LB7: Daily Driver/Tow Rig Rebuild

[Bdsankey]

Not sure how correct these are but these were my calculations when I did mine

Oil pump gear teeth 33
Crank gear 59
= 1.787 ratio overdrive
GPM
650rpm=1161 4.35/4.86
2000 =3574 13.39/14.96
3200= 5718 21.42/23.94
3600= 6433 24.09/26.94
4000= 7148 26.77/ 29.93
OLD/LML
.
The copy/paste didn't work so well, data goes from Engine rpm to pump rpm, the old pump gpm vs LML gpm. This was just using a pump calculator per gear/housing specs ect.

Thank you. So let me make sure I understand this swap correctly:
1) Machine pump housing to fit block/reluctor wheel
2) Run LML pump gear and trim shaft
3) Run LML pickup tube
4) Trim front support gusset inside upper oil pan/windage tray


Does the pump relief need to be shimmed like earlier pumps?

 

[TheBac]

You two might want to add that info to that LML pump thread, too.


Sankey, you want to run the ring set with the steel top ring, like James said. The -909 is cast.

 

[Chevy1925]

Thank you. So let me make sure I understand this swap correctly:
1) Machine pump housing to fit block/reluctor wheel
2) Run LML pump gear and trim shaft
3) Run LML pickup tube
4) Trim front support gusset inside upper oil pan/windage tray


Does the pump relief need to be shimmed like earlier pumps?

if you would like higher pressure, yes.

 

[rcr1978]

Thank you. So let me make sure I understand this swap correctly:
1) Machine pump housing to fit block/reluctor wheel I also had to trim a small amount of the raised aluminum behind the pump shaft for drive gear clearance
2) Run LML pump gear and trim shaft I used my stock pump gear, trimmed the back of the pump shaft and just pressed the shaft deeper in the gear lots easier to trim the back then the shouldered threaded side
3) Run LML pickup tube yes
4) Trim front support gusset inside upper oil pan/windage tray I had to trim the relief valve area on the pump and corresponding bolt boss on the upper pan,
one of the oil pan bolt casting bosses for the pickup tube, notch windage tray


Does the pump relief need to be shimmed like earlier pumps? No it's higher already than any OEM or Melling pump, I posted the relief valve settings on all three pumps in the oil pump thread if I remember the LML was around 85psi

It's been a while I could be forgetting something

 

[Chevy1925]

It's been a while I could be forgetting something

i do not agree, the LML pump will not hold the same pressures as the melling, same oil for same oil, same engine for same engine.

 

[rcr1978]

James, it's possible the aluminum housing grows and the pump has quite a bit of slip but in my eyes nothing beats pressure and pump displacement. LML had a higher relief setting and thicker gears. I bought the Melling M316 pump and when the gears from it fit in the stock LB7 pump housing I starting looking further, tested the relief valves on all of them. I just don't see the melling is anything more than a shimmed relief valve and a iron housing.

Edit: even know the LML pump has the highest psi relief you still have the other relief valve in the front cover that may be the issue, the LML pump probably just blows the thing open, I posted the specs of my LB7 cover relief valve to. I've been wanting to order a LML ne to compare.

 

[Bdsankey]

if you would like higher pressure, yes.

What pump would you run, LML or M316? How much of a shim should I use? Do I need to shim the cover relief valve also?

James, it's possible the aluminum housing grows and the pump has quite a bit of slip but in my eyes nothing beats pressure and pump displacement. LML had a higher relief setting and thicker gears. I bought the Melling M316 pump and when the gears from it fit in the stock LB7 pump housing I starting looking further, tested the relief valves on all of them. I just don't see the melling is anything more than a shimmed relief valve and a iron housing.

Edit: even know the LML pump has the highest psi relief you still have the other relief valve in the front cover that may be the issue, the LML pump probably just blows the thing open, I posted the specs of my LB7 cover relief valve to. I've been wanting to order a LML ne to compare.

Is the LML cover relief the same fitment, I.E. can I put it into my LB7 cover?





I just got my oil analysis back and it's not good, the engine is killing a bearing. I am hoping it's a cam bearing where the turbo feeds from but I doubt I'll be that lucky. I'm betting the oil got hot/thin towing and it is finally is popping up.

 

[techperry]

Will the 2020 cooler fit the older engines? What all has to be changed?

 

[Bdsankey]

Will the 2020 cooler fit the older engines? What all has to be changed?

Yes, look at this post. You'll need the oil cooler, oil filter, gaskets, adapter housing, bolts, and trim an ear on the exhaust manifold for a heat shield. It's a few pages back. https://www.duramaxdiesels.com/forum/showthread.php?p=1139593#post1139593

 

[rcr1978]

What pump would you run, LML or M316? How much of a shim should I use? Do I need to shim the cover relief valve also?



Is the LML cover relief the same fitment, I.E. can I put it into my LB7 cover?
I'm not sure haven't ordered one yet to see for sure.





I just got my oil analysis back and it's not good, the engine is killing a bearing. I am hoping it's a cam bearing where the turbo feeds from but I doubt I'll be that lucky. I'm betting the oil got hot/thin towing and it is finally is popping up.

Reply in red

 

[Bdsankey]

Yeah, I had my crank magged and polished, and wasn’t happy with the clearances with either set, so I split them.


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When you say split (sorry if this is a dumb question) Is there an issue miss-matching bearings one each rod throw? I would assume not but I am nowhere near as skilled in actual assembly of these. I've only done 2 so far and I've had the machine shop measure for bearings each time. I'm just trying to figure out if I can pick these up from you or if I need to buy a matching set. I'm planning on buying one H and one HX to test fit and check clearance across all 8 rods.

 

[rcr1978]

GM mismatches bearings all the time, I bet your current motor has different top/bottom rod bearings and possibly some on the main bearings if its stock.

 

[Bdsankey]

GM mismatches bearings all the time, I bet your current motor has different top/bottom rod bearings and possibly some on the main bearings if its stock.

I didn't know that you could put an H and HX (one each) on one rod. Didn't know that was acceptable.

 

[Chevy1925]

we are not building a stock engine. by no means would i ever put a HX on bottom and H on top or vise versa for a single main or rod. For one, the bearings will not be matched and off .0005 at each lip of where they end. this dont seem like much but when clearances are down to the .0001, it very much is. running different upper and lower is a damn good way to put the crank out of center. rods have more leniency there but again, i wouldnt want to off set center of rod to the journal. the edges of the bearings will not create good wear patterns on the crank surfaces.

you can use a upper and lower HX on one main and a upper and lower H on another main as long as your clearances are within spec. IIRC, gm has 3 or 4 different bearing options. all a softer metal and all in much smaller incremental changes than .001. you will need to check my facts here but im recalling this from somewhere.

if clearances are off .001 or more after an align hone/bore, you have a bigger issue with your machine shop. if the block is not being align hone/bored, i can see a clearance issue being a problem IF you do not follow proper torque of the stock main bolts or deciding to add main studs.

if you guys are using plasti-gauge, you shouldnt be changing bearings around based on that.... this is a bore gauge and out side mic area that must be done with indicators readable down to .0001 to get the best results and a happy bottom end. just a few specs of dirt under the bearing can drastically change clearance.

 

[PureHybrid]

we are not building a stock engine. by no means would i ever put a HX on bottom and H on top or vise versa for a single main or rod. For one, the bearings will not be matched and off .0005 at each lip of where they end. this dont seem like much but when clearances are down to the .0001, it very much is. running different upper and lower is a damn good way to put the crank out of center. rods have more leniency there but again, i wouldnt want to off set center of rod to the journal. the edges of the bearings will not create good wear patterns on the crank surfaces.

you can use a upper and lower HX on one main and a upper and lower H on another main as long as your clearances are within spec. IIRC, gm has 3 or 4 different bearing options. all a softer metal and all in much smaller incremental changes than .001. you will need to check my facts here but im recalling this from somewhere.

if clearances are off .001 or more after an align hone/bore, you have a bigger issue with your machine shop. if the block is not being align hone/bored, i can see a clearance issue being a problem IF you do not follow proper torque of the stock main bolts or deciding to add main studs.

if you guys are using plasti-gauge, you shouldnt be changing bearings around based on that.... this is a bore gauge and out side mic area that must be done with indicators readable down to .0001 to get the best results and a happy bottom end. just a few specs of dirt under the bearing can drastically change clearance.

All sounds good, but bearings aren't round to begin with. I don't have a pair of H/HX bearings to measure, but I would venture to bet the thickness of the bearing shell in the crush zone is the same.

 

[TheBac]

What the hell is wrong with using plastigauge? :rofl:

 

[Chevy1925]

All sounds good, but bearings aren't round to begin with. I don't have a pair of H/HX bearings to measure, but I would venture to bet the thickness of the bearing shell in the crush zone is the same.

No kidding but they don’t just make the bearing thicker in the center and vary sizing from there. Measure them and you will understand.

It again does not stop the fact you will be off setting center within the bore.

 

[Chevy1925]

What the hell is wrong with using plastigauge? :rofl:

if you got a trustworthy machine shop, not much. But doing this finagling of screwy bearing stuff doesn’t lend well to it!

 

[M.A.M.]

When you say split (sorry if this is a dumb question) Is there an issue miss-matching bearings one each rod throw? I would assume not but I am nowhere near as skilled in actual assembly of these. I've only done 2 so far and I've had the machine shop measure for bearings each time. I'm just trying to figure out if I can pick these up from you or if I need to buy a matching set. I'm planning on buying one H and one HX to test fit and check clearance across all 8 rods.

Don’t know as this is the first time I’ve done it. Don’t have enough miles on the setup to be able to tell you that it holds, only about 5k miles, but they’re hard ones. I purely went by what the machine shop told me, which was that it’s done on gassers all the time. I guess time will tell.


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[PureHybrid]

No kidding but they don’t just make the bearing thicker in the center and vary sizing from there. Measure them and you will understand.

It again does not stop the fact you will be off setting center within the bore.

I told you I didn't have both sets. How about you measure and tell us the results?