D4-260 V Clamp questions

[Martin610]

Hi Guys,

I finally got around to removing the exhaust elbow on my D4-260. Inspected the turbo. Basically good news. While I did have carbon build up I was able to clean it up. I treated a bit of corrosion around the turbo and elbow. Did a test, boat ran well.

Never having done this job before, I'm not sure about the V clamp. I bought a new one as mine was 11 years old. It didn't come with any gasket or sealant. Pretty confidant I got the correct part. I'm not sure how tight I should make it. I can't find a reference on torque for it. Right now I have a small gap that leaks a little exhaust air. Doesn't seem right. Am I supposed to torque it to the point where both ends of the clamp meet? Is there any gasket or sealant I should be using?

Any help appreciated.

-martin610

 

[BB marine]

Clean the mating surfaces so that all surfaces are smooth with no high spots. Fit the V clamp and move it clock wise then counter clock wise to make sure the V clamp is seated properly. Move it back and forth as you tighten the clamp this to maintain a proper seat. For exhaust flange fasteners and the V clamp mating surface I use a dry lubricant.Coating the inside of the retainer with dry-film lubricants helps reduce friction between the coupling and flanges. As you tighten the clamp, inspect the fit and make sure there is good alignment of the turbo and exhaust elbow. I use a clamp torque of 45 inch pounds. After the installation is done check for exhaust leaks. If there is an exhaust leak, inspect and find the culprit. It is usually a poor metal to metal fit. Flange surfaces or V clamp. I will re-torque after I have run the engine up to temp and proper sealing is achieved.

 

[Martin610]

Thanks Brian.

Just one follow-up, when I have this torqued down correctly do both ends of the V camp meet?

-martin610

 

[BB marine]

Thanks Brian.

Just one follow-up, when I have this torqued down correctly do both ends of the V camp meet?

-martin610

I'm not sure how to answer your question. The theory behind a V clamp is it provides clamping forces that force Both sealing surfaces together. You must have a clean, level, smooth sealing surface on bot mating surfaces in order for the Turbo to exhaust elbow fit to seal. The clamp forces the surfaces together. When you torque the clamp you must make sure there is a good alignment between the surfaces meeting. The clamp pushes the surfaces together making the seal. It the clamp ends meet and restrict the clamping force you will not have a good seal.

 

[Martin610]

That's what I was missing. I didn't have the fundamental understanding of how the clamp works. Got it now.

I followed your advice from earlier, ran the motor. I loosened and rotated the clamp back and forth. All good now!

Thanks again Brian.

-martin610