Valves problem
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 48
Likes: 0
From: Luxembourg europe
Valves problem
Hi there
I have some strange problem with the valves, I spent the last 3 weekends trying to resolve it and I just don't know what it is anymore. I put a new cam in and new headers on, in the shop they set it more or less ok. However the engine just doesn't run smooth. RPM are not stable, vacuum advance also goes weird. so I started fiddling with the valve settings, vacuum is higher, runs a bit smoother but now some valve is "slapping" ( real loud tapping noise..). I thought a hydraulic lifter was broken so I replaced all of them, no difference, I set the valves like said in the book, tighten the nut until the pushrods don't turn anymore and then add 1 turn. Then the engine does not run smooth, and 1 valve slaps. when I set the valves just so the pushrods don't turn anymore and I don't add the 1 turn the engine runs quite good, but the one valve still slaps. Any help is appreciated, I am loosing my nerve here..
I have some strange problem with the valves, I spent the last 3 weekends trying to resolve it and I just don't know what it is anymore. I put a new cam in and new headers on, in the shop they set it more or less ok. However the engine just doesn't run smooth. RPM are not stable, vacuum advance also goes weird. so I started fiddling with the valve settings, vacuum is higher, runs a bit smoother but now some valve is "slapping" ( real loud tapping noise..). I thought a hydraulic lifter was broken so I replaced all of them, no difference, I set the valves like said in the book, tighten the nut until the pushrods don't turn anymore and then add 1 turn. Then the engine does not run smooth, and 1 valve slaps. when I set the valves just so the pushrods don't turn anymore and I don't add the 1 turn the engine runs quite good, but the one valve still slaps. Any help is appreciated, I am loosing my nerve here..
Advanced
Joined: Apr 2008
Posts: 91
Likes: 0
From: Stockton California
There is a way to see if it is indeed your valve adjustment or something else, but it is messy.
Get your car warmed up, shut it off and remove valve covers. Turn the car back on and find out which valve is making the noise then loosen the rocker arm nut until your engine stumbles and tighten it slowly 3/4 turn. If the noise persists throughout the process, then you can rule out valve adjustment and start looking elsewhere.
Be advised that this is a messy process and oil will be flying everywhere so be prepared to work as quickly as possible and have all your tools ready to go.
Get your car warmed up, shut it off and remove valve covers. Turn the car back on and find out which valve is making the noise then loosen the rocker arm nut until your engine stumbles and tighten it slowly 3/4 turn. If the noise persists throughout the process, then you can rule out valve adjustment and start looking elsewhere.
Be advised that this is a messy process and oil will be flying everywhere so be prepared to work as quickly as possible and have all your tools ready to go.
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 48
Likes: 0
From: Luxembourg europe
I think this is the last possibility, I know what side it is on but not which valve. should I tighten or loosen? why does it make noise anyway? what else could it be? it worked fine before, maybe a bit low on compression but no noise.
Racer
Joined: Apr 2006
Posts: 340
Likes: 0
From: Warrensburg MO
I set the valves like said in the book, tighten the nut until the pushrods don't turn anymore and then add 1 turn. Then the engine does not run smooth, and 1 valve slaps. when I set the valves just so the pushrods don't turn anymore and I don't add the 1 turn the engine runs quite good, but the one valve still slaps. Any help is appreciated, I am loosing my nerve here..
Tommy
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 48
Likes: 0
From: Luxembourg europe
yup you were right! 
I just checked the headers, almost all screws were loose and one was missing !! I didn't think of checking this because I expected the shop to do the job right..
p.s. always double check, and don't rely on new parts they may be faulty too.. and service is getting worse every day. had to get that out.
Thanks guys.
I just checked the headers, almost all screws were loose and one was missing !! I didn't think of checking this because I expected the shop to do the job right..
p.s. always double check, and don't rely on new parts they may be faulty too.. and service is getting worse every day. had to get that out.
Thanks guys.
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Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
Just because the header bolts were loose, doesnt mean that the shop did a bad job.
Header bolts are notorious for loosening back up at least a couple of times after you installl them.
Be sure to check them again, even after you tighten them this time.
After a week or so they will stay tight.
Header bolts are notorious for loosening back up at least a couple of times after you installl them.
Be sure to check them again, even after you tighten them this time.
After a week or so they will stay tight.
Le Mans Master
Joined: May 2006
Posts: 7,708
Likes: 266
From: indy indiana
NO<NO<NO<NO, you do NOT tighten untill the pushrod doesnt turn! great way to bend pushrods,burn a valve,wipe out a cam shaft! You tighten untill resistance is felt..thats it. Then you tighten 1/2 to 1 more turn....SLOWLEY,a 1/4 turn at a time. Hope ou havent bent anthing,,good luck.
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 48
Likes: 0
From: Luxembourg europe
Just because the header bolts were loose, doesnt mean that the shop did a bad job.
Header bolts are notorious for loosening back up at least a couple of times after you installl them.
Be sure to check them again, even after you tighten them this time.
After a week or so they will stay tight.
Header bolts are notorious for loosening back up at least a couple of times after you installl them.
Be sure to check them again, even after you tighten them this time.
After a week or so they will stay tight.
but it isn't the first bolt or screw that falls off or isnt tight..Thats why they made the split screws an similar things.
I certainly will keep an eye on them
Thread Starter
Intermediate
Joined: Sep 2003
Posts: 48
Likes: 0
From: Luxembourg europe
NO<NO<NO<NO, you do NOT tighten untill the pushrod doesnt turn! great way to bend pushrods,burn a valve,wipe out a cam shaft! You tighten untill resistance is felt..thats it. Then you tighten 1/2 to 1 more turn....SLOWLEY,a 1/4 turn at a time. Hope ou havent bent anthing,,good luck.