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Discussion Starter · #1 ·
Yes. I said it. I joined this forum just because some of those with knowledge of these builds are members here. I am picking up the rods from the machine shop today. I only had them separated from pistons and magnafluxed. I want to build a long rod roller cam 351 with efi that idles smooth and quiet for a daily driven station wagon I am trying to build.
My Daddywagon - Tacoma World Forums
 

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Discussion Starter · #3 ·
Some say not so irrelevant. Anyway. I am going to build one, hopefully. Here is the plan. F4te block, kb333 hypereutectic pistons, probably .030 over, I picked up a set of gt40's but if I can swing it I might go for afr165's in the 58cc variety, gonna try the stock 1986 speed density cam to start with. Maybe step up to the new g303 cam eventually. Of course, the obvious 6.580 inch long c-c connecting rods out of a 351m/400. Daily driver Daddywagon
 

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Indo-Canuck-Yankee
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I've run a long rod Windsor many years ago before I decided to stroke to 408, I believe it was a Speed-o-motive kit. The longer rod keeps the piston at TDC and BDC longer, so there is slightly better efficiency regarding cylinder filling and exhaust. You might benefit fast opening/closing cam and will certainly be able to run one with the roller setup. I'd say it's a good choice for a daily driver, for sure. Beware of structural issues from having the piston pin too close to the ring land, select a quality piston; I've had this issue with early stroker assemblies too.
 

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Indo-Canuck-Yankee
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I guess I'm hoping those that have built one will chime in. I'll try to build it regardless.
I think the other fellow was correct. I'm open to anyone correcting my reasoning, but it seems to me the change would have to significantly impact angle to have any noticeable effect. The 351W rod is already long compared to stroke.

At half stroke I calculate a stock 351W rod to be at 82.36 degrees.

At half stroke, a 351M rod will be at 81 degrees.

The force at 81 degrees is 1.012 times the force at 90 for an infinitely long rod.

The force at 82.36 degrees is 1.009 times the force at 90 degrees for an infinitely long rod.

Dwell time changes at or near TDC are even less.

With the 1/2 inch longer rod you reduced force caused by angle by less than 0.3 % at half stroke, and reduced it much less when closer to TDC or BDC.

Since angles are a sin (sine) function, the change doesn't get large until the angle approaches 60 degrees.

sin 90= 1
sin 80 = .9848
sin 70= .939
sin 60 = .866
sin 50 = .766
sin 40 = .643

1/.643 = 1.56 times the initial load.

This works with rope tension also. If you look at the beta column in the link below, an infinite rod length would be 90 degrees. Both of your rods are around 80 degrees. It would be more important to get a stronger rod than a longer rod.

Tension Increase in Ropes due to Angle
 

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Indo-Canuck-Yankee
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Sorry, don't mean to threadjack... but...

Mark, I have an old CHP 408 stroker kit with Probe flat tops, a 400M modified crank, and Chrysler 360 (6.125") rods. What sort of max power level is this kit good for and max RPM?
 

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The Lurker
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One of my favorite engines that I used to want to build was from a '93 or '94 issue of Mustang and Ford. It was a 351W with 400 rods and they used a retrofit hyd. roller cam with "Crane Fireball" aluminum heads. The goal was to "get the combustion area out of the head and onto the top of the piston" or something like that. They were hyping the long rod combo, but I later learned it was pointless.
 

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The strangest compromise of compromises. Use a weird piston on an odd stroke to say the piece that connects the crank to the piston is different.

Want a great combination? Start with a great head. Then decide if your traction limited, or would you rather have durability. Traction limited, decrease torque, put smaller displacement under great heads and RPM the crap out of the thing. Hard on parts, requires lots of unobtainium. Want durability, shove as much displacement under the head that offurs the flow to get you the HP you want.

The connecting rod... does just that. Connects piston to crank. The rod is a function of crank and piston design, not the other way round.
 

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I did it about 15 years ago, plus or minus a couple years.

Spent about $400 on the 400 rods. Then a bunch on pistons, but I'd have spent that on pistons anyway. Found absolutely zero improvement over the old cast piston 9.1:1 stock length rod 351w. Used the same heads too.

Should have spent the money towards HEADS, as the D7TE heads were absolute piles of steaming feces from a performance standpoint. Sold the truck with that engine in it, don't know how long it lasted or whether the new owner liked it or hated it.

Only thing I noticed out of the ordinary was that it didn't like a lot of timing. I think about 32 is all I could run without getting into ping. It just was not a worthwhile "build". Thought I had a great idea and it flopped.
 

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Sorry, don't mean to threadjack... but...

Mark, I have an old CHP 408 stroker kit with Probe flat tops, a 400M modified crank, and Chrysler 360 (6.125") rods. What sort of max power level is this kit good for and max RPM?
God, you don't ever replace anything do you..:)

Probably 6 to 650 ad 7 grand. It's always a guess.
 

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I don't know who kim, or toddturbo are, but if you want to go fast, listen to them.

Of course, if bench racing is your forte, by all means grab a theory and run with it.

"Average cross section" is a good one.
 

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The wagon is kind of cool but a gt40 head stock cam 351 is...ummm...good luck lol

What's that thing gonna weigh with an iron head windsor and irs?
 

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Indo-Canuck-Yankee
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God, you don't ever replace anything do you..:)

Probably 6 to 650 ad 7 grand. It's always a guess.
I do! My 408 has been running SRP slugs and Scat H-beam rods with a 4340 crank for years now. However, I've had the old kit on my shelf collecting dust and some people have been asking about its limitations (stock cast crank, usually being the point of concern). Thanks for the info.
 
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