M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: Boyracer on October 12, 2007, 07:03:13 AM

Title: Stock hydraulic lifter -> solid conversion!
Post by: Boyracer on October 12, 2007, 07:03:13 AM

Hi there!

I mentioned on my build thread about M42 race engine that used stock hydraulic lifters that were converted to solids. I have not asked the team how they did it but here is info on how to perform it on Rover K series engine:

http://www.sandsmuseum.com/cars/elise/thecar/engine/kseriesmods/k.html

http://www.sandsmuseum.com/cars/elise/thecar/engine/kseriesmods/ktappet.htm

(http://www.sandsmuseum.com/cars/elise/thecar/engine/kseriesmods/ktapshim.jfif)

Not sure what is the weight saving with stock rover K Series lifter (no idea about original weight) but it seems to be around 10-20 grams / lifter.

In M42 engines:

E30 78 gram -> 58 - 68 gram
E36 67 gram -> 47 - 57 gram

That is quite respectable weight loss. What is more important you can rev shite out of the engine without worrying about lifters (you still do have to worry about bottom end etc). In Rover it seems to be safe upto 8500 and the finnish race team is ok to 9000 in M42. This is the "good" kind of solid lifter, having the shim under the bucket so no risk of it flying off in high revs like in S14/S50 or other BMW M engines.

It should be quite cheap mod also. What you need is a small part machined to fit the lifter and then shave off material from the shim to adjust the valve clearance. And you have to solder shut the oil hole in the lifter oil groove.

Also lots of good 16 valve engine tuning info in general in that first link, well worth the look.

Can anyone pull one BMW lifter apart to see if it looks similar inside? Mine are now some 400 km away and I can do it maybe in two weeks time :(

Title: Stock hydraulic lifter -> solid conversion!
Post by: cecotto on October 12, 2007, 01:42:25 PM

Very nice description of the project, and nice find!

I'd just like to make a remark about the solid conversion (in general). I'm all for converting if you're doing a tuning project. (I have converted my engine too)

But before starting the conversion you need to be sure your cams are made for mechanical operation. There is a significant difference between hydraulic and mechanical cams.

Here you see my inlet-cam(mechanical) compared to a standard-inlet(Hydraulic)
(http://m42club.com/forums/attachment.php?attachmentid=868&stc=1&thumb=1&d=1173060247)

Notice that the hydraulic cam is virtually without ramps. However you can see a very little ramp compared to the mechanical profile. But when you count in the valve lash you pretty much move out of this ramp. This will result in the valve hammering into the seat, this may introduce valve bounce which will loose power. This hammering may also result in fatique with broken valves smashed seats and maby worse.

BTW. Schrick offers some spacers designed for converting hydraulic buckets to mechanical. They come in different heights.