Did a compression test on my stroked Olds 215, not good. #4 cylinder at 50 lbs.

[Gswest236]

I was able to get the engine stand bracket bolts off of the flywheel, so we can now rotate the crank. This is #4 cylinder and there are some serious gouges that can be felt with the finger tip. I'm afraid honing that cylinder wont be enough. I'm sure it will need to be  bored. The question is can it be bored enough to get it back to good. So far the other cylinders look good.
Next step is to remove the #4 piston. First time for me!
Also, Jim, that valley pan is for Buick, will my Olds heads line up correctly?

[mgb260]

Scott, The intake fits both. Those grooves look deeper than they are. If they are too bad you could have the machine shop sleeve that cylinder but probably would cost more than boring all eight. I would pull that piston and rod. You will at least need a new piston and I bet there is broken rings. I'd pull everything and try to hone it out and see. Worst case scenario bore to .040 over and get the same pistons we have.

[Gswest236]

OK, the grooves in the cylinder are fairly deep. The photo doesn't really show it. But if boring it to 040 solves it, thats plan B. Thanks for the valley pan tip, gonna order it.

[MGBV8]

What is the hurry?  Seems to me a valley pan is the least of your worries, at this point, Scott.  When you get your short block issue resolved, you can have one in a few days.

[Gswest236]

Both compression rings were in pieces. Extremely brittle, almost plastic like. The piston looks fine to me, but the cylinder wall is the issue i guess. Since I have no experience, how much material can honing it remove? If you can feel the gouges with your finger tip, does honing seem unlikely to get it right? Will boring 40  over be risky? The other cylinders seem fine, cant feel any scratches.
 

[Gswest236]

Timing chain has a fair amount of slack, Assume thats not right.

[Gswest236]

Little bit of rust at the bottom of the cylinder.

[mgb260]

Scott, You won't know if honing will remove it until you try. We took the worst one on Jon's motor and I counted about 30 up and down strokes before they were almost gone. Adjust max tension on the hone and go fairly fast without going out of the cylinder for a good crosshatch. Spray WD 40 in the cylinder first and about every 10 strokes spray the stones. Did all of them about 40 strokes to be the same. Wipe out with ATF on a clean lint free rag. Machine shop honed again. New cast pistons usually are set up with tight tolerance of about .002 clearance. You can go up to about .007 clearance before they will rattle when cold. Little pieces of the rings ended up in the pan and on the way down nicked the big ends of some connecting rods. We touched them up with a file. You definitely need a new timing set. .040 isn't risky but is as far as you can go. Sounds like you are in the same boat we were.

[Gswest236]

I'll give it a shot, nothing to lose. Any particular of hone you guys use?
Thanks!

[mgb260]

I use the one with three stones, It is more aggressive where the flexhone with balls on the end are for a finer finish. My brother when he refreshed his race engine used 400 grit wet and dry paper powered by the hone to break the glaze. Something like this one would be fine:

https://www.amazon.com/EWK-Brake-Engine-Cylinder-Honing/dp/B07DCMY9NH?tag=bingshoppinga-20&linkCode=df0&hvadid=80058254320539&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4583657823611359&th=1

[mgb260]

You need to know the thickness of the rings and if you look at the backside of the rod bearing it will say std. or oversize. Our rings were 1.5 mm top, 2.0 mm second and 4.75 mm oil ring space. The other size was 1.2 mm, 1.5 mm and 3 mm.

[Gswest236]

The rod bearing says STD. The mic says 1.58, 2.00 and 4.73. There's a little ridge on the outside of the first compression ring slot. Maybe that will clean up?
Only matters if i don't need to bore it out I guess. Did you guys have to bore to .040 or was it already there and you honed it to clean it up?

[mgb260]

Scott, It was already .040.

[mgb260]

I wouldn't use that piston. The skirt looks pretty scuffed up in the picture and what you described about the top ring land. If the scratches hone out you can find a single new piston like this one on Ebay, same as yours only coated or buy a single 1463 .50 Silvolite direct from Silvolite.

https://www.ebay.com/itm/186675153206?_trksid=p2332490.c102020.m5276

Summit has this one and also Enginetech 3010 .50 interchanges:

https://www.summitracing.com/parts/uem-s1463-5mm

[Gswest236]

Yes, new pistons are fairly inexpensive so i will replace it rather than reuse it. Here's what I'm thinking though, if it cant be honed and I need to go .040 over, then I'll need new pistons; correct?  I have no experience evaluating the depth of the gouges as to whether they can be honed or if even boring 040 over will make it usable. I think I'll start with honing it first and maybe that will get it close enough that I'll be confident that boring will resolve the gouges; may even fix it completely. In my mind it's still possible the block may need to be replaced. Again, based on my zero experience dealing with damaged cylinders.

[mgb260]

Scott, You will find out. If they are pretty much gone but not quite .040 will get rid of them.

[Gswest236]

OK, getting a Cylinder Hone. Thanks

[mgb260]

Another alternative. Call Johnson machine in Olympia and ask them how much it would cost to install this sleeve and bore to 3.524. (89.5mm)
May be cheaper than going .040 and new pistons.

https://www.rockauto.com/en/moreinfo.php?pk=8528704&cc=1319622&pt=5312&jsn=626

[Gswest236]

Ok, I'm leaning towards removing all the pistons so I know if any other cylinders have issues. That way I know if re-sleeving #4 is all I need vs over- boring all 8.
So far I'm not seeing any issues, but there may be other broken rings and the compression test showed 130 lbs or so in multiple cylinders which doesn't seem great.

[mgb260]

You want to remove them all anyways, you will have to hone them all if #4 cleans up. You will have to pull the crank and can look under a main bearing to check the size. Inspect everything especially big ends of rods. Probably had about 160 compression when new with that cam and rings are worn. Just bad luck #4 broke

[Gswest236]

I'm watching a bunch of videos on SBC rebuilds. Building courage to take it all the way down. What's the worst that can happen.
A lot I'm sure!
Thanks!

[mgb260]

You'll be fine. We'll guide you.

[mgb260]

Keep everything organized in the same order they were in the motor.

[Gswest236]

I've bagged and labeled each piston with its cap, bearings and nuts. 3 more pistons had broken rings but were somewhat intact. So the compression was down but not like #4. There is more gouging in those cylinders. I'll try honing #4 tomorrow, if it works I'll do them all. If not, the machine shop will get it for probable 040 bore.

[Gswest236]

This doesn't look too good! Others have similar scoring but not as bad. All getting replaced so..