How to build a motor for top end power ?

[6.2 turbo]

I had some nv4500 parts cryotreated,they all broke except one.

 

[Cumminsfever]

I had some nv4500 parts cryotreated,they all broke except one.

Is there ANYTHING you haven't broke? LOL

 

[sshewins]

Yeah, no joke. Start calling you master of disaster LOL

 

[dieselfuelonly]

Talked to Delta cams today,he recommended their 206 regrind. I think Ill get one done,only $137.

Wow, that's a good price. Is it good to 5,000 rpm and capable past it or....?

 

[sshewins]

I would think that using the old valve springs wouldn't be the best thing ever. I would opt for brand new ones.

Anybody know if there are aftermarket ones available for us?

 

[red]

Heath has better springs that come with his cam kits. Don't know if he would be willing to sell them separate or not.

 

[3500GMC]

I bet a guy could source a set of springs from comp or crane with the specs you need.

 

[6.2 turbo]

It shouldn't be hard to find springs,might even consider beehive. Don't know if Delta's cam will go past 5000 rpms. Another question,would stainless steel Manley valves work in a diesel ? I think it would be ok,at least for the intake valve.

 

[Mike K3500]

Found this on SS diesel site, not real sure of the manufacturer though and kinda pricey at 599.00

Performance Roller Camshaft kit for all 6.5's in all trucks, all years, all VIN's.Includes a custom ground performance roller cam, new hydraulic roller lifters, and a free tube of cam assembly lube.Add power to your 6.5TD with our performance cam kit.
Specs as follows...

Advertised Duration (Exhaust):300 Deg
Advertised Duration (Intake):260 Deg
Cam Lift (Exhaust):.281"
Cam Lift (Intake):.281"
Cam Timing at .050" Lobe Lift (Exhaust Close):17 Deg BTC
Cam Timing at .050" Lobe Lift (Exhaust Open):39 Deg BBC
Cam Timing at .050" Lobe Lift (Intake Close):11 Deg ABC
Cam Timing at .050" Lobe Lift (Intake Open):13 Deg ATC
Degrees Overlap:65 Deg
Duration at .050" Lobe Lift (Exhaust):202 Deg
Duration at .050" Lobe Lift (Intake):178 Deg
Lobe Centerline (Exhaust):120 Deg
Lobe Centerline (Intake):101 Deg
Valve Lash (Exhaust):Hyd.
Valve Lash (Intake):Hyd.
Valve Lift (Exhaust):.422"
Valve Lift (Intake):.422"

Not real sure how this cam would behave with 300* ex duration.

 

[3500GMC]

It shouldn't be hard to find springs,might even consider beehive. Don't know if Delta's cam will go past 5000 rpms. Another question,would stainless steel Manley valves work in a diesel ? I think it would be ok,at least for the intake valve.

Intake yeah. Exhausts for the 6.5 are powdered metal stellite coated. Pretty damn tough. It would take some real good valves to compare to these I would think.

 

[3500GMC]

Degrees Overlap:65 Deg

Huh? If this is the same 'overlap' that I'm thinking, that's 65 degrees of crank rotation that BOTH valves are open at the same time.. Doesn't seem right, Idunno.

Maybe that's the magic? But you would think that with any kind of boost, it'd be like blowing the fuel from the cylinder..

 

[sshewins]

Ok, here's a question about valve guides. Would it be better to have the old one drilled out and a new one pressed in? Or ream out the existing bore and knurl it (or did I get that backwards - knurl then ream) either way, my former bro-in-law did it both ways, just not sure which is better for us.

 

[3500GMC]

Usually shops can drill your existing iron guide and do what they call a 'bronze liner' then fit them to your valves..

 

[6.2 turbo]

Huh? If this is the same 'overlap' that I'm thinking, that's 65 degrees of crank rotation that BOTH valves are open at the same time.. Doesn't seem right, Idunno.

Maybe that's the magic? But you would think that with any kind of boost, it'd be like blowing the fuel from the cylinder..

Not sure how they came up with that,there is no overlap at all.

 

[ak diesel driver]

I'd always heard the knurled guides allowed for better lubrication of the guide. but most shops seem to disagree and think it's a bandaid for guides

 

[sshewins]

Yeah, that's what he told me, better lubrication. And it was faster to do, quicker turn around time. I just wasn't sure if it was really the best/right option.

 

[littleboy]

Not sure how they came up with that,there is no overlap at all.

On the stock cam .... but when you make a new cam you can do whatever you want. Could easily be a misprint too ..... Having overlap helps on the top end but you lose bottom end torque.

 

[6.2 turbo]

I wonder how late the intake closing point could be,and still be able to start ?

 

[buddy]

The later you close the intake youd be lowering compression, but you'd probably be fine out to 25 degrees or so if you need the duration for lift, that "dynamic CR" is something I have in my CR calculator for changing intake closure. I think SSDS' 65 degree overlap is at advertised duration, not the .05" lobe lift point. You dont really want overlap at the .05" lift, unless you have divided exhaust manifolds with dual scroll turbo or sustained boost greater than your backpressure. Otherwise there would be reversion.

By shaving the piston down to 18:1 you could gain some clearance to get the exhaust valve closure closer to TDC, or machine valve reliefs instead for the most clearance while maintaining at least 18:1 CR. Opening the exhaust a little earlier may also help a bit, since combustion should be expended by 120 degrees of rotation. I would also recommend the turbo sized precups.

I picked up some Beehive Scorpion springs to possibly use in the future, and Rhoads customized lube channel lifters that bleed down at low RPMs to cut lift and duration below the set RPM point (if using a bigger cam).

If this was using stock exhaust manifolds, I would say extrude honing them is a great idea.

 

[3500GMC]

By shaving the piston down to 18:1 you could gain some clearance to get the exhaust valve closure closer to TDC, or machine valve reliefs instead for the most clearance while maintaining at least 18:1 CR.

That would be about the best bet. It would do some to lighten the piston, get some valve clearance back and lower comp.. Then we have to watch 'dome' thickness. I would flycut the valve reliefs symmetrical to 'maybe' induce more turbulence, leaving the rest of the piston close to the head. (close collision)