High compression 12v piston - Page 2 - Competition Diesel.Com

CorneliusRox · 01-17-2017, 06:47 PM

Quote:

Originally Posted by cumminsman315

The key to not having a problem with it is to get filler rod that is the same alloy, definitely don't want to slap some 4043 on and hope for the best. Same with all aluminum heads, some heads are different alloy than others but if you use a rod that is the same as the head it works perfectly

From everything I've learned, autogenous welding is not as strong as using the proper filler rod. You typically use at least one grade down to make up for the heat affected zone, so you'd use 4043 or 5356 for 6061.
I'm not 100% sure if going autogenous and then annealing it would be the best case though.

All I'm saying is, I'd do a LOT more homework before fill welding and machining.

cumminsman315 · 01-18-2017, 09:46 AM

Quote:

Originally Posted by CorneliusRox

From everything I've learned, autogenous welding is not as strong as using the proper filler rod. You typically use at least one grade down to make up for the heat affected zone, so you'd use 4043 or 5356 for 6061.
I'm not 100% sure if going autogenous and then annealing it would be the best case though.

All I'm saying is, I'd do a LOT more homework before fill welding and machining.

Could be true, I don't know the fancy stuff about it. All I know is on v8 aluminum heads on all the drag racing motors I've helped fix from 600hp-2300hp if you call the manufacturer they will send you filler rod the right alloy. Which we were always told was the same as the head but it could be like you said

Levi_plummer · 01-21-2017, 10:35 AM

Did you look into 6b pistons? Then on turbo engines should run the higher compression you are looking for.

blackdiesel · 01-26-2017, 08:49 PM

Ok I came up with a 6.7 crank. My machine shop said my block will clean at .020" over. My question is what is the highest factory compression ratio piston available to start with? That will hopefully ensure that I end up with the highest Cr possible without custom pistons.

9724VF350 · 01-27-2017, 08:25 AM

As far as Mahle goes, 17.5:1 is .020 bore, 18.5:1 in std bore.

I think you can get the 18.5:1 pistons through Cummins.

Tate · 01-27-2017, 06:31 PM

Quote:

Originally Posted by blackdiesel

Ok I came up with a 6.7 crank. My machine shop said my block will clean at .020" over. My question is what is the highest factory compression ratio piston available to start with? That will hopefully ensure that I end up with the highest Cr possible without custom pistons.

Based on an old spreadsheet I cooked up a couple years ago, if you ran a 286020 piston with about .075" milled off the top, you'd be in the 21.5-22:1 CR range, based on a 102mm bore.

SuperiorRam · 02-14-2017, 05:35 AM

Love this thread!
What about 4b pistons with the knob in the center of the bowl do these have a higher cr for emissions reasons?

I also thought, hey why not just tig in some filler into the bowl and re machine before I read it lol

I very much miss my m35a2

SuperiorRam · 02-14-2017, 05:53 AM

Which Mahle Piston Is Right For Your Engine? - Hot Rod Network

01-21-2017, 10:35 AM	#23
Levi_plummer Name: Levi_plummer Title: Too Much Time Status: Not Here Join Date: May 2012 Member`s Gallery Posts: 346	Did you look into 6b pistons? Then on turbo engines should run the higher compression you are looking for. __________________ 92 W250 sclb. "Jinny" 962/1472. 7.08@98mph RIP.. 96 sclb 4x4 new racetruck in the making 97 sclb 4x4 tow rig

01-27-2017, 08:25 AM	#25
9724VF350 Name: 9724VF350 Title: Tractor Guy Status: Not Here Join Date: Mar 2010 Location: Northeast Ohio Member`s Gallery Posts: 2,784	As far as Mahle goes, 17.5:1 is .020 bore, 18.5:1 in std bore. I think you can get the 18.5:1 pistons through Cummins. __________________ 97 F350 4X4 CC Dually 5spd 24V 913 S300/HT3B Ranch Hand. Playtoy-Oliver 1655. 12V now, 13mm, S475 Wife's ride-03 Excursion 12V swap in the works.

02-14-2017, 05:35 AM	#27
SuperiorRam Name: SuperiorRam Title: Too Much Time Status: Not Here Join Date: Dec 2008 Location: Northern Minnesota Member`s Gallery Posts: 1,239	Love this thread! What about 4b pistons with the knob in the center of the bowl do these have a higher cr for emissions reasons? I also thought, hey why not just tig in some filler into the bowl and re machine before I read it lol I very much miss my m35a2 __________________ 97 12v 5spd 83 Grumman Olson bread van 4bt and a chev nv4500 83 RCSB 12V almost all the way in cab more fiberglass than steel SRT Challenger 6 speed Last edited by SuperiorRam; 02-14-2017 at 05:36 AM.

02-14-2017, 05:53 AM	#28
SuperiorRam Name: SuperiorRam Title: Too Much Time Status: Not Here Join Date: Dec 2008 Location: Northern Minnesota Member`s Gallery Posts: 1,239	Which Mahle Piston Is Right For Your Engine? - Hot Rod Network __________________ 97 12v 5spd 83 Grumman Olson bread van 4bt and a chev nv4500 83 RCSB 12V almost all the way in cab more fiberglass than steel SRT Challenger 6 speed

01-26-2017, 08:49 PM	#24
blackdiesel Name: blackdiesel Title: Diesel Enthusiast Status: Not Here Join Date: Feb 2009 Member`s Gallery Posts: 243	Ok I came up with a 6.7 crank. My machine shop said my block will clean at .020" over. My question is what is the highest factory compression ratio piston available to start with? That will hopefully ensure that I end up with the highest Cr possible without custom pistons.