[hurryinhoosier62]

Originally Posted by Tim Corcoran

HF Eddy current is only applicable to aluminum it is not used on iron, steel or other metals. Ultrasonic is usually used on composite materials to determine if there is delamination or voids. Radiography (x-ray) is very expensive, requires very expensive equipment and would cost a lot of money to have an engineer write a test plan to inspect an automotive crankshaft it, would cost more than the price of my new engine will. Dye penetrant will detect surface discontinuities and cracks not normally visible to the human eye. Mag particle (magnaflux) can detect surface and sub surface discontinuities, there are two basic types wet and dry. Most machine shops use the dry method using a dry magnetic dyed powder and applying a current through a set of prods to the test article. The dry mag inspection is only as accurate as the operator is trained and is not the most accurate method and can miss a lot or give inaccurate results. Wet mag particle is much more accurate but requires more specialized equipment and training and these inspections should only be performed by a level II certified technician. The type of dye penetrant that would be used in a machine shop is simple but is very accurate and does not require a lot or training or skill just follow the procedure that comes with the kit. I have been trained and certified a level II in magnetic particle, Radiography, dye penetrant and HF Eddy Current. I would leave it up to a level III to determine if dry mag or dye penetrant was a better test method to inspect for crack in a crankshaft.

WHERE did I say eddy current a ferrous component? You left out magnesium and titanium as metals that can be subjected to eddy current inspection. In case you are not aware the FAA mandated ultrasonic inspection of the primary turbine blades on the CFM56 turbofans after the fatal in-service failure of a primary fan blade on a Southwest Airlines 737s. The primary fan blades used in the CFM56 engines are titanium forgings. Additionally, the FAA MANDATES magnetic particle inspection of ALL ferrous engine components of aircraft reciprocating engines and has for decades. The AERA ( Automotive Engine Re-manufacturers Association) and strongly advises their members to utilize magnetic particle inspection when checking ferrous engine components for cracking and other anomalies. Pratt and Whitney MANDATES magnetic particle inspection of ALL ferrous components of their piston reciprocating and gas turbine engines. Cummins, Detroit Diesel, CAT, Navistar, etc. mandate magnetic particle inspection of ALL of the internal ferrous components of their engines during overhaul. The ONLY time we utilized dye penetrant for NDT in my nearly thirty years in aircraft maintenance was on cast aluminum turbocharger housings or on cast aluminum/ cast magnesium wheel halves ( until we started using eddy current). We also used dye penetrant on cast iron turbocharger exhaust housings per the ADs( we would confirm the results through magnetic particle inspection). In my years as an ASE master engine machinist for JET we used dye penetrant to crack check aluminum engine blocks and aluminum heads, but subjected hundreds of cranks, cams and connecting rods to magnetic particle inspection every week. It your chit, so do what you want to. I’ll stick with my forty years of experience AND the over one hundred years of experience of the men who mentored me over the years. Guess the FAA has no idea as HOW to perform NDT on ferrous metals….BTW, ultrasonic testing on cylinder walls is not only for judging thickness; it is also use to establish the amount of internal corrosion and voids in the internal cylinder walls. It’s pretty smart when engine machinists use ultrasonic inspection before attempting to bore a block with substantial internal corrosion.

[Tim Corcoran]

We were talking about my engine failure, and you butted in saying how eddy current, X-ray and ultrasonic were more accurate and those are not even applicable to a Pontiac crank shaft which is a bunch of bull. You didn't even have any business contributing to this thread if all you wanted to do is criticize an NDT method that actually found cracks. Stay out of my post.

[hurryinhoosier62]

Originally Posted by Tim Corcoran

HF Eddy current is only applicable to aluminum it is not used on iron, steel or other metals. Ultrasonic is usually used on composite materials to determine if there is delamination or voids. Radiography (x-ray) is very expensive, requires very expensive equipment and would cost a lot of money to have an engineer write a test plan to inspect an automotive crankshaft it, would cost more than the price of my new engine will. Dye penetrant will detect surface discontinuities and cracks not normally visible to the human eye. Mag particle (magnaflux) can detect surface and sub surface discontinuities, there are two basic types wet and dry. Most machine shops use the dry method using a dry magnetic dyed powder and applying a current through a set of prods to the test article. The dry mag inspection is only as accurate as the operator is trained and is not the most accurate method and can miss a lot or give inaccurate results. Wet mag particle is much more accurate but requires more specialized equipment and training and these inspections should only be performed by a level II certified technician. The type of dye penetrant that would be used in a machine shop is simple but is very accurate and does not require a lot or training or skill just follow the procedure that comes with the kit. I have been trained and certified a level II in magnetic particle, Radiography, dye penetrant and HF Eddy Current. I would leave it up to a level III to determine if dry mag or dye penetrant was a better test method to inspect for crack in a crankshaft.

Originally Posted by Tim Corcoran

We were talking about my engine failure, and you butted in saying how eddy current, X-ray and ultrasonic were more accurate and those are not even applicable to a Pontiac crank shaft which is a bunch of bull. You didn't even have any business contributing to this thread if all you wanted to do is criticize an NDT method that actually found cracks. Stay out of my post.

No, what I said were eddy current, x-ray and ultrasonic inspection methods are more accurate than dye penetrant, which is FACTUAL. There ARE valid reasons WHY FAA. EASA, DOD, NASCAR, NHRA, IHRA, USAC, IMSA, SCCA, etc mandate magnetic particle inspection over dye penetrant when inspecting ferrous components. If you choose to use dye penetrant, that is your business. It’s something I would NOT encourage as a retired engine machinist.

[Tim Corcoran]

My post wasn't about trying to impress everyone with your vast knowledge about aviation the FAA and NDT that doesn't apply at all to a Pontiac crankshaft or about my engine failure. Get lost.

[Half-Inch Stud]

Originally Posted by Tim Corcoran

If you referring to AV Gas I think that is 100LL not 110

Yeap. Forgot the two choices. 110 Lead, and 100 LL

[Half-Inch Stud]

Originally Posted by Tim Corcoran

My post wasn't about trying to impress everyone with your vast knowledge about aviation the FAA and NDT that doesn't apply at all to a Pontiac crankshaft or about my engine failure. Get lost.

Uhm, caution, let's walk that back. Mag-flux Inspection (for eddy current "loops" around cracks) is thee way i had all my Cast and Forged Pontiac cranks inspected. Some fail, usually in the rod-throw armpit.

Whereas flourescent dye-penetrant has a following, that which i have ZERO automotive experience and some Professional exposure. I do recall a machine shop set-up for both inspection types.


Story:
Some other sorry local Pontiac guy had cracks found under all 8 armpits, (all4 throws) of his 455 N-crank, while my N-Crank passed. So i was only a little pensive about making sure MY crank, was indeed My crank. I sure dye-penetrant would have failed that fella's 103N crank, whereas i'm not sure i'd sleep well with my crank having passed a dye-penetrant exam.

[Scarebird]

Originally Posted by Half-Inch Stud

Yeap. Forgot the two choices. 110 Lead, and 100 LL

Last time I fueled up a plane it was 100LL or nothing.
Some FBO's have MoGas but not seen it myself.

[Tom Vaught]

Originally Posted by Tim Corcoran

My post wasn't about trying to impress everyone with your vast knowledge about aviation the FAA and NDT that doesn't apply at all to a Pontiac crankshaft or about my engine failure. Get lost.

Experience with Pontiac Crankshafts.

I have sold 14 short stroke (3.375" stroke cranks made by Kellogg (a forging house that made special cranks for Pontiac/Tom Nell.

Moldex finished each one of the cranks for the Pontiac people who bought one from me.

'All Pontiac' sold crankshafts (made from Chinese Steel) that was checked out for "Dirt" in the forging by Ford Research. Compared to several Pontiac suppliers stuff, the material was about 96% clean steel.

Moldex billet cranks made from Ball Bearing Timkin steel was about 99.5% clean high grade steel.

The cast pontiac cranks were good castings but not up to the level of a forged
421 SD or 303/366 Forgings.

In my experience, clean steel (even if it is 'off shore') is everything).

The O*IO Cranks are down on the list vs most stuff. But it is a Pontiac dimension crankshaft.

For Years Moldex and Crower made excellent cranks. (and still do)
Bryant cranks, $$$$) also makes very good clean steel cranks, (they buy the same steel as Moldex).

So while comments from others are better than nothing in selecting a good steel crank, You must pay if you want an exceptional Pontiac crankshaft.

(I still have 4 Kellogg 366 steel forgings (RAW) that are designed for a 3.375
stroke engine. I sold 14 cranks (finished by Moldex) over the years.)

Cast cranks are only capable of a given number of cycles. THEN THEY FAIL.

Just Saying.

Tom V.

[Scarebird]

Originally Posted by Tom Vaught

...(I still have 4 Kellogg 366 steel forgings (RAW) that are designed for a 3.375
stroke engine. I sold 14 cranks (finished by Moldex) over the years.)

Tom V.

Had I known a bit more a decade ago...

[Half-Inch Stud]

The Goodman diagram is reality. I think it can actually count crank rotations! Like working hardening a Paper Clip...

[Tim Corcoran]

Stroke, RPM, compression, weight of the rotating mass, quality and condition of balancer, how good the rotating assy is balanced and of course the tune all play a part in how long a crankshaft will last. With all that said if I had upgraded to a forged crank i'd probably still be running strong. I will be getting a forged Scat crank for my new build the Scat has straight shot oiling so based on my performance level I think that will meet my needs.

[GTO-relic]

Originally Posted by Tim Corcoran

4.25 Ohio cast crank, when I put this engine together years ago the forgings weren't available yet. I sure wish I would have upgraded to a forged unit. The thing is, I had a warning car slowed down about .4 from what is should have been running and oil pressure seemed a little sluggish the first two runs before the one when it broke. All the bearings look good so it wasn't starving for oil.

old thread, compelled to comment:
IIRC Ohio cranks were Chinese cores?
cast cranks and stock blocks at that power level must be magged for cracks regularly.
and discarded when cracks in the fillets begin, or if cracks begin to form in the engine block main saddles/oil galley holes area.
I've thrown away 3 factory 428/455 cranks that were cracked, bent.
the 428's crack, the 455 crank had spun a bearing, overheated, and was very slightly bent.
when shop tried to straighten it, it broke the entire front snout, first main journal, and 1st rod throw off the crank.
having said that, you should have a forged or billet crank at that power level,
right from the get go. there is no cheap way out.
pay now, or pay later.
IMHO, the worst crank you can get, is a Chinese core cast crank.

[hurryinhoosier62]

Originally Posted by Half-Inch Stud

Yeap. Forgot the two choices. 110 Lead, and 100 LL

Nope; no 110 Avgas. Hasn’t been since the 1950s. The standards through the 1990s were 80/87, 100/130 (green). 100/130 LL (low lead…blue) and 115/145 (purple). The standard today is 100/130 LL until UL100 is standardize and no longer requires an STC to use it. 115/145 is being manufactured by one supplier in Poland, primarily for the large radials and inlines in warbirds in Western Europe.

[hurryinhoosier62]

Originally Posted by Scarebird

Last time I fueled up a plane it was 100LL or nothing.
Some FBO's have MoGas but not seen it myself.

Mostly smaller FBOs here in the Midwest carry non-ethanol Mogas for light aircraft using the EAA Mogas STC.