4.3l sohc v6?

[2000StreetRod]

crankshaft oil passages

Is offset grinding the stock crank an option? I seem to vaguely recall reading, somewhere on here, that it wouldn't work because of the oiling passages in the crank or something like that. Anybody know?

I found this response to a question posted January 10, 2006 on StangNet:

"The 4.0 crank is not suitable for offset grinding in power adder applications, this means we'd need a custom billet crank, high strength forged rods, and custom forged pistons. We'd shoot for 4.4-4.5L displacement with .060 over bore. The estimated cost of a stroker kit suitable for a power adder would be $3800-$3900 and would include the billet cranks, forged rods, and forged pistons. This crank/rod/piston kit would be capable of well over 500-600 horsepower but of course we really don't know what the upper limit of the block would be. with good preparation, good balancing, the block should tolerate similar power levels.
Tom Yentzer
www.supersixmotorsports.com
478-256-7766"

However, in Super Six Motorsports' 4.0L SOHC Tech Note dated 7 Nov 2005:
"The crank is neutrally balanced and actually looks pretty sturdy. It appears to be heavily counterweighted and is probably close to a 50% balance factor. The crank is robust enough to allow off-set grinding since it uses single pin rod journals, so the potential for stroker motors is there, based on the crank."

Since Tom Morana offers a 4.3L stroker kit using an offset ground OEM crankshaft he must have an alternative solution.

 

[SVO]

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[SVO]

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[2000StreetRod]

Terlingua Mustang SOHC V6

Greetings Jeff. It's good to see you posting on the forum again. I hope that you have recovered from your heart scare.

I was hoping that you would contribute to this discussion. First hand experience is always more valuable than speculation or theoretical analysis. Your photos have answered several of my questions. You were able to retain the block cradle after stroking the engine. Did you have to modify it?

It appears that at least one notch was ground in the block to obtain clearance for the longer stroke.

The bore of the stroker connecting rod looks about the same diameter as the stock rod bore.

Did you use a new billet for the crankshaft or offset grind the OEM crankshaft?

What is the stroke?

 

[SVO]

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[SVO]

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[SVO]

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[jd4242]

Greetings Jeff. It's good to see you posting on the forum again. I hope that you have recovered from your heart scare.

Hi Dale, yes it's nice not being dead any more, was quite comforting, but kinda a drag too, Life Flight is expensive.

Thanks

I returned cause Jon asked me to.

I was hoping that you would contribute to this discussion. First hand experience is always more valuable than speculation or theoretical analysis. Your photos have answered several of my questions. You were able to retain the block cradle after stroking the engine. Did you have to modify it?

It appears that at least one notch was ground in the block to obtain clearance for the longer stroke.

The bore of the stroker connecting rod looks about the same diameter as the stock rod bore.

Dale, please don't take this as being mean, but I spent a nice chuck of a nest egg that we had saved up to do all the R&D on this and try and produce an affordable forged bottom end for boosted/spray applications.
I was pinned under the gun after too many phone calls to both of the Tom's with absolutely no results, only the knowledge that all the products that the Tom's have are for drag racing application and NOT for street use, and NONE of it is in stock. (Tom's = both Moranna and Super Six)

Now a year ago MMR list a rod and piston set, and one of my customers went that route, guess what?

Today he called me and said that after waiting since August of last year ordering he STILL has received anything but empty promises, so he will be dropping his Shelby with me in two weeks.

OK, to get back on track, and again sorry to sound mean here, but another guy with way deeper pockets was having his engines build but another guy, but they start at $15,000 and got to $25k plus, and he took three of my customers with him, on a sucker punch, after they were already on MY books for engines.
So, I will give you a little help here BUT if you really want to know (ALL the secrets), I have a short block waiting to go on a pallet to your point of origin of your choice, for my cost plus shipping.
I'm not trying to make a business deal out of it, I just want the last one I have in stock gone, the monies would be betting in my account than short block doing nothing.

I hope you understand.

The rods are 800hp Scat rods

Pistons are custom 4" BRC forged flat tops

Crank is stock and good to 500hp it is NOT offset ground

Block is punched and sonic tested for voids in the casting

Compression is 9:1

Did you use a new billet for the crankshaft or offset grind the OEM crankshaft?

What is the stroke?

Stroke is 4.7 as stated above, the stroke is based on the piston/rod combo plus the punch.

I have lost my ass on this deal, and it need many more hours of research to be right, of which I don't have the time nor the monies to do.

There are also differences in head castings, degree the cams, and intake set up also.


SVO :navajo:



I take it Turdle said something about my coaking? Luv Ya Jon

I dont understand this...

If the crank is stock and not offset grind then the stroke should still be 3.31, correct??..also piston or rods dont change the stroke..also no way does a 4" piston with stock stroke equal 4.7.:scratch::scratch:

So is the stroke or displacement 4.7??

But sounds like it doesnt matter anyways because one hasnt stayed together. .

 

[2000StreetRod]

4.7L stroke

4.7L = 286.81 cu. in. To get that displacement with a 4" bore the stroke would be about 3.8" or an increase of 0.49 inch.

I suspect the reason the engine failed was too much total compression or possibly valve float. Is the 9:1 compression ratio of the pistons with the stock heads (chamber size = 65.2 cc)?

I'm not interested in racing and my objective is increased torque at low to midrange engine speeds. That's why I was looking at stroking and possbily boring the engine. I know it would be a waste of performance potential but would your 4.7L short block be compatible with stock heads? My max boost target is 8 psi which should work fairly well with 9:1 pistons. Do you think the block would hold up under normal driving with infrequent rapid starts? I only drive my Sport about 3K miles per year.

 

[jd4242]

The rods posted dont look to be a 1/2 smaller nor does the CH on the new pistons appear to be smaller, if anything the new pistons look to have a increase in CH..to keep a good rod to piston ration he would have to run damn near 5.9" bare minimum rods so CH would have to decrease..also how is a sohc block taking a 4" bore??

Something is not adding up or things are being posted to try and protect secrets..only thing is there is no secrets in math..

And Dale you would be OUTA your mind if you pay $3,500+shipping for a block and especially one that has not proven to work...or any SOHC BLOCK

 

[Dono]

Looks like SVO put incredible resources at the SOHC motor.
Having a failure after 40 miles is a nightmare come true. I can't see from the pics if the valve hit the piston and the stem broke or what.
The bottom end looks like it held fine, and you gotta know huge money went in to that bottom end.

 

[2000StreetRod]

deck height?

One specification I haven't found in my workshop manual is the deck height (distance from crankshaft main journals axis to top of deck surface). The piston top should be even with the deck surface so:

piston compression height = deck height - (rod length + stroke/2)

If the stroke was increased .5" and the rod length was increased .2" that would allow a piston compression height increase of .05" for the same deck height.

I suppose it is possible to build up the crankshaft rod journals at an additional offset using welding and then machining to the desired bore to increase the stroke.

 

[Jakee]

The deck height is in the thread I started, referenced above.

I'm curious what caused that engine failure.

 

[2000StreetRod]

only 1 exhaust valve

Since only one exhaust valve failed I doubt it was due to camshaft timing. Many Mustang owners have reported valve float above 5800 rpm. However, with the stock camshaft it normally doesn't result in damage. With an aggressive high lift camshaft valve float is more likely to result in damage.

 

[Sedition]

Subscribed

 

[Sedition]

4.7L = 286.81 cu. in. To get that displacement with a 4" bore the stroke would be about 3.8" or an increase of 0.49 inch.

I suspect the reason the engine failed was too much total compression or possibly valve float. Is the 9:1 compression ratio of the pistons with the stock heads (chamber size = 65.2 cc)?

I'm not interested in racing and my objective is increased torque at low to midrange engine speeds. That's why I was looking at stroking and possbily boring the engine. I know it would be a waste of performance potential but would your 4.7L short block be compatible with stock heads? My max boost target is 8 psi which should work fairly well with 9:1 pistons. Do you think the block would hold up under normal driving with infrequent rapid starts? I only drive my Sport about 3K miles per year.

If you're only looking to run 8 psi of forced induction then you wouldn't need forged rods and pistons. you can easily get away will much cheaper Hypereutectic pistons and rods.

 

[Sedition]

I suspect his engine failed because the standard timing chain components let go somewhere and the piston kissed the valve, with passion! I'd say that possibly one of the un-keyed sprockets slipped on either the cam or jack shaft. Keep in mind with a centrifugal super charger that big I would say he was running over 30 psi of boost.

 

[QueenCitySleeper]

Saw this a week or so ago and finally found the page again. Ask this guy how he got 4.6 liters out of an ohv. Must have a decent stroke to it and claims its daily driven. He may have some insight.

http://louisville.craigslist.org/cto/4465616426.html

 

[Bronco2]

Im still in for a Stroke..

 

[Sedition]

Yeah same here. I finally got a garage (workshop) again and I'd like to put a hell chunky crank in mine. Then shift kit the trans so it won't rev over 4krpm with my right boot buried in the carpet.