Advice on Cylinder 1 Please

[jedwards]

Gentlemen,

I honed the bores on my 1953 Series 1 that is running a later Spread-bore 2litre motor.
When I took off the head, cylinder 1 yield up the top compression ring in multiple pieces. Cylinder 1 also has a worn gudgeon Pin, plus two shallow score marks in the piston skirt.

Todays hone showed up some score marks in bore #1 but in none of the others.
The advice I need is a sense of now critical these score marks are in #1. I've provided two pictures from slightly different angles. I'm hoping you experts can tell what I should do with it.

I had desperately hoped that I could replace piston #1, put new rings in all round, and reseat the values, which are all OK in their guides but need reseating, not replacing. If that plan was possible, then I could do the car myself at home without breaking the bank, which is under severe stress while I try to bring up the family on $1,500 a fortnight, thanks to the Pandemic.

So, can I still do this or are the score marks in #1 so bad that the engine has to come out, be sent off for reboring, and about $5,000 worth of parts required to put things right. If that is the case, then the car will have to come off the road and be stored for a few years while I get my self back on my feet.

So can I proceed with plan A and fix it at home, or is it out under tarp for a few year?

What should I do?
regards
Jeff

[jedwards]

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

thanks
Jeff

[101RRS]

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 [thumbsupbig]

Garry

[powerband]

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.

[bblaze]

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

[p38arover]

Threads merged

[Blknight.aus]

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.

[Markf]

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.

[gromit]

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 (https://www.australianonlinecarparts.com.au/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 (https://generaltools.com.au/product-category/hand-tools/engineers-bearing-scrapers/)

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

[jedwards]

Many thanks for the terrific advice, gentlemen. As cylinder #1 has the wear banding at the top of the stroke, and had the broken top ring, then I will focus on removing that as a priory.

It was a great relief to read so much helpful advice and now I will tackle the tasks ahead with enthusiasm rather than dread.

Many thanks and have a great weekend.

Jeff