Thread: Advice on Cylinder 1 Please

Sorry, I forget to add that I can see these marks but cannot feel them with my finger nail.

thanks
Jeff

Hi Jeff - Sorry not following - what marks - what are you enquiring about.

Edit - just spotted your other post - I guess you created a new thread instead of a new post in your other thread - maybe the mods can move this for you.

As top your question - sorry I do not know if it is an issue but it is wise to ask

Garry

Hi, It looks like the marks are not bad enough to have to re-bore.
A good hone should do the job.
When you hone move the hone up & down to get a good cross-hatch.
Also it looks like there is a lip at the top of the cylinder. Concentrate on getting rid of that otherwise you will brake the compression ring.

Paul.

its not a race car, worst case it may use a little oil and maybe a bit of compression but you wont notice in day to day running
cheers
blaze

Threads merged

not optimal but it does look like honing has already started to blend the edges.

for occasional use and low power use it wont be too big of a problem but if its going to be a daily.......
I'd be doing a hone up till the marks were barely perceptable checking out the overbore dimensions and seeing if it was still in tolerance for the piston/ring limits. IF it is build it and send it. if not, its time to bore it, oversize it or line it then build it.

For what it's worth, back in the early '70's my SIIa developed a "noise" which transpired to be a LOT of broken rings with #1 being the worst with all rings broken and the piston cracked. There was a rounded groove down the thrust side of the bore about 0.5 - 0.75 mm deep and about 5mm wide and about the radius of a one cent coin. All I did was a quick hone, a set of new rings in all cylinders and a new piston in #1. It was as right as rain for the next 30k miles until I sold it and got a diesel SIII. Between them the other three cylinders only had a couple of compression rings intact and all the oil control rings were broken.
Given my experience I wouldn't be too concerned at all about the markings that you have.

I'd be more concerned about the ridge at the top as Powerband suggested. In the picture it looks like the unworn bore at the top is honed then there is a short section that is not honed because the honing tool is being supported by the ridge.

Problem is how to remove the ridge. There is a tool for removing a wear ridge but it doesn't work on an 'F' head due to the angle of the top of the block.
Cylinder Ridge Remover Standard T&E Tools 4289 New

You used to be able to buy 'ridge dodger' top rings that had a step in them so that they didn't hit the ridge. On the badly worn motor in an Austin Somerset years back I fitted NOS pistons and left the top rings out (yes I know, a bodge, but it worked for about a year till I sold it).

On my 6-cylinder Land Rover motor, also an 'F' head, I hand scraped the wear ridge to remove it. I also borrowed a bore comparator to measure the bore and found that it was just in tolerance.
Engineers & Bearing Scrapers – General Tools

You could re-assemble with new rings and there is no problem but if over revved you might end up with top rings broken.


Colin