289 to 331 Problems?

[ratio411]

I wouldn't hesitate to stroke a 289 to 331, but if i was to do it all over again i would probably do a 327 stroker as per this article.....it uses chevy pistons -alot cheaper than probe industries-i think you could probably do the whole rotating assembly for less than $800. Crank,rods,pistons,rings and the machine work.
http://www.rodandcustommagazine.com/techarticles/ford_small_block_stroker_engine/

I glanced at that article.
I will read it later, I like that stuff.

However, I noticed right away that they are welding and offset grinding the stock crank for 3.25" stroke. They are also using .030" over pistons.
That is a 331.
If they used a standard 4" bore, it would equal 327 cubes.
Therefore, could you not get a cast 3.25" stroke crank (331) for cheap, use stock rods (or whatever the article calls for), and use the pistons called for... and come up to the same price?
A cast crank is new and will be the same or less than welding and offset grinding the stock crank. At least around here shop time is about 60 bux an hour.
4-5 hours of that and you have paid for a new crank. Can they weld and offset grind from start to finish in that time? I wouldn't think so if I was to guess.

Dave

 

[starchiefus]

Yes, it would be better to buy a crank from Summit,etc. I thought the article might be pretty old when i read how they had to weld and build up the crank, when we all know you can go and buy one. It still seems like an interesting way to go, especially like you said with the overbore you basically end up with a 331 anyhow, at a reasonable cost, I would think.
I'm almost tempted to build one up and put it my 55 Pontiac just for the sake of interest, now that the mustang is almost done. Hmmmm......

 

[washMO66]

I read in the High Performance Small Block Fords book that the 289 has shorter piston sleeves but it is ok for "small" stroker kits'. I'm not exactly sure to what that means but I am thinking it means 331ci which is actually the better of the two (331 vs. 347).

Not trying to "defend my displacement" or anything but I am in the early stages of planning my new build, based around a dart block (mine is a paper thin 87-93 5.0) and I want to be well informed before I commit to a ci.

I want to know why I hear from time to time that 331's are a better choice than a 347? Is it the shorter stroke? Higher rev potential? I really want to know and am not arguing / starting a debate, just want back up.

Before you answer;

Mine has never had any oiling issues (extra care was taken to smooth the inside walls of my entire block to speed oil return, is that why mine does not have oiling issues?

Built in 02, not a radical build, 475FWHP, pulled it last winter to do a cam swap and went ahead and ring & bearinged it - everything looked great, really didn't need to be freshened.

The reason I am moving away from the factory block is I want to spray it hard or psuh some air through it.

 

[ratio411]

I want to know why I hear from time to time that 331's are a better choice than a 347? Is it the shorter stroke? Higher rev potential? I really want to know and am not arguing / starting a debate, just want back up.

The debate is over 'rod ratio'.

When the stroke gets long and the block, rod, piston are short, in order to cram it all in, you lessen the rod ratio.

A short rod on a long stroke is known, for a fact to:
*Put more side load on the piston bore, wearing the cylinder bore egg shaped, causing excessive friction, and giving another point for something to fail.

*Dwell the piston for a shorter length of time at TDC. Soaking up less power from the combustion event.

*Then, not related to rod ratio... The short pistons needed to fit the long stroke in the small package are compromised as far as ring langs, pin location, and all this can lead to short life and/or oil consumption.

Now, before anyone flames me for being anti-347, I am just throwing out the valid points of the 331 vs 347 debate for the sake of washMO66.

There is a very passionate debate between the camps as to exactly how much difference these facts make to a street engine.
The pro-347 crowd feels like these issues are not a big deal and the negatives are far outweighed by the extra cubes.

The 331, 306 crowd believes that not pushing the envelope to the limit will reward them with longer engine life, and in the case of the 331, they believe that a little extra power could be available in piston dwell to make up for the 16 cube difference.

It comes down to:
If you want every last bit, and don't mind a little risk of shorter life, go 347.
If you want an engine that you know for sure will not consume oil or wear out a block, go 331.
Not the the 347 will for sure do these things, the 331 is just for more conservative folks.
Dave

 

[ratio411]

Btw: I also know of people that would rather build a 306 with 5.4 rods and short piston than to add stroke.

Not only does a long rod take side load off the block, the dwell at TDC allows the piston to use every bit of push put on it by combustion.
Makes more power, the piston changes direction more slowly causing less stress on everything, and revs higher.

Again, just putting forth the 'long rod' crowd's arguement.

Rod ratios:
289 = 1.796:1
302 = 1.696
331 = 1.661 (when using 5.4" rod)
347 = 1.588
LR 302 = 1.800 (5.4" rod)
LR 302 = 1.848 (5.545" rod)
Boss 302 = 1.718
351w = 1.701
LR351w = 1.880 (351m/400 rod)
351c = 1.651
LR 351c = 1.721 (Aussie 302 rods)
Just for giggles, the Aussie 302 = 2.008!

 

[D.Hearne]

I was going to stroke my 289 to 331, but the expense wasn't in the budget at the time so i just installed a 302 rotating assembly-crank,rods and pistons (cannot use 289 pistons as the piston skirt is longer and will hit the 302 crank counterbalances).

I wouldn't hesitate to stroke a 289 to 331, but if i was to do it all over again i would probably do a 327 stroker as per this article.....it uses chevy pistons -alot cheaper than probe industries-i think you could probably do the whole rotating assembly for less than $800. Crank,rods,pistons,rings and the machine work.
Just another suggestion.
Steve.
http://www.rodandcustommagazine.com/techarticles/ford_small_block_stroker_engine/

Although the 327 stroker is the same bore/stroke as the Chevy, it does not use Chevy pistons. The only way that would be possible is if the pistons had centered pins (Fords are offset slightly) to allow you to install half the pistons "backwards" (the chevy valve layout isn't the same as Ford) to orient the valve reliefs to accomodate the valve arrangement. The pin height would also need to be correct to match the stroke, rod length and pin height to the block deck height.

 

[ratio411]

Although the 327 stroker is the same bore/stroke as the Chevy, it does not use Chevy pistons. The only way that would be possible is if the pistons had centered pins (Fords are offset slightly) to allow you to install half the pistons "backwards" (the chevy valve layout isn't the same as Ford) to orient the valve reliefs to accomodate the valve arrangement. The pin height would also need to be correct to match the stroke, rod length and pin height to the block deck height.

In the article they tell you that they recut the valve reliefs and honed the small end of the rod .015" to take the Chevy pin.

I have heard of plenty of folks using Chevy pistons in Fords.
They even make aftermarket Ford rods with Chevy pin bores to accomodate this.
Kinda like they make aftermarket cranks setup for Chevy rods.

 

[D.Hearne]

Lotta ifs and machining there, easier and probably cheaper to just buy the correct 331 stroker pistons for a Ford.

 

[washMO66]

ratio, thanks for the info, still learning...... and will be for a long time.