408 issues

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Robzilla

Robzilla

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I am trying to put together a 408 and I ran into a pretty significant issue. The bottom of my Probe pistons are hitting the counter weights on my Eagle crank. Has anyone else had a similar problem? Oh yeah I have Scat H beam rods.

Rob
 
Robzilla said:
I am trying to put together a 408 and I ran into a pretty significant issue. The bottom of my Probe pistons are hitting the counter weights on my Eagle crank. Has anyone else had a similar problem? Oh yeah I have Scat H beam rods.

Rob
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Are those Probe pistons made for a stroker? Welcome to the site.
 
Yes they are for a 408, part # pro13744040. They don't come out of the deck they just barely hit the crank!
 
I've got the same Probe pistons but mine are .030 I have a Eagle cast 4" crank too . I haven't put the motor together yet so I'm very interested in your outcome! Maybe I'll call Probe and ask them if they're aware of this issue.
 
sumbitmopar said:
I've got the same Probe pistons but mine are .030 I have a Eagle cast 4" crank too . I haven't put the motor together yet so I'm very interested in your outcome! Maybe I'll call Probe and ask them if they're aware of this issue.
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That's a good idea. Call the source. Something isn't right. I know sometimes you have to trim a bit off the block, but shouldn't have to trim anything off the crank for clearance. I'd be interested to know how this problem is solved also.
 
i have srp pistons and eagle crank. the crank seems to have flats ground on the counterweights to clear the pistons as well the block was clearanced at the bottom of the bores to clear the rods(eagle h beams).
 
I had my machinist buddy come out and look at my problem. He took a piston home and machined 60 thou. off the bottom of the piston on the balancing block area. After mock up again I have clearance by 50 thou. on all counter weights. I sent the crand and the pistons back with him so he could clearance the rest of the pistons and re-balance the crank to the lighter piston rod combo. I of course had to clearance the block a little for the rod bolts also And yes this is a eagle cast crank with Probe SRP piston combo.
Rob
 
Moparmal said:
Good to hear!
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Yes, that part work great. Although it was not necessary, I clearanced the block for the rod bolts for added insurance. Eagle cast crank and rods.

ScreenHunter_07 May. 04 07.40.jpg


ScreenHunter_08 May. 04 07.40.jpg
 
Moparmal said:
Has anyone had the same issues with KB slugs in SB stroker applications?:read2:
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I am running KB745 step dish forged with 4" Scat cast crank no clearance issues. Also running Scat I-beams and no block clearancing was needed.
 
Maybe the Scat crank was the way that I should have went. The price for the Eagle crank through Mancini was a deal that I couldn't turn down. I had to notch my block some but not much. When I get my parts back from the machinist I will take some pictures of the rod bolts by the clearancing and post them. I am going to run home ported Edelbrock heads with the MP .508 cam and performer RPM air gap. What are the other fellas out there with 408's running?
Rob
 
Oh yeah, the 408 is going into the Yellow Duster under my username. It will have a 200hp shot hooked up also.
 
You shouldn't have to notch the block with i-beams..h-beams only..as for the pistons hitting the crank,something does'nt sound right..i run Diamond pistons in my 416 with no issues..
 
I remember reading about this, but not sure if it was a small block Chrysler issue or not. Shaving the counter weights on the crank was what they did and left the pistons alone.
 
The machinist decided to take it off the pistons because of the amount of material there and if he took it off the crank and made the crank lighter than the piston rod combo the crank would have needed mallory to get back to the proper balance. I am using Scat H-beams so I had to clearance the block.
 
I just talked to Eric at Probe and he said it's not a problem with the pistons, it's the Eagle crank ( I expected him to say as much). He commented on the Asian origin of the crank and said it was not unheard of and that I may or may not have a problem when I go to put mine together. He said if there is a problem to machine the crank and not the piston. He also said to call him if I have a problem ( to what avail I don't know) I'm calling Eagle next......
 
zilla any news from the man yet on your parts.looking to register for devils run.must be working in the field.i was in minot today?
 
Troy, I am not sure what Duster I will take to Devil's Run yet. How long do I have to register? If I have the 73 running than I am going to bring that. Otherwise the 340 car. On the 408 issue, according to the machinist the crank actually is a nice piece for obviously being made in China, balanced nuetral with little work, but he also said that it was due to the light weight of the piston, rod combo. The crank is new with standard bearing sizes. Let me know what you find out from Eagle!
Rob
 
Sumbitmopar, I would make sure that you have your machinist check your balance weights before you make your decision, if you have the same issues as I did. The 60 thousandths off the bottom of the piston is minimal and it prevented having to add mallory to the crank due to the rod, piston weights being heavier than the crank counter weights.
Rob
 
No issues with Eagle cranks and Diamond pistons. Not even close...
 
Robzilla said:
Sumbitmopar, I would make sure that you have your machinist check your balance weights before you make your decision, if you have the same issues as I did. The 60 thousandths off the bottom of the piston is minimal and it prevented having to add mallory to the crank due to the rod, piston weights being heavier than the crank counter weights.
Rob
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Thanks Rob. What balancer are you using?
 
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