Stroker kit?


B

Bigrigger

Member
Oct 17, 2009
15
With the hundreds of stroker motors out there, why hasn't anybody made one for the GT block?:confused

Are there clearence issues that prevent this or does everyone just say "the motor is perfect" and leaves it at that?:thumbsup
 
IMO torque is not an issue with these gals as such putting a longer arm in her would make no sense because in doing so would decrease the maximum operational RPM so as to stay within the maximum safe "mean piston speed".

Takes care

Shadowman
 
Your right but, there are numerous stroker kits for almost every performance engine (espically V8's) you can think of, not to mention lots of import and euro motors so... why is it that the GT motor has remained untouched?
 
The GT already has a lot of stroke. In a roots blower car, there is really no need for more stroke. There is already ample low end power. I would rather destroke it and spin it higher.
 
As mentioned above and then if that were not enough then the fact that the crank is unique to the Ford GT means that the ability to market it once created would be "very" small"

The power band of these gals is very long which makes for a very versatile piece of machinery and stroking her heart would make her even more volatile down low with much shorter legs.

Can a solo crank be created as well as the remainder of the rotating assembly; absolutely.

Takes care

Shadowman
 
kumar said:
I would rather destroke it and spin it higher.
Click to expand...
Me to. Have you seen that Japanese one with a Ford 3.5L V8? Max revs somewhat over 10k RPM I'm told.
 
I have been studying and trying to experiment with as many different combinations in conjunction with a friend of mine as possible the last couple years as I have an all aluminum big inch engine build in the works right now too. So I thought I might share a little of what I have learned.

There are both stroker cranks and de-stroker cranks already out on the market and have been for quite some time that fit this application. Several different brands in both forged and billet options.

The stock 5.4 stroke is 4.165" which utilizes a 6.658" rod which gives it a 1.60:1 rod to stroke ratio and nets 330Ci.

The most popular stroker combination consists of a 4.415" stroke which utilizes the stock 6.658" rod thus giving it a more negative 1.51:1 rod ratio. However, I have seen strokers of this combination torn apart after extensive use (1 over 800+hp of drag racing two seasons) and with the proper maintenance did not show any increased signs of wear. The one was a drag race only engine and did to have any street duty or high mileage though. This results in an approximate 351Ci with near standard bore size and 380Ci with a 3.7" bore size.

The newer and becoming more popular stroker setup consists of a 4.350 stroke which utilizes the stock 6.900" rod (iirc off the top of my head) thus giving it a more similar to stock 1.59:1 rod ratio. These will net you approximately 345Ci in a near standard bore while giving you 374Ci with the larger 3.7 bore.

The most common destroker at this time utlilzes a 3.75" (4.6 stroker) crank, but is usually only used when in combination with the larger 3.7 bore netting 323Ci. This is used on some well known drag race setups on some 10.5 cars.

The negative effect on the rod ratio is what scares most people out of stroking the already long stroked 5.4l based engine. And the effect it will have on your rpm range. Not only this, but cost always comes in to play as well. With a different stroke comes a complete new build basically as you'll need different pistons, new rods (even if stock size you want to upgrade to forged or billet h-beam/i-beam), bearings, and new timing components (never a good idea to reuse those on a build of this nature IMO) all new blue printing, machining, and balancing, etc. The cranks alone can range from about $700 to upwards of $3000.

Another nice choice is going with a big bore stock stroke 5.4. This is almost the perfect combination IMO. I have helped build a handful of these and they are nice. They have the added cubic inches without the negative effect on the rod ratio and rpm range. The spin up fast and can really make some great power. With the 3.7" bore and stock 4.165" it nets you 358Ci.

Hope that helps share some info with you guys. FFS
 
FordFanStan: Thanks for your write up on the rod ratio of the engine. That is a very important number in engine design and longevity. Personally, I would not build an engine with less than 1.6 rod ratio. Ive seen engines with rod ratios in the range of 1.55-1.58 with oval led cylinders and excessive piston scuffing. As that ratio gets smaller, the side forces on the piston/cylinder increase rapidly (tangentially as a function of the angle of the rod to the cylinder wall). Bottom line: This engine architecture was optimized for compactness and weight, and allows very little opportunity for increasing displacement. Going to a larger bore is about the only option, and even then, there's not much room for more bore diameter. Spending many thousands of bucks to get 28 CI more displacement is a poor return on investment. Increasing the boost gets you much more for much less.
 
PeteK said:
FordFanStan: Thanks for your write up on the rod ratio of the engine. That is a very important number in engine design and longevity. Personally, I would not build an engine with less than 1.6 rod ratio. Ive seen engines with rod ratios in the range of 1.55-1.58 with oval led cylinders and excessive piston scuffing. As that ratio gets smaller, the side forces on the piston/cylinder increase rapidly (tangentially as a function of the angle of the rod to the cylinder wall). Bottom line: This engine architecture was optimized for compactness and weight, and allows very little opportunity for increasing displacement. Going to a larger bore is about the only option, and even then, there's not much room for more bore diameter. Spending many thousands of bucks to get 28 CI more displacement is a poor return on investment. Increasing the boost gets you much more for much less.
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All true but why not increase the compression and keep the same size hole. We found out 9.5 to 1 even with 26 psi boost was better than more compression and more boost. Less heat from spinning the blower slower. We went faster but the tune had to be closer.
 
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PeteK said:
FordFanStan: Thanks for your write up on the rod ratio of the engine. That is a very important number in engine design and longevity. Personally, I would not build an engine with less than 1.6 rod ratio. Ive seen engines with rod ratios in the range of 1.55-1.58 with oval led cylinders and excessive piston scuffing. As that ratio gets smaller, the side forces on the piston/cylinder increase rapidly (tangentially as a function of the angle of the rod to the cylinder wall). Bottom line: This engine architecture was optimized for compactness and weight, and allows very little opportunity for increasing displacement. Going to a larger bore is about the only option, and even then, there's not much room for more bore diameter. Spending many thousands of bucks to get 28 CI more displacement is a poor return on investment. Increasing the boost gets you much more for much less.
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Bigger bore gives the added benefit of unshrouding the valves.
 
I didn't quite understand that--if you increased the compression to 9.5 from 8.4 and upped the boost to 26 psi, that IS more compression with more boost. Did I miss something? Yes, you could do that too.
SMOKDU said:
All true but why not increase the compression and keep the same size hole. We found out 9.5 to 1 even with 26 psi boost was better than more compression and more boost. Less heat from spinning the blower slower. We went faster but the tune had to be closer.
Click to expand...
 
pacettr said:
Bigger bore gives the added benefit of unshrouding the valves.
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Hmmm. What I've seen of 5.4 4-valve heads doesn't look like the valves have a shrouding problem. Does anyone have flow bench results?
 
I would also like to hear the opinion of some of our guys that do head work, concerning valve shrouding and 4V heads. I just did a 1.8 Mazda 4V head for our escort lemons car, and one of my thoughts was that you could get away with bigger valves without any real shrouding issues, as opposed to my big inch ford 2V heads. Looks like you have a fair amount more flexibility with cam selection and tuning as well. Hope I'm not sidetracking the thread too much.

Steve
 
598

You aren't "Souping up" the lemons car are you???? HaHaHa You know that bad boy isn't supposed to be more than $500. Hope you are still having fun with it. We just finished a 2 day WRL race at Texas World Speedway that was fun. WRL is a small amount more serious but you can still run the Lemons car. They are trying to set up an overnight race in August, so we can beat the heat.

Larry
 
We run from 10 AM til midnight at the autobahn CC in Joliet, July 26. It costs nothing to lap the seats on a few valves. Grinder runs on nothing but air. Head was warped. What's a guy to do? It is a real $500 beater. Actually $325 I think. My time has no apparent value. Have a $5 electric smog pump off a 90s chevy that will make a fine declared vacuum pump when we spin past 7K. I swear, as go to the RT 66 nationals this weekend to spend 1200 on a set of slicks for my top sportsman car, this lemons stuff is the most fun I have ever had in racing. Its just the hillbilly in me I guess.

Steve
 
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