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7/15/2016 2:26 am  #1


Salvaging a Screwed up Bore:(

I had a screw up with a Chev 454
I bored the first hole to about .0015" of finish, bore is +.060". I used a freshly sharpened bit. It will be using Wiseco forged pistons and a set of Hastings Moly rings. I have a honing plate and use vitrified stones, 220 to less than .0005" of finish, 280 to finish, touch with 400 and a couple of reverse strokes with a honing brush.

I really wanted to d a good job, to fix it, should I sleeve it, I am concerned about having enough depth to properly oil the rings in the .0015"?

What would you do?

I've been loosing sleep...
Thanks

Last edited by rcull (7/15/2016 10:46 am)

 

7/27/2016 11:45 am  #2


Re: Salvaging a Screwed up Bore:(

This is REALLY off the deep end- but I have made pistons "grow" by squeezing them in a vice on the pin sides. This sounds stupid and risky but it works. You have to make the piston  slightly yield, so when you release the pressure the skirt will measure slightly bigger. Good luck

 

7/28/2016 5:47 pm  #3


Re: Salvaging a Screwed up Bore:(

Yeah if you needed to get out of mexico cause the federales were on your tail then maybe lol


 


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

7/28/2016 6:03 pm  #4


Re: Salvaging a Screwed up Bore:(

rcull wrote:

I had a screw up with a Chev 454
I bored the first hole to about .0015" of finish, bore is +.060". I used a freshly sharpened bit. It will be using Wiseco forged pistons and a set of Hastings Moly rings. I have a honing plate and use vitrified stones, 220 to less than .0005" of finish, 280 to finish, touch with 400 and a couple of reverse strokes with a honing brush.

I really wanted to d a good job, to fix it, should I sleeve it, I am concerned about having enough depth to properly oil the rings in the .0015"?

What would you do?

I've been loosing sleep...
Thanks

You always need .005 before finished size regardless if using a Torque plate or not.
The block will be totally out of round after bolting it on the block. And if using an iron plate for alloy heads thats going to be different when they are installed.
But I have seen some guys go as tight as .003 before finished size and get away with it on a strong casting but not always 
I always leave .005" minimum for honing to round up the bores and remove any tooling marks in the bore to produce a good finish.
Just a note for those that may have missed the moly ring 101 class,
Sealed Power used to put honing instructions in their ring box's with the following requirements for what stones to use 

The Sunnen stone numbers for use in a CK-10 or XCV-616 were as follows.
With .005 to finish use a EHU 123 or 133 then a EHU 518 or 525 then a JHU 625 then a JHU 818 or 820
I go 123 to .004 then 518 to .003 then 625 to.0005 then 820 to finished size. Now the cross hatch angle is critical here and nothing more then 60 degrees or nearly flat in appearance or it will suck oil bad if the cross hatch is too steep.

Do a Google search for the info in back issues in engine builder magazine anything less then that will not yield good sealing results as too coarse of finish will tear the moly out of the top ring which after a short time will spike the blow by meter.

I see shops that only go to a 625 stone and call it good then have blow by issues but a moly ring needs a smoooooooooooooooth 400 grit finish to seal and last and very important with newer thinner ring packages.

An easy way to check is if you can catch your finger nail on the cross hatch its too rough.


Happy honing guys


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

7/29/2016 4:38 am  #5


Re: Salvaging a Screwed up Bore:(

To Conway's remark: I have built race engines for 50 years and set many NHRA records. I did NOT like your smart a__ remark.  I can build better engines than you!

 

7/29/2016 5:01 am  #6


Re: Salvaging a Screwed up Bore:(

Who moderates these posts? I'm new, and on my very first comment trying to help someone, I get a smart a__  remark back ! Sort of takes away the atmosphere and desire to help someone. I have a lot of knowledge to share, but I won't be here long if this happens again.

 

7/29/2016 1:07 pm  #7


Re: Salvaging a Screwed up Bore:(

I did not mean to insult you but in reality that would be a last ditch effort to make the final round cause there was no other options and parts available.
I would NEVER suggest that a guy did that on a new build regardless of what then engine was used for and as for better then me well I just won't go therehttp://cdn.boardhost.com/emoticons/tongue.png
.

While I am not new here and have been on here since the very beginning of the AERA site and had 1000's of helpful posts I just call them as I see them as I do not know the level of certification behind anyone's post except the long time members here.

And while this site is intended for anyone not just AERA members as it was at 1st but the purpose is the correct and accurate way to machine or correct a problem. While your suggestion would work in a pinch as I mentioned its not the best way to correct an error in a new build 

 


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

7/29/2016 1:11 pm  #8


Re: Salvaging a Screwed up Bore:(

One option to correct your extra clearance issue is to have the skirts coated.
This is a common practice when a looser then wanted fit is found. There are several options to get the skirts built up but that would be mostly for a freshen up where bores are marginally too large in size.


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

7/29/2016 1:27 pm  #9


Re: Salvaging a Screwed up Bore:(

I know about coating. I don't know how old you are, but I am 71. I've probably forgot more about pistons than you KNOW ! So I will just tell you Mr "know it all"-- I actually used that "squeeze" process on some used 283 super stock pistons. the engine produced 500 horsepower as it should have with new pistons ! By the way-- I attended University of Illinois for my Mechanical Engineering Degree.

 

7/29/2016 3:43 pm  #10


Re: Salvaging a Screwed up Bore:(

I am almost the same age and have seen lots of these things done at the track but NEVER for a new build for a customer because I made an error. Get over your self!!!

This is not a race car this is for a customer that is paying good money for a marine application and there ain't no tow trucks on the water if you have a bad day.Sure to make it through a season things can be done to get by with but this is way a different situation here.
Low buck racers are creative and I am one of those guys but I know the limitations of my integrity  and squeezing skirts is not in my list of things to do for customers if it was my stuff I still would not do it with over nite shipping so cheap and the cost of parts lower now then 20+ years ago 

As for my qualifications I went to UBC for my degree but that's beside the point.I also have 40+ years of seeing broken parts others have tried to band-aid  and expected them to last a long time and did not.

While you got lucky as have others out there been as I said before I would NEVER suggest anyone doing a new build to do that for a customer that is paying for correctly installed components.

The OP called me at the shop regarding his issue and we did talk and now he has it under control now.

 


Pro Power Engine & Machine
Victoria BC Canada
250 652 6985
www.propowerengines.ca
 

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