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66geeto · 07-10-2006, 06:22 PM

pictures are very blurry, sorry but i tried to point out the breaks and outline where the oil pump shaft broke the guide for it

http://putfile.com/pic.php?pic=7/19018073371.jpg&s=f10"]http://putfile.com/pic.php?pic=7/19018073371.jpg&s=f10"]http://putfile.com/pic.php?pic=7/19018073371.jpg&s=f10
http://putfile.com/pic.php?7/19018164024.jpg&pic=s=f10
http://putfile.com/pic.php?pic=7/19018183260.jpg&s=f10
http://putfile.com/pic.php?pic=7/19018211080.jpg&s=f10

hope those work, never tried pics before.

masshole · 07-10-2006, 09:23 PM

pics dont work for me...

chiphead · 07-10-2006, 09:24 PM

do an autopsy of the oil pump. Did it hang up for some reason? Was the driveshaft new? Which rod broke again? Seems like the pump would have to stop dead cold to throw the pump shaft thru the shaft retaining boss and into the rotating assembly.

What do the bearings look like? How abouts that oil pump?

chip

lunaticeh · 07-11-2006, 12:41 AM

That sucks eh... I've seen a couple of SBC shafts broken off at the tangs both on either end. Not really much anyone can do to prevent something like that. Just like if you put in brand new rod bolts and then one fails at 7k... Had that happen... Should change the title of the thread to "Engine blown on break-in... **** happens..."

Jack Gifford · 07-11-2006, 12:54 AM

That "guide" (if you mean the part of the block that surrounds the top of the oil pump drive shaft) does absolutely nothing once the engine is assembled.

goquick · 07-11-2006, 02:32 AM

If I looked at the picture right, the nick in the block won't affect the engine if you grind it out smooth, (radiused notch style) like needs to be done for long stroker kits that are 4 1/2"+.

Half-Inch Stud · 07-11-2006, 07:34 AM

Soooo, Oil Pump lock-up (usually related to a coolant leak) dropped the pump drive&cast loop, for interference into the connecting Rod. Is thaaat it?

chiphead · 07-11-2006, 07:40 PM

Thats why I suggested taking the oil pump apart. I find it hard to believe that coolant/oil mix would lock up the pump in such a manner. Or perhaps that shaft was old and about to go? Too little distributor end-play? How did the dist and cam gears look? How old was the pump shaft? Whats hiding in that oil pump?

Half-Inch Stud · 07-12-2006, 01:16 PM

I held an oil pump in-my-hand that locked-up because hot antifreeze converted the slick glaze into a tack-varnish. Drive gear was as-good-as welded to the housing.

Pump was run-in for 10years LOL. NO real varnish to talk about on the engine internals. Just a tint.

66geeto · 07-12-2006, 07:39 PM

I left the pump with the machinist, otherwise i would tear it down (which i'm sure he already has). The pump turned like the day i pulled it out of the box after we pulled it off the block. NO COOLANT ANYWHERE but the radiator and where it was supposed to be. I don't know what to tell you guys, I just think the shaft failed, for what reason is a complete mystery. It was the original shaft so i guess it could have been weakened or possibly the pump momentarily plugged in its past life before i rebuilt the engine and stressed/hairline cracked the tangs on the shaft.

66geeto · 11-14-2006, 07:10 PM

block is still at machinist...........haven't heard from him since.

chiphead · 11-14-2006, 09:59 PM

When is the last time you talked to him? Sounds like its time to get another machinist.

Thumpin455_GTO · 11-15-2006, 03:58 PM

Check your PM...

66geeto · 05-09-2007, 10:32 AM

this issue has been super resloved......sorry for not updating if anyone is still watching this thread or is curious. I haven't been on this site in awhile. When the crankshaft was balanced (by the only other employee of the machinist whom has since retired) weight had to be added. It went on to the rear counterweight and the short block was wrapped up and sent to me for final assembly. I installed the came oil pump heads distrib. etc. got it running. The weld on the back of the counterweight was ground down but stuck out enough to just touch my oil pump drive shaft. I couldn't tell by turning it over by hand as it would barely even touch it. we're talking a couple thousandths. By the time i broke in the cam for 3 min. it had had enough of that business (got into a harmonic with the crank and got worse and worse.) broke the pin off the oil pump, the tangs off of the oil pump shaft . broke the guide for the shaft, the bottom out of the distributor then dropped down on the oil pump at an angle, was hit by the counterweight, candycaning it and the next time around hooked the rod with the oil pump shaft and broke the rod. all within a bout a second. the last part is the one i heard. as i was getting out of the throttle from hearing a slight tic of all the other precursors going wrong.

66geeto · 05-09-2007, 10:37 AM

The machinist did take a long time to get it back together, however that's kinda how it goes with him and i hadn't contacted him very often to crack the whip so it was partly me. I had to buy a junk 400 for a rod and the other new parts. He replaced the bearings piston rings @ rehoned the #7 cylinder. when i picked it up we both agreed that there was no way he could have know that it was going to contact the oil pump shaft as he didn't assemble it all the way. After we came to that conclusion i started getting my checkbook out and he let me know that this one was on him. good guy and i fell bad for ever questioning him. It was a bad situation and could have been avoided by checking his employees work but I would rather go to this guy from now on seeing how he won't stiff me and has good customer service. Thanks for all the help in diagnosing this whole ordeal but, in the end all i was really out was 6 months and this is a 5 year project probably.

Johnny406 · 05-09-2007, 11:59 AM

Glad it worked out for you!!

Half-Inch Stud · 05-09-2007, 12:18 PM

Hmmm, then could the Root Cause have been a TIGHT Piston Pin//Slug fit that bound-up and caused the Rod undue (un-do) stress?

gpsonthebrain · 05-09-2007, 03:10 PM

66gteeo,

glad to hear that it has worked out very well in your favor. Obviously, your were dealing with an individual (machinist) that has a lot of business ethics. It is good on your behalf that you delt with him in a civilized manor as well. A lot of people would blown a head gasket and went after him with both barrels even before learning what caused the problem. This whole ordeal could have gotten out of hand and the end result being the machinist not standing behind his work and you being out of extra money to have the block repaired by someone else. Kudos to the both of you for how this unfortunate incident was handled.

66geeto · 05-09-2007, 06:25 PM

Quote:

Originally Posted by Half-Inch Stud

Hmmm, then could the Root Cause have been a TIGHT Piston Pin//Slug fit that bound-up and caused the Rod undue (un-do) stress?

What we determined was that the rod hit the oil pump shaft after it had broken off of the pump and out of the distrib/oil shaft guide and had fallen down on the pump. It was hit on the counterweight once or twice (scarring on counterweight) to bend it in a position that caught the rod and hooked it from going up. Hope that somehow makes sense.

Thanks for responding to my dead thread guys.

Jack Gifford · 05-10-2007, 02:41 AM

Quote:

Originally Posted by 66geeto

The machinist... let me know that this one was on him.

Nice guy- and smart businessman.

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