Honing cylinder liners

[Dave McCulloch]

If I fit new Omega pistons in the 1800 K series I'm building, do I need to hone the existing liners to ensure the piston rings / liners bed in properly with one another? The engine has done about 18k miles, and the original honing marks are very clearly visible.

 

If the answer is yes, what is the method for honing liners, and do I need to remove the liners from the engine to do this.

 

As an aside, I read somewhere on BC thathe liners should protrude slightly above the block surface to minimise the risk of HG failure - when I measured this, there is less than 2 thou clearance (this being the smallest feeler gauge I have, and it wouldn't go in the gap when I place a steel rule across the top of each liner in turn) - though for all 4 liners I can "just" see daylight under the steel rule either side of the liner. Is this going to cause a problem, and if yes, what can I do about it?

 

Thanks

 

Dave

[tiddy1]

Dave

 

you need to check the liner diameters, and the reccomended clearance for the omega pistrons. Ideally you need to hone the liners in the block with a torque plate bolted on the top in place of the head. you can "de-glaze" hone the liners loose but it is hard to remove much metal, holding them in a lathe will distort them.

 

as for liner protrusion you should ideally have between 0.002" and 0.006" but you need to make sure all the protrusions are the same. you are better with 4 at 0.0003 the some at 0, some at 0.002 and some at 0.006. I have seen some that are -0.004! I had to deck a few thou of the block

 

Try speaking to dave walker re- honing and omega re piston clearances( they are very different from acculite)

Simon

 

 

[Dave McCulloch]

Thanks Simon

 

All 4 liners appeared to be the same protrusion - in that I couldn't get a 2 thou feeler under for any of them, but for all four I could just see daylight between block and steel rule - so I appear to have less than 2 thou on all 4. ISTR the current Rover HGs are more tolerant of this situation than the uprated Mike Satur version - or am I asking for trouble?

 

I'm surprised that I'd have to remove metal from the liners - thought the only "adjustment" required was to the piston rings - by measuring the gap in the ring with it part way down the liner bore. From what you're saying, am I right in thinking that I may need to get the liners machined to give the correct clearance to the pistons?

 

Dave

[Jason Plato]

Given the grief that many have had after having tried to hone the liners themselves and the protrusion heights plus the cost of having to possibly strip the engine again if the oil consumption is high , I would simply fit new liners .

 

Dave