3.7 Piston Removal

[Logan Savage]

I read a thread that said the pistons could be removed from the bottom of the block on a 4.0 engine . I would like to know if this is possible on a 3.7 . The crankshaft would be removed . I know the 4.0 is an inline 6 & the 3.7 is a V6 .

 

[TwoBobsKJ]

I read a thread that said the pistons could be removed from the bottom of the block on a 4.0 engine . I would like to know if this is possible on a 3.7 . The crankshaft would be removed . I know the 4.0 is an inline 6 & the 3.7 is a V6 .

Once the crank is out of the way the pistons come right out :waytogo:


Bob

 

[CactusJacked]

What are you trying to do, partially rebuild the engine without removing the head? :happy175:

 

[Logan Savage]

The engine very recently had a complete top end rebuild then a rod started knocking . I was hoping to install a new rod & piston & a crank kit from the bottom .

TwoBobsKJ---Do you know that for a fact ? Since I posted this I've also been told it can't be done .

 

[Cpt Marvel]

Last I knew (long ago) Pistons were always removed from the lower end. But since you need to compress the rings to get them back in, they had to go in from the top. The reason that they were removed from the lower is because of the ridge at the top of the bore, caused by normal wear. Hence the ridge reamer.

 

[TwoBobsKJ]

The engine very recently had a complete top end rebuild then a rod started knocking . I was hoping to install a new rod & piston & a crank kit from the bottom .

TwoBobsKJ---Do you know that for a fact ? Since I posted this I've also been told it can't be done .

Yep - it's getting them back in that will be a challenge. Like Capt. Marvel said above the rings need to be compressed.

Bob

 

[M38 Bob]

If you're gonna remove em without pulling the engine, it's gonna HAVE to come out the top. If yer gonna pull the engine, the front timing assys got to come off to remove the crank. Might as well buy a head gasket set also and do it right.

Bob

 

[Hockeygoon]

The engine very recently had a complete top end rebuild then a rod started knocking . I was hoping to install a new rod & piston & a crank kit from the bottom .

TwoBobsKJ---Do you know that for a fact ? Since I posted this I've also been told it can't be done .

Probably meant it "SHOULDN'T" be done. As mentioned by others you install a piston from the top, compressing the rings to feed it in from the bottom sounds like a giant PIA - if its possible but about anything is. If you are going through the ordeal of pulling the engine, the crank and the timing assembly removing the heads are the easy part. With a new piston and rings I'd think you'd want to hone the cylinder - that's not that easy to do from the bottom side either. If you don't hone it you might be in for a surprise with the amount of oil consumption.

 

[Cpt Marvel]

I remember back when I was like 13 (and I'm 55 now, so that was a couple years ago) my father took me in his old Chevy pick up to Grandpas garage. Pick up was a 50s something, inline 6. The kind where the the door pillars kinda leaned forward, and the windshield did a little wrap around. Anyway, drove the truck about 70 miles to Grandpas garage, old kind with a pit in the floor because they didn't have lifts back in Grandpas day. He put that pick up over the pit, drained the oil, pulled the oil pan, unbolted the rod bearing caps, pulled the pistons, took them to get knurled, put new rings on them and slid them back in. Bolted everything back together, filled it with oil and we were home before dark. Just a memory.

 

[Hockeygoon]

I remember back when I was like 13 (and I'm 55 now, so that was a couple years ago) my father took me in his old Chevy pick up to Grandpas garage. Pick up was a 50s something, inline 6. The kind where the the door pillars kinda leaned forward, and the windshield did a little wrap around. Anyway, drove the truck about 70 miles to Grandpas garage, old kind with a pit in the floor because they didn't have lifts back in Grandpas day. He put that pick up over the pit, drained the oil, pulled the oil pan, unbolted the rod bearing caps, pulled the pistons, took them to get knurled, put new rings on them and slid them back in. Bolted everything back together, filled it with oil and we were home before dark. Just a memory.

Probably a 216 or 235 I6. The rod bearings were "splash lubed" with a low pressure oil system for the most part and had babbitt bearings. The babbit bearings were replaced on a somewhat regular basis - sort of like changing the transmission oil today. Drive them somewhat hard and the babbitt bearings would need replaced every 30K or so.