4.3l sohc v6?

It's been several years since there's been any posts on this subject so I decided to start a new thread to discuss it. There are several ways to significantly increase the power and torque of the SOHC V6: supercharging, turbocharging and stroking. All three are fairly expensive modifications and many members would probably comment why bother when it's possible to upgrade from a V6 Explorer to a V8 Explorer for less money. Well one reason is the V8 was not available in the 2 door Explorer and another reason is I have become comfortable with the SOHC V6 in spite of its potential timing chain death rattle. I am approaching the end of what I hope to be a successful supercharger installation and for various reasons I am not interested in a turbocharger installation so I would like to limit this thread to discussing stroking (and possibly boring) the SOHC V6.

Tom Morana Racing offers a 4.3L stroker kit for $2,600 and a 4.3L short block for $4,550 with the short block requiring a $300 core charge. They claim an increase of 30+ hp and 30+ tq with no other modifications. Additional costs would be gaskets, TTY bolts, and probably a custom tune increasing the total cost of the stroker kit to around $3,000. That's about $100/hp which is comparble to other performance enhancements. In spite of the V6 use in the Mustangs I'm not aware of any other commercially available stroker kits.

I wonder if the Morana kit would hold up on a daily driver and if the pistons would provide adequate oil control. It's hard to determine from the photo of the kit components if the oil control ring is far enough above the piston pin for good oil control. I also wonder if the height of the piston is adequate to prevent "rocking" in the cylinder bore. There's no mention of clearance issues between the block and the crankshaft counterweights or rod caps. Maybe no modifications to the block are needed.

I have no experience with stroking an engine. I will appreciate your comments.

 

[2000StreetRod]

Excessive honing?

I don't know what your setup is for honing but the simple honing tool I have is only for removing the glaze on the walls to obtain a better ring seal. I use a ridge reamer to remove the ridge at the top of the cylinder that builds up due to the gap between the top of the compression ring and the deck surface. With 0.6mm overbore with a hone I would be concerned about bore taper, alignment and out-of-round tolerances.

 

[jd4242]

any OHV number to search for?

I would like to see a 90 tm 1990 block..I dont know the cast number though, have to dig the block out

 

[colintrax]

Even at 5 mm thick, that still not enough for a 4" bore....5mm=.196 You take the minimum wall thickness of .15 and only leaves you a .046 over bore (4"= .047 over bore) I wouldnt trust it,especially for a boosted applications. ..

JD 5mm is .19685" which rounds up to .197"

 

[Greg_DonWindsor]

You gentlemen have done very thorough research, hats off! I have long been considering ordering a custom built motor from supersixmotorsports, as I have so much money into my truck now it makes more sense to take the plunge for another $10-$15k than it would to finance a new vehicle. Besides, I really love the 2nd gen explorer and don't think I can ever get rid of it.

This being said, I know that Morana offers the stroker kit, and super six's site makes mention of it, but the only short block they list has 4.0L displacement. Of anyone who has contacted super six, are they able to perform the stroking option as well? I think I prefer the super six short blocks due to the fact that they claim to use all new parts.

 

[Sedition]

Excessive Wear from oiling issues.

The bores on my block are worn from oiling issues, as are the bearings.

I just use a 3 legged medium grit hone to remove the ridges and create a cross-hatching score pattern in the bores. It would take many days of straight honing and many stones to achieve a .6mm overbore with this kind of hone.

 

[Sedition]

I know that Morana offers the stroker kit, and super six's site makes mention of it, but the only short block they list has 4.0L displacement. Of anyone who has contacted super six, are they able to perform the stroking option as well? I think I prefer the super six short blocks due to the fact that they claim to use all new parts.

Anyone know what diameter pistons are in the 4.3L Tom Morana stroker kit?

He doesn't actually list sizes on the website.

http://www.moranav6racing.com/category.html?CategoryID=32

 

[jd4242]

Anyone know what diameter pistons are in the 4.3L Tom Morana stroker kit?

He doesn't actually list sizes on the website.

http://www.moranav6racing.com/category.html?CategoryID=32

I swore he told me they were stock bore when I was talking to him..he is kind of hard to understand tho, talks fast and with accent. .but then again I talk slow and with a accent. .LOL


O but everything we ever talk about is the ohv...so may be different for sohc

 

[Bronco2]

I talked to supersix, and he offered me a custom grind crank if i want it, is posible

i also think both stay on standart oversize and just use custom build short pistons

 

[2000StreetRod]

undersize rod bearings?

I think there are only three ways to retain the stock rods and stroke the engine:

1. A new crankshaft of the desired stroke and standard bearing sizes is forged or machined from a billet;

2. The stock crankshaft is offset ground and undersize rod bearings are used;

3. The stock crankshaft rod journals are asymmetrically built up with welding and then reground to the stock bearing size.

I read on one of the Mustang forums that a member's stock rods didn't fail until 600 ft-lbs (I assume rwtq) running 16psi of boost and a 75 shot.

I would be interested in more details on what Super Six Motorsports is proposing.

 

[4pointslow]

Thread

2000Streetrod,
Can you find that thread about the mustang with the 600 ft lbs,16 lbs of boost, nitrous, and post a link to it here?
That guys set up sounds like something I would like to read about.

 

[2000StreetRod]

replaced 4.0L with 5.4L

I don't know how much information is still posted because he replaced his 4.0L with a 5.4L after blowing the 4.0L engine. Here's a link to get you started: Anyone stroked and blown? See post 8.

 

[Bronco2]

Its not possible stroking with stock rod...
The compression hight from piston then has to move

 

[2000StreetRod]

crank estimate confirmed

Tom Yentzer of Super Six Motorsports has just confirmed my new billet crankshaft estimate and provided some displacement increase guidance:

"We usually run them at .030" over but many of the guys across the pond want a 4.0” bore. I don’t like going there but it is doable.

Yes we talked about a billet custom crank. Like you, I could not work an offset ground crank using a stock cast iron crank, that’s just a recipe for an expensive repair…

We have not built a stroker for the 4.0 SOHC yet because the cost of the crank really makes it almost unaffordable for most people, but it appears to me there's room in the crankcase to do it, would require clearancing down there and as long as we stay out of the oil gallery, shouldn’t be a problem.

Stroke increase would be moderate, on the order of .30-.35” stroke increase. You’d be looking at kit costs in the area of $5000-$6000 or so due to the cost of a billet crank, rod selection, forged pistons, etc."

 

[Bronco2]

if i would pay a billet crank.. i would stroke it anyway..

 

[Bronco2]

after jigsaw the block.. i found 3.8mm as smallest point

 

[Sedition]

Where abouts in the bore did you find the thinnest spot Bronco? I can't see your Pic.

 

[jd4242]

Its sounding more and more like a 4" bore wont fit in a sohc.


For us OHV people I got my 4" JE asymmetrical pistons in today.so if you can end up fitting them JE can make them to any spec you need in 4"

For those that aren't following my thread

 

[Bronco2]

looks nice!
how much is the deck hight?
sorry here are the pic

its standing upside down...
smalles point is 2 1/2inch from bottom.. in car location its from top engine surface
if you get a close look you can see it..

 

[jd4242]

looks nice!
how much is the deck hight?
sorry here are the pic

its standing upside down...
smalles point is 2 1/2inch from bottom.. in car location its from top engine surface
if you get a close look you can see it..

Did you check bore size before cutting it?? This is starting to make me VERY NERVOUS about the OHV block...I wish I could seen cut block pics like this of ohv..

JE can make them to any specs. I run a long rod(6.058) so my ""compression height""
1.132, I believe thats what you mean by ""deck height""

 

[Bronco2]

Yes Sir ...
Compression hights sometimes named deck hight also ..
any price number by je?