Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
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.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> So I adjusted the valves and..., help out a newbie
danimal
post Sep 18 2004, 06:30 PM
Post #1


Newbie
*

Group: Members
Posts: 4
Joined: 18-September 04
From: Monrovia, CA
Member No.: 2,780



havent had the car for long, it was backfiring so I figured I'd adjust the valves.
Pretty sure I did everything right. I re-checked 4 times. Now it runs ok but it's really loud. I know some valve clatter is ok, but it sounds like a diesel rabbit.
I know it's hard to recreate a sound on a forum post but it sounds like something is pounding.
Is this normal or did I miss something.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
tracks914
post Sep 18 2004, 06:44 PM
Post #2


Canadian Member
****

Group: Benefactors
Posts: 2,083
Joined: 15-January 03
From: Timmins, Ontario, Canada
Member No.: 153
Region Association: None



Any chatter should go away once the engine is warmed up.
How much clearance did you leave? I leave about .004" on both intake and exhaust.
Did you also rotate the engine and check the cam wear all the way around? I found on one of mine, when I adjusted it at TDC, it was OK but on the opposite side of the cam (as TDC) I had about .004" more wear. This meant my cam was worn unevenly and there isn't much you can do about that but to replace it.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SGB
post Sep 18 2004, 08:25 PM
Post #3


just visiting
****

Group: Members
Posts: 4,086
Joined: 8-March 03
From: Huntsville, AL
Member No.: 404
Region Association: South East States



Do you have any idea if it is a stock cam. I replaced mine with a hydraulic one made by Webcam. It is (or was) a fairly common improvement at one time, although there is now greater debate on the value provided. The idea is to eliminate or reduce valve adjustment every 3k miles. They tend to be noisy for a few seconds if the engine has been sitting for more than a day or two before it is started. More importantly, they are hard to set properly. I messed mine up tightening 'em up too much, trying to make 'em "quiet", but now I finally did get them set right. Do a compression test. When I did I found out I had low compression in two cylinders- my intakes were to tight and what I thought was valve noise was actually combustion leaking into the intake manifold. If you think yours are hydro, the important thing is to commpress the oil out of the lifter bfore adjusting. Each lifter has a little oil chamber that is held open with a light pressure spring inside. I went round squishing each pushrod down, then tightened the adjuster screws about 1/4 turn past when I felt the spring in the lifter start to resist. Then I ran the engine at 2000 rpm for about 30 sec. I went round to each valve again, checking to see if the oil chamber in the lifter had pumped full. With hydro valves there is no "clearance". The oil in the little chamber pushes the pushrod up against the rocker even when cold, so if there was any "clearance" I tightened the screw about 1/16th turn. After another "pump-up" run to 2k rpm for a bit, I checkd again. Then I did a final compression check to make sure there were not ant too tight. I can't really tell you how to determine if yer car has this cam and lifters except to see if you can compress a pushrod and it feels squishy or pull off a rocker assembly so you can take out a pushrod and pushrod tube atleast far enough to get a lifter out and see if it has holes in it...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 15th May 2024 - 03:49 AM