M110 valves = Intake .08mm Exh=.20 ?

[wolf_walker]

This is tighter than the service manuals .10 and .25. The tighter limits are on the plate under hood on my 73 280, am I just the last to notice this?

[79Mercy]

I have .10mm and .25mm on the sticker under my hood.

[wolf_walker]

So, the question is were the earlier cars different, or did they change there collective German minds later on? Mine for 100% sure say .08 and .20.

[79Mercy]

an m110 is an m110, so I would asume everyone would follow the .10mm and .25mm guide lines.

What do you mean by plate, all I have is a black sticker.

[wolf_walker]

on the pass side front top of the front core support there is a metal data plate with timing and valve specs. This is a 73 w114.

[79Mercy]

I guess I would go with the .8mm and .20mm since thats what on the plate. Make sure that is the specs for when the motor is cold.

[wolf_walker]

Yeah it specifys cold on there. I did so and we'll see how it runs. They were all loose, again. This is the 3rd adjustment in 1500 miles, they were way tight when I got the car.

[79Mercy]

does your m110 have any oil leaks? has the motor been rebuilt?

[wolf_walker]

To my knowledge, it's original with 118K, has about 4-5 degrees of chain stretch using the quick method to check, and uses no oil but weeps some here and there. No drips. I'm still fighting with this darn solex carb, it's perpetually lean on the primary side, was badly warped. Has a good hot idle and good wide open throttle though, which is more than a lot of them apparently manage.

[wolf_walker]

Been running the tighter listed specs since the 25th, also switched to an old favorite oil of mine, Rotella 5w40 synthetic. Car seems happy, valve noise is low, no smoke, no oil usage. Also, the noise on warm re-start I thought might be chain slap is much less, weather it's from the oil doing happy things to the tensioner or from the tighter valves I don't know. I do have a suspicion that it was not chain slap, but actually some sort of detonation from the crappy carb on a heat-soaked motor.
Or, I might be wrong. But chain stretch was 5 degrees if that and the motor is clean otherwise. I for some reason don't trust it any further than I could throw it still. We'll see.

[79Mercy]

I have an oil question. 5W40 means that its 5 wieght when hot and 40 when cold, correct? The lower the number the thinner the oil, correct?

Hows your oil pressure running that oil?

[wolf_walker]

Yes to the weight.

I call the oil pressure very good for an old merc.
Hot at idle is about 18-20psi, any sort of increased RPM and it pegs the gauge. The oil pressure is more stable at very hot temps, such as after a long highway run, with the synthetic, also the engine coolant runs slightly cooler on the gauge. I've observed this before going from relatively heavy (15w40) dino oil to this weight synthetic on a handful of older motors. And plus it's $19 a gallon, which is a real plus to me.

[79Mercy]

Im running 20W50 Castrol GTX.

Did your oil pressure go down when you changed from 15W40 to 5W40?

[wolf_walker]

Nope, not a bit. In theory, when hot, they are about the same weight. There is a lot of gray area in there though for manufacturers to play around with published "weight" of oil. I really think this thing would be fine with a lighter oil, least this time of year. But that's just a hunch.

[cheapold280ce]

79 mercy, 20W50 is find in FL where you live. here in Northern VA I run 10W40 GTX in winter as it gets into the teens but not below zero. 10W stands for 10 weight winter 40 weight hot. I didn't see a drop in oil pressure but my car seems to smoke more though. In summer I bump it back to 20W50 GTX