurements. They all changed by about 0.020 mm. This was very surprising to me.

Additionally when I first brought them in and did the measurements there was a bit of drag caused by the closers. I run them very tight due to the engine seeing mostly near redline rpms. This bothered me as I always set them as close as possible but with NO resistance if you spin the cams with your fingers.

When I checked them again when the heads warmed up to room temp there was no resistance to spinning the cams.

Just some observations I made, take them as you want but I will be adjusting my valves from now on at room temp. Or is that average temp for Italy.......

[stevel]

Interesting, 20 micron change just through what, 15 deg C change in temp sounds a helluva lot..........if that was due to different rates of expansion between steel and alloy, there must be a huge change from cold to operating temperature?

Ponder that one..............where's Phil da Ghost?

[thumper749]

Surely that is why there are tollerances, the true temp. is when the engine is at full running temp. that is when everything needs to be "Just So"

0.020mm is not a lot of error, I'm sure most mechanics (even Ducati mechanics) would be glad to get near that!!!

[ducati2242]

Originally Posted by thumper749

Surely that is why there are tollerances, the true temp. is when the engine is at full running temp. that is when everything needs to be "Just So"

0.020mm is not a lot of error, I'm sure most mechanics (even Ducati mechanics) would be glad to get near that!!!

Closers get slacker with heat . tighter the better.