Loose liner on rebuild

[Geko]

Gents, on current rebuilt and upgrade, i dropped my block and liners new 89 mm liners at the machine shop for fitting. They found that one of the liners (cyl 1) is quite loose. The dry fitting in the video is made without the Fo8. I told them to do a proper cleanup of the the liner seats and try again. I'm not too worried or should I ? Advice please

 

As always

 

 

[Rob Salisbury]

Be inclined to move the liners around the block see if the wobble follows 1 liner, or if they all wobble in bore no.1 ..... If it's 1 liner get all the spigots miked up for a tolerance check, return the odd one, ..... if it's the block be inclined to use one of the modern Locktite sealants as a couple of rings below the flange seat, and make sure the head torquing sequence is followed carefully.

Cheers Rob

[Motorsport Mickey]

It doesn't seem stupidly excessive.

Ask them to measure the spigot on the liner (the sleeve which pushes down into the block) and compare with the other liners, hopefully all the same. Also ask them to measure the spigot sleeves receptacles in the block, hopefully all the same.

Then ensure there is no bit of crap which has dropped upon the Figure of 8 seats midway down the liner, or that the block liner seat hasn't got a build up of corrosion upon it built up through the years. No 1 cylinder runs second hottest in the engine, No4 is hottest because it receives the water last after the others have warmed it up, No 1 is second hottest because it's much closer to the pump and the flow is too fierce pushing past the liner before collecting enough warmth from the liner.

The build up of spigot shoulder crap is biggest on No 4 (hottest cylinder burning off antifreeze and the flow being slowest at that area coupled with the backward tilt of the engine allowing the suspended crap to settle there. Then No1 gets a build up and sometimes difficult to scrape off the shoulders because wen all fear damaging them.

DON'T let them apply a ring of Wellseal or other gunge onto the spigot below the shoulder to firm it up, it will prevent the liner cooling in that area and likely cause piston pinching.

 

Mick Richards

[Geko]

Thanks gents, i'll ask them to proceed as instructed. Mick, could you elaborate on your last paragraph? I had told them to apply some silicone or the like sealant on the Fo8 to make it watertight in that area. Is it a No-no or can if the liner seats flat on the seat ?

cheers

S

[Motorsport Mickey]

A little movement as shown in your video is not a problem. The movement shown was obtained by pulling the liner sidewards and the clearance between liner spigot sleeve and block spigot allowed the liner to "tilt" slightly. If you push down onto the liner without a sidewards force it's likely the liner will sit square upon the without tilting, which is how it will sit in use when clamped by 105 lb ft of fastenings around it.

The FO8 gaskets when finally being fitted should have Wellseal (or your choice of sealer Hermatite etc) applied to surfaces of the liner seat on the block and gasket, there being 4 surfaces requiring sealing. Block spigot shoulder, underside of FO8 gasket, top side of FO8 gasket and bottom of the liner spigot shoulder. When coated (lightly)and clamped together the block obtains it's rigidity and water tight sealing, in reality most of the sealer being squeezed out which is why Wellseal is good because it's thin and remains pliable.

If because of perceived corrosion or "looseness" in the block, you fit the liners with any sort of added sealer around the diameter of the spigot below the FO8 shoulder between liner and block it interferes with the heat transfer between the liner skirt material and the block. This area then is prone to "pinching" the piston when the heat levels build up in the block, ask me how I know this !

 

Mick Richards

Edited July 6, 2018 by Motorsport Mickey