i have 1986 3.8TBI .the crank went out ,just wasn't holding the oil pressure any more. the car ran great, started find but when i took the crank in to have it turned. the machine shop say the crank non-turnable. so i want to make it into 4.2 but still use my top end with intake/stuff. so my questions are;
1- from what parts 4.2 do i need and of what years?
2-can i reuse my block ?
3- what year 4.2 short block can i use with my heads and intake?
from what i can find out, the 4.2 is a stroked 3.8 . kinda like the 302 is of the 289V8 but im not sure because the years are different from the two.
i want to keep the car as V6 because in the next year or so ,i will be giving the car to my youngist when he completes high school. i figure the 4.2 would make more low end power to help in the city driving but still keep the gas milage up because my son allready has 2-V8 cars (1987lincoln VII LSC 5.0H.O and a 1979 T-bird with a400c) to get the low gas mileage with.
well you will need the crank/rod/piston combo for sure. and yes you can use your existing block im about 90% sure on that and if you want a short block allt he 4.2's are gonna have a newer type head... which you can use yours on they mostly interchange. Here are some sites that may help you out
http://www.babpen 15s.com/editorial/ar/ar90134.htm
also talk with Supersix motorsports
http://www.supersixmotorsports.com/
I have talked with supersix and they are very helpful
this is another one Tom Morana V6 Racing
http://www.moranav6racing.com/category.html?CategoryID=32
I havnt really talked with these guys much mainly cause they are not in the united states and i dont want a big phone bill lol
Hope you can gather the necessary information thru these guys
Have you considered a split port swap for the 4.2?
NO, you can not use your block with that crank. point blank no if's ands or buts wihtout balance problems.
However,,, all bottom end parts fit like a glove (crank / rods / pistons).
the only 3.8 fox engine that would qualify for the 4.2 stroker option would be the 1988 motor.
hmm my bad the crank front main journal difference. forgot about that lol
someone over at FEP(plskjnkr or something like that) has done this with a pre-88 block, his was an '85 if i remember correctly.
there are probly others.
your right about the balanceing but I don't recall him complaining about the balance issues.
i think its safe to assume the 83-4 blocks wouldnt work with it though.
this is where i ran into a show stopper.
I had no idea what to do beyond researching. The crank was totally different meaning the leack of a balancer. The 4.2 is internal balanced like the 88 3.8 which makes is farily a direct swap.
since i did not do the conversion, maybe i should not talk but from all the reasearch and questions i asked, i didnt want to put all the work into it not knowing the dynamics or the consequences of all my work.
The 4.2 crank is steel , the rods are broken caps. Broaching the 4.2 rods means you can only go oversize vs a rod you find typically in the traditional index (if thats what you call it) caps.
the_intimidator03:
thanks for the enfo. it looks like i need a 1989 to 95 short block but what years 4.2 crank and rods do i need?
on the secound site:boy ,8 grand for long block 3.8 ?why would we spend that kind money on just a v-6?
V8Demon; no change style of heads. want to keep the style i have. I need to replace my current 3.8 crank. so i'm just looking to do a stroker of some kind at this time.
before i would go through all the work split port swap , i would put a V-8 IN HER.
if you have to replace the crank. i allwise look for the easyier way to make more cubic inches! like
making a 289 into a 302,
making a 351M into 400,
making a 429 into a 460,
i see a 3.8 is a same bore as the 4.2. so i'm just looking to make it into 4.2... any help i would enjoy.