Correct valve clearance m20. Solution to ticking e30

[whodwho]

High mileage engines can have dished valve stems and gives a false measurement as the feeler gauge bridges the dished part.

There isn't much you can do when like this other that use a dial indicator or compensate gauge thickness for the rocker ratio and use the feeler gauge on the cam lobe.

Also to be clear on the post title, there will always be "ticking" with manually adjusted valves

[digger]

rocker ratio is approx 1.5 when on base circle so measurement at the cam should be 0.0065-0.007".

here is a plot of the inlet opening and exhaust closing ramps at overlap. you can see that if you go looser than 0.25mm on inlet you are starting to shock the valve train more than the cam is designed to have and that will be noisier, even below 0.25mm should be noticeably quieter, however on the exhaust you could go to 0.3mm and youre still on the linear ramp portion.

you can also see that adjustments in clearance will affect crank angle-lift areas slighty which potentially could improve midrange and top end power a smidge at the expense of bottom end power and idle quality (slightly). going to 0.20mm gives 6 degrees more seat-seat duration.

you would be better off with a larger duration cam with proper clearances as there would be much better crank angle-lift area for the same seat to seat duration but ofcourse this cost money compared to simply using a thinner feeler gauge.

[jeffnhiscars]

How does anyone know this without their brain exploding :)

rocker ratio is approx 1.5 when on base circle so measurement at the cam should be 0.0065-0.007".

here is a plot of the inlet opening and exhaust closing ramps at overlap. you can see that if you go looser than 0.25mm on inlet you are starting to shock the valve train more than the cam is designed to have and that will be noisier, even below 0.25mm should be noticeably quieter, however on the exhaust you could go to 0.3mm and youre still on the linear ramp portion.

you can also see that adjustments in clearance will affect crank angle-lift areas slighty which potentially could improve midrange and top end power at the expense of bottom end power and idle quality (slightly). going to 0.20mm gives 6 degrees more seat-seat duration.

you would be better off with a larger duration cam with proper clearances as there would be much better crank angle-lift area for the same seat to seat duration but ofcourse this cost money compared to simply using a thinner feeler gauge.

[FrostedE30]

Well my engine has more than 200k miles so I think .007" will be too tight an burn a valve, so do you guys think adjust at the cam at .008" for intake and .009" for exhaust would be okay?

[digger]

Well my engine has more than 200k miles so I think .007" will be too tight an burn a valve, so do you guys think adjust at the cam at .008" for intake and .009" for exhaust would be okay?

how the hell are you going to burn a valve at 0.007" lol

[FrostedE30]

how the hell are you going to burn a valve at 0.007" lol

that doesn't really answer the question lol. So what would your recommendations be? I've adjust my valves at the eccentrics @ .010" but it still ticks pretty loud.

[digger]

0.008in/0.009ex will be fine, wont idle as nice though. but has zero risk of burning valves.

[BMWManiac]

How often do you adjust the valves? Every time you do timing belt? Every year? Every 30k/60k miles?

[estoguy]

Valve adjustment check is every 15 K miles (24,000 km).

You might want to refer to this thread: http://www.r3vlimited.com/board/showthread.php?t=364705

[FrostedE30]

0.008in/0.009ex will be fine, wont idle as nice though. but has zero risk of burning valves.

wont idle as nice as the valves being adjusted to .010"? or because it's adjusted to .008"in and .009"ex? Sorry for asking so much questions.

[digger]

wont idle as nice as the valves being adjusted to .010"? or because it's adjusted to .008"in and .009"ex? Sorry for asking so much questions.

in general tighter settings degrade idle quality a little bit especially running on stock motronic. The sky wont fall down but its noticeable/perceivable. having slightly different inlet and exhaust settings is not inherently an issue

[richardb]

Here's a quick video guide I just made! Hope it helps.

[SLEEPYDUB]

.Does having a Schrick 284/272 cam make a difference at all? I'm planning on refreshing the valve train next winter so I'll be replacing worn components then (unless something is really whacked out)

Looking for answers to this quesiton. I am running a 280/274 cam and after putting the head on and setting to .009 the engine barely runs at all and is ticking like crazy. Please advise

[digger]

schrick recommend 0.25mm. i would set it at that. if it doesnt run properly (and the clearances are set correctly)there is some other issue(s) you need to start looking for/diagnosing

[ELVA164]

Wait, who is dyno?

lol