3500_6.5
Well-Known Member
Easier breaking is possible, but as long as it's 3 or 4 degree max per keyway, he should be ok. Just make sure there is no slop. If he is trying to run over 100,000 miles then, yeah they will strip or snap. Performance is not longevity.
3500 hasn't told a lot about his cam, or set up- so I didn't pry. But maybe should. If you don't want to share details-it's ok. But what I've caught so far:
Regrind cam, so not as much lift and duration as stock so he is trying to shorten the power band. In doing so it becomes more important to move the range of that power band up or down in rpm to match acceleration rate and gearing. The rule of thumb is 1 degree per 100 rpm. So a 10 degree advance would move his peak torque down 1000 rpm. Colder burn on startup, and intake valve hitting piston is only concearns here.
This helps a lot keeping IP output in lower rpm so high fuel rate is easier. If still running the hx35/40 then a quick spool is going to be required to maximize the stump puller build. It will also help cool the valves better to beat egt. He just looses the top 250 rpm from the engine.
The opposite-a 10 degree retard will cost the lower end but help the easier flow top end rpm and maximize fuel savings if boost is back down to half its peak and a little more egt as the burn gets to the exhaust valves a bit more. Or if he is pouring on the coal at high rpm and able to ramp boost to the peak, like a little fuel kicker (propane or meth wmi) can push his torque curve up closer to the horsepower curve. The danger here is burning valves, increased egt, exhaust valve hit piston.
If we see you hooking up to a tractor sled, I guess we know.
I haven't said much about the cam bc I am more or less testing it to see if it will even work on the 6.5 the way it does on the Fords. He has some of the info on it posted on his site. It is machined to the same specs as his stage 1 cam for the Fords. These are the advertised specs:
Intake Duration: 178*@.050"
Exhaust Duration 190*@.050"
Lobe Sep: 108*
Lift: Int .410"/ Exh .412"
Comparing it to the specs given on SS Diesels site for his performance cam (which I was thinking was the same as the marine cam Peninsular sells), intake duration is the same, exhaust is less. Lift is also less. Per his instructions of where to set the intake centerline, his icl is roughly 10 degrees more (110-112 vs 101). Since it is not my cam grind and I am running it more or less to test it, I don't feel like it is my place to give out much more info than what he already publicly gives out. Now if it works out and he is able to market these to the 6.5 crowd, then by all means, be as curious as you want with him on all the details[emoji4].
On my end, I think I've shared everything I have done, or plan to do with the engine. I will still be running the same modified marine pump and hx35/40 hybrid as of right now. I will be running the Harland Sharp 1.6 roller rockers so long as they will work on it. I will still be running an intercooler. The only thing that may change there is that I would like to move it to behind the grill, but the one I am currently running will not work there. So that's still up in the air.
The only other possible change will be the exhaust manifolds and converting it to centermount. But that part is still up in the air. I contemplated changing the precups to larger ones, but for the time being I am just going to leave the factory diamonds. Other than that, I haven't made any secret changes unless I've forgotten to mention it along the way. And if I end up changing anything or doing anything more, I will happily post it on here. I like to feel like I have a one of a kind truck/build, but I also don't mind sharing the details to help others along the way or to get advice from others who may have tried the same things. I don't build these for a living so I don't have to keep anything secret to get people to come pay me to build their engine. But if you want to pay me to build you one, I'll gladly spend your money[emoji4].
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