Motor damage

mooreken
Posts: 170
Joined: Sat May 09, 2015 12:25 pm

Motor damage

Post by mooreken » Fri Nov 24, 2017 10:16 pm

I pulled the motor today. The damage is about what I expected. Thou I have not seen a connecting rod this bent before.
Looks like it was the piston that gave up first....not that it matters all that much.
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Tom Wells
Posts: 385
Joined: Fri May 08, 2015 7:34 pm
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Re: Motor damage

Post by Tom Wells » Sat Nov 25, 2017 7:56 am

Ken,

Ouch!

Thorough destruction. Way above average...

Was the pin seized to the remnants of the rod? Could that have happened first and then the piston cracked to pieces?

It would be interesting to try to pinpoint (sorry, no pun intended) the initial cause of the failure.

If the pin froze in the small end of the rod, it might point to a lack of lubrication.

Did the crank show anything on its bearing surfaces?

This will be a good test of forensic accuracy :(

Let us know what you think!

Anyone else want to go have a look?

Tom

BlackSnake
Posts: 92
Joined: Mon Jul 13, 2015 4:09 am

Re: Motor damage

Post by BlackSnake » Sat Nov 25, 2017 2:42 pm

Tom,

SBC piston pins are almost always pressed into the rods, so unless Ken went with full floaters, I'd say a rod bolt let go or the piston shattered. :W:

mooreken
Posts: 170
Joined: Sat May 09, 2015 12:25 pm

Re: Motor damage

Post by mooreken » Sat Nov 25, 2017 3:59 pm

The pins are press fitted into the rods. So far oiling looks ok other than the journal that gave up. However I have not taken the crank out. Its all in a nice neat bundle on the stand for now. I'm gathering up parts info and such at the moment. I've decided to go with the 421 ci. instead of the 434 ci. I'm just afraid that pushing everything to the max will come back and bite me. The 421 is 3.875 stroke with a .030 bore. 4.155". I will be upping the compression a little too.

I don't expect to have it back up until spring or so...have to sneak the upgrades into the budget. 5th gear synchronizer needs replaced so I hope to keep motivated to take the trans back apart again and go thru it. I had new synchronizers for all the gears except 5th when I put it together the first time. It did last about 2yrs before it gave up. This will also let me clean all the oil out of the nooks and crannies under the car a little easier.

I do need to get the cam out so I can look at it. Hopefully I don't have to add a cam to the budget.
The piston seems to have broken thru the wrist pin area, all pieces below the pin are smaller than a marble no big chunks.
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mooreken
Posts: 170
Joined: Sat May 09, 2015 12:25 pm

Re: Motor damage

Post by mooreken » Tue Nov 28, 2017 10:20 pm

Sometimes it the little things we make that we can be most proud of. I'm using the cam over so I made this to keep the lifters and pushrods in order. I might have even saved $29.95 from Summit Racing.
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BlackSnake
Posts: 92
Joined: Mon Jul 13, 2015 4:09 am

Re: Motor damage

Post by BlackSnake » Tue Nov 28, 2017 10:48 pm

Ken, I see you're running canted valves, who's heads are those, Brodix?

mooreken
Posts: 170
Joined: Sat May 09, 2015 12:25 pm

Re: Motor damage

Post by mooreken » Wed Nov 29, 2017 12:23 am

No they are an old Trick Flow design."Twisted Wedge" They don't make them any more. Had to get special intake rockers to make it work.

pops
Posts: 39
Joined: Sat May 09, 2015 11:14 am

Re: Motor damage

Post by pops » Wed Nov 29, 2017 10:47 am

Ken I guess this must be another one of those little things but I noticed you have a petcock installed on your block. Great idea do most blocks have a tap to do this or is it a SBC thing

mooreken
Posts: 170
Joined: Sat May 09, 2015 12:25 pm

Re: Motor damage

Post by mooreken » Wed Nov 29, 2017 2:32 pm

Yes all SBC's have a pipe plug on each side. It makes it a lot easier to manage the water. I had heard that some tracks don't want anti-freeze so I added these to drain and save (with a hose on the petcock) the anti-freeze if needed.

BlackSnake
Posts: 92
Joined: Mon Jul 13, 2015 4:09 am

Re: Motor damage

Post by BlackSnake » Wed Nov 29, 2017 2:51 pm

I've always installed petcocks on those drain ports on all of my engines, but the rust and silt that always clogs the port openings clogs the petcocks even worse, rendering them useless. Kind of like the shutoff valves under the sink that never work when you need them...:-(

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