First engine build
Thread Starter
Staging Lane
Joined: Apr 2023
Posts: 69
Likes: 7
From: Tx
First engine build Hey guys, i came across a used ls2 in great condition a couple months ago along with ls3 823 heads both had them machined and the block just hone and clean.
im going for a street race build and to handle boost later on (to poor for that now), i have been contacting patg and he is setting me up with the build, i have the build all planned out and the parts and let him tweak the build
shooting for 450-500hp at the crank starting out with no bolt on mods just long tubes, but im mainly throwing money at internals but will be adding fbo after my break in period,
im at the point of buying main bearings and cam bearings along with crank this weekend, im going for forged internals aswell to handle boost and overall strength, i have gotten patg's insight but have other questions he couldnt answer.
i need help with bearings, i measured my main bearing bores and cam bores, main were around 0.001-0.003in smaller than oem spec but some could be measurement accuracy of 0.001in, https://drive.google.com/file/d/1h2x...usp=drive_link - main cap # listing measurements, with those measurements i need help getting bearings, i have come to the conclusion i should run h bearings since it will add 0.001in more than stock bearings size, also curious if different sized bearings are needed between each cap, they dont look to terrible but wanted an extra opinion other than mine since this first rebuild is a little overwhelming even tho i am prepared with information/knowledge aswell with some experience i am still a little overwhelmed.
cam bores were very consistent averaging 0.001-0.0035in and also the cam bores are different sizes but overall were very consistent
appreciate it.
im going for a street race build and to handle boost later on (to poor for that now), i have been contacting patg and he is setting me up with the build, i have the build all planned out and the parts and let him tweak the build
shooting for 450-500hp at the crank starting out with no bolt on mods just long tubes, but im mainly throwing money at internals but will be adding fbo after my break in period,
im at the point of buying main bearings and cam bearings along with crank this weekend, im going for forged internals aswell to handle boost and overall strength, i have gotten patg's insight but have other questions he couldnt answer.
i need help with bearings, i measured my main bearing bores and cam bores, main were around 0.001-0.003in smaller than oem spec but some could be measurement accuracy of 0.001in, https://drive.google.com/file/d/1h2x...usp=drive_link - main cap # listing measurements, with those measurements i need help getting bearings, i have come to the conclusion i should run h bearings since it will add 0.001in more than stock bearings size, also curious if different sized bearings are needed between each cap, they dont look to terrible but wanted an extra opinion other than mine since this first rebuild is a little overwhelming even tho i am prepared with information/knowledge aswell with some experience i am still a little overwhelmed.
cam bores were very consistent averaging 0.001-0.0035in and also the cam bores are different sizes but overall were very consistent
appreciate it.
You’ll want to buy x bearings along with standard bearings and do the mock-up measuring. You may or may not need the x bearings (+.001 Oversize) and sometimes you’ll have to half-shell them together…x on top and std on bottom…to get the clearances you want. I keep a drawer of all sizes in the shop just for this purpose. I hate having to order bearings and waiting two days when I’m mocking up my stuff. Do the same for rods also. If you don’t use one or the other, you can always send them back, or sell them off.
LS engines use 3 different sizes of bearings per block, and this sizing is different, depending on what year block you have. Hope this helps some…
LS engines use 3 different sizes of bearings per block, and this sizing is different, depending on what year block you have. Hope this helps some…
Thread Starter
Staging Lane
Joined: Apr 2023
Posts: 69
Likes: 7
From: Tx
alright so i get some x bearings as you said along with standard and stack them, and the number i am shooting for is just enough for the specific oil clearance i am trying to get between my crank and bearing, from what i know it is 0.001in of oil clearance for every inch of crank journal diameter so in my case it is 2.559in for the journal and my main bore is roughly 0.001 - 0.0025in average per cap (this is when i start getting confused, with calculations should roughly put me at 2.749 bore so 0.0002 from factory and the journal is 2.559 making my gap 0.19 so i need 0.0025-0.0026in of oil clearance and i need to make up 0.17 roughly of bearing?
Torque a main cap to spec with bearings in place. Measure the inner diameter at 12 to 6 o’clock. Do not measure 3 to 9 o’clock. Take that number you get there, and subtract the 2.559 journal size. That’s your clearance number. I’d shoot for .0025 to .003 for a boost engine, or .0025 for a big rpm n/a build.
If you get…say a .002 number with standard bearings, throw an X bearing on half of the setup, torque it to spec, and re-measure. Should go to .0025 in theory, but if not, and you need more room, throw the other half of the X in, re-torque and see where your at. Keep all your numbers written down in front of you, with each type of bearing you try. Keep good notes here, as you’ll need them to do the math correctly. Rinse and re-peat for other journals if you feel you need to…depends on how they measure out with caps on and torqued. I always start with number one bearing cap and go from there. Take your time and be patient. This can take hours to get right. Rods will be same way…
If you get…say a .002 number with standard bearings, throw an X bearing on half of the setup, torque it to spec, and re-measure. Should go to .0025 in theory, but if not, and you need more room, throw the other half of the X in, re-torque and see where your at. Keep all your numbers written down in front of you, with each type of bearing you try. Keep good notes here, as you’ll need them to do the math correctly. Rinse and re-peat for other journals if you feel you need to…depends on how they measure out with caps on and torqued. I always start with number one bearing cap and go from there. Take your time and be patient. This can take hours to get right. Rods will be same way…
Thread Starter
Staging Lane
Joined: Apr 2023
Posts: 69
Likes: 7
From: Tx
Alright im going to buy some oem bearings along with x bearings, and do you recommend bi or trimetal, i was personally wanting to go with bimetal for a bigger oil clearance and to prevent possible spun bearings but since you know my application what do you recommend
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Bi-metal or tri-metal will not affect clearances. That’s up to you, and how you set it up. I’d purchase the same bearing makeup as whatever your X bearings are, in a standard bearing.
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Thread Starter
Staging Lane
Joined: Apr 2023
Posts: 69
Likes: 7
From: Tx
alright man, i remeasured my main bores and got .003 on about all of them i think the 3rd "thrust bore" was .0025 (without bearings), and i somehow made the mistake of ordering the wrong bearings and bought bearings for 2002 and older and mines a 07 lol, also the x bearings would take over a month to get here,
So since my measurement is - 0.003 without bearings ( putting my bore size at 2.568, stock is 2.751 and crank journal is 5.559) what bearings would i need, still get standard and X - 0.001 undersized?
So since my measurement is - 0.003 without bearings ( putting my bore size at 2.568, stock is 2.751 and crank journal is 5.559) what bearings would i need, still get standard and X - 0.001 undersized?
Last edited by BrackenG8; Jun 28, 2023 at 05:34 PM.
alright man, i remeasured my main bores and got .003 on about all of them i think the 3rd "thrust bore" was .0025 (without bearings), and i somehow made the mistake of ordering the wrong bearings and bought bearings for 2002 and older and mines a 07 lol, also the x bearings would take over a month to get here,
So since my measurement is - 0.003 without bearings ( putting my bore size at 2.568, stock is 2.751 and crank journal is 5.559) what bearings would i need, still get standard and X - 0.001 undersized?
So since my measurement is - 0.003 without bearings ( putting my bore size at 2.568, stock is 2.751 and crank journal is 5.559) what bearings would i need, still get standard and X - 0.001 undersized?
Your main bearings and crank bearings aren’t year dependent. Doesn’t matter the year block, main and crank bearings are the same. Now your camshaft bearings do matter about year, so you want cam bearings for an ‘07 block.
Thread Starter
Staging Lane
Joined: Apr 2023
Posts: 69
Likes: 7
From: Tx
late reply, i bought a k1 forged 4340 steel crank , 2.559 journal with 2.100 rod journal, yes it will be a forged internals with the crank and rods being forged 4340 and pistons being forged aluminum. i ordered some x bearings, budget isnt really able to get some standard but i dont think i will need standard since my block was honed and resurfaced and its around 0.003 larger than stock which is 2.751 putting my main bores at 2.754 and i can run a x bearing. .125 fillet radii i actually just installed my cam bearings which are stock bearings. those main bearings were for like a 5.7 or something so the bearings usually snap in and you know that so when i went to snap em in they just kinda moved around and you would spin a bearing in a millisecond on start up if i ran those so now im ordering some x bearings from lsx performance 0.001 undersized