L5P Weakest Links
- Thread starter kidturbo
- Start date
.920" is what I measure with my calipers. I couldn't find anything that was a drop in, but like I said earlier, after doing a little looking at an L5P block and making some comparisons to an earlier Duramax block, we figured out a little machining should make the old style lifters and hardware work. We had fully planned to try it, but we didn't get to finish the project we had planned to test it on.
I just called and that is an odd ball size that is why you could not find anything off the shelf.
So even if I send them lifters to analysis it's like a 6 month deal if they will even do it....
Retro fitting the old style would be faster/ easier.
From what I am told, GM now out sources the lifters and they come from an over seas manufacture. I don't know which one or how to confirm that.
Yeah that's few thou off from being a Ford. But it's certainly doable, if there is a demand. One would hope GM addresses it with their OEM. 6.0L Powerstrokes suffered similar issues. Rare, but is noted failure point.
Not solids chart, but good ref list below.
Hydraulic Roller Lifters - Crower Cams https://www.crower.com/media/pdf/lifters.pdf
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Not solids chart, but good ref list below.
Hydraulic Roller Lifters - Crower Cams https://www.crower.com/media/pdf/lifters.pdf
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While searching for a good parts engine to crack open, was just told that main bearing issue should be our primary concern. Which could be related to cam / lifter oiling also if ya think about it..
Also just learned 2024 6.7L Ford is packing monotherm pistons from factory now.
Squirrel...
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Also just learned 2024 6.7L Ford is packing monotherm pistons from factory now.
Squirrel...
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They do list solid rollers. They have a .9361 Body With .850 Wheel for various applications... Chevy and Ford...
I haven't seen any issues with cam oiling, and there is no direct oiling for the lifter. Back a long time ago they used to do something with oiling through the pushrod, but I'm not sure what it was for exactly. I think that was changed with the LLY maybe, but I'm not sure. I know there is no oil band or oil hole anywhere on any Duramax lifter that I've ever seen. I always assumed they relied on splash oiling.
I believe they started using the steel pistons in 2020.
If you're going to go to the trouble to open up the lifter bores to fit a .9361 lifter, you might as well retrofit the 01-16 lifters IMO.
This is true... I wasn't sure if there was a specific reason GM Switched to the smaller lifter. Such as if they made the base circle smaller for clearance or something like that.
Like a majority of their decisions, I'm sure it was related to $$$. I can tell you cams are a direct swap.
I was thinking about the oil passages routing up to the cam from the mains. In my younger days, we used to tap the cam bearing holes and put restriction plugs in there to restrict flow to top of the block. Now everything is roller tappet.. One would expect that old moto transferred into production castings. No need to pressurize the lifters on solids, so be interesting to compare passage changes. Why would they be spinning mains some 30yrs later. Thought everyone would have been well beyond that by now. But is what I was just told to look at..
Last I knew, I was only person to spin bearing in a Duramax without breaking a crank... lol
They completely redesigned the main bearing by making them wider and adding an extra oil hole in the top half with a groove in the main web under the bearing that connects the second hole to the cam oil feed galley. I'm not exactly sure why they did it, but I've opened up a few of these motors and seen excessive wear at the main bearing around this second hole. We tried using a set of early style bearings in a motor we put together and setup to run on LBZ electronics, but it developed some sort of noise in the bottom end after we got it started. We haven't had a chance to open it back up to inspect, but it could be related to the bearings, I'm not real sure yet. I'll see if I can get a couple of pics to show what I'm talking about.
I just went out and looked. I have 3 junk short blocks sitting out in the rain for various failures. If you want one or all, you can have them if you want to send me a crate or something to ship them in, or I can try to strap them to a pallet or something.
Most interesting.. I can see the new approach is to not route it behind the bearing as done for decades. Let's cut down the surface area on the top main because load is always towards the bottom bearing. Groovy. Brilliant...
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