loud ticking #6 cylinder after rebuild
 

Hello,
I just finished rebuilding my 80sc 3.0 following Wayne's book. I followed all the break in procedures and just got back from a long trip in the car. I knew the valves needed adjusting...following the book i adjusted the valves... and I thought the tick was an exhaust leak coming from one of the ssi's flanges....Today I adjusted the valves...which were way off. The loud tick from # 6 I thought was the valve being way out of adjustment. The loud tick is still present...only from #6. Also the car will not run on its own following the valve adjustment???? Please help! I hope I don't have to drop the engine again and tear it apart :( to find out whats wrong.....


Thank you! Alan

deleted - I should have read your whole post..... :-(

Hello,

I got the car to idle on its own....I took a oil hose and put my ear to it and held it up to #6. The tick is coming from cylinder head #6. Also, when I speed up the throttle the tick quiets down almost goes away.... Otherwise the car runs fine???
thaks!
Alan

When you rebuilt the engine did you put in new valves? I ask because sometimes the stems can get a ridge worn in them which makes it impossible to adjust the valves using a feeler gauge. When you adjusted the valves did you then wiggle them and note the gap?

Hello,

No I didn't put new valves in the shop said the old ones were fine. Yes I did wiggle them and noted the all wiggled the same.....I'm thinking ill drop the engine tomorrow and take #6 head off....I really don't know what else to do? Could improper cam timing cause this? That's the only thing in the rebuild that I questioned myself on....
thank you!
Alan

The noise is from the exhaust part of the head on #6.....any ideas before I take it apart? Also, Why would adjusting the valves cause the engine to not idle?
Thank you!
Alan

Depends on how loud the tic is? My 2.7 has always had a tic sound, before rebuild and after.

If the valve clearances were way off when you checked them, I would start with checking the valve clearances again. The clearances should not have changed much if at all. Take off the distributor cap, make sure that the rotor lines up with the notch in the distributor for #1 at TDC. There have been other posts similar to this.
http://forums.pelicanparts.com/porsche-911-technical-forum/503022-valve-adjustment-gone-bad.html

exchange the rockers to a cylinder on the other side and see if the rocker is bad or bushing is worn.

Bruce

Hello,

Thank you so much for the replys. I'll adjust the valves again today. I did it incorrectly. Thank you for pointing this out. However the tick is very loud and sounds like it is the exhaust valve for #6. I'll adjust the valves again and let you all know what happens.
Thanks again!
Alan

Hi Alan,

As you can imagine, its challenging to accurately diagnose noises in an internet forum (or over the phone) but you should check a few things.

1) Check valve clearance

2) Rocker arm bushings and shaft for wear

3) Make sure the head is torqued correctly and still tight

4) Make sure the exhaust gasket isn't leaking


If no joy, then you should pull things apart and make sure:

The piston was installed correctly.

Valves are not touching the piston (see above)

Piston isn't touching the head at TDC. You'll see tell-tale marks at the edges if this is happening.

Hi Steve,

Thank you for the reply. I checked the valves they are all correct....I pulled the ssi off to look at the valve....it looks different than the others in color...the others are gray the #6 has strides of color coming down it....I'm assuming it is not closing correctly...perhaps it is bent? or a spring broke... I'm going to go ahead and drop the engine this afternoon. Yes the cylinder has a small exhaust leak but I wouldn't see how it would create such a loud mechanical ticking noise.

Alan

Don't discount this leak, you might be surprised!

As Cgarr said, it could just be an exhaust leak. My neighbors pickup had an ear splitting squeal that you would swear was a bearing. He changed the water pump and power steering pump, but it was just a small intake leak at his throttle body.
It wouldn't take much to just change the gasket and reinstall the ssi's to check before you pull the whole engine.

Hello,

Thanks for the replies! I went ahead and took the engine right bank of heads and cam tower off....The head looks ok but I ordered two new valves to be safe...their not that expensive. I'll take the head to the shop when I get the valves in and have them check the springs and install the new valves. I know I may have jumped the gun but :) I also found in the cam tower a washer floating around. Being the brilliant mechanic I am i left it in there! Sometimes I amaze myself....Anyway that could have caused the noise. However the ticking sound was from the head on #6 exhaust??? Anyway....on my way to figuring it out :) I'll keep all posted as to my progress. Here are a couple pics of the heads and cylinders. I don't see any evidence of the valves hitting the pistons and the pistons look correct.
Thank again!
Alan

http://forums.pelicanparts.com/uploa...1280531902.jpg
http://forums.pelicanparts.com/uploa...1280531930.jpg
http://forums.pelicanparts.com/uploa...1280531953.jpg

Looks like a pretty good exhaust leak on the middle one..

OMG, yesssss,...:)

That can certainly account for the noise you heard.

Yes i see it is leaking pretty good. How do I stop that leak? Could I double the gaskets on the exhaust flanges?

thanks!
Alan

I was wondering why you pulled all the heads on that side if it was just # 6 that had the problem. I was planning on doing that on mine.

Hello,
You have to pull all of them because thery are all connected to the cam tower. Once off you can remove them individually...Also you have to remove the cam first if you dont take the cam housing off. Therefore you'll have to remove the rocker arms while it is still attached to the engine.

Thanks!
Aan