I‘m back to working on what is to be an interim engine for my S2 OTS. Should I hone and put in new rings? Or will this hold up for a few years / 10thsd miles? This is cylinder #1, not the best one but also not the worst. While honing might not take care if all the markings, it surely won‘t make anything worse will it? Thanks for opinions.
It all depends on the roundness or ovality of the cylinder bore. The cross hatch pattern holds oil and helps seat the rings. This only works if the bore is round. If it has significant wear on the thrust side, new rings won’t seal in an oval bore, no mater how the cylinder walls are finished.
The ridges, if I remember that right, cannot be felt by hand. The Engine is said to be low mileage (90000 km) and looks the part, all looks as if kept in good condition apart from pitted cam bearings and a bent valve.
We were concerned about the ridges and whether it would make sense to re-hone.
On the other hand the rings seem good and I‘m sure I have seen worse pistons online?
So, as long as the Engine is apart anyways, is anyone in favor of going through with a ball hone or do you think it is better if left as is?
If you are going with new rings then yes do a hone, I would hone even if you were keeping the rings that are on the engine.
So you are saying we can keep the rings and should hone, provided that the bore has not become oval too much.
New rings should be used, with a hone.
I would never reuse old rings, unless in a dire emergency.
When you re ringed your old 3.8, you reported that it consumed oil like mad.
what methods did you employ to get that result?
A ridge reamer should have been used before those pistons were removed. Chances are the lands have been damaged as a result. Re ringing without removing the ridge and subsequent de glazing without a ball hone will lead to further damage and higher oil consumption IMO.
We, or I, checked for a ridge and felt nothing, neither with my nail nor with my fingers. So is that really necessary if the rings have nothing to catch on while driving out? I know what a ridge reamer is but without a measurable step I wasn’t worried about using something.
A piston ring set is like 60 pounds UK so it really is a case of while it’s apart I would say… right?
If there is minimal ridge, and the piston can be lightly tapped out, no prior ridge reaming is needed.
I’d use new rings (NOT CHROME) and a ball honing: won’t be perfect, but most definitely an improvement.
i feel compelled to back wiggles - i have seen pistons popped up just enough to break oil control ring off and immediately replaced just to get less friction loss on 3.4 & 3.8 - more oil fog is inevitable. but desired.
Thanks for your responses. Piston #1 slid out with no resistance at all, easy job. This evening #2 thru #6 will be out, I‘ll report later. A flex-hone is on order.
Keep track of rod-piston/ bore orientation.
For some perverse reason, upon reading this, I was immediately reminded of the old W.C. Fields quote, “Always carry a dragon of whiskey in case of snake bite, and furthermore, also carry a small snake.”
Got that. The pistons are installed and marked „front“. Since the pistons and rods are not getting disconnected I‘ve got the orientation. #2 now out:
Hmm looking at the marks on that bore I’m not sure a ball hone will do the job? I would be inclined to use a stone hone on that, just my 2c.
Dalwhinnie and Cragganmore are on site. For the snake, I‘ll ask David to bring the one he was handling last week in Constance. We would have to teach it to bite though.
I think it depends your goals. 20 years ago my engine had similar mileage and the cylinders looked similar. I ringed it and used a ball hone. With the exception of cylinder one, all the marks came out. The minor scoring that remained after the hone in that cylinder was only sufficient to drop its compression by about 5psi or so.
After 23k mikes the engine seized due to a thrown upper timing chain guide. It was sufficient to bend a rod. Had that not happened I’d still probably be driving on that engine because it was running great. If you do change the rings, make sure you gap them all properly in their intended cylinders. Given the wear, you probably won’t have to do anything to get them in spec but do verify that. Also invest in a pair of ring pliers and a ring compressor for installation lest you break them in the process.
^^What she said!!!^^
Ball hones, well-oiled, are remarkable effective in cleaning up older, still-usable bores.