Pulled a stupid (valve adjustment gone bad)... - BMW M5 Forum and M6 Forums

Go Back   BMW M5 Forum and M6 Forums > BMW M5, M5 Touring, M6 and Z8 Forums > E34 M5 Discussion

E34 M5 Discussion 1988-1995 Sedan and Touring

LinkBack Thread Tools Rate Thread Display Modes
Old 1st September 2009, 07:14   #1
Member, P500 Sport, MDM on (>800)
AMP's Avatar
Join Date: Feb 2001
Location: Tucson, AZ

Garage: '08 M6 Coupe - Stratus Gray

Sales Feedback: (0)

Thanks: 22
Thanked 342 Times in 187 Posts
Pulled a stupid (valve adjustment gone bad)...

I took on the valve adjustment on my S38B36 today. Everything was going great aside from the fact that ALL 24 valves are out of spec. I need to look through the previous owner's service records, but I'm pretty confident that the valves have not been adjusted in this century.

In advance of my new shims showing up I decided to shuffle the few that could still be used in other positions. I had everything mapped out and knew where everything was going to go. Of course I got distracted when a customer came in and walked away from the car with a rag that had two shims wrapped up in it. This got left in my office and when I returned to the car I found no leftovers and completely forgot about the two shims sitting on my desk.

So I move on to the next set and rotate the engine.... adjust a couple more... rotate some more and then it just stops. I look around and realize that I left the shims (yep, the one's sitting on my desk) out of both E4 positions. The cam lobe has made a rotation through the bucket and is now getting caught up on the edge of the bucket. CRAP!

Through some very careful maneuvering I manage to free the cam from the bucket and get the shims in place. Unfortunately, the damage is done. On either outer edge of both lobes (right at the apex) I've managed to grind away a bit of mateial... maybe 1/2mm.

So now I'm sitting here wondering if I've completely hosed the cam or if I'm OK. Sure, the primary contact point is the center of the lobe (undamaged), but have I created a weak point? Have I created an irregular edge which will catch the shim when the engine is at speed and eject it? Should I just put it back together (with all of the proper shims) and see what happens?

'12 Alpina B7 SWB Alpina Blue/Black (On Order)
'11 1M Coupe Alpine White/Black
'08 M6 Coupe Stratus/Black
'03 M5 Sedan Imola Red/Black (gone, but not forgotten)
'93 M5 Sedan (3.6) Sterling Silver/Black
'11 550i Dark Graphite/Oyster-Black (wife's car)

Past: '11 M3 Coupe | '08 M5 Sedan | '10 M3 Coupe | '07 M6 Coupe | '07 Z4 M Coupe | '04 M3 Coupe | '02 M5 Sedan | '95 M3 Coupe -- x2
AMP is offline   Reply With Quote Quick reply to this message
Old 1st September 2009, 08:50   #2
M5 Expert (>4000)
Join Date: Aug 2006
Location: Suffolk

Garage: E34 M5 3.6 Sebring Grey

Sales Feedback: (0)

Thanks: 1,073
Thanked 670 Times in 538 Posts
What a shame ......... Distraction can be the biggest source of destruction ...... we have regular tea breaks at our workshops and it is so easy to walk away part way through a job and have something like this happen .

I was recently part way through an oil change , left the oil draining , went for a tea and returned to the car , totally forgetting the fact that I hadn't replaced the sump plug , and promptly poured 5 litres of oil into the engine ....... thankfully , I'd left the drain tray underneath !

Meanwhile , back to your problem , it would be a brave man that would bolt the engine back up with compromised cam lobes .

It may be an opportunity to fit a set of Shricks , although I have a set of stock 3.6 cams if you would rather stay original ......shipping can be a bit painful though .

Better a day as a tiger than a lifetime as a sheep !

91 Sebring 3.6 | E28 UK RHD M5 | E34 UK RHD 3.8 | E34 M5 Touring | E24 M635CSi UK RHD

davidoli is offline   Reply With Quote Quick reply to this message
Old 4th September 2009, 16:20   #3
Member, P500 Sport, MDM on (>800)
AMP's Avatar
Join Date: Feb 2001
Location: Tucson, AZ

Garage: '08 M6 Coupe - Stratus Gray

Sales Feedback: (0)

Thanks: 22
Thanked 342 Times in 187 Posts
Well, I finished the valve adjustment and bolted the cover back on. Fired her up and crossed my fingers. Nothing went BOOM so that was a good sign.

The valve train is quieter, but not as much of a difference as I had expected. Engine performance on the other hand is much improved. Power delivery seems much more predictable and the motor revs up much more freely than it did before. I'm still convinced that my cats are clogging up, but don't want to tackle that until the following is taken care of.....

Now I just need to sort out all of the carbon that has built up on the pistons and I should be all set. I guess the previous owner didn't really "drive" the car. We ran a couple of cans of BG Injection System Cleaner through the fuel rail via canister and that made a dent (literally -- there is now a dent in the carbon layer) but after talking with my BG rep I don't want to try anything more drastic than that. I guess I'll be running many cans of 44K through the tank until it clears up. On the bright side the carbon appears to be limited to the piston tops and the upper part of the combustion chamber. All of the intake valves look clean and the exhaust valves that I could see with the borescope looked clean as well.
AMP is offline   Reply With Quote Quick reply to this message
Old 4th September 2009, 19:10   #4
m5board.comoholic (>1000 posts)
Lantz's Avatar
Join Date: Sep 2006
Location: London/Sweden/Brussels

Garage: BMW M5 E34 Granitsilber Metallic 3.8

Sales Feedback: (0)

Thanks: 226
Thanked 123 Times in 93 Posts
I think carbon build up on the pistons is pretty standard in any engine. I have yet to see a well used engine (inc S38's) with clean pistons, though it is important to give the car a few good high rpm pulls to clear excess carbon build up. Using a high quality fuel with plenty of cleaning agents, like Vpower, will help too. If I were you I would not be too concerned...
3.8 E34 M5
18" BBS LM
76mm Eisenmann Race
Lantz is offline   Reply With Quote Quick reply to this message


Quick Reply

Register Now

In order to be able to post messages on the BMW M5 Forum and M6 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Valve Adjustment RudeDumbAmerican E34 M5 Discussion 7 31st October 2008 19:34
B11 3.5 Valve Adjustment JeffCullen ALPINABoard.com | BMW Alpina Discussion 5 3rd September 2007 19:16
B6 2.8 valve adjustment b6driver ALPINABoard.com | BMW Alpina Discussion 1 3rd February 2004 16:39
Valve Adjustment (UK) e34m5uk E34 M5 Discussion 18 27th October 2003 22:11
Valve clearance adjustment mikek E34 M5 Discussion 3 29th January 2002 21:28


All times are GMT +2. The time now is 11:17.

Everything Copyright 2000-2008. Do not use ANYTHING from this site without written permission. All images, graphics, sound files, video files and text appearing on this web site are the exclusive property of m5board.com and are protected under international copyright laws. All images, graphics, sound files, video files and text on this site are for on-screen and on-site viewing and listening only. No part of this web site may be reproduced, copied, saved, stored, manipulated, or used in any form for personal or commercial purposes without the prior written permission of m5board.com. Use of any image or graphic as the basis for another photographic concept or illustration is a violation of the copyright. Any copyright infringement will be prosecuted to the full extent of federal and international copyright laws. M5board.com is an enthusiast board and we don't condone any dangerous activity. Our airfield events are completely safe based on years of experience, we conduct them during clear visibility with mature participants that have several years of experience with high-performance automobiles, large unobstructed run-off zones on sealed off private former military airbases and we clearly mark the braking zones. If inexperienced with high speed driving we do not recommend organizing your own event but attending a high-performance driving school. The use of the term "BMW" on this site is for reference only, and does not imply any connection between m5board.com and BMW AG or BMW North America.