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Discussion Starter · #1 ·
Searching came close, but a few details still elusive. If you've built a D16, performed one or both of these modifications, and have racked up miles I'm interested in your experience. I'm building a mild street daily driver, no forced induction, just a slight bump in compression. Otherwise bone stock.

1. Which bearings are typically opened up? Of the five main bearings it appears to me that only 2,3, and 4 are suitable to open up and match the oil feed hole in the cradle. 1 and 5 are so off center I'd be removing too much bearing surface for my comfort level. It also seems that 2,3, and 4 are the weakest in feeding rod bearings and would benefit the most.

2. What brand and type of epoxy has been used and stood the test of time? Oil pump epoxy modification at the outlet to smooth the 90 degree turn. Brand new motor so I'm more than a little leary stuffing epoxy in the oil passage fearing one tiny bit comes loose and I've got a problem. I'm looking at ITW Devcon Aluminum Putty.

Any first hand experience is greatly appreciated.

Thanks, S.

Reference:
Energy Dynamics Article
ITW Devcon Aluminum Putty
 

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i haven’t heard of these mods, but did you shim the oil pump too? i’ve heard you can do that to bump the pressure. good luck man
 

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devcron as a filler. Read its directions and follow closely.

flute the bearing oil holes.

Shim the oil pump enough to see more pressure. You dont need as much pressure as you would think, some folks have used the eyelet of a 12awg wire terminal as a shim.
 

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Discussion Starter · #4 ·
Thanks for the input @mattliston. When you modified your bearings did you modify all of them? By flute do you mean slotted, which would make sense to me? Devcron assuming you meant Devcon, which Devcon product did you use, there are dozens? What sort of miles have you put on the engine you performed these modifications on?
Thanks, S.
 

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Think beach and puddle of water. tapers down to the hole, then tapers back up. promotes oil flow

Dont do this if you cannot properly deburr the holes. 800 grit is not enough to smooth it.

A small number of golfball style dimples on the oil pump gears will also promote oil retention, reducing friction.

honestly, it is not 100% necessary to add material to the oil pump. Cleaning up the sharp corners is enough to help, and plenty of people run untouched oil pumps also.


you can carefully dig the inside of the sharp corners if you want oil to have a better chance at flowing, rather than hitting a hard corner. This can be done with a tiny diamond tip style dremel bit or a small grinding stone tip, just lubricate with oil to prevent the grinding bit from gumming up and simply scoring the aluminum.

Do a ervy thorough bath of teh parts, using degreaser soap like Ultra Dawn dish soap that is diluted somewhat. Use distilled water as a rinse, and use a heatgun to fully dry and ehatsoak the pump. Then let it soak in a container of oil overnight to get oil saturation as much as possible.

Used pumps are very very dirty, and steam baths can clean it up nicely.
 

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Discussion Starter · #6 ·
I've lived in/around machine shops for most of my adult life so your language is a little foreign to me, my apologies. The oil feed hole in the main cap is roughly 8mm, bearing hole is 4mm. Are you suggesting an 8mm hole in the bearing with a healthy chamfer on the crank side? I believe you're taper analogy would be a chamfered edge, not clear which side of the bearing you added this taper, crank side or main cap? Did you modify all bearings? Yes, oil pump is likely only going to get mild fillets on sharp corners and some match porting. I'd be a nervous wreck worried about epoxy bits coming loose.
 

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Discussion Starter · #8 ·
Thanks @slo_eg8. Looking for two bits of information not mentioned in those, or any other sources I can find. Although one mentioned Devcon Aluminum for the epoxy it did not specify which Al epoxy they offer. Just trying to find specifics on a modification that's been kicked around for a very long time without much organized data.

When you modified your engine:

1. Which bearings did you open up? Of the five main bearings it appears to me that only 2,3, and 4 are suitable to open up and match the oil feed hole in the cradle. 1 and 5 are so off center I'd be removing too much bearing surface for my comfort level. It also seems that 2,3, and 4 are the weakest in feeding rod bearings and would benefit the most.

2. What brand and type of epoxy did you use for the oil pump modification? Oil pump epoxy modification at the outlet to smooth the 90 degree turn. Brand new motor so I'm more than a little leary stuffing epoxy in the oil passage fearing one tiny bit comes loose and I've got a problem. I'm looking at ITW Devcon Aluminum Putty.
 

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my build is mostly stock except for the rods/pistons/turbo lol
 

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Hello sdb999-
I built a D16y8 that now has 10K or so on it. I did everything on the Endyne 'The Old One' write ups on oil pump and oil passage shaping and porting including matching all the bearing shell oil holes to the 8mm crank oiling passages and chamfering where the oil exits from the high pressure side to the load bearing surfaces. Obviously that stuff needs to be done very carefully and cleanly. I drilled the main oiling passage between the pump and the filter as well which was mentioned my Endyne but not specifically described. I cleaned and all the casting flash internally that oil flows over as well. After reading tons of stuff on epoxies I went with what all the engine builders on 'speed-talk.com' recommended which was dont do it- always weld in material. I just left the little eddy that would be filled with epoxy as is. I did not add more pressure via spring shimming as I knew I was going to have allot more flow. I cleaned every little passage oil flows through in the engine with wire or little bushes or whatever and cleaned it all really really thoroughly. I used Derale filter relocate plate and thermostat bypass kits to relocate the filter and keep cold oil away from 12 plate oil cooler I added to the circuit. I used 1/2" NPT barbed with 10AN push on oil line with good hose clamps. Pretty large I.D. as I was trying to bump oil system capacity. It takes 5 quarts now with the little d series filter. 15 psi at idle and 50 psi at 3k and lots of oil making it up the the top end. Ichecked the valve lash valves 2X in 8K or so and they didn't need to be touched so it looks like things are working.

If it is a y7 or y8 or any finger follower motor I would use a high zddp motor oil. I dont think any OEM engines use finger followers anymore... FWIW I'm using high zddp Ford Motorcraft 10w-30 for older powestroke diesels- less that 20 bucks for 5 quarts at wally world. The high zddp racing Valvoline is cool but really spendy...

I also ported the whole cooling system. I'm trying to have headroom to move as much heat out of the engine as possible via oil and coolant for the eventual installation of a JRSC I have sitting here. 10.5/1 OEM pistons, ARP studs and rod bots, COMP cams 105300. Zippy.
 

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Discussion Starter · #12 ·
@mini-e Thanks, that's the detail I was hoping for. I'll get some pics when I start modifying bits and we can discuss. I too walked away from epoxy and opted to smooth and port match what I can from pickup -> pump -> block. As for bearings thanks for confirmation of modifying all five main bearing shells. I'll post up images of my test mods (on old bearings) for review. Number one and five are so offset I'm not sure what I'll do there yet. What size drill did you run through the block oil pump -> filter?
Thanks again, talk soon.
 

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I wish I remembered the oil galley drill size and I didn't take notes- By the time I was done the ported oil exit from the pump matched the galley O.D. and I left the O-ring support wall on the oil pump un-touched. That should give you a good idea of the drill size. I think I took a couple passes with increasing diameters. I bought the correct color coded main and rod bearings from Honda (the crank looked great and everything was round) and was not confident in 'drilling them out' to the crankshaft oiling passage size on a drill press without a fixture so I held each bearings in one hand and used a 1,000-10,000 rpm dremel (the slowest one you can buy) and opened each bearing up slowly to its respective mating oiling passage on the crank. It was slow but safe.
 

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Discussion Starter · #14 ·
Understood, when my block gets back from the shop I'll look at that gallery. As for the bearings, correct: You can't just run a drill through them as they are not centered with the oil feed holes. A dremel tool and maybe fine small files to finish/chamfer. Picture below clearly shows the shadow of the oil feed hole. Bearing 2,3 and 4 I'd say are candidates. 1 and 5 would remove more bearing surface than I'd like, but who knows if it would hurt anything. Crank is at the shop too or I could say for sure, but either 1 or 5 does not feed a rod bearing from what I remember so no need to open that one. Maybe someone can confirm.
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Discussion Starter · #15 ·
Looking at Main #5 above did a test mod opening up to match oil feed hole. Doesn't look as bad as I imagined.....but still a bit thin on one side. I'm not sure it's worth risk with no certain benefits.
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I feel elongating the oil groove in the bearing the whole width of the oiling hole would be better than drilling that much material off the bearing surface face....

You can see right there, the wear pattern on your example bearing, the crank literally needs as much bearing surface area as it can get right there by the oiling hole to be properly supported. Remember, the crank rides on the tiny film of oil between the bearing and the journal. Hydraulic principle and oil materials engineering is what transfers the weight and forces of the crank into the bearing, and uses the bearing face to transfer load into the block. If you take that much material away, no matter how much oil you throw at it, the crank will not be supported as well on that thinned out area, where it is needed most as evidenced by your wear pattern. You risk significantly higher wear on those bearings/journals with that much taken away.

Remember, oil pressure coming through the oil hole doesnt support the crank during operation, its only needed to shove oil in the gallery, and keep it constant. The crank journal downward force from the rods will laugh at the measly 80-90ish psi coming out and push it right back down into the hole lol.

Its the hydrodynamic principle, combined with good oil clearances,and the way oil flows, rolls, and moves over the bearing/journal surfaces that does the work of supporting the crank. The oil film that makes it between the bearing/journal will show off its non-compressible hydraulic properties and film strength, and is what really matters. This is why people say high oil pressure at the journal, while still important to keep it shoved up at the bearing, is less of an overall importance factor, oil volume supply availability is what is needed moreso, AS WELL AS full bearing to journal surface area to effectively transfer and spread the load as well as possible.

Remove load-bearing surface of the bearing, and you're just asking for problems, especially when the greatest crankshaft force is being applied in that exact area!

Honda B series heads have big holes in the cam cap journals down in the head for the head bolts themselves to pass through, leaving only a tiny cam bearing surface left for it to physically ride on. They only get away with this, because the cams are pushed UP against the top of the cam caps in this design, which have a full surface area for an oil film to exist.

Never take load-bearing material away from a bearing at its highest load point. Just asking for problems!
 

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Discussion Starter · #17 ·
@drtalon123 I have many similar thoughts as I mull over what, if any, mods I do on this build. Many engines have passed under my hands but this is my first D series and I've never seen a bearing with such an obvious miss-match with its mate. There is no way it was missed at Honda so the question that begs is Why? We may never know for sure, but opening up the bearing to full diameter will remove a clear obstruction in oil flow, however the path to the rod bearing is choked right back down as it follows the center groove in the bearing around the crank journal (save once per rev when the holes line up). Does the rod get more flow, pressure with this modification? How would we know or measure that? Is the integrity of the bearing compromised? Do we see split bearing failures or trashed cranks with this mod? Do rod bearings still spin?

At the end of the day I'd rather make modifications that address a documented deficiency and clear evidence that the shortcoming was overcome. I've found neither in hours of reading posts here and other sources. There are numerous accounts of spun bearings, ruined cranks, poor oil pressure etc. There are engines that have been modified and run for 1000's of miles, along with bone stock that have done the same, and those that grenaded in both camps. Stories, clues, data for consideration....yes it all has value. But at the end of the day there is zero hard proof of a problem with the bearings or a solution.

I feel @mini-e followed a prudent path of non intrusive mods to the oil supply system to improve flow as much as reasonably possible. He opened up the bearings as well, and all looks good at 10k miles, I hope that lump runs for 200k+ without a hitch. But we'll never really know why/why not.

So if conservative mods are on the table that might help an issue that may/may not exist, I'm exploring just what they may be and let the masses take pointy sticks and stones to the logic. We are all better for the process. If bearings are to be opened up, this is what I would prefer, still going to call my bearing manufacturer and get insights on what (if any) concerns they have.
Cheers, S.

Slotted Bearing front.jpg
Slotted Bearing back.jpg
 

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That looks better :)

I feel you will improve oil volume through the bearing shell with that, which will allow for more supply up to the rods.

Oil pressure to shove the oil volume up to the rods is improved with good oil clearances on all journals, tight/spec oil pump rotor to housing clearance with as little case scoring as possible, tight/spec rotor to rotor clearance, good oil pump porting to improve volume movement and reduce restrictions and pumping losses, and running an oil with good film strength and the right viscosity for the temps it will see.

It should run a long time with all those boxes checked. And its a Y7, so no worrying about VTEC stealing your bottom end oil :)
 

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Leave the backside untouched. See how you ovalled the hole? Do that on the front, and smoothly transition. Think like a velocity stack
 
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