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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.
 



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

I paid $920.57 for their new 4" asymmetrical design piston, rings, pins and locks..I dont think its a bad deal considering its a new design and made perfectly to you specs..I paid $485 for my rods, which are off the shelf forged rods for falcon turbo, no crank changes.....im ruffly at $1,400 for forged rods and pistons..

They CAN make it and any bore size, dish/flat and any compression height. .there is a charge if you go smaller than 4" though, their standard core in that design is 4"..I just spoke with Henry (4219) again to confirm this..

Im sure I may have left some power on the table from not stroking it but It was just to difficult to figure out and I am going for as strong as possible

http://www.jepistons.com/
 



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pictures

There are some interesting pictures in that thread. I wish I could read German!
 






Cosworth heads on a 4.0L block

That looks like another thread about installing the Cosworth DOHC heads on a 4.0L block. In another thread I've seen it documents all of the machine work required to make the heads fit: 4.0 OHV into 4.0 24v COSWORTH It looks like the Cosworth 2.9L block used sleeves as shown in the comparison with the 4.0L block.
 






He adopt the BOA Heads on the 4,0 OHV engine.

As i told to the ingenieur who develop the 2,9 to 4,0 and to sohc, he told me that thy casted a few blocks (like5 pieces) and adopt the BOA heads also by cosworth.
This engine makes over 300hp in a early scorpio.
Never seen it.



I still wait on more infos from the ingenieur.. as he wa a young guy when the engines are develop he is now the last in the firm and in front of his retirement.
 






he is stuck for the moment because he need money.. as i ;(
 






That looks like another thread about installing the Cosworth DOHC heads on a 4.0L block. In another thread I've seen it documents all of the machine work required to make the heads fit: 4.0 OHV into 4.0 24v COSWORTH It looks like the Cosworth 2.9L block used sleeves as shown in the comparison with the 4.0L block.

I ""think"" I contacted him and asked for more details awile ago. .I ""thought"" he told me it was a 4.0 block that he sleeved and reason he did was because he used larger than 4" pistons ..

It could have been the guy over on RPS that did same basic swap but runs twin turbos..so dont 100% quote me..
 






he will use twin turbo .. yes..
he is from Germany Berlin
 






For the moment no more Info

the biggest the Ford developper bore was 4.3 ccm but gone with 4.0 at least
got no Info why

Another Info was that the 4.0 SOHC will not hold the Brasilien fuel full throttle test. Engine failed
 






update

Im still in progress and searching and testing for parts...
after magnafluxing the engine it hast arround 4,5mm thick walls
so 1mm more bore will hold up..
 






Yeah, that's the thing with these engines.

If they get timing-chain guide shards stuck in the oil pickup the crank gets starved for oil and the rod jets don't oil the cylinder walls enough so the rings cut into the cylinder walls.
I have had the chance to strip down and rebuild a few SOHC engines in the last 6 months for people. And as a result I now own 3 blocks (two healthy and one roasted) and three good sets of heads.

I would at the very least like to come up with and price up a viable stroker kit for the SOHC. Especially seeing as the rear timing chain guide has just cracked in my truck and I gotta pull the motor.
 






out of my price range

. . . I would at the very least like to come up with and price up a viable stroker kit for the SOHC. . .

$5K for a new billet crank, $1K for custom pistons and $500 for block machine work is just out of my price range for only a modest increase in performance. That's why I installed an M90.
 






Just a little update on my ohv block..i sonic tested it today..it has 3 spots that are pretty thin..one is on the driverside near the very bottom of the first cylinder measuring .193 the other 2 are on the passengers side about 3" from top of cylinder 1 and 2, on inner or near the lifters,these spot are in a non main thrust side and measures .183 all main thrust sides are well over .240 some even thicker.i asked my guy about the minimum standard and he did confirm that .200 for main thrust is the standard but has seen many at .170 for main thrust and .125 non thrust without issues. .he said the amount of boost i plan to run (16psi) isnt considered to be alot in the performance world and feels that a 90tm block ""should"" hold a 4" bore without issues. .

This is a copy from my thread but felt it was important here also
 






Im not dead in this ...
I just get the finger on a cusom grinded and welded Crank with chevy 5.7" rods from scat and some ross .3 over piston
That set should have 4,220cc
Now my next goal is to get a set of heads and cams
Then i have to bore a block over and rebuild

just my updates
 






How much was the crank, pistons, and rods?
 






How much was the crank, pistons, and rods?

it was 500


anyone know about a good head/cam kit? is it worth to modify the heads or just go with stock and comp cams?
 






it was 500


anyone know about a good head/cam kit? is it worth to modify the heads or just go with stock and comp cams?
You got a crank,pistons and rods for $500?? Thats little hard to believe. .i paid $500ish for my rods and think $950 for my pistons. .crank costed me $450 to get balanced and turned
 






it was 500


anyone know about a good head/cam kit? is it worth to modify the heads or just go with stock and comp cams?

If you have the 4.0 SOHC then I only know of two sources for heads and cams, they would be Supersix motorsports and Tom Morana Racing.
And they are not cheap.
 






Why kot be lucky sometime... im normaly more on the bad site ;) and pay more...

i know them both... but they are expensive yes... but its a lot of work to get them done...
on the other hand...
after heads.. i need cams springs and shims ...

a pair of new heads costs me 450 to my house... work could be done.. i need the right valves

i do have the SOHC
 



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I forgot about this thread, I read it once when it was about 1/3 through what's here now.

I wonder if anything has changed for stroking/boring the 4.0 engines? I should have found time to root around among some old friends i ran into last year who were prior machinists. I bet there are enough rods and pistons to put something good together.

The rub would be the crank, cost to offset grind, the bore thickness of course, and heads. Not much has been posted about SOHC heads, actual data showing airflow. Without decent airflow, any engine would be choking to death with bigger cubic inches, or boost. I bet the DOHC heads are also relatively small for a 4.0, they should be great for a 2.9 turning 6500, but not so good for a 4.0 doing 6k rpm. I hope they flow 225cfm or better, someone post up here anything you may know about head airflow.
 






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