Cylinder liner protrusion ?

[veggie]

Today I finished hooking up the cooling system.
While filling the cooling system with water and inspecting for leaks or loose connections, I noticed some water on the side of the engine.
Upon closer inspection, the whole joint between the cylinder and the head was leaking.
All the way around the head  
Not sure what the problem is. I used a bunch of copper head gasket spray and torqued the head to the recommended 150 ft.lbs.

I'm trying to determine if the fire ring is too thick causing the rest of the gasket to remain uncompressed ??
Or....maybe my cylinder liner is standing too proud above the deck ?? ( mine is + 0.5mm)

How much should a cylinder liner protrude above the cylinder ? (or maybe not at all ?)

veggie

[mobile_bob]

.003-.005" maximum in my opinion

anything over that is likely to leak

.5mm is about 20 thousands and that is likely to leak like heck

be sure to use some pipes or something over the studs to hold the liner down before you measure
it is common for the orings to hold thing up a bit on a new install and give you a false reading.

bob g

[veggie]

Makes sense....
The 0.5mm protrusion plus the thickness of the gasket's fire ring may be too much to allow for adequate crush of the surrounding gasket material.

What is the proper way to remedy a liner with too much protrusion ?

veggie

[mobile_bob]

check to see that it is firmly held down to check for protrusion

then if it is too much, remove the liner and check for grit or swarf that might be holding it up

if it is clean and still too high you either have to cut the counterbore down or reduce the step on the liner

you might want to check with another liner to see if the one you have is too thick before cutting the counterbore.

there is a special tool made to cut the step or counterbore on engines that have wet liners, automotive machine shops will have one
or a hd truck shop should also have one.

or you can take the cylinder to a machine shop and have them use a bridgeport to cut it to the proper depth

or alternatively have the liner lip reduced to get it right.

in any case i would sure check for swarf or grit carefully before doing anything.

bob g

[billswan]

remember that as the liner goes down so will the head and the squish between the piston and head will get smaller.

If you lower the head .015 or so the piston will run that much closer to the head and you may need to increase the gaskets below the cylinder block to get the piston  to head clearance right.

Bobs got the .003 to .005 inch sleeve standout right as far as my experience tells me also. The indians missed the mark by a mile on that engine, .020 is a guaranteed leak.

Billswan

[Crofter]

Veggie, at this point you should make sure that cylinder protrusion is equal all around. This relates to cylinder deck being true with the bore for the liner. I had the same general amount of protrusion you had but it ranged from around .015 to something around.023 diagonally across the cylinder. I had to correct that first and then had even greater protrusion.

The option then would have been to either drop the recess in the cylinder casting, cut the lower surface of the top lip on the liner as Bob mentions, or remove metal from the top surface of the sleeve.

If you had faith that top lip thickness was standardized in view of future sleeve replacements, then it would be best to make the correction on the recess in the cylinder casting; that is a fairly cumbersome piece to chuck in a lathe though, so I  opted to machine the top of the sleeve and settled for .010" protrusion but that is at the high range of desirable. Probably more in the range Bob suggests, like .003 - .005" More protrusion gives more bite on the fire ring but less to the water sealing area.

[veggie]

Thanks everyone !

Hindsight sure is 20/20 in this case.
This would have been so easy when I had the the engine torn down a few weeks back.
Still learning 

veggie

[quinnf]

The figure I saw from India specified 0.009" protrusion.  Seems a little much to me, too.  But there you are.

The Beta test engine was much higher than that, so I turned the shoulder on the sleeve down a bit.  My Ashwamegh was pretty much right on, so I left it alone.

Quinn

[veggie]

Well......it would make my life much easier if I did not have to open up the bottom end and remove the con-rod.
I would prefer to just slide the cylinder off the piston and leave it connected to the crank.

Has anyone had success installing the piston from the underside of the bore while lowering the cylinder into place ?
If so, any tricks to share in this regard  (fingers crossed    )

veggie

[mobile_bob]

remember the old proverb grasshopper

"the shortcut is often the longest way around"




bob g

ps don't ask me how i know this!

[veggie]

This practice is standard on big bore motorcycles.
The cylinder is slid over the piston.
A taper is machined into the bore at the very bottom to allow the rings to compress as they slide in.

[Tom Reed]

When I did the liner on my Ashwamegh recently and checked the protrusion it was WAY high. Upon removing the line I found that one of the O rings had a knarf in it and the chunk was holding the liner off the seat in the cylinder housing. What I ended up doing was putting the O rings on the liner while it was half way in the cylinder housing. This wasn't easy to do, but the protrusion is now right and it sealed up perfect. Good luck with yours.

[luv2weld]

I have pulled and replaced the cylinder without unbolting the bottom end.
You just need to be very careful not to let it get away from you. If it slips
and the rings end up supporting the weight of the cylinder, you will likely break
a ring. Now how would I know that??
If you don't have someone to help you with this, then I suggest a small hydraulic jack.
Or anything else that you can think of (some blocks of wood?) to support the weight
but still allow you to control the lowering a little at a time.
Use the rotation of the flywheel to inch the piston into the bottom of the sleeve.
You can use your fingers to align the rings and compress them enough to get
them started. Be careful not to slide your fingers along a ring. You can get a
pretty bad cut if you do.

Ralph

[Tom Reed]

I did it a similar way too. By supporting the cylinder on a 2x4 on edge, you can turn the flywheel to raise the piston into the cylinder while compressing 1 ring at a time with your fingers. The simple design of these engines is just awesome!