MigsD16

This is turning into the never ending build... I've searched like crazy and found plenty of info and videos about overlapping oil expanders, but could not find a single mention of how large the end gap can be in the case that they have an end gap. In the factory service manual, it states that the end gap for the "oil rings" can be up to 0.8mm, but there are two 3 rings that make up the oil rings and though the top and bottom oil rings are well within spec, the middle (wavy) expansion/spacer ring has a much larger end gap of 2mm or so.

I have two different sets of piston rings here, both standard size. Every ring other than the oil ring expanders, on both sets, are well within spec, but the gap of the expanders is seemingly huge. Will this be ok or do I need to buy a 3rd (larger) piston ring set just for the expanders?


thanks

TomCat39

If I recall, when I pulled my OEM pistons, the wave ring had a much larger gap as it's a spacer/draining ring, not an oil scraping ring. I believe the crucial part is the two outer oil control rings that need to have the proper gap.

I am beginning to think the regular engine builders that tend to monitor this section may be on vacation this summer as they seem to be MIA for the time being.

Best of luck.

MigsD16

Thank you for the reply, I've been feeling like the lack of response was just because of the questions I've been asking...

I was thinking the same thing that you stated, but it helps to have a second opinion. I figured that the gap shouldn't matter too much for the oil expander since its primary purpose is to separate the two oil rings and allow oil to flow properly. Lack of info on this also tells me it must not be too critical. What's important is that they don't overlap.

I installed the crank today, it felt good to finally begin assembly. The rings have all been gapped, cleaned and are all numbered and laid out, ready to go on the pistons, then into the block tomorrow! It's getting fun now that all of the cleaning and such is done.

Thanks again!

TomCat39

Also just a side note concerning your other thread with the plastigauge. That is supposed to be a secondary test after measuring with micrometers and dial bore gauge in the .0001" ranges.

I realize lots of people only do the plastigauge and your readings look decent but it's only supposed to confirm what you found by measuring. And I'm not saying this to say your's will fail as a great many people have success just plastigauging and going. Just commenting that it's not the best practice method.

Cheers.

MigsD16

Thank you again for the info, I appreciate it very much. I will be sure to reiterate your words on the plastigauge as a double check in the other thread as well.

I took my block, crankshaft, pistons/rods, girdle - basically everything important in the bottom end - to a machinist who measured everything. He measured the runout, the diameter of the main and rod journals, including out of round and taper, as well as end play. This was all done with the old used bearings though. He told me I should replaced the bearings and piston rings, then sold me a set of standard King bearings for cheap, under $50. I only plastigauged as a double check to make sure I had enough clearance for the oil to coat the journals. After installing the crank yesterday, it feels nice and tight. I'm not sure exactly how tight it should be, but I can turn it by hand with a firm grip on the front end of the bare crankshaft.

I'm getting ready to put the rings on and install the Pistons today.

PyroProblem

I believe the wavy spacer ring is mainly there to keep the top and bottom oil rings located and doesn't really contribute to oil control. As long as the ends aren't butted up, i think you'll be ok. TBH, I can't remember a spec on that spacer ring and my manuals are all packed up getting ready to move. Ask your machine shop to be sure though. Good luck on the build.
It's good that you can turn the crank by hand, but this doesn't necessarily mean your clearances are exact.

Were the old bearings the same brand as the new ones?
Hopefully the guy measuring is confident the new bearings are exactly the same thickness as the old ones. Double check with plastiguage to be sure.

MigsD16

I ran two rounds of plastiguage with pretty much identical results. I've called my machinist a little too much and feel like he's getting annoyed. This was my first time there and he was acting like I'm being paranoid. He said that it's ok if the gap is the sap distance apart as the other spaces and it's almost exactly 2mm like all the other wave tops are. There was one other thing he mentioned about the oil rings that I overlooked. He didn't explain why and I didn't think to ask, but he said to have the tips of the gap point downward.
Aside from that, the piston ring compressor I used moved the rings around while I was tightening it around them. It was probably user error, but it was tricky to used so I ordered a tapered ring compressor and will redo them as soon as it arrives.
Also, I decided to take a torque wrench to the crank with pistons in and everything tightened to spec (main caps 38ft lbs, rod bolts 23ft lbs) and the engine turns over at 8ft lbs. Does that sound about right? For assembly I used Lucas High Performance assembly lube, but thinned it just a little with marvel mystery oil since some people feel that assembly oils are a little too sticky.

Again, the more you can give me to think about, the better. This is a learning experience for me. The next engine I do will be for performance gains.

Thank you for all of your help!

TomCat39

Assembly lube is supposed to be sticky so it sticks tot he parts until oil can arrive and wash it away. I wouldn't water it down with solvent (MMO).

I've never seen an engine being built that did anything other than straight assembly lube.

MigsD16

Do you think this will be a problem? Not sure if it makes a difference, but I used alot of it to make sure everything was coated real well.

There is so much to know and I read things from all over. Maybe I should stick with the Honda Tech Forum. On another forum I read a post by someone who seemed to be an engine building guru. He said to mix one part assembly lube and one part marvel mystery oil because assembly lube can be too thick and gunk up the oil filter, causing it to bypass and that this would be the worst time for an oil filter to go into bypass. I think it was on some chevy forum I strayed off to. I'm guessing now that this is either completely bogus info, or doesn't apply to these engines...

TomCat39

I'm sure you will be fine. I've never heard of it, but then again I haven't been reading everything I can get my hands on.

That is a good point if it's true. If the assembly lube causes the filter to clog prematurely, it would definitely be the worst time for the bypass to be activated.

However, it's my understanding, the oil filter is only on for the initial 20 minute break in. Then both the oil and filter are changed.

The following website is what I believe to be a proper break in and is very much in line with what I believe car factories do now before the engine gets into the car.

The only part I am not sure is done is if they drain and refill the oil after they run it and swap the filter. Might be the first thing a person should do when they buy a brand new car.

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

PyroProblem

Good link there Tomcat. That's what I subscribe to as well.
8 ft lbs sounds about right. When I was mocking up my build a couple months ago, I remember similar numbers ( under 10 lbs, initial torque to turn it was highest but maintaining rotation, it was lower.
I wouldn't worry too much about clogging up the oil filter. Most assembly lines are thick to do exactly as Tomcat stated. Stay in place and form a thick film until oil pressure is reached.
The small amount (ounces?) of assembly lube won't really affect much once your 4 quarts of engine oil is circulating.

Before you actually start the engine before the first time, remove your spark plugs, disable fuel, hook up a battery charger if you have one, and crank the engine over for about 8 seconds at a time. I say 8 seconds to prevent your starter and battery cable from getting too hot. Removing the plugs removed all pumping resistance to let the engine spin over easier.
Once your oil pressure light goes off on your dash, you know you have oil pressure and your ready to start the engine. It will take a few cranks before the light goes of finally. Spark plugs in, fuel pump fuse/relay in, and you should be good!

PyroProblem

A little MMO (kerosene base isn't it?) prob won't hurt anything. I would prefer a thicker lube over a thinner lube, but once you got oil pressure, it's doesn't really matter much at that point. In fact, I'm actually using ARP Moly lube as my assembly lube. Its really thick almost like anti seize compound. Too thin and it just runs out the bearing.
Keep in mind it's sole purpose it to prevent metal to metal contact until you get oil pressure.

MigsD16

I appreciate all of this excellent advice. These are all good things for me to keep in mind. I've read so much over the past 6 weeks or so that it's tough to remember it all. The tapered ring compressor finally arrived the other day, and I decided that it's best to redo the bearings with straight assembly lube since it may sit for a while as I try to find the time to finish this build. So I pulled it all back apart and did it right this time. The rings didn't move all that much using the cinching collar type compressor, though I had the orientation wrong on piston #3 and 2 of the 4 pistons had the oil expansion ring tips facing up. So now I have peace of mind that it was all done correct this time and I'm ready to move on to the next steps now: Front & Rear Engine seals, oil pump, etc... I took the oil pump apart and bought a new relief valve spring and seal washer. I'm now trying to decide whether or not I should shim it to increase the oil pressure a bit. Decisions decisions... I think this will be my last post for this thread since it will only progress further off topic from here.

Thank you again for all of the support and advice, it is all very much appreciated!