Engine autopsy

[GeorgiaDieselGTO]

I guess i would have picked up several 10ths if i wouldn't have skipped that step , daaaaaaaang :rofl:

JK guys I agree its best but i see no real penalty from skipping it on my build. and for what the motor was built for . If it was being built for DD / 10's of thousands of miles , then yes , and if the crank would have been pulled it would have went out for a balance , but the crank never left the block.

Ya its best, but i seen Harleys Dad take a router to his pistons with them in the block that motor has been used and abused for quite a few miles with no problems so it works

 

[770JOHNNYW]

Ya its best, but i seen Harleys Dad take a router to his pistons with them in the block that motor has been used and abused for quite a few miles with no problems so it works

tell me your joking

 

[TrentNell]

Ya its best, but i seen Harleys Dad take a router to his pistons with them in the block that motor has been used and abused for quite a few miles with no problems so it works

That man is my hero :rockon::rofl:

 

[JD4440]

Well, at least the ones that have cracked one are most likely well beyond what I'm looking to be at HP wise.

 

[mytmousemalibu]

Router'd pistons :rofl::thumb: I dont think i could do that nor get away with it :spit: But thats F-in awsome:rofl:Was that freehand That would be mighty brave! A nice 1/4 shank carbide burr fits in a router like a peach and cuts aluminum like a mofo! Hell if a guy made a good guide jig for the router and cut the lip back and blended the edge in, could prolly get a decent result Biggest issue is aluminum slivers everywhere. That would be a huge Pita! lotta work to seal it off. Put clay or tape or somthing over the piston to wall gap.

:redneck: Genius:thumb:



Wait.......... Did this dude use a carpentry bit!

 

[jlawles2]

I know that there are some router artist out there. I would be afraid that I could not get the same cut on each piston and would have 8 different compression ratios.

I guess someone could have a router bit custom cut for the de-lipping job and just run them on a table or something. Would take a bit of layout work, but I can picture how to flip a piston top down to the table and run it in a guide.

On the other hand, to stop the Al slivers from getting everywhere, grease and a shop vac could be your best friends.

 

[othrgrl]

Ok, thanks for clearing that up. Only the second set of delipped pistons I've seen fail.

You can add 8 more pistons to the list.

Here is the one that completely let go:



The other 7 were cracking in the same places - on each side of the bowl directly above the wrist pin:

 

[Akdiesel]

Ouch! Sorry to see that Dustin

 

[Gmclbz]

You can add 8 more pistons to the list.

Here is the one that completely let go:



The other 7 were cracking in the same places - on each side of the bowl directly above the wrist pin:

Whose motor?

 

[05chevy]

Whose motor?

i believe thats dustins motor. sorry to see the carnage cant wait to see it run again

 

[GeorgiaDieselGTO]

tell me your joking

That man is my hero :rockon::rofl:

Router'd pistons :rofl::thumb: I dont think i could do that nor get away with it :spit: But thats F-in awsome:rofl:Was that freehand That would be mighty brave! A nice 1/4 shank carbide burr fits in a router like a peach and cuts aluminum like a mofo! Hell if a guy made a good guide jig for the router and cut the lip back and blended the edge in, could prolly get a decent result Biggest issue is aluminum slivers everywhere. That would be a huge Pita! lotta work to seal it off. Put clay or tape or somthing over the piston to wall gap.

:redneck: Genius:thumb:


Wait.......... Did this dude use a carpentry bit!

Hey i watched him do it and yes we closed everything off we could I think he spent 2 days driving around the country to find the bit.
he just run the pistons up to the deck and use the deck as his surface. the bit had a bearing on the tip so thats how he got them equal. dont no if it was a carpentry bit or not, might have been that truck is still on the road today and runs like a champ
I sure wouldnt have done it, but is worked Neither Harley of his dad are rednecks at all, but they sure arent scared to try stuff

I guess i need to change my sig from hole in one to crack in 3, just got it apart. one split all the way across, and there were 2 more starting Cut and Coated LB7 piston, so add mine to the list

 

[othrgrl]

The pics I posted are of my motor, finally got to tear into it. It broke at the track back in June when I coasted to a 10.74 - mechanics trucks is always the last one to get worked on. I also found the stock flex plate was starting to crack - I'm surprised it held up to the abuse for so long. Haven't gotten into the bottom end yet - parts came in for the truck that was tying up a lift and I had to get back to the real work.

 

[dmaxalliTech]

Hey Dustin, I feel your pain for having to work on your own truck last. I've been building a pull truck for two years now

 

[SteveFord]

The pics I posted are of my motor, finally got to tear into it. It broke at the track back in June when I coasted to a 10.74 - mechanics trucks is always the last one to get worked on. I also found the stock flex plate was starting to crack - I'm surprised it held up to the abuse for so long. Haven't gotten into the bottom end yet - parts came in for the truck that was tying up a lift and I had to get back to the real work.

Are you going with forged pistons this time around?

 

[GeorgiaDieselGTO]

The pics I posted are of my motor, finally got to tear into it. It broke at the track back in June when I coasted to a 10.74 - mechanics trucks is always the last one to get worked on. I also found the stock flex plate was starting to crack - I'm surprised it held up to the abuse for so long. Haven't gotten into the bottom end yet - parts came in for the truck that was tying up a lift and I had to get back to the real work.

X2 i no all about the waiting part

 

[JoshH]

I have a cut/coated LB7 piston with a crack in it too. I haven't got the head off yet; I just looked at it with a bore scope through the injector hole.

 

[othrgrl]

Are you going with forged pistons this time around?

Yes, most likely the Arias but looking into a few other options.

 

[DIESELMAFIAPER.LB7]

what driveablity issues if any are there with froged pistons any dd issues that would arise i'll only be making in the 600-650 range till i get rods!! but just curious if the forged pistons those of you that have run them. Also i had my pistons rods and crank all balanced really well my motor dont shake at all at idle unless i have an injector issues

 

[othrgrl]

Forged pistons need more piston to wall clearance than cast pistons (.008" on the Arias, .006" on the Mahle IIRC), which means that when they are cold they will be looser in the bore which will cause more wear on the skirts and cylinder walls. The Hellfire rings used with the Arias also don't last as long as a steel ring on a cast piston would. A forged piston will have the same drivability of a cast piston with the same compression ratio, but the engine will need torn down for new rings more often. The only time I would really recommend a forged piston is if you are going to be over 900 rwhp - that seems to be about the limit on stock cut and coated pistons. I also wouldn't get in a motor to do pistons without doing rods. If you are like me and "need" a daily driver that's over 900 rwhp you will have to decide if you want to replace pistons (and possibly have to over-bore each time until you need a new block) or if you want to replace rings - at over 900 rwhp nothing is going to last for hundreds of thousands of miles.

 

[sweetdiesel]

Forged pistons need more piston to wall clearance than cast pistons (.008" on the Arias, .006" on the Mahle IIRC), which means that when they are cold they will be looser in the bore which will cause more wear on the skirts and cylinder walls. The Hellfire rings used with the Arias also don't last as long as a steel ring on a cast piston would. A forged piston will have the same drivability of a cast piston with the same compression ratio, but the engine will need torn down for new rings more often. The only time I would really recommend a forged piston is if you are going to be over 900 rwhp - that seems to be about the limit on stock cut and coated pistons. I also wouldn't get in a motor to do pistons without doing rods. If you are like me and "need" a daily driver that's over 900 rwhp you will have to decide if you want to replace pistons (and possibly have to over-bore each time until you need a new block) or if you want to replace rings - at over 900 rwhp nothing is going to last for hundreds of thousands of miles.

I have put those pistons thru living hell, Id rather replace rings than have cracked pistons.