Author Topic: Cylinder liner protrusion  (Read 12431 times)

piperpilot3tk

  • Full Member
  • ***
  • Posts: 195
    • View Profile
Cylinder liner protrusion
« on: May 27, 2009, 02:43:13 AM »
Tried looking in the manual but could not find the dimension for how far the liner should protrude past the top of the deck surface of the cylinder block.  Measured mine today and it is .018.  This seems excessive, I looked at the old (maybe 30 min run time) copper head gasket and it has a large ridge/depression where the liner smashed the crap out of it when the head was torqued.  After a few more coats of British Racing Green I will be just about ready for reassembly, and this is one of the last things to look at/fix before it all goes together.  So what is it supposed to be?  Thanks, Mike.

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2940
    • View Profile
Re: Cylinder liner protrusion
« Reply #1 on: May 27, 2009, 03:19:11 AM »
you have too much protrusion by a bunch

.003-005" is about right,

pull the liner and inspect for a piece of crap trapped under the lip
sand, piece if rag, swarf, part of a fingernail are but a few odd things that might end up
in the counterbore and hold the liner up too high.

look very carefully deep into the corner of the counterbore, look carefully at the seating ledge, and
look at the liner lip, its ledge, and into the corner for any flaws in machining as well.

reinstall the liner without the oring to double check protrusion, turn the liner in the bore and see if it rides up
and down, if so: turn it into a position that gives you the correct protrusion and mark this position
then on reassembly put the liner back in with orings to this position. sometimes a much as a thousands or two
can be found and corrected in this manner, but not what you are seeing,, my bet is crap caught under the liner.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

piperpilot3tk

  • Full Member
  • ***
  • Posts: 195
    • View Profile
Re: Cylinder liner protrusion
« Reply #2 on: May 27, 2009, 11:24:54 AM »
No trash in the counterbore.  I have even run the cylinder block through the bead blaster and cleaned up the counterbore and the inside of the water jacket area and the dimension is the same.  Also tried rotating the liner.  So it will have to be machined, I am guessing that the liner should should be cut down and not the counterbore cut deeper?

billswan

  • Sr. Member
  • ****
  • Posts: 439
    • View Profile
Re: Cylinder liner protrusion
« Reply #3 on: May 27, 2009, 01:18:45 PM »
Hello piperpilot
 My 10/1 had the same problem. I agree the stand out should be as bob wrote in his post. If the ledge in the block is properly machined and the shoulder of the sleeve is properly machined then find a machinist that can take some off the sealing edge of the sleeve. You can double check the way the shoulders fit together by using a blue magic marker on one shoulder then put the sleeve into place without the oring and rotate it to wear away the blue. Check the pattern that is formed and repeat the process with the other shoulder. This will give you confirmation that the shape of the ledges is correct and that the sleeve and block are in correct relation to each other. As you can tell I have a hard time with words, I hope you get my drift.

I had to have about .007 inch ground off my sleeve to get it into proper stand out.

Billswan
16/1 Metro  in the harness choking on WMO ash!!

10/1 OMEGA failed that nasty WMO ash ate it

By the way what is your cylinder index?

piperpilot3tk

  • Full Member
  • ***
  • Posts: 195
    • View Profile
Re: Cylinder liner protrusion
« Reply #4 on: May 28, 2009, 02:17:11 AM »
Billswan, Thanks for the bringing up the point to check the fit with a marker or some dye, I think I have some machinist's dye at the hangar.  I did eyeball it by pressing the liner firmly into the cylinder block and rotating and checking for scuffing, so far it looks to be a decent fit.  I am starting to think that machining the cylinder block may be the way to go.  The liner looks like it was CNC machined and subsequent replacement parts (if made by the same outfit) should have repeatable dimensions, so If I corrected the cylinder block counterbore dimension and I wanted to swap in a new piston and liner somewhere down the road it should fit correctly.

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2940
    • View Profile
Re: Cylinder liner protrusion
« Reply #5 on: May 28, 2009, 03:16:41 AM »
be sure to use either of these two methods to check protrusion

1. without orings, check the liner height, or

2. with orings and use clamps to hold the liner down

otherwise the orings will give you a false high reading

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

apogee_man

  • Sr. Member
  • ****
  • Posts: 288
    • View Profile
Re: Cylinder liner protrusion
« Reply #6 on: May 28, 2009, 03:26:59 AM »
Piper,

If I were you, I'd have the liner machined down to fit the block.

What if the liner you have now is longer than a potential replacement?

It's far, far easier to knock a bit off of the replacement liner, than to use your double cam liner stretcher hoping to make the new one fit when the hole in the block is too deep...

And yes, it's definitely too high as it is...

Just my $.02...

Steve 
« Last Edit: May 28, 2009, 03:32:30 AM by apogee_man »

oliver90owner

  • Hero Member
  • *****
  • Posts: 861
    • View Profile
Re: Cylinder liner protrusion
« Reply #7 on: May 28, 2009, 09:44:23 AM »
My first thoughts are: are the edges chamfered off ('radiused') as this is one place where there may be a point contact - check with engineers' blue - if the internal 'corners' are left with a radius.

I am guessing that the liner should should be cut down and not the counterbore cut deeper?

It is not too difficult to shim up the liner if it is too low but, yes, easier to machine metal off to make it fit - if you have the facilities.  Shim metal doesn't take up as much space as a lathe.......and the machining job only needs to be done once, hopefully.  You takes your choice.  I would be clamping the liner, even without the O rings fitted, to check the protrusion height.

If you have a spare liner, now is the time to check that one out and make a decision on where to machine.

Regards, RAB

Quinnf

  • Rest in peace
  • Hero Member
  • *****
  • Posts: 645
    • View Profile
Re: Cylinder liner protrusion
« Reply #8 on: May 28, 2009, 03:36:15 PM »
FWIW, I had to turn 0.021" off the liner on the Beta Test engine.  Used a new carbide cutter, slow speed and lots of Cool Tool.  The liner was made of pretty hard stuff.

Quinn

http://www.utterpower.com/kit_engines3.htm
Ashwamegh 6/1, PowerSolutions 6/1 "Kit" engine, and a Changfa R175a that looks like a Yanmar I once knew

12 gauge

  • Jr. Member
  • **
  • Posts: 71
    • View Profile
Re: Cylinder liner protrusion
« Reply #9 on: May 29, 2009, 08:17:14 PM »
piperpilot3tk,
As RAB said about the radius of seating shoulders, that's where I found a problem on mine.  The sharp lip of the seating ledge in the block was riding up on the radius left on the inside corner of the liner's ledge.  Fixed the problem by hand scraping a chamfer on the ledge in the block.  Then the liner was still too high so I cut a little off the sealing end in a lath as Quinn did.  BTW I don't think these liners are anything very hard and I cut mine like butter with a freshly sharpened high speed steel tool bit.  As an amateur machinest I've had much better luck with high speed steel then with carbide tool bits.  Hope this helps.
RH

piperpilot3tk

  • Full Member
  • ***
  • Posts: 195
    • View Profile
Re: Cylinder liner protrusion
« Reply #10 on: May 29, 2009, 11:20:41 PM »
I did have the o-rings removed when I checked the protrusion.  I also checked to see if the sharp edge of the liner was fouling in the radius of the cylinder block, but no joy there either.  I put some machinist dye on the liner and mated the parts to check the fit, the liner had about 85% contact.  I used some valve lapping compound and lapped the liner into the cylinder block and the contact pattern got really close to 100%.  Removed, cleaned and remeasured.....still about .018

12 gauge

  • Jr. Member
  • **
  • Posts: 71
    • View Profile
Re: Cylinder liner protrusion
« Reply #11 on: June 05, 2009, 03:11:25 AM »
piperpilot3tk,
You probably need to reduce that much protrusion, as stated by others, and I would take it off the end of the liner.  Easy to do and if you screw up it's not an expensive part.
RH

prof.blink

  • Newbie
  • *
  • Posts: 45
    • View Profile
Re: Cylinder liner protrusion
« Reply #12 on: June 05, 2009, 04:52:52 AM »
piper, take your dimension off the block, and you will have to dismantle and boil out. start all over again. also,do they have service shims for those motors? have fun finding shims that match the ledge if they dont.  blink