Machining press fit for spirolox - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 07-01-2008, 09:59 PM
KA67_72's Avatar
Member
 
Last photo:
Join Date: Jan 2003
Location: Knoxville, Tn
Posts: 313
Wiki Edits: 0

Thanks: 1
Thanked 4 Times in 4 Posts
Machining press fit for spirolox

I have a new (5 years ago) set of press fit forged speed pro pistons I don't want to spend $500+ to replace, but I just bought a set of Scat H-beam rods to go with my 4340 Eagle crank. Not that I'm going to have the nards to wind this thing to 7500+ at 20 psi, but it'd be nice to know it's there for climbing the hills around here. As they are, the pins are .080" shorter than the pin bore. What determines if there's enough meat here to machine these pistons for retainers. How much of the pin boss does the pin need to be in contact with. These are on a 454, 7.8:1, turbocharged. I have a set of 4.155" JE's. Looking at them, I'm going to need to take .1875" off the 454 pins to clear the locks. This will leave 1.422" of pin in contact with the pin bores.

Thanks,
Kevin

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-02-2008, 05:50 AM
Hotrodders.com Moderator
 

Last journal entry: PICTURE TEST
Last photo:
Join Date: Jan 2004
Location: york pa
Age: 52
Posts: 2,795
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
pistons

I assume that you are going to do the machine work yourself..

I wouldn't want any less the .100" of a land and the end of the piston for the retainer to push against.

You should be able to get the correct length pin to compensate for the retainers. IMO i would buy the pins first, then machine the grooves for the locks. You can't just place those grooves anyplace. There is a close tolerance on the distance between them. If you get to much clearence between the pin and retainers , the pins will beat the crap out of them..

All-in-all it's going to be a project. You might want to really think about sending the rods back and getting pressed fit rods....

This will probably turn into a pissing match but, the only thing a floating rod gets you is the ability to swap pistons with-out pressing them off. There is no performance or strength advantage.


Keith
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-02-2008, 07:06 AM
KA67_72's Avatar
Member
 
Last photo:
Join Date: Jan 2003
Location: Knoxville, Tn
Posts: 313
Wiki Edits: 0

Thanks: 1
Thanked 4 Times in 4 Posts
I'll be doing the work myself if I can't find someone to do it for a reasonable price. I really wanted H-beam rods and I haven't found any press fit ones. As far as performance gain with floating, it looks like you sacrifice piston strength to gain rod strength and reduce friction.

Kevin
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 07-02-2008, 08:03 AM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
Quote:
Originally Posted by KA67_72
I'll be doing the work myself if I can't find someone to do it for a reasonable price. I really wanted H-beam rods and I haven't found any press fit ones. As far as performance gain with floating, it looks like you sacrifice piston strength to gain rod strength and reduce friction.

Kevin
There's really no piston strength loss. Have you thought about sending the pistons to have the grooves cut & ordering the correct pins? I don't believe anyone makes H-beam rods that are press fit. You can get some nice I-Beams that are press fit tho'. Such as Scat's 2IIRC, they come in press or bushed floating, forged 4340 with 3/8" or 7/16" Cap Screws and stroker clearanced.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 07-02-2008, 09:55 AM
Hotrodders.com Moderator
 

Last journal entry: PICTURE TEST
Last photo:
Join Date: Jan 2004
Location: york pa
Age: 52
Posts: 2,795
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by KA67_72
I'll be doing the work myself if I can't find someone to do it for a reasonable price. I really wanted H-beam rods and I haven't found any press fit ones. As far as performance gain with floating, it looks like you sacrifice piston strength to gain rod strength and reduce friction.

Kevin

How were you planning (on what type of machine) on machining them if you do it your self???


I can tell you in my shop it's $50.00 per piston to do the job. If a person would charge much less for that job with all that is involved in doing it correct he would be loosing money IMO.

Keith
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 07-02-2008, 10:11 AM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
Here is a guide for installing snap rings and spiral locks. It will show the edge margin you need for snap rings. It a pain to put these grooves in if they aren't in the pistons. I've done it in a lathes with a home made fixture.

Go to rings then to spriral and there is a pdf on specs and installation.

You may have to delete the # sign if you have trouble with the link.

http://www.tfc.eu.com/#

Here is Spiralox site

http://www.spirolox.com/

Last edited by bentwings; 07-02-2008 at 10:16 AM.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 07-02-2008, 10:24 AM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
K-star I'm sure there is a lot of setup time involved in that type of process whether using a boring machine or a lathe. Sounds like he may need to sell those pistons and buy new ones if he's set on floating pins.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 07-02-2008, 10:34 AM
KA67_72's Avatar
Member
 
Last photo:
Join Date: Jan 2003
Location: Knoxville, Tn
Posts: 313
Wiki Edits: 0

Thanks: 1
Thanked 4 Times in 4 Posts
I'll call around here, but $400 is more than the pistons are worth to me. If I can't figure out how to do it myself, I'll save these for a lesser project and buy new ones. I have a standard bore 454 in the shed, but like everything else around here it'll end up turbocharged too. I was planning on using my Bridgeport. What type of cutter do you recommend? I was thinking about a keyseat cutter. I have a trashcan full of pistons I melt down for castings. I'll try it on them first.

Kevin
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 07-02-2008, 10:57 AM
Hotrodders.com Moderator
 

Last journal entry: PICTURE TEST
Last photo:
Join Date: Jan 2004
Location: york pa
Age: 52
Posts: 2,795
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
pistons

Quote:
Originally Posted by SSedan64
K-star I'm sure there is a lot of setup time involved in that type of process whether using a boring machine or a lathe. Sounds like he may need to sell those pistons and buy new ones if he's set on floating pins.
Yep you’re right, pain in the butt to get set up. Then there is the problem where you have to be 100% correct with every piston, there are no DO-OVERS. If you make a mistake the piston is scrap. You need a tool the correct width and it needs to be small enough to fit into the pin bore, there not growing on trees.

They almost need done on a lathe, or other suitable machine that can spin the piston. If you do them on a mill you have a big problem with how your going to get the tool in the pin bore, and then feed it out while the spindle is running. There is a very expensive boring head that will feed out while the spindle is running, even if you had one you stand a really chance of blowing the outside diameter of the groove oversize because they have no positive stop. You could put the spindle in neutral, turn it by hand and manually feed the boring bar out .001” at a time. You can see where that would get you in a hurry…

A lathe is nice because you can easy make a mandrel that fits the pin bore, locate the piston from that. But your still left with figuring out how to clamp the piston. It’s not that hard but still needs some engineering.

So now you have the piston all chucked up and ready to machine…How are we going to check the finished OD of the groove????, Need another expensive tool…How about the finished width??? The pin bore is way too small to get gage blocks in, Need another expensive tool…..

Let’s say we have all those issues covered. The big issue that’s left is locating the grooves in each end in the exact correct position with each other (not the end of the piston), and centered in the piston.

All-in-all not a do-it your self job if you want it done correct. IMO
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 07-02-2008, 12:47 PM
KA67_72's Avatar
Member
 
Last photo:
Join Date: Jan 2003
Location: Knoxville, Tn
Posts: 313
Wiki Edits: 0

Thanks: 1
Thanked 4 Times in 4 Posts
What about one of these grooving tools:

http://www.mcmaster.com/#catalog/114/2472

Kevin
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 07-02-2008, 01:23 PM
bentwings's Avatar
bentwings
 
Last photo:
Join Date: May 2002
Location: St.Paul, Minn
Age: 72
Posts: 1,798
Wiki Edits: 0

Thanks: 0
Thanked 16 Times in 15 Posts
I've done this on a Bridgeport also. I used a rotary table and a boring tool. Just make the tool the groove width, set the dia of cut such that the tool will go into the Piston pin hole with the spindle on and dial the axis off untill you touch off on the bore of the piston . You just dial the table around and off set the the axis as much as the depth of the groove. Another PIA set up but if you don't have to pay anyone but yourself it's acceptable. Figure about 3 hours set up and machining time at least if you have the tooling around. You are going to need a vice to hole the piston. There is a hotrod piston vise available if you look around. Speedway I think.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
What crank ect will fit on a 283 SB chlsnk Engine 12 06-18-2008 06:39 PM
Will any of these intake fit? TekeTorvo Engine 13 05-30-2008 12:04 AM
To fit ..or not to Fit.. that is the question! chevyluvnpuppy Body - Exterior 3 05-04-2008 01:31 PM
Seats to fit a 28 Coupe Gramps Interior 7 09-24-2007 10:41 PM
Ford 400 Press Fit Hose Outlet ???? gohealthyhome Engine 4 07-09-2002 06:31 AM


All times are GMT -6. The time now is 01:05 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.