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

[Gswest236]

Looks like it was hit with a grinding machine wheel to add some clearance. Hopefully the scratches didn't happen while running. 

[mgb260]

Could be a piece of broken ring got caught between the cap and counterweight?

[Gswest236]

That makes sense. I got the rest of the piston rod bearing clearances confirmed. All are .0015.
I read online about people mixing main bearings with one half undersized or oversized to get that .0005 tighter or looser. Is this sketchy? I'd be willing to try it just to see if I can get the mains to .001 or at least closer. If it's a bad idea, I'll leave it as it is at .0015.

[mgb260]

Scott, that only works for Standard and .001 bearings. You are at .010 on rods and mains. You could try the shims and be perfect at .001 if you are .002 on the mains. Did you check the mains again?

[Gswest236]

Not yet, tomorrow. I thought I mixed the wrong plasti-gauge in with the correct stuff, but I didn't.
So, the only issue was that I left some old plasti-gauge on the caps and it seems to get hard once compressed. So, for that reason I'm redoing it. If it's still showing .0015, I'll have to make a decision. Does the plasti-gauge err in one direction like showing too loose. Or is it just not exact either way loose or tight. I know its supposed to get you in the ball park.

[mgb260]

If .0015, it is fine. You have to get the oil pump cover clearance tight at around .001 also.

[BlownMGB-V8]

In this clearance range the biggest effect will be on operational oil pressure and bearing life.

As a reference point, a factory engine with just the typical oiling mods can make 65 psi of running oil pressure fully warmed up and running 0w20 modern oil. That is the engine I have in my car right now, it has roughly 60K original miles. So that makes a good reference point.

Our goal during the rebuild is to match that performance and it is not usually accomplished I feel obligated to say. If you search the web you will see clearance specifications all the way up to about .0023" but rarely will you see any reference to a factory standard. Original factory service manuals are the closest thing you will find and they are by and large intended for the dealer mechanics doing service work and are not the manufacturing standards. In all my years of research I have on a few occasions seen those references and much to my regret  have not recorded or saved them. But what I can tell you is that the numbers I saw were a range from .0008 to .0012" and this complies very nicely with modern manufacturing standards as well as general precision machine shop practice. It's about as tight as you could reasonably expect the bearings to be and get reliable smooth easy rotation. And if you think about what is happening inside a pressure fed bearing you can understand that  the thinner you can make the oil film that separates the parts the longer it will last and the lower the volume requirement will be. It is possible to reduce clearances in a shaft and bushing to as little as .0005 and possibly with ultra precision hardened parts to as little as .0003" and still get smooth and free rotation mostly unaffected by temperature changes for similar metals but that's not a split bearing running bi-metal inserts. I simply added that as an example, theoretically you could closely approach zero clearance and still not have an interference fit but in practice it wouldn't make a good bearing, some clearance is still required due to the microscopic surface irregularities, deviation from perfect roundness and so on. But half thou clearances are common in many industries and has been a common practice for well over half a century, maybe a full century so the clearances used by Buick back in the 60's while pushing the envelope a bit, went right along with their advanced use of thinwall casting and high nickel block alloys. Buick really was making the very best engine possible in many ways, whatever our feelings might be about their pistons, valve sizes or intake port designs.

So to answer the question of will .0015 be adequate? Yes it certainly will. Will it be optimal? No it will not. But it's a balancing act like most things and is entirely dependent on your objectives. Can you live with 10w40 oil and 45 psi of running pressure? If the answer is yes than you will be fine.

Jim

[mgb260]

Original Buick factory shop manual bearing clearances for 215:

[BlownMGB-V8]

Yes, note the spec for the crankshaft bearing clearance is .0005-.0021" and it gives the crankpin spec as a single number: .0022" rather than a range which by itself should raise a question, why is there a range for the mains but not for the rods? And as I noted before this is a service manual, not the factory spec. You can't just assume the specs in the service manual are the same ones as those used in the factory building the engines.

If we are going to make any assumptions at all, we should assume the clearance range is the same for both the rods and the mains in which case the range for the rods would be .0006-.0022"

Now if you want good oil pressure which end of that clearance range do you want to be at? Certainly not the big end. And bear in mind these engines were also fitted with an idiot light that came on at something like 5psi of oil pressure. If that's your limit then .002" clearance is fine and perfectly suitable for the dealer's mechanics. But that's not the way the engines were built.

Jim

[Gswest236]

Thanks guys! I printed the Engine specs for reference, much appreciated! I think I'm fine, not optimal but for my use probably fine. My oil pressure was around 40-45 psi. If I'm there or better it's a win.
We'll see! The spec sheet for the stock motor shows 33 psi at 2400 rpm. I understand the oiling mods and fine tuning of the oil pump improves that and thats what I'm hoping. I'll do the mains one more time and see where it lands. Any improvement over .0015 would be nice.
Thanks!

[mgb260]

Olds main cap specs were 5lbs more than Buick. Rocker hold down is a head bolt so 50-55.

[Gswest236]

Did the mains again and they're at .0015 across the board. So, We'll run with it. Looking at the reassembly sequence and I guess its cam installation next. Do you guys have a set way you go about
The reassembly? It's out there in the web universe I know. Of coarse the oil pump has to be done, so maybe thats next on the list.

[mgb260]

Scott, You have to pull the crank one more time and put assembly lube on the bearings if you haven't already done it.

[Gswest236]

Thanks, I have the assembly lube ready. I watched some videos of various aspects of the reassembly.
Installing the crank and pistons then cam shaft seems to be an acceptable order. Checking the cranks rotation after each main was tightened. It's the oil pump mods that have me intimidated. The new timing cover apparently has a couple passages that have to be drilled out as well. So, if the crank, pistons and cam go in without issue I'll get the timing gear set on. That will need some studying beforehand; got no idea on timing setup and I have the new timing marker to install as well. Thinking out loud here.

[BlownMGB-V8]

Since you've already drilled out the suction galley that's the hard part done and I suppose you also drilled out the downleg that goes to the pickup. No real need to drill out the passages in the cover. The one big thing remaining in the oiling mods is setting the clearance on the gears. This can be done several ways and a micrometer does help but with the TA shim pack there should be a list of which shims are what color so you lay them out in order of thickness then assemble with different shims until the gears just slightly drag but are easily turned by hand using a big screwdriver in the slot of the shaft. You may have to stack 2 or more shims to get this right.

Note here, I like to use a fine jeweler's file and knock the sharp edge off the gear teeth before doing this and it is a good way to check for a burr. The goal is to just break the edge, not to round it off as such.

Next pack the gears with petroleum jelly being extra careful to not get it on the gasket surface, use a thin sealant to coat both sides of each shim and assemble and torque the bolts. Use a sealant on the threads and copper washers under the bolt heads. (McMasterCarr) IIRC I think the torque is about 14 in/lb (NOT Ft/lbs) but check the specs.

...and that part is done.

If you like you can use one of the steel wear plates, claimed to improve oil pressure but probably doesn't. I usually do that but I'm not sure it helps. It does give a fresh wear surface for the gears. You can also port the oil passages a bit if you like, mainly rounding sharp corners and smoothing anything that might impede flow. I usually enlarge the port in the wear plate a bit as I'm smoothing it, mainly to match the opening in the cover. Use the V6 pickup and that's about it. No real need to spend a lot of time on it but you can if you want.

Jim

[Gswest236]

Thanks Jim! I did watch a video of the process you describe with the oil pump. I have the shim kit and the booster plate. So, I'll tackle the pump after I get most of the rolling assemble in and functioning.

[Gswest236]

I did forget that I had to set up the D+D rear main seal adaptor thing. Since my original one was altered while being machined. You have to secure the main cap portion of the adaptor with 2 dowels or rolled pins??
The main cap had already been drilled for 1 pin and the other hole was pilot drilled slightly and they must have decided one pin was enough. I now know why they stopped drilling. This steel in the rear main bearing cap is hard! Dulled all my bits and I had to go get a new one to finish it. Was actually happy to at least get that small thing done today. Tomorrow the crank goes in,,, hopefully.

[Gswest236]

Went about getting the crankshaft installed today. First I drilled out my main cap bearings holes to match my corresponding 9/32" oil passages in the block. Then I had to get the rear main seal adaptor in with the new 2 piece seal. I noticed as I re-read the instructions that huh! I was supposed to put RTV in the adaptor before driving in the adaptors rolled pins. After looking at it for a while and tugging on the piece, I decide to apply the RTV to the adjacent groove to the seal adaptor. If I get a rear main leak, I'll know why. But it should be good,,,,for a while maybe?? I thought trying to remove that adaptor with the pins installed would be a disaster. Then oiled up the bearings and journals and put in the crank. Torqued it to spec and it rotates with no issues. The piston rod bolts come Monday, so we'll get pistons in at that point.

[mgb260]

Scott, you don't want to change the rod bolts unless you resize the connecting rods! The big end will distort and not be round!

[Gswest236]

Thanks for the heads up. I would never have thought that. I guess I can install the pistons now.

[mgb260]

Scott, When you install pistons use a clean lint free rag and wipe oil in the cylinders and on the rings. Make sure the rod journal on the crank is straight down and do them in pairs making sure orientation is right.

[Gswest236]

Yes, lots of lubrication and focus on correct piston orientation. Tomorrow I'll  get them in or some of them. Another first!
Thanks!

[BlownMGB-V8]

As to your rear main seal and sealing it to the block... I do have a few comments, do what you will with them.
Firstly, oil leakage is the SBB's Achilles heel. It takes meticulous attention to detail to get rid of them all. It likes to leak from various places. The main seals, the oil pump, the valve covers, sometimes the intake, occasionally the distributor, and the timing cover as well. Each of these places needs a comprehensive approach to keeping the oil inside.

Typically the rear main seal is a source of much leakage. It leaks past the seal itself, it leaks past the pan gasket, it leaks past the side seals on the cap and it leaks through the corners between surfaces. Each of these places has to be individually sealed off to prevent it as the oil will creep through any little gap. That seal adapter adds at least one more leakage path. That's the overall perspective.

Next, RTV sealants. Some are better than others but practically all of them are affected to some extent by prolonged exposure to hot oil. Where it is clamped in a thin layer between two surfaces it does its job rather well but may not do so good if expected to adhere on one side. You see this on teardown where a strip of sealant easily peels away.

So ideally you would remove your seal adapter and re-seat it with a good sealant. The question is how to do that without damaging the adapter. My first thought on that is to grab one or better two, large vise-grip pliers, preferably new, preferably genuine vise grip, and preferably the 10WR if the jaw will fit in the gap far enough to get a good grip. Then a prybar and block of some sort to lift the seal adapter out, bearing in mind that the prybar needs to be parallel to the block surface for maximum effect.

HTH

Jim

[Gswest236]

Thanks for the info. I'm certain getting the spacer out with those rolled pins driven in will be difficult if not impossible without damaging the $250 piece. I tried grabbing it with players and a soft cloth. Of course nothing! Vice grips and some leverage might have worked. I've moved to installing pistons which has me stalled. The generic piston ring installer I got isn't working to well or at all actually. I get the #1 piston down to the oil ring and it wont go past it. Took if off put it back on and get it as tight as it will go. The piston slides down to the ring and stops. So I think I need a better compressor tool maybe specific for the size?? What I've read is some work better than others. Local auto parts store carry basically what I have. Its like a one size fits all type.

[mgb260]

Scott, maybe it is upside down. Adjusting screw should be on bottom half. Make sure the screw turns clockwise to tighten.