98 V70XC rings and bearings

[div4scpro]

was planning on doing a bare block up rebuild on above make and model engine w/ 98K. already completed full cylinder head build with all valve recut, lapped, stem seals, etc. no known compression, main or rod bearing issues. haven't torn lower end down yet so not committed, but have become a little intimitated with the combined cost of rings, main and rod bearings. not looking to build any monster, just wanted to start with everything fresh. any suggestions on brands, good or bad, and any ways to manage cost of said parts, combined sets, etc, greatly appreciated.

[JimBee]

I tore down a 96 850 last fall, so I can make a few suggestions. It's been a long time since I last did this, but the basic bones of the engine are the same, as are the processes.

First, if you had decent oil pressure but you've gone to the trouble of rebuilding the head, I assume you plan to keep the car for a while, maybe a long while.

You're further into a ring/rod bearing repair than you might be thinking.
You'll want to drop the pan anyway to replace the O-rings. There are tutorials on this site. Plan to drop the subframe on the passenger side, at least six to eight inches. If your oil pan doesn't have an oil cooler manifold on its "front" end, under the crank pulley, you might be able to work the pan out as shown in the tutorial. You'll want to "hang" the engine from a sturdy cross bar, if you're going to remove the front engine mount, which you likely will. I suggest removing the mount bracket for additional clearance.

You'll need to remove the oil pickup pipe to swing the pan out. It's tight in there, but with the pan loosened you can reach in with a small bar and socket to remove two bolts.

With the pan removed, of course you're right there at the bottom end. Rod caps are fastened with star bolt heads. Technical bulletins state those bolts must be replaced if they are longer than 55mm. I couldn't find anything authoritative that stated you can reuse them if they are not stretched (they are a stretch type bolt). After talking with three engine rebuilders in the Twin Cities, all of whom told me they reuse them, I got over the panic of retorqueing to squeak (look up the torque + degrees spec) and all went fine. I did measure mine and they're all 50mm which is presumably the new bolt length.
Harbor Freight sells a digital caliper for $12.00 on sale.

So pulling your bearing caps is easy. You'll find out if there's any bearing wear. A new set will run you about$120, if I recall correctly. You'll notice the number of the cylinder is stamped on both the rod and the bearing cap (numbers must match numerically, but also proximally when you reassemble.

If your crankshaft is mirror smooth, your oil pressure was okay (and will be great with new Orings) don't worry about your main bearings. Those are factory fitted to within one ten thousandths of an inch. It's not unusual to find 3 different sizes of main bearing inserts, varying only by one or two ten thousandths (according to racing engine builders I read on line). Anyway, if all looks good on the bottom end, the pistons and rings are next up.

Before jumping into the cylinders, get an inside mic and measure cylinder bore diameter. How much wear do you have? Check with a rebuilder for wear specs within reasonable tolerance.

If there's any scoring in any of the cylinders I'd get a professional opinion whether to proceed. You can see that with the head off. Just move the pistons up and down to inspect.

Your bores will have a ridge around the top, which might be a few thousandths.

To remove the pistons, you'll need to shave off those ridges. Fortunately, Autozone and O'Reilly's both have a loan tool for that and once you get the hang of it, each bore takes about ten to fifteen minutes to cut. Once you get the hang of it Naturally, you'll want to pack something on top of the pistons to catch metal filings. Then shopvac the cylinders. Use a push stick or something from below to pop the pistons out.

New rings will run about $120, I think I paid. There's a U.S. company in California (Grant) that's been around since early 20th Century. They make two qualities, for a normal rebuild their tech told me most rebuilders use the standard variety (not the stainless steel).

I had a rebuilder clean my pistons and they literally looked like brand new (I think they used a boiling tank). They first strip off and toss the old rings. Then the cleaning process will remove any buildup from the grooves behind the rings. Have them put on the new rings.

Before reassembling, you need to prep the bores. They will have burned in carbon deposits that you'll want to clean out thoroughly. You can do that with degreaser and rags. A lot of soaking and rubbing will get them back to clean metal.

THEN, you need to hone the cylinder bores. The modern way to do that is with a "ball hone" (also called a dingleberry). It's drill driven. My rebuild supplier loaned me his. You run this inside the bores rapidly maybe twenty to thirty times up and down while it's turning fairly quickly, so you very lightly scratch the bore surfaces with a cross-hatch pattern. You'll need that to chafe in the new rings.

Before reinstalling, make sure to squirt oil into the ring grooves, turning them a little to get the oil behind them. Arrange the 3 rings so their gaps are equally offset at 0, 120, and 240.

To replace the pistons, you'll need a ring compressor, also a loan tool at Autozone and O'Reilly.

Use a rubber hammer or a piece of wood block on top of the piston. Align the rod from underneath.
Make sure the crank journal for the piston you're working on is at BDC to avoid damage. You'll need to tap the piston fairly smartly to get the rings out of the cuff (compressor sleeve) and into the bore, but don't dirve them really hard to avoid damage below. Ideally, you'll have somebody underneath to guide the rods down.

Keep track of your bearing inserts if you plan to reuse them. Rebuilders told me that's often done if they don't show signs of wear.

Good luck.
PM me if any more questions.

[Ozark Lee]

I'm wondering why you are tearing down the bottom end if there were no problems. Unless you are building up a 350 - 400 HP monster engine the bottom end on the whiteblocks is incredibly durable. The only rod problems I've seen around here are as a result of having a half a car length lead on a Mustang 5.0 and the tach is at about 7500 RPM.

If you do proceed I think Jimmy57 had a source on rings that was fairly reasonable. The same supplier might have the rod bearings.

...Lee

[draser]

Here's a variation of this: I opened up an engine at 140k, with good compression but piston slap - my fault running it low on oil. I left head alone and removed pistons and con rods.
Upon inspection piston skirts were scuffed, however crank journals were in spec and cyl bores just before repair limit (I got my hands on a bore gauge and full set of mics.). I order!d crank and rod bearings and piston set. No rings since comp. was very good as said.
I had access to a full repair manual which saved me cost of head and rod bolts, existing weren't stretched. Only mod I did was to match the bearing oil holes to crank oil passages, chamfer top con rod oil hole, weight match con rods by polishing outside beam, weight match new pistons ;by grinding inside of crown until I had equal weights for the moving mass sets (within .5 gram).
I ordered identical bearings as original, counting that with the engine wear I would not be too tight, I did not want to waste more time to Plastigage or measure and compensate for wear. And I had ,zero cyl ridge.
At re-assembly I reused old rings which were paired to their cyl at dissassembly. I also used assembly lube on everything. Cost of parts about 600 plus my labor. Sold car at 200k running like new, except for the tranny that was starting to slip.

[JimBee]

I agree with Lee. The lower end of these engines is amazingly beefy.

If a guy wants to rebuild one just for fun, why not? If I had the pan off another car that I'd planned to keep, to do the seals or for any reason, even if it had good oil pressure, with no light at idle or other symptoms, I'd pull the bearing caps just to inspect them for abnormal wear (any copper, brown or reddish spots, or serious scratches or pitting). If none, put it back together. As draser said use assembly grease on the journals. Just a little smear is all you need. As long as the oil pump and seals are good, you'll have oil pressure in about 10-15 seconds of turning it over, including to the top side. No need to prime the filter.

If the head and pan were both off at the same time, on a 200k engine, I'd probably do the rings and bearings if I planned to keep the car.

One thing I did notice on my engine is a little oil had accumulated behind the bearing inserts. The contact surface between the back of the bearing and the cap should be dry. In a situation with high rpm's, if the bearing to journal (oiled surface) got even a tiny bit dry, oil behind the bearing might cause it to spin.

NOTE: just occurred to me that even though the bearing caps and mating points were notched to receive a matching relief on the corner of the bearing that locks the bearing from spinning, my inserts didn't have that bearing relief.

That's all the more reason to pull the caps and dry the back of the inserts, there's really nothing to stop them from spinning except the clinch force of the cap. My inserts were OEM. Had "Volvo" and the date Oct. 1995 stamped into the back of them so they were made that way. Were they all in that era? Maybe jimmy57 could answer that question.

If so, and you plan to run the engine hard, that would be all the more reason to install a set of Clives or some other quality insert, being sure that they have those locking features.

[div4scpro]

I'm restoring this Volvo, engine and all, because it's cheaper than therapy, I always wanted a little red wagon, and it's got more moving parts than any previous model I've built. That being said I appreciate all the tips and ideas that I have picked up at this site. My next big challenge is finding all the bushings necessary for the rear end suspension.

[jimmy57]

The ring source, rod bearings too, is: http://www.importperformanceparts.net/i ... olvo1.html

Unless you find something terrible with the rd bearings then there will be no reason to pull the motor apart and look at mains. The mains are selective fit. The bearing kit includes 6 shells per journal to give you the assortment to choose from so the crank sizing and block journal opening size markings can be used to select the correct shells. The bottom end of these engines only gives issues in engines with 30000 mile oil change interval. In that case you'd already have found lots of reasons to not proceed with any repairs on that engine.
Tangs on bearings serve no purpose to keep bearing shells from spinning. They were only for indication for lateral location in rod or block. If the engine goes without oil the tang may make a 2-3 crank rotation difference to when the shell moves but the damage was already done. The interference fit of rod bearings in rod (called bearing crush) is what keeps the shells in place. Oil on the backside of bearings is of no consequence. When you apply oil or liquid assembly lube to bearings prior to installing in engine the lube will end up behind the bearings.