3.8 4.2

troy81 · 03-25-2008, 08:18 PM

ok, so ive read all the 3.8to 4.2 conversion posts i could fine. pretty much what im finding is that, you could get a 4.2 crank and 4.2 pistons, rebuild the gaskets bearings rods etc... using all 3.8 parts and end up with a 4.2. am i correct or am i missing somethin, cuz that seems simple, especially if you can pull the engine.

LilRoush · 03-25-2008, 09:56 PM

Pistons are the same. You'll want an 01-04 oil pan to clear the crank. The 99-00 pans were a little different.

troy81 · 03-25-2008, 11:03 PM

i read that the 3.8 pistons on the 4.2 crank and 3.8 rods(which i read are the same as the 4.2 rods) , would sit tohighand hit the valves, which makes sense. the 4.2 pistons hook up deeper into the skirt of the piston therefore lowering the piston enough to clear the valves.
right now i have an 02 3.8, i would like to try to go to a yard and get a crank and pistons out of an f150 4.2 and put them in my block. would i be able to use my fuel rails and all my other internal parts?
or am i completely wrong about all of this and ive been misreading

l_shizzle_l · 03-26-2008, 12:08 AM

correctumudo!
I don't know if i would trust used pistions tho. don't forget about honing the block/

moontang · 03-26-2008, 12:30 AM

this is something i would love to do but i have to have something to drive which is really a killer

oh and money too

oh and time to

fack

but is it really just as basic (used very very out of context) as swaping the crank?

troy81 · 03-26-2008, 08:19 AM

well i can get the crank for like 175 i guess, but what about pistons? also do you know where i could get an overhaul kit for the engine? gaskets bearings etc... what do shops charge to do hone a car engine? i worked on boat engines and i could always get them done for free...

LilRoush · 03-26-2008, 11:11 AM

For the cost of having a shop machine your block and do the work, you'd be better off just buying a used short block, tossing on your mustang upper/lower intakes, oil pan and dropping it in that way.

l_shizzle_l · 03-26-2008, 01:14 PM

Quote:

ORIGINAL: troy81

well i can get the crank for like 175 i guess, but what about pistons? also do you know where i could get an overhaul kit for the engine? gaskets bearings etc... what do shops charge to do hone a car engine? i worked on boat engines and i could always get them done for free...

It depends on what you want done ontop of the hone, new freeze plugs, oil galleys cleaned, paint, etc. A rough estimate for what is getting done to my block(whenever i get arround to it) is arround $650.

troy81 · 03-26-2008, 08:13 PM

well are car engines like boat engines... where you can pretty much use wire brush to hone it, i know boat engines are softer cylinder walls but i wonder if i could do it like we used to do the boats. basicallyu just need to get the old pistons scratches out of the cylinder walls right?