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Push rods, rockers and bridges in, studs torqued down. After the stud torque discussion on the other thread I decided to break the torque sequence down to 10 steps of 25 ft/lbs for a final torque of 225. After 100 ft/lbs and after final I rolled the crank a few times and had no valve contact. Calculations were correct! I’m glad I didn’t leave the rocker boxes unpainted. Injectors cleaned, resealed and torqued down. Today I finish the other side.
The master machinist Jeff spoke with Geoff at Colt and Scott and Bob at UCF spoke with Jeff and they figured the valve clearance and piston protrusion and went with a shorter piston just to be safe. I make too many mistakes to take all day calling people while I have to work my other job. I left it up to Jeff and he was correct. I can get the figures from everyone if you need them or would like them for your records.
The reason I ask is I’ve gotten two different numbers from Geoff, plus I asked for a spec value for the piston protrusion and valve recession and couldn’t get it. With a direct geared cam that should be a easy thing to do for a cam grinder. That was over a year ago. So I did dynamic measurement with the head torqued down. I also had a discussion with Zeb over on PSA who does engines and he did some measurements for me to compared to what I got. But he cuts his pistons to 0.020” protrusion. So I came up with an untested ratio for the 6.0. Recently on Kill Devil’s site for their cam they show piston and valve recession values needed for their street cam, which is what I thought Colt should have on their site rather the the oblique statement of “check your clearance” and giving different values depending on when you call. Maybe Geoff finically came up with a spec or he was more willing to talk to a machining business.
I’ve not found anyone who has had clearance values with the Stage 2, although there are hints. But my pistons right now at 0.025” protrusion, 0.010” under spec. The valve recession can be a variable depending on who does the valve work.
UCF adjusts valve recession according to what they have to remove from the head to get it to spec. Jeff took .003” off the block to clean it up and the pistons are 0.01” off the top. I’m not sure about the Colt Stage 2 additional lift.
I would not have been able to roll the crank over if there were clearance issues correct? Does that change with a warmed up, running engine?
Yeah, it does. The piston and connecting rod have thermal growth, and the valves have minor growth in the valve head, but that’s in microns. Valve stems grow, especially the exhaust, but that taken up by the hydraulic lifters, as is growth of the pushrods as they warm. Everything expands, including the block and head along with the fasteners. Block and head growth tightens the head gaskets, which is why taking off with a cold diesel is a bad idea. Old school training was get the engine up to temp before taking off in a tractor trailer. Somewhere here in a discussion about Ford programming is a statement the in later programming Ford backed off power until the motor got to a specific temp due to probably HG warranty. The aluminum pistons have the highest growth, but not as much as many think as the growth is between the wrist pin and top surface.
Geoff gave me two numbers, 0.035” and 0.030” clearance, which is way tight compared to what I’m used to on gas motors, 0.060 to 0.080”. Which is why my ears went way up and I got hyper.
NICE! I’m prepping the block and a few parts for paint today and painting tomorrow. Front and rear covers after that and hopefully going back in with it this weekend.
NICE! I’m prepping the block and a few parts for paint today and painting tomorrow. Front and rear covers after that and hopefully going back in with it this weekend.
Excellent! I'll keep my fingers crossed it goes smooth!
I got the block and most of the other parts cleaned and painted. I like the VHT Flame Proof paint so much I decided to paint the oil cooler cover and oil filter housing tomorrow. I’m going to get the front and rear covers on, touch up some paint on the block and see about getting the Cerakote guy to refinish my exhaust headers because I noticed rust spots showing through. Cerakote is supposed to be impervious to wear, good to over 2000 degrees and much better than powdercoating. He must not have prepped the parts properly.
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