Another 416 Stroker Build-Pic Heavy

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RAMM

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Since there are quite a few threads concerning the venerable 4" stroked SBM currently on FABO, I thought why not one more?

I'm actually getting pretty excited about this one as I haven't done one of these at a higher comp ratio / ported LA heads and a solid roller cam with an Eddy SV intake in....well I've never done one quite like this.

Quick run down on the back story goes like this:

Customer (referred to as TM from here on out)has another machine shop handle the block machining and cylinder head work and has his neighbour "port" the heads and assemble the engine in his home garage. Nothing wrong with that. TM installs the engine in his Duster and proceeds to enjoy his new found TQ/HP in his 340/416 for awhile a very short while.

I cant remember how much the mileage worked out to be but it was very very little --the engine "locked" up solid while driving at low speed and that was that. TM was referred to me and he brought his disassembled engine in the back of his truck and a plan was formed.

Basically the cast crank was multi piece, bent rods, and a cracked 340 block was the result of many things ending in catastrophe. The build featured some nice parts but with the .484" PS cam, stock rockers, "ported" '894 heads, Air-gap, 3/8" stem valves, low compression, and stock width rod bearings, I'm pretty confident this was a 400hp-425 hp deal. Funny thing is TM told me it was really strong while it lasted. TM also told me it cranked real hard and didn't change when race gas was tried. Ok so I check the 340 block and it can't be sleeved as it cracked from the beating right down to almost the pan rail. So I try to console TM by telling him to find a 360 block and we can get underway. TM says he knows of at least 3-4 360's for like $50.00 I say great. A week later TM is told by those in his circle that the 408's don't run nearly as well as those 416's so he is on the hunt for a 340 block. I tell him to bring all of those 360 blocks in and I will sonic check them and we will do one @ 4.07" bore if possible there by getting him his 416 cubes and a stronger crank with more journal overlap to boot. Another week goes by and TM shows up with a very nice and very expensive 340 block. Oh well , he wants what he wants and I get that.

Anyways the plan is a high compression 416 (TM says close to 12-1 comp), solid roller, heavily worked X heads, Eddy SV intake, as much HP (500+-?) possible with his LA heads, dyno tested and tuned. Now that we're getting close I thought I'd share. J.Rob

p.s. Here is some pics of the "before".

bentrod.jpg


smashedbalancer.jpg
 
What in the world caused the catastrophic failure of the initial build?
 
Some specs. It's going to be pretty rowdy with this cam-but that's what he wants. J.Rob

416CAMSPEC.jpg


416PW.jpg
 

The heads are where I have been spending my time. Moving to a 11/32" stem 2.055"/1.60" valve and the exhaust guides are a hardened iron versus the bronze intake guides. I like this arrangement much better than bronze across the board. I've taken the time to properly machine the guide bosses and spring seats for the spring seats. Also the intake guide boss will wind up .300" shorter in the port itself-freeing up volume to try and supply the cubes. The springs feature 200lbs on the seat @ 1.750" IH. Looking forward to getting the porting complete. J.Rob

416SW.jpg


416GSSW.jpg


416RG.jpg


416HS.jpg


416SG.jpg
 
What in the world caused the catastrophic failure of the initial build?

I think it was poorly chosen parts along with a comedy of errors. I doubt the rod bearings binding up on the crank fillet helped much and probably added to the issue of hard cranking. J.Rob
 
You're right. "one more" almost as bad as LS engines everywhere. I'm waitin on one of you whiz bangs to do a high powered slant build. You know.....somethin different?
 
That’s what a junk **** damper will do.

There was a rash of those cast stroker cranks that were breaking a while back. They were all the same brand......it was either Eagle or Scat I don't remember which. But we saw a lot of them break right here on the forum.
 
There was a rash of those cast stroker cranks that were breaking a while back. They were all the same brand......it was either Eagle or Scat I don't remember which. But we saw a lot of them break right here on the forum.

Eagle cast cranks

But many seemed to have a little “help”.
 
Eagle cast cranks

But many seemed to have a little “help”.

Oh I'm sure. It's not like those cranks were made for extreme use, yet I'm sure that's what they get. "Cast steel" is still cast. lol
 
Oh I'm sure. It's not like those cranks were made for extreme use, yet I'm sure that's what they get. "Cast steel" is still cast. lol
it's that the Metallurgy was ****.
You can put 550 -580 through a GOOD cast/nodular crank and it'll hold up.
After that...its like tap dancing in glass shoes.
Scat is quality and so are ohio crankshaft & mopar cast cranks, all known to take abuse.
 
Hang in there J.Rob. Factory iron head builds always carry our interest here in Backwoods, Idaho.
 
Hang in there J.Rob. Factory iron head builds always carry our interest here in Backwoods, Idaho.

That's exactly what I find interesting about this build--freedom to work the LA heads pretty extensively. Care to offer any direction on this while I have your attention? J.Rob
 
Several years ago a bunch of Eagle 4" cast cranks broke, IIRC most broke right behind the #1 main cap or in front of the #5 main cap. Several of them were in mild builds that weren't beat on hard.
 
I gave my guesstimate on power output in the first post, if I'm even close--I would put it in the category of "not beat on that hard" . J.Rob
 
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