![]() |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
![]() |
Dave Blackburn |
![]()
Post
#1
|
Member ![]() ![]() Group: Members Posts: 116 Joined: 9-April 03 From: Issaquah, Wa Member No.: 551 ![]() |
Ok. So I have my engine out and decided to take one head off and check some things out. Everything looked great!
While the one head was off I checked valve lash on the opposite side. It was about .012". When I put the other head back on and the valve train back together it went back to around .006". I adjusted all the valves to the .006" @ TDC, but noticed the valve lash will become larger (up to .009") when I check it at different spots through out the cam rotation. It seems to be related to the load from the valve springs on the opposite side of the cam from where I am measuring. Is this normal? Is this because of worn cam bearings? Something else? Any thoughts would be great. Thanks, Dave |
![]() ![]() |
Bleyseng |
![]()
Post
#2
|
Aircooled Baby! ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Group: Members Posts: 13,036 Joined: 27-December 02 From: Seattle, Washington (for now) Member No.: 24 Region Association: Pacific Northwest ![]() |
QUOTE(Dave Blackburn @ May 20 2003, 10:19 AM) Ok. So I have my engine out and decided to take one head off and check some things out. Everything looked great! While the one head was off I checked valve lash on the opposite side. It was about .012". When I put the other head back on and the valve train back together it went back to around .006". I adjusted all the valves to the .006" @ TDC, but noticed the valve lash will become larger (up to .009") when I check it at different spots through out the cam rotation. It seems to be related to the load from the valve springs on the opposite side of the cam from where I am measuring. Is this normal? Is this because of worn cam bearings? Something else? Any thoughts would be great. Thanks, Dave If you have one head off you can't adjust the valves because the motor will stretch when you put the other head back on. When you adjust the valves @ TDC you can ONLY measure that one. You must first set the engine to TDC for number one cylinder, then adjust it to .006. The rotate the engine to number four top of the compression stroke by looking at the dizzy (cap off) and seeing where the rotor lines up with the firing of spark plug number four. Then adjust it and rotate the engine to number three's top of compression stroke the number two's. At the top of each cylinder's compression stroke is where you adjust the valves for ONLY that cylinder. That's when both intake and exhaust valves are at rest and seated. Other cylinders valves will be opening and closing so you can't check them. You can rotate the motor and check number ones intake valve when it's seated during other parts of it cycle but it will be off clearance. The motor moves when its rotating due to the stresses of the valves opening and closing. So only adjust the valves at the top of each cylinders compression stroke for accuracy. Geoff |
![]() ![]() |
![]() |
Lo-Fi Version | Time is now: 9th May 2025 - 12:42 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |