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Pistons for short deck 557

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BLOWNBBC

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Discussion starter · #1 ·
Does anyone know if you can get an "off the shelf" flat top piston for a 4.5 inch bore, short deck, with a 4.375 stroke and a .385 rod. You know, for a little 557 inch rat. Is there anyone out there running one of these? If so, do you like it? I checked JE's and Diamond's web sites and had no luck. I haven't tried calling anyone just yet. Just trying to get an idea if this is purely a custom job. I'm thinking my 540 build could benefit from an extra 17 inches to go with that Procharger. I'm one of those guys where if I don't do it now I'll wish I had.:yes: Merry Christmas:thumbsup:
 
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#2 ·
I would worry about the location of the oil ring and the piston pin. I settled for the 4.25 stroke just because it allowed the oil ring to not cut into the wrist pin bore as much. I still had to run a support rail.
Check out Ohiocranks web site and see if they offer the 4.375 crank and they could tell you if the piston pin is going to be a problem.
If you are running a pro charger why not just settle for 540 and up the boost a couple of pounds. I went with the 540 and run extra boost to make up for going so small:yes:
I love my 540

Just look around here and see what they say
http://ohiocrank.com/bbcCranks.html
 
#4 ·
BLOWNBBC said:
Does anyone know if you can get an "off the shelf" flat top piston for a 4.5 inch bore, short deck, with a 4.375 stroke and a .385 rod. You know, for a little 557 inch rat. Is there anyone out there running one of these? If so, do you like it? I checked JE's and Diamond's web sites and had no luck. I haven't tried calling anyone just yet. Just trying to get an idea if this is purely a custom job. I'm thinking my 540 build could benefit from an extra 17 inches to go with that Procharger. I'm one of those guys where if I don't do it now I'll wish I had.:yes: Merry Christmas:thumbsup:
Click to expand...
You won't find too many pistons available just yet for the .375"+ strokers but I can tell you they are on the horizon.

Have (4) 4.375" Eagles in the "works" as of today. Already have the pistons "on the shelf" for half of them. Eagle had sense enough to see that they kept the +.250" connecting rods in the program. This saves many customers from needing to change existing rods from the 4.250" deal.

As I said, the pistons will be "boxed" items shortly, but not right now.

The other issue you personally will find with the "blower" program is they may not offer pistons up too quickly for your deal. Most "blown" app's along your lines are going to need a "dish" about 20 cc's or so to hit around an 8.5:1 C.R. This measurement depends on each individual build!

Using a 4.500" bore aftermarket block requires no add'l "fitting" over the 4.250" platform, at least with respect to the 4.375" crank/rod/piston combo we have going here so far.

One of these cranks is heading to a MK-IV block (4.280" bore, 504" N.A.) build and those pistons are already here as well.

This year for these "blown" units we may decide to use some "Diamond" pistons on a few "trial" builds, we feel they might just have a slight edge in this area? This remains to be tested however in the near term!

Just "love" those "blown" units!!!

Thank's, Gary in N.Y.

P.S. Would like to wish all here a "Merry Christmas" and a "Happy New Year" as well!
 
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#5 ·
If your going to put a Procharger on this engine keep it smaller and use a little extra boost. You'll make more power and get it to the ground better. A 509 with 16 lbs. of boost or more will overpower the tires at any speed. Call Morris and find out the best combination for what your trying to do. The 540 Chevy powered '67 Olds at the pumpgas drags had tons of traction issues at Memphis Motorsports Park at the PGDs. Sometimes less is more. All the power in the world is useless if you can't get it on the ground.
 
#6 ·
Harold Sutton said:
If your going to put a Procharger on this engine keep it smaller and use a little extra boost. You'll make more power and get it to the ground better. A 509 with 16 lbs. of boost or more will overpower the tires at any speed. Call Morris and find out the best combination for what your trying to do. The 540 Chevy powered '67 Olds at the pumpgas drags had tons of traction issues at Memphis Motorsports Park at the PGDs. Sometimes less is more. All the power in the world is useless if you can't get it on the ground.
Click to expand...
I can't see using an after-market block and only building a 509.
Why not do more work to the chassis.
 
Discussion starter · #8 · (Edited)
The blower that I'm gonna run, because I already own it, is already maxed out (d1sc) so I can't up the psi. In fact, all that I'm looking for from the blower is the 1400 cfm that it will generate (good for 925hp). Boost is only a function of restriction so the fact that I expect numbers of 5psi or less is ok with me because the 1400 cfm will still be there. Considering this, I'm looking to run 9 - 9.5 compression. A flat top piston will be perfect with my 120cc chambers. What I'm looking to do is make the most of my new Bowtie blocks 4.5 inch bore. I know that the .375 crank will fit without much problem so I just want to be sure that I'm not shorting myself by installing a .25 crank. GOSFAST, if you have some of these projects in the works, tell us, how is the oil ring vs. pin location? And, correct me if I'm wrong, but even with the 4.25 stroke and the 6.385 rod, the pin is already sitting behind the oil ring.
 
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#9 ·
If you go with a longer stroke you will move the pin further up in the oil ring?

If its "race only" do a two ring piston, a top compression ring and an oil ring
Bill Miller pistons or Venolia
 
Discussion starter · #10 · (Edited)
Yes, I know that the stroke increase will move the pin deeper. The question is how deep is to deep? This is going to be a "street" engine so I'll need all the rings. We need to hear what GOSFAST says, he has the pistons.
 
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#11 ·
Check with him or a piston company

I dont like the pin to move into the oil ring but if it does you can live with it. The old high rpm small blocks made more HP with two ring pistons
 
Discussion starter · #13 ·
pdq67, did JE think that the piston would operate correctly? How do you guys feel about using a "full round" piston with a tight ring pack? I think that it should be ok, not ideal, but ok.
 
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#16 ·
If you run a tight ring pack you will need one heck of an accumulator groove betweent the top two rings You dont want the rings tight, pro stock engines use a larger bore and a shorter stroke for the following reasons:

1- less ring drag from a shorter stroke
2- some pro stock pistons are 2 rings, some 3
3- 3 groove pistons can use a "looser ring pack"

A tighter ring pack will most likely lead to ring flutter
 
#18 ·
BLOWNBBC said:
The blower that I'm gonna run, because I already own it, is already maxed out (d1sc) so I can't up the psi. In fact, all that I'm looking for from the blower is the 1400 cfm that it will generate (good for 925hp). Boost is only a function of restriction so the fact that I expect numbers of 5psi or less is ok with me because the 1400 cfm will still be there. Considering this, I'm looking to run 9 - 9.5 compression. A flat top piston will be perfect with my 120cc chambers. What I'm looking to do is make the most of my new Bowtie blocks 4.5 inch bore. I know that the .375 crank will fit without much problem so I just want to be sure that I'm not shorting myself by installing a .25 crank. GOSFAST, if you have some of these projects in the works, tell us, how is the oil ring vs. pin location? And, correct me if I'm wrong, but even with the 4.25 stroke and the 6.385 rod, the pin is already sitting behind the oil ring.
Click to expand...
Hi George, let me answer one at a time here!

1-Correct with respect to the wrist pin "through" the oil rings using a "rail-support", it is considered a "non-issue" here. Use them all the time.

2-In your application, "Pro-Charged", you will definitely not need the dish, a flat-top will "fly" here.

3-We are staying with a 1.220" C.H. and "CNC'ing" the blocks to 9.795". This will give us just about a "zero" deck minus a few "thou". Given these are ALL new "Bow-Tie" S.D.'s we have no issues with any previous milling numbers! Future piston orders MAY come through at 1.200", again, depends on the blocks and what "condition" they're in when they return! These will most likely "see" 4.530" x 9.785" (nom.) and specific head gaskets.

4-The +.375" cranks we have here should be able to handle a 2300 "target" bobweight. Easily balanced unit with the +.250" rods still!

5-Most "blown" units we build are NOT "under-the-hood" deals and have either 8's, 10's, or 12's on "streeter's".

I would like to add this here, NORMALLY, there are no add'l charges for the type of "custom" pistons that we're talking about here. There MAY be some add'l time, but NOT charges. These piston configurations' you guy's are using here, at least in my opinion, DO NOT constitute true "customs"!!! As I said above, you WILL see the 1.200"/1.220" C.H.'s showing up next year! Most likely they will use the "shorter" C.H. for convenience!!

(Add) On ALL the blown units we've done with respect to head gaskets, so far we believe you CANNOT beat the Fel-Pro "MLS's". This is my own opinion as of today. (Tip) DO NOT unseal any of these gaskets until they are ready to install!! Do not let them lay around "opened" for any length of time! This is most "critical" to the head gasket's longevity!

Thanks, Gary in N.Y.

P.S. George, your pistons, as flat-tops with a 3 cc intake pocket, should come in near 600 grams or so! Just a "guess" here of course.
 
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#19 ·
GOSFAST said:
Hi George, let me answer one at a time here!

1-Correct with respect to the wrist pin "through" the oil rings using a "rail-support", it is considered a "non-issue" here. Use them all the time.
Click to expand...
=
Absolutely 100% correct :thumbsup:
I do not know who started the crap floating around that this is an issue

I have a couple of propane engines I did about 5 years ago that are well in access of 100,000 miles with a 1.270 c/h in motor homes & they are still going strong as far as I know & these things get worked to death :)
Many 6" rod 3.75" + stroke small blocks, 6.385" rod 4.25" stroke big blocks & have never had any issues with a support rail.

I do not know how people think that a spring steel support rail is less wear resistant than an aluminum piston groove & the only place you are not 100% supported by the piston is about a half inch at the pin
 
Discussion starter · #20 ·
So, what I'm gathering from the latest bits of information here is this configuration really should be just fine. I am using a virgin, short deck, bowtie block so I know exactly what the deck height is and from what GOSFAST states this combo works. Do we agree?
 
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BLOWNBBC
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