Adjusting the valves with different valve lash.
Adjusting the valves with different valve lash.
forkintheforest
08-07-2008, 08:46 AM #1What would happen if you added a little extra clearance when adjusting the valves? I'm talking about like Intake .25mm and Exhaust .45mm would it improve anything. I remember reading somewhere the more valve lash there is the louder the valve sound would be. And what would happen if you only increased the valve lash on the exhaust side of things. Would that create a better scavenging effect? Just wondering. Thanks
forkintheforest
08-08-2008, 06:11 AM #3Annnd, if you adjusted them tighter then spec it would be better performance? Or only in theory because, they would be slightly in the combustion chamber on the combustion stroke and it would burn the valves right? Something like that?
forkintheforest Annnd, if you adjusted them tighter then spec it would be better performance? Or only in theory because, they would be slightly in the combustion chamber on the combustion stroke and it would burn the valves right? Something like that?Nope to tight and you end up with open valves during combustion. Lower compression. Less HP.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
forkintheforest Annnd, if you adjusted them tighter then spec it would be better performance? Or only in theory because, they would be slightly in the combustion chamber on the combustion stroke and it would burn the valves right? Something like that?Nope to tight and you end up with open valves during combustion. Lower compression. Less HP.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
ForcedInduction
08-09-2008, 05:17 AM
#5
Winmutt got it right. The lash specs MB chose are for a reason. As the engine heats up the gap they set closes to almost nothing. Too loose and the valves are open for less time, too tight and the valves are held slightly open. Both result in reduced power, tight lash can cause accelerated cam wear.
forkintheforest
08-09-2008, 11:08 PM #6Ok, cool. Just wondering you know. Mainly cause I thought about how if you buy aftermarket cams they have all these different ratings. and I thought "Hmm, I wonder if you can do basically the same thing just by adjusting the clearance a little differently. But, since you told me either way I'd be mucking it up I'll go ahead and leave them at the stock clearance. Btw, whats "excessive" cam wear?
Here are some examples.
![[Image: Worncam1178.jpg]](http://members.cox.net/lnewcomb99/Pics/Worncam1178.jpg)
![[Image: worncamalertbadcam.jpg]](http://members.cox.net/lnewcomb99/Pics/worncamalertbadcam.jpg)
ForcedInduction
08-10-2008, 05:08 AM
#7
A shape that is not like an egg, has grooves, pits or discoloration (bluing from heat).
Here are some examples.
Fork, most after market cams have longer lobes allowing for more gasses to pass through during the specified interval. Others also change the valve timing as well.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
lolz wow is that second pic an om6XX?
Fork, most after market cams have longer lobes allowing for more gasses to pass through during the specified interval. Others also change the valve timing as well.
1987 300D Sturmmachine
1991 300D Nearly Perfect
1985 300D Weekend/Camping/Dog car
1974 L508D Motoroam Monarch "NightMare"
OBK #42
winmutt Fork, most after market cams have longer lobes allowing for more gasses to pass through during the specified interval.
Mercedes did this with the OM617a in 1980 when they increased the lift which gave enough airflow for 13hp (110-123hp).
ForcedInduction
08-10-2008, 05:14 PM
#9
winmutt Fork, most after market cams have longer lobes allowing for more gasses to pass through during the specified interval.
Mercedes did this with the OM617a in 1980 when they increased the lift which gave enough airflow for 13hp (110-123hp).
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