CSK

AZ-Z71 · December 10, 2003

Ok I thought my truck had CSK. Seemed to start maybe 20,000 miles ago around 74,000 miles. In the morning when I started the truck for 10 to 15 seconds you could hear it click clack then it would go away. I heard the sound clips of engine knock and definately thought I had it, maybe not as bad or as long as the sound clips but it sounded like mine on initial start up.

Ok, incase you have not been following my story on the O2 Senors, I had a broken exhaust manafold bolt in the head on the drivers side. Long story short, I had to have them remove the head and machine the bolt out of it and replace the head and its gaskets. I did have a small leak that could only be detected on the highway when jumping on it but not detectable under idle.

Before anyone thinks maybe it was the exhaust leak causing the noise, that was more of a tick tick instead of a click clak.

This morning I went out to start the truck and the click clack was gone. So in amazement I shut the truck off and back on again and it was still gone.

Here is what I'm throwing out on the table, could the noise have been lifters? I don't believe they did anything to them when they had the head out but I don't know what else could have caused the noise or where it went. No other parts were changed except gaskets and bolts. (BTW - I was told the head bolts and manafold bolts are "torque and yield" bolts and should not be reused)

Any ideas? I'm not complaining it went away but if this helps some of you out there and if someone can figure this out....

JayMan · December 10, 2003

First, I do believe that ALL head bolts used over the last 20 years or so are "torque to yield," which means you use them once and throw them away. Most of my family is from Motor City and an Uncle finally explained why they use "torque to yield" and "torque angle" :

Engine assembly is almost fully automated now, which improves efficiency in a mass production environment. The CNC/CIM (Computerized Numerically Controlled - Computer Integrated Manufacturing) machine assembly tools are calibrated to read peak torque and then "break free," so head bolts and other fasteners are designed to twist or "yield" once their engineered torque value is reached.

The CNC/CIM system then knows the peak torque is reached and goes to the next fastener in programmed sequence. The thing is, it's hard to maintain calibration on any gadget that reads applied - versus "derived" - torque. So it's $$$ for the manufacturer to keep the calibration in spec.

However, it IS easy to measure and/or calculate ANGLE. The math is a lot easier, therefore faster, to compute as well, and calibration becomes a non-issue. So that's why the Helm manual mentions the use of "torque angle" instead of using a regular torque wrench. Us humans have a hard time working in angles as it isn't intuitive at all.

So the machine shop is correct: they had to throw the bolts away, and I would have been very suspicious if they had NOT thrown the bolts away! Like I said in the other post, sounds like you found a real good shop.

I think you've finally uncovered the "missing link" with all our CSK or lifter pump-up issues!

When the machine shop had to remove the head, they obviously had to remove the valvetrain - rocker arms, pushrods, etc. I'm also willing to bet they tanked the head to check for cracks, so the head is spotless (Ask them if they did).

When they reassembled the head, the valvetrain had to be reassembled and readjusted. I sure hope it's as straighforward as simply readjusting your valvetrain!

Yeah, I don't think an exhaust leak would make a "clack clack" or "tick tack" sound: more of a farting sound. At least all my exhaust leaks have made that noise, if you know what I mean!

AZ-Z71 · December 10, 2003

I'll ask them. This shop seems to be fairly thorough in their work so I'm sure that is what they did. They have been in business for 25 years and they are truely gear heads, hot rodders, and customizers.

I'm actually glad I had a bad experience with the first shop or I would have never thought about going here.

JayMan · December 10, 2003

If their dual exhaust job for you turns out as good as your motor repair, you had better email me their address. I think I'll pay them a little visit!

Yeah it sucks how we have to learn from bad experiences. Just wish it wouldn't cost so much to learn those lessons!

AZ-Z71 · December 15, 2003

Jayman,

You are correct. Asked the shop and they totally cleaned and checked the head. Then they reassembled the complete valvetrain since it had to be stripped off for removal of the head.

Been one week so far and nothing yet. Looks like this took care of that problem too for now. I guess it was money well spent to get rid of that noise as a bonus to the other problem.

JayMan · December 16, 2003

Hmmm, I think you really ARE onto something regarding this CSK issue!

I wonder if it diassembling / reassembling / adjusting the valvetrain or getting the head spotless that cured your "CSK?" Since some folks claim to have had "CSK" from new, I doubt it was carbon deposits. Though getting the combustion chambers and valves spotless doesn't hurt either.

Since the head assembly is automated, I wonder if GM was having a calibration problem with their CIM/CNC machines? So when the heads were mated, the valvetrain was out of adjustment??

Still, it does sound like you've found the perfect machine shop. Seriously, I have known folks to go 1,200 miles out of their way just to find a machine shop or engine builder they could trust!

Do you still need a cat and/or O2 sensors??