Memory check

[Mike McKown]

I'm thinking the '62-'65 SHP solid lifter 327's had a swatch of blueish green paint on the outside of the block, on the crank counterwieghts, across the beam of the connecting rod and between the cam lobes on the 097 cam.

I also remember the only factory drilled crank snouts were the tuftrided cranks.

Any comments?

[Michael H.]

Re: Memory check

Mike,

Good memory!! There was a light blue paint ID on both sides of a solid lifter 327 for at least 62-65. I have a pic here somewhere. I don't remember the other areas that this color appeared but I do remember that there were several.

I believe the tuftride crankshaft first came to production in the 67 Z28.

[Michael H.]

Blue Paint On Block *NM*

[Mike McKown]

Re: Memory check

You're probably right on the hardening treatment. I thought there was some special journal prep on the SHP cranks.

[Michael H.]

Re: Memory check

I remember that this process was mentioned here on this board a few months ago as being used on 327's but it wasn't. The easy way to spot a tuftried crankshaft is the machined areas on the counterweights. This area will be shinny on a 327 but the tuftried process turns this surface to a dull grey on the 302" Z28 crankshaft.

[Mike McKown]

Re: Memory check

Seems you're right here. The 327 crank I have does have shiney counterweights, just like they were machined. I have a '67 302 crank and it is dull grey.

I learned something here.

[Michael H.]

More Blue Paint

Here's a better pic of the blue paint areas. Also note the large "17" on the side. This number seemed to change from bolck to block. No idea exactly what these things mean but obvious that they indicate a finished operation of some kind. All of these ID symbols would also have been on a service block and that block would have had a large "S" on the side instead of the engine suffex code RF etc.

[Clem Z.]

mike back in the good old days

we had more trouble with cracked cranks,showed up with magnafluxing, with the nitrided ones than the std ones. if you grind the crank journals .010 under you are thru the nitriding

[Mike McKown]

I had a number of them with the "S" on the side

Always wondered what that meant.

[Mike McKown]

Clem

I think you're saying the journals were Nitrided rather than Tuftrided on the 327's?????????

I had on of these break at the #5/6 rod journal. It was a SHP crank. Engine was very low miles. Three other guys had the same problem but we all used a 265 harmonic balancer and I always attributed the problem to that.

[Clem Z.]

Re: Clem

i could be wrong but i believe that they are one and the same. we need of the engineer types to step in here

[Michael H.]

Re: Clem

I'm sure someone will have all the correct info for us on this. I believe tuftride was a second heat treat process that increased surface hardness (.0005 deep) and nitride was actually a chemical process that produced same results.

In the late 60's or early 70's, engineering released info that stated the minute surface cracks that appeared in a C/S journal fillet were a result of the tuftried process and were not to be considered the result of stress. Many brand new crankshafts showed these small cracks.

[Michael H.]

Re: I had a number of them with the "S" on the sid

If I remember correctly, the service short block with the "S" had the character rotated 90 degrees and was much larger than the typical engine code characters. Also remember two short lines that intersected the center of the "S", on some new short blocks. Difficult to remember exactly because that was 40 years ago and no one paid any attention to things like this. I only vaguely remember what I did yesterday.

[Michael H.]

Re: mike back in the good old days

Clem,

Found it. I knew it was here somewhere in all this rubble. This came directly from engineering in late 1969 and discribes the cracking on the tuftride crankshafts;

"Tufftride cracks are not serious except at the radii to throws. Magnaflux inspection may show small heat treat cracks around oil holes. These are not detrimental as long as they do not extend into journal fillet radii".

Also found the info on the difference between tuftriding and nitriding. They discuss both and also go into detail on the process used for each. Both are a heat treat methods but tuftriding is a dip into a hot cyanide powder bath and nitride is a process that introduce nitrogen into the surface using an electrical field and high temp. I'll give you the entire story when I return in a few hours if interested.

Michael

[Mike McKown]

Re: I had a number of them with the "S" on the sid

You have a good memory too. The top of the "S" faced the rear of the block. The bottom faced the front. Or, is it the other way 'round?

Alan Colvin adds in his book that the SHP crank "tuftriding" started in '64. Also says that the cranks were cross drilled. I'd forgotten that.