J M R Automotive Developments.

AVCS timing would/could explain the intake valves kissing the pistons, but Minaj also had the exhaust valves kiss on a few cylinders.

Here's Kelfords cam install and minimum clearance specs:

http://www.kelford.co.nz/checking-piston-to-valve-clearance

Minaj what were your cam specs (lift/duration) and what were the adjustable timing gears set to?

 Rosssub said:

AVCS timing would/could explain the intake valves kissing the pistons, but Minaj also had the exhaust valves kiss on a few cylinders.

Here's Kelfords cam install and minimum clearance specs:

http://www.kelford.co.nz/checking-piston-to-valve-clearance

Minaj what were your cam specs (lift/duration) and what were the adjustable timing gears set to?

Cam Lift:

Intake:

11.50mm

Exhaust:

10.75mm

Intake duration 272 and Exhaust 268. The adjustable cam gears was 5 and 7 degrees. I was told there was 4.5mm PTV clearance.

Here's another detailed write up on checking PTV clearances, also stating the same minimum PTV clearance as Kelford:

"How much clearance is enough? A safe rule of thumb is .080-inch for intake valves and .100-inch for exhaust."

http://www.enginelabs.com/engine-tech/engine-blueprinting-how-to-check-piston-to-valve-clearance/

So 2.032mm minimum for the intake valves and 2.54mm minimum on the exhaust valves is enough. If your engine had 4.5mm PTV clearance, mechanically there is no way the exhaust valves should of hit the pistons. Unless the tuner has then gone and added a lot of cam timing, which isn't the case.

Surely the 5-7 degrees of cam timing that was dialled in would not be enough to effect 4.5mm of PTV clearance near TDC. More likely minor adjustment compensating for head machining and block decking.

 Rosssub said:

Here's another detailed write up on checking PTV clearances, also stating the same minimum PTV clearance as Kelford:

"How much clearance is enough? A safe rule of thumb is .080-inch for intake valves and .100-inch for exhaust."

http://www.enginelabs.com/engine-tech/engine-blueprinting-how-to-check-piston-to-valve-clearance/

So 2.032mm minimum for the intake valves and 2.54mm minimum on the exhaust valves is enough. If your engine had 4.5mm PTV clearance, mechanically there is no way the exhaust valves should of hit the pistons. Unless the tuner has then gone and added a lot of cam timing, which isn't the case.

Surely the 5-7 degrees of cam timing that was dialled in would not be enough to effect 4.5mm of PTV clearance near TDC. More likely minor adjustment compensating for head machining and block decking.

Yup, even if there was a lot of cam timing or avcs advance added on the intake side, wouldn't all the intake valves kiss? The exhaust is not controlled by avcs just a cam gear, but doesn't explain why the other cylinders don't have valves marks on the piston.

Do you know whats the maximum decking limit for the block and max machining for the head is ??

I get the feeling youre going to have a hard time in court since you keep dragging it out. I dont think anyone on here can give you credible court permissible evidence no offence meant. Murch gets called on for court but you already had his opinion months ago...

 evowrx said:

I get the feeling youre going to have a hard time in court since you keep dragging it out. I dont think anyone on here can give you credible court permissible evidence no offence meant. Murch gets called on for court but you already had his opinion months ago...

I'm already onto it, I'm in the process of completing my statements backed up with evidence and it's not a easy process.

there can be small differences in avcs cam timing between banks due to belt stretch, lower block deck heights and oil pressure differences. But the valves would have hit happened the first time the cam timing was advanced on the dyno, your engine ran for a while first...

 Optical said:

there can be small differences in avcs cam timing between banks due to belt stretch, lower block deck heights and oil pressure differences. But the valves would have hit happened the first time the cam timing was advanced on the dyno, your engine ran for a while first...

Yup that correct, would've heard it on the dyno.