Author Topic: Are valve guides screwed in, pushed in or part of head itself? (Read 3978 times)

Hondo · « **on:** January 22, 2009, 11:02:18 PM »

Which leads me to part two: to change out is it a simple screw out, push out, or do I need to find a milling machine and drill the old one out and push in the replacement?

1991 E30 M42 · « **Reply #1 on:** January 23, 2009, 01:43:40 AM »

take it to a machine shop, its pressed in

ps. good luck finding new ones, it took me a couple months to find new ones

peerless · « **Reply #2 on:** January 23, 2009, 10:39:33 AM »

Are you sure they need to be changed? The M42 head design has the valve almost straight up and down so there is very little side loads to where them out. Then you have cam over bucket lifter design which also eliminates and scrubbing and side to side loads.

Of the few M42's I have worked with the heads where trouble free with very little if any guide wear. Valve grind, surface and new stem seals was all that was needed. Also the valve guides must be pressed out and pressed in. Technically you are supposed to heat the head to a temperature of like 400*F or some shit. But a lot of shops won't do that for the simple reason is sometimes the valve seats fall out when you heat them up so most do them cold.

But if you really need them, RM European has them. They are about $4 each. Also the ones listed here are for the early E30 M42. The later M42's went to 6mm valve stem size.

Quote

Part Number: 09-0387-860 Valve Guide I.D. 7 mm (12.56 mm) Manufacturer: CANYON Application: 318i M42 (16 Per Car) E30 318iC (16 Per Car) E30
Yes 0.00 $3.83 Quantity: * *

Hondo · « **Reply #3 on:** January 23, 2009, 12:10:38 PM »

someone changed the timing chain and one of the cams is in the wrong place. It idles fine. when I turn it by hand a valve in #1 cylinder is bent I can feel it. I haven't pulled it apart yet I just figured if the valve bent, the guide was toast.

Boyracer · « **Reply #4 on:** January 23, 2009, 02:14:07 PM »

BMW defines valve guide wear to be measured in a way that top of the valve stem is at same height as valve guide seal. Then valve is rocked sideways and movement is measured. Anything over 1 mm means guide must be changed or oversize valves fitted and guides reamed etc.

In my spare head there was around 2 mm movement so they should be changed.

Appletree IS supercharged · « **Reply #5 on:** February 25, 2009, 10:47:34 AM »

Anyone know what date the valves changed to the 6mm stem size? would new 6mm stem size guides fit in and old head?

colin86325 · « **Reply #6 on:** February 25, 2009, 06:50:11 PM »

Starting in 9/1992 valves were 6mm.

http://bmwfans.info/original/E36/Cou/318is-M42/USA/L/M/1994/02/mg-11/ill-11_1143/

bwawuz02 · « **Reply #7 on:** June 30, 2011, 11:58:10 AM »

just ordered a set from MM. Jim was super helpful