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FE Technical Forum / Re: Tell me how well this will work.....
« on: June 15, 2020, 04:32:54 PM »
Smart move.
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FE Technical Forum / Re: Tell me how well this will work.....
« on: June 11, 2020, 06:16:01 AM »
Short-Lived Certain Death
There are two forces to harness in crankshafts: bending stiffness and torsional stiffness.
Bending stiffness deflections occur from firing load and inertial forces, and is essentially the crank webs opening and closing. Main to pin overlap area, material strength, and fillet radius are the key input factors. Failures occur typically in the fillets.
Torsional stiffness deflection occurs from firing and management of driveline inertia and post dampening. The flange end is typically dampened, while the post is free. Inertia mass is added to the post to counteract this force. Key input factors for controlling torsional deflection are mass management, cross sectional thickness between the oil hole and web, and to a lesser extent material strength as if torsional are not managed, no material can contain torsional deflection.
As for this crank with its oil holes, both the torsional hot spot and bending fatigue hot spots are in the same area, the fillet, and the oil hole is so broad, it is likely into the peak area for torsional stress - not good.I
As another member noted, the oil hole breakout location is set when the holes are drilled, and their proximity is strategically placed to keep away from the stress hot spots. This condition is not the fault of the crank grinder other than he should be aware of it when reducing journal size, and caution against it. Apparently that wasn't the case of he didn't know.
Hope this helps; you can trust this info as I'm FoMoCo's Global Mfg. Engineering Technical Specialist for Crankshafts.
There are two forces to harness in crankshafts: bending stiffness and torsional stiffness.
Bending stiffness deflections occur from firing load and inertial forces, and is essentially the crank webs opening and closing. Main to pin overlap area, material strength, and fillet radius are the key input factors. Failures occur typically in the fillets.
Torsional stiffness deflection occurs from firing and management of driveline inertia and post dampening. The flange end is typically dampened, while the post is free. Inertia mass is added to the post to counteract this force. Key input factors for controlling torsional deflection are mass management, cross sectional thickness between the oil hole and web, and to a lesser extent material strength as if torsional are not managed, no material can contain torsional deflection.
As for this crank with its oil holes, both the torsional hot spot and bending fatigue hot spots are in the same area, the fillet, and the oil hole is so broad, it is likely into the peak area for torsional stress - not good.I
As another member noted, the oil hole breakout location is set when the holes are drilled, and their proximity is strategically placed to keep away from the stress hot spots. This condition is not the fault of the crank grinder other than he should be aware of it when reducing journal size, and caution against it. Apparently that wasn't the case of he didn't know.
Hope this helps; you can trust this info as I'm FoMoCo's Global Mfg. Engineering Technical Specialist for Crankshafts.
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FE Technical Forum / Re: My curiosity spurred by the 2 block discussion posts ( CGI block )
« on: June 07, 2020, 08:59:45 PM »
Grainger Worrall poured the GM, Ford and Hemi NASCAR and Pro Stock CGI blocks. CGI has some chemical alloying differences, but cooling and/or subsequent heat treat controls the final mechanical yield and tensile strength. Depending on this, strength can be as much as 4x that of gray iron. CGI is very tough in machining, and hard on tooling. For the 6.7L and 2.7/3.0L V6 which use it, we see about a 30% tool life reduction, and significantly lower speeds and feeds. Advantages are that for space constrained areas (bore bridges, main bulkheads), it offers strength otherwise unobtainable. For lower stressed areas, it enables lightening. Not only is CGI expensive, availability of casting suppliers is also limited. For the JC50 Pro Stock engine, Ford had G-W cast 75 blocks and 150pr heads. This is per the individual who ordered them. These are the ultimate Ford pushed V8, but these engine as are obviously very rare.
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FE Technical Forum / Re: 390 still using oil
« on: April 19, 2020, 06:24:32 AM »
Have someone follow you again to watch exhaust while you get on it hard and let off the throttle entirely. If it smoked while on the throttle hard, it's rings, if it smokes off the throttle or heavy downshift deceleration, it's the guides. Just because they're new valve guides doesn't mean that they are clearances right. Sounds dumb, but check that valve seals are installed properly or that they weren't forgotten entirely.
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FE Technical Forum / Re: Compare Dove Heads To Other Manufacture's ?
« on: April 18, 2020, 05:52:38 PM »
I have 3 sets of Dove heads, and the casting quality varies greatly. The C4AE-F high risers leak check great, look good with no porosity, and have no issues. The other sets are raised and relocated exhausts with raised intakes and they have pinhole leaks from porosity. I've worked with a set of Raised intake and exhaust std loc and they were unmanageable and castings so dirty they would not take weld. Scarfing out an area the size of a golf ball and welding up proved futile as the casting had so much sand in it. Bottom line is that they are not for the faint of heart. They can produce some fabulous numbers but are questionable quality. If you want a set with no fiddling, go elsewhere.
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Private Classifieds / C8AX-6250-D Reissue Camshafts
« on: March 25, 2020, 10:29:55 AM »
I have about (6) C8AX-6250D flat tappet cams left in inventory now available for sale from the second run of them. Specs are 0.600"/0.600" and 272 deg @ 0.050", originally advertised by Fpord as 330 deg (which is at 0.0145" lift, an abstract figure). Cams are exact duplicates made from Adcole measuring (3) original C8AX-D cams, 2 NOS, 1 with limited time (showed no measurable wear). Cams were produced by Comp Cams and include dowel pin, cam card, cam lube, and standard Comp Cams packaging. Valce springs and lifters are available from Comp or other suppliers. Cost is $195/ea plus actual UPS shipping and PayPal feed of 2.9% + $0.30. If interested, email me at mkopmani@ford.com with your shipping address so I can calculate shipping cost and I'll quickly reply. Once payment is received, cams ship immediately. Thanks - Mike K
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