So... I have about 800 miles on my engine build, and there's a noise that I really don't like. Over the last 100ish miles I've started to become aware that the engine seemed to be making more noise, and possibly vibrating more as well. I first thought it was valvetrain noise. I readjusted the pushrods a couple of times... A little bit more preload, a little bit less preload... Sometimes it seemed better, but ultimately I realized it really wasn't. Today I started thinking that it might be a clearance issue in the rocker boxes, or a lack of oil reaching the top end. I pulled the front rocker cover, and there were no signs of interferance anywhere. There also seemed to be plenty of oil up top. To be sure, I ran it on the starter in 5th gear with no plugs for a little, and I could see oil coming up through the pushrods properly. I also checked rocker shaft end play, and it seemed fine. In fact, with the cover off, the top sounded fine turning with the starter. I also looked at the pistons with a phone camera borescope. It was hard to see, but it didn't look like there was any valve contact.

But when I turned the engine slowly from the wheel, I realized there was a loud metallic click once per revolution (I think). It happens as the front cylinder is passing through the bottom of it's stroke. First I thought it was coming from the cam chest, but I can't be sure. I can hear it from both sides, and it comes from the bottom half of the engine. Without a second person to turn the wheel it's hard to pinpoint.

In this video you can hear it clearly. The first click happens has I turn the rear wheel in it's normal direction. The louder click is when I reverse and go back over the same spot.


Any thoughts? I was planning on heading out of town on the bike tomorrow, but now I don't know... It doesn't sound good to me.

A quick summary of the engine:

2000 88 bored to 97", S&S forged pistons, cam plate, oil pump, lifters and 585 chain drive cams (not Easy Start), Zipper's Red Shift tensioners, head porting, big valves and beehive springs.

 

Listening further, it really seems to be coming from the cam chest. Everything is new in there, which doesn't mean I didn't screw something up... I think it's too loud to be a sticking lifter, although I guess it's possible (although I don't think it goes away when warm)... I don't think the oil pump would make a noise like that (and I took a lot of care to make sure it was centered and torqued properly). I really don't feel like taking the chest completely apart, but maybe I have to.

 

What pushrods did you use and how many flats did you adjust them to? Looks like you used S&S parts for the most part. The S&S video that everyone uses says 20 flats but the instructions that come with the pushrods say 24 flats and if you research it a bit people will tell you to do 24 flats. Something to think about if your lifters don't have limiters in them. Going from 20 to 24 I could feel and hear a difference using S&S lifters and adjustable pushrods.

 

Valve spring getting caught, maybe out of seat?.. intake valve spring on the front?.. .I would pull the rocker covers and put an eye on and finger on, the rockers and springs... I know you said you pulled the front... but...

 

Thanks for the input... I really don't think it's a pushrod/valve adjustment issue though... I'm very careful about TDC and the base circle when adjusting them, and I've now tried .125, .135, and .145 of preload. This sound is not affected. When spinning the engine with the rocker cover off, there is no ticking from up top, but this sound remains.

I really don't think it's valve springs either... There really is no sign of interference, and the sound really seems to come from below the barrels somewhere, although it's hard to pinpoint where.

It's annoying. I can't think of anything in the cam chest that would sound like this. I hope it's not from in the crankcase, but again, I don't know what would sound like this. I guess it could be from the primary side, but it seems louder on the right.

I guess I have to take stuff apart.

 

Did you clearance the cam chest for the cams?

 

I wish I had a suggestion, but I haven't gone that deep into the motor yet, so I'm less then useless. Good luck though!

 

Jason: Yes, I did clearance the inside of the chest. When I hand fit the cams they each spun without contact, but I didn't have the room specified by S&S (.030, I think). I took out enough for the right feeler gauge to have plenty of room everywhere.

I had a similar thought though... I will disassemble the chest, but I can't until Monday afternoon.

 

I would say it's either the cam hitting or it's in the rocker box. If you take the top rocker box cover off there should be some witness marks

 

That was my first thought, and I did that. The inside of the cover was completely untouched... I'm now pretty certain that the sound is in the lower half of the engine, but I can't pinpoint where...

But thanks for thinking about it!