2 silly rebuild questions

#1

Are the crankshaft main bearing cap bolts TTY? Or can they be re-used?

Do I remove the pistons first, or the crankshaft?

#2

Rod and head bolts are TTY, main bolts are not. I remove the pistons before removing the crank.The pistons went in from the top, so I take them out the same way.

#3

Follow up silly question…

I was told NOT to truly hone the cylinders since I plan to use standard size pistons/rings, just to de-glaze the cylinder walls. To do this, I should use a ball (flex, dingleberry, whatever) hone. Nobody carries one locally, but I can order anywhere pretty much. What size/grit? 3 1/2" fine?

#4

Get a feel for how out-of-round your cylinders are at top, bottom and middle. Let that drive your decision to hone or not.

My perception is that there are a couple different kinds of rings and they have their own preferences on what grit to use. I would attempt to talk to the mfr of the ring, or at least to someone very experienced with building engines with that ring type.

Save your old rod bolts. You will need them when you are working to get good rod bearing tolerances. Just take care with them because each used rod bolt will probably only be good for 3-5 more uses and then you will start to feel it yield. Don’t snap a bolt. Detect the yielding early and pull the bolt back out. Once you have your rod bearing tolerances cherry, then use your new rod bolts.

Carefully check your rods for wear. The tolerance in the rod journal for out of roundness wasn’t much. 4 tenthousandth maybe? I’d have to check my notes. If they fail that test consider getting them reconditioned.

#5

I don’t expect to see much going on there, the engine (cylinder walls, bearings, pistons) looked great. Probably didn’t need to tear this engine down just yet.

#6

[quote=“OriginalSterm” post=57397]Follow up silly question…

I was told NOT to truly hone the cylinders since I plan to use standard size pistons/rings, just to de-glaze the cylinder walls. To do this, I should use a ball (flex, dingleberry, whatever) hone. Nobody carries one locally, but I can order anywhere pretty much. What size/grit? 3 1/2" fine?[/quote]
Honing, done properly is de-glazing. The goal is just to re-establish the cross hatch hone marks for oil retention. When done properly the cylinder diamater is unchanged.

It is best to have the honing done on a machine that controls both the rotational speed of the hone and it’s rate of advance. That results in the ideal cross hatch. That pattern can’t be duplicated without the appropriate machine.

#7

If I needed honing because some material needed to be removed in order to make the cylinders round, I’d take the block to a machine shop or other specialist. If I just intended to break the glaze, I might be tempted to try to do it myself, once I talked to some folks that knew my rings.

I’ve gone from barely able to change my oil to the #1 engine blower upper in SpecE30. Of the many things I’ve learned en route to that prestigious title is to get real cautious when I start getting the idea that the “next step” is best left to professionals.

#8

I’d really like to tackle this de-glazing myself. I’ve watched videos, talked with machinists at work, and am someone mechanically inclined. I’d love to pay to have this engine rebuilt, but I’d prefer to do it myself. Just looking for advice on what type of hone to use (type, grit size, hatching angles, etc.).

#9

Use a ball hone with 300-400 grit. The aim is to leave honing marks that are at 45deg to the cylinder bore.

#10

Most of the time, you can’t “see” problems lurking in your engine. I would be very surprised if your cylinders were in fact round and not tapered a bit. The only way to really “see” your engine condition is with a high precision cylinder bore gauge as you can’t determine with the naked eye. Same goes for your rods. You can see bearing wear obviously and visually inspecting your rod/main journals should be good enough.

There is no reason why you can’t build this engine on your own (other than machine work), but you need the precision tools to make sure you aren’t throwing cash at a future grenade. Buy or borrow a .0001" cylinder bore gauge (avoid the .0005" variants), zero the bore gauge at the top of the cylinder, take measurements (top, middle, bottom in both directions)to check each cylinder for roundness and taper. More than .0003" variance is more than what I would allow and less variance is always better. If you have more than .0003" you really should have a machine shop tend to the cylinders. If they are in tolerance, deglaze and be done with it…

To check your rods, use your old rod bolts to assemble each rod without bearings. Using the dial bore gauge, measure vertically and at 45* past vertical. Again, more than .0003" is too much. If the rods are out of spec, you’ll need to rebuild or source another set. It’s probably easier just to find a used set that has never been raced.

To set your piston and bearing clearances, you’ll need a set of .0001" micrometers (not a caliper) to measure rod/main bearing journals and the piston diamater just above the skirt and perpindicular to the pin. You could use plastigauge on the bearings but the micrometer method is more precise… Piston clearances should be no more than .0035". Bearing clearances should follow the rule of .0010" for every inch of bearing diameter. Therefore, ideal clearances are .0017" for rod bearings and main bearing clearances should be .0024".

Tools you would need include a .0001" cylinder bore gauge that will measure 3.3" (piston) and 1.7" (rod) alsong with a 2", 3", and 4" .0001" micrometer.

You could just reassemble the engine with new parts and a deglaze, but that’s kinda iffy. The machine work on the block will likely be less than $200 and think of the tools as an investment…

#11

What FishMan said…double. (The cylinders need to be round so the rings can seal. 3 thousands may be specification, but my motors are 0.) Also note, if you want the motor to last like the original build, you MUST re-establish ALL clearances correctly. Otherwise, you are running on borrowed time. As I get older, I have finally learned it is cheaper to do it correctly the first time than do it again, and again, and again, and Ranger. (Sorry Scott…could not resist:lol: ) Reassembling the motor is only time consuming. The trick is to have all the machine work done, or redone, so that the clearances are correct. Depending on the machine shop, you may have to have things redone a couple of times before all is good. A side note…find a shop that specializes in road race or drag race motors. Chuck

#12

When I said this engine looks “good”, I meant by comparison. I have a 190k+ mile engine that looks more “worn” than this <70k mile engine.

I planned on the hone work myself after reading the Bentley manual and talking to a few machinists at work (General Motors). De-glazing, according to them, isn’t rocket science and I shouldn’t be removing too much material. If I needed to remove more material, oversized pistons and rings would be needed. For that, a machine shop would be doing any real work the block required.

I know it’s the not the same, but I watched several videos (thank you YouTube) on using a ball or flex hone, and none of them have anything more than a cordless drill. I figured, I own a cordless drill! How hard could this be?

Since I am cheap and stupid, I think I’m going to attempt this myself and cross my fingers. Check back in a few weeks with your I-told-you-so’s. But I hope to actually report back with good news…

#13

Just remember you are getting advice from guys that have been to Metric Mechanic to help build their motors and a guy that builds motors. I’m rooting you on as a DIY guy that prefers to take the simple approach.

#14

I would like to state right now, I do not think I know better than ANYONE who is trying to help me in this thread.

I am taking every bit of advice as a caution of what might happen should I f this up and where things may go wrong.

What I hope to accomplish is rebuild this fairly low mileage engine will all new seals, gaskets, bearings, rings, belts, and pumps so I’m not dealing with oil pressure or compression issues or oil leaks over the next season or two. All while doing it for around $1k.

I do not have expectations I’ve built a championship winning motor in my garage with simple hand tools.

#15

You’ve seen videos of the process so you do have a general idea of what is involved. My suggestion is that you find something to practice on before honing your block. You’ll have to figure out what speed to turn the hone and how fast to work it back and forth in to bore to get a 45deg pattern. The angle of the pattern isn’t critical and any hoing will hold enough oil to get the rings to seat. But the closer you are to a 45deg pattern the better it will be.

While it would be best to go the full nine yards on measuring everything, you can get away with a bit less. It would be smart to check the cylinder bores for wear and you need to know the rod & main journal dimensions The first is to be sure that the bores aren’t worn excessively. Rod bearings come in two sizes (red & blue) and main bearings come in three sizes (yellow, green & white). There is a table in the Bentley that tells you which color to use based on the journal diameter. So you need to know the diameter to pick the right bearings. It would be great to check rod and main bearing housings, but on a low mileage engine & budget rebuild you can probably get away with not doing so.

The measuring equipment necessary is a touch pricey. For a single engine rebuild you can have a shop with the right tools get the essential measurements for a lot less than the cost of the tools.

#16

One of the guys at work will be loaning me a few measurement tools to verify the standard size parts I already ordered and received (backwards, I know) will be appropriate.

Drill speed I have from the hone manufacturer.

The angle of the hatch isn’t important? I thought too shallow or too steep could affect lubrication and/or break-in of the rings?

#17

The angle does matter and in a perfect world you would have the marks at 45deg. But even if that condition isn’t met the scratches will retain oil. So the rings will seat. It might take a bit longer and they might not seat as well as they would if the honing was perfect.

#18

Jim has a great idea here!!! Instead of dropping cash on tools, have a machine spec your rods and cylinder bores. It will only take a few minutes and any machine shop should be able to inspect your rods,block and piston for cheap. Atleast you’ll know if you have a good engine foundation or garbage before re-assembling.

I understand being cheap, but assembling with understanding the condition of your motor just isn’t smart and will likely cost you more money in the long run. I’m a DIYer myself, but I’ve found that going cheap is ALWAYS more expensive in the long run.

What kind of rings are you using? Cast iron with moly inserts I hope…

#19

To be honest, I don’t know what the rings are. I ordered 6 sets rings from Bimmerparts and got Goetze in a yellow box.

#20

You should measure your bores for roundness and tell us the results. That way we can all tell you how wrong you are and generally drive you crazy.