How to Calculate and Measure Main Bearing Clearance -- Engine Building 101

Setting bearing clearance for a performance engine is a fundamental step in the building process.
There are no quick and easy ways to establish this critical clearance; however with patience and the right tools, it's not a monumental task. You'll need an accurate micrometer in the range of the journals you will be measuring, along with a dial bore gauge. The best ones to use are accurate down to 0.0001-inch. With these two tools you can quickly determine the optimal clearances in any engine. These clearances should allow for proper oiling with minimum friction.
In this video, we use our Summit LS Engine to demonstrate the process of calculating and checking main bearing clearances.

[@spearotv587]

Great video guys! Thank you for putting this information out there. Mixed shell halves is something I was not not aware of.

[@SummitRacing]

Thank you for watching!

[@Kenny-1958]

I always use gauge blocks and the Fowler fixture to set the dial bore gauge.

[@johnbehneman1546]

Great video and a great education. I learned so much. Thanks for sharing.

[@SummitRacing]

Thank you for watching, John!

[@glenfreeman6119]

Great video with special racing engines you probably need higher standards but i use plastigauage and have had no problems😊

[@canadianmarauder1923]

I love this stuff. Thanks you guys

[@SummitRacing]

Thank you for watching!

[@billbonu1639]

I always go aboard the BACK side of mine with a piece of 600 grit sandpaper to take a half a thousand off if I need to get a little more clearance just be sure to sand the whole thing evenly, never had a problem with it

[@elonmust7470]

Didn't know Summit had that database!

[@1pimpmuke4life]

Excellent video

[@strongme80]

Where do you really take readings from the bearings to get a precise measurements? I am asking this because from what I have gathered, the center section of the bearings are thicker compared to the section near the parting lines.

[@SummitRacing]

Thank you for your question. You are correct that bearings are thinner next to the centerline. This helps avoid “pinching” the rod journal when the rod is under high tension loads and the round bore becomes ovalized. For this reason, always measure the bearings from top to bottom (90 degrees from the parting line).

[@thatnightmarinboogeymanfh1985]

So if for example if i was in the same situation i would need to buy 3 different type of bearings ?

[@isaiah-lava5.086]

Was the journals line honed beforehand? I used hx in both halfves of my ls engine and i have 0 clearance. Is there a QC issue? Im lost

[@chimpun1979]

Did you scratch the bearings when measuring the ID?

[@b00sted_SS]

I 2nd this question, would like a close up of the bearing after you measured it

[@engineheader]

what is the formula to calculate which bearing halves you need? if you know the bore diameter and the journal diameter and the oil clearance desired? there should be a way to calculate it. not all of us want to buy dozens of sets of bearings to mix and match with. does Summit have a tool to calculate it?

[@MrGsxrme]

I built my engine alittle loose too and had to step up a heavy weoght oil to correct the oil pressure issue. Of course I'm also running loose because of the new RPM limit.

[@drakevelazquez8728]

Mixing bearing shells. Would there be any alignment issues In other words do the bearing sizes have to be on the same side of each cap going through 1-5

[@elonmust7470]

no

[@b00sted_SS]

Seems like it would be cost effective for a diy’r to just have the block align bored rather then buy 4 sets of main bearings?

[@spearotv587]

I would think the same, though my concern would be, how do you know your line bore is accurate to 1-2 tenths of a thou unless you measure it all your self to be sure and then you need to know your crank is ground to the same concentricity for it to be worthwhile. Both of which require some decent equipment to measure.

[@selectusedauto5976]

Please, Is there a way to file and measure a journey for the main with the engine in the car?

[@Very_Angry_Citizen]

Any update on the Summit Racing Burnout van?

[@beachboardfan9544]

Damn y'all have one of those spec pages for the hayabusa motor?

[@clasvirhodes4969]

I am looking for a light weight (aluminum) small block build to put in my 2004 Jeep Rubicon for both offroad and street use. My budget for the entire pull and replace project is $10,000. Would you be so kind as to point me in the right direction ? I am told It will be cost inefficient to use a Ford Z351 block.

[@richardprice5978]

For warning ⚠️ if you’re not a die hard ford fan I’d steer you away from that as ford transmissions or at least my knowledge of them makes them more harder and expensive to adapt to the new process transfor case I know because I haven’t finished one with a mustang 3V / coyote engine and a ford automatic 5 or 6 speed transmission. However it’s still possible just takes a Machine shop for the adapters and maybe one out put shaft / sungear repacment sorry it’s gotten pushed back in the q ( my dodge and K1500 jumped in line as higher priorities for me right now ) and been awhile sense I’ve worked on it and can’t remember all the specs I do like the idea of that as a ford has more wow 😮 factor but the Chevy lsx or ltx platforms are easily to swap then a dodge engine and transmission. Keep in mind if you’re in the USA 🇺🇸 at least you more than likely have to pass emissions and at least in Hawaii or Alaska and Utah or California if I’m remembering the engine and transmission has to be in your case 2005 ( and in one of those states they check the block numbers etc. or at least they used to and I was told if it rebuilt or not doesn’t matter if older they’ll still kick it out ) or newer to pass and with all of its smog items intact and working to even think about passing for road worthiness. If have any questions I’m happy to help as I like ford powered jeeps reminds me of ww2 ones

[@richardprice5978]

What t-case and transmission are you planning on using? As the Atlas is more of a aftermarket one but it’s more money

[@clasvirhodes4969]

@@richardprice5978 Makes sense. Thank you

[@speedracer3033]

What is your part number for the digital bore gauge?

[@chukchee]

Can you get rid of the stupid background music? What's up with that?

[@user-bn3fk3tz5e]

رائع وشكرا للترجمة للغة العربية

[@dan1906]

Measuring out to a 100,000th is bullshit. Not realistic. Especially in a 2 tool setup and no temperature control. The tool won't hold that and a few degrees of temperature change will cause that to drift. Getting a true measurement out to a 10,000th is an accomplishment.

[@spearotv587]

Dead honestly It's not bullshit. Loads of people do it all the time including myself. It's measuring in microns or tenths of a thou which is exactly what any good micrometer does. Your right that temperature will affect this measurement so one must be mindful of that. It takes a bit of practice and intelligence for measurements to be accurate but that's what being a professional is all about. Good crankshafts are ground to a tolerance of 1-2 tenths of a thou (1.25 to 2.5 microns) and this is easily measured with a test indicator and micrometers etc. If I machine parts on a lathe I will clock them up within 2 tenths of a thou before turning whenever possible. It's standard practice.

[@dan1906]

@@spearotv587 tenths of thousandths is a 10,000th, not 100,000. No commonly available micrometer will measure that. You're talking 1/10000, not 1/100000. Huge difference.

[@spearotv587]

@@dan1906 correct, although it doesn't really matter that it's included in a couple of their measurements as the tenths of a thou is the smallest change in clearance that will affect bearing selection or re working etc

[@freddyyblock]

What is the best one you sell (tenth thousand bore gauge set )?

[@SummitRacing]

SUM-900041-01 is a professional-quality dial bore gauge set that measures from 2-6" and is accurate to 0.0001

[@joeross6523]

Oh man,.I fell asleep!

[@lachechaurvanard1827]

Envía pieza a otro país

[@parkeranderson5074]

Si

[@lachechaurvanard1827]

🇩🇴🇩🇴🇩🇴🇩🇴🇩🇴🇩🇴🇩🇴🇩🇴🇩🇴✈️

[@shawnp001]

Great video but there is not an intro to the LT1 for my corvette C4, any ideas?

[@JN-mc1jk]

Long speech wtf?