Main bearing clearences

[Malthael]

So I am putting together my 5.7 2009+ when I measured the crank journals the mains were at the smallest allowable tolerance. Now I was installing ARP main studs so I had the block align honed and bought standard bearings, now since I didn't have a dial bore gauge I used plastigauge which showed .001 of clearence on all the mains. This has me concerned the crank still rotates freely, but I'm going to have around 11.3:1 compression so 0.8 higher than factory and plan on shifting at 6000 rpm maybe 5900 rpm, with a BTR stage 2 cam, was wondering if getting different main bearings would be the smart move here? Like -.001 undersize(oversized for more clearance) to increase my clearence to .002. my main concern is spinning a main bearing the first time I hit 6000rpm I am thinking of buying these bearings CLE-MS2220HX to increase my oil clearence.

 

[work truck ram]

Wear and machining is going to increase the gap. The only way the gap is too tight would be "under sized" bearings, oversized journal/caps. Under sized bearings refers to the journal undersized diameter. Undersized (journal) bearings are thicker to decrease space. Are you sure you had all of the oil cleaned out of there when you gauged it?

If you are running stock diameters or used stock parts it will not be too tight with stock bearings. Plastigauge is not that accurate. If you can still spin with a wrench it isn't too tight. Sloppy clearance worked on old, pre gen 2, race motors but not on new motors that you don't plan to tear down each season.

 

[Malthael]

Yes I wiped both the bearing surface the cap the block and the crank down with acetone before I gauged it. Is it worth it to spend the $366 on the dial bore gauge to check the clearences,. Last thing I need is to find out the hard way that it is to tight.

 

[Wild one]

Yes I wiped both the bearing surface the cap the block and the crank down with acetone before I gauged it. Is it worth it to spend the $366 on the dial bore gauge to check the clearences,. Last thing I need is to find out the hard way that it is to tight.

Buy the dial bore guage,and measure it properly using it and a good micrometer. Plasti gauge is okay on a junkyard build that you don't care about,but shouldn't be used on a good build. That cam should make power to at least 6400,you're definitely leaving power on the table shifting it at 5900

 

[Malthael]

Buy the dial bore guage,and measure it properly using it and a good micrometer. Plasti gauge is okay on a junkyard build that you don't care about,but shouldn't be used on a good build. That cam should make power to at least 6400,you're definitely leaving power on the table shifting it at 5900

I know I'm leaving power on the table but I'm using the stock connecting rods and really don't need it to spin to 6400 I'm okay with 10 horsepower on the table. I ended up using my t gauges and micrometer came out to .0013 on the mains but I'm getting different bearings so the clearence is closer to .0023 still checking the rods journals

 

[Wild one]

I know I'm leaving power on the table but I'm using the stock connecting rods and really don't need it to spin to 6400 I'm okay with 10 horsepower on the table. I ended up using my t gauges and micrometer came out to .0013 on the mains but I'm getting different bearings so the clearence is closer to .0023 still checking the rods journals

I spun the stock bottem end on my 5.7 to 6600 for 10 years and had 700+ nitrous dragstrip passes under it's belt when i sold the truck,and it still hot idled at 51 psi and carried 78/80 psi at it's shift points,and still pumped 218 psi on all 8 holes,last thing i ever worried about was the bottem end.There's quite a few guys with bigger cams then i had spinning their stock bottem end 5.7 to 7,000+ rpm. I even know of a couple guys spinning a stock bottem end 5.7 to 7200 rpm with a big cam

 

[Malthael]

I spun the stock bottem end on my 5.7 to 6600 for 10 years and had 700+ nitrous dragstrip passes under it's belt when i sold the truck,and it still hot idled at 51 psi and carried 78/80 psi at it's shift points,and still pumped 218 psi on all 8 holes,last thing i ever worried about was the bottem end.There's quite a few guys with bigger cams then i had spinning their stock bottem end 5.7 to 7,000+ rpm. I even know of a couple guys spinning a stock bottem end 5.7 to 7200 rpm with a big cam

Was that with the stock Pistons or lighter forged pistons?

 

[Malthael]

Was that with the stock Pistons or lighter forged pistons?

I find it extremely hard to believe that it hot idled at 51 psi with the stock pump when mine idled at 22psi hot unless you had an aftermarket pump or extremely thick oil

 

[Wild one]

I find it extremely hard to believe that it hot idled at 51 psi with the stock pump when mine idled at 22psi hot unless you had an aftermarket pump or extremely thick oil

Stock pump with 5W-30 Redline and the idle set at 750 rpm and dual remote filters. I never once touched the bottem end of the motor. The way it left the factory is the way it was
Turn the idle up to at least 750,even my bone stock 300 with 80,000 miles on it's 5.7 hot idles at 49 psi with the idle turned up to 750. Something was whacked with your 5.7 if your truck only idled with 22 psi,i'd guess either the pick-up screen was close to being plugged or the o-ring on the pick-up tube wasn't sealing properly,as i know of lots of 5.7's and not one of them idles with that low of oil pressure. Even with the 550/600 stock idle rpm,most of them still idle in the mid 30 or higher range even with 5W-20 in the crankcase

 

[Malthael]

Stock pump with 5W-30 Redline and the idle set at 750 rpm and dual remote filters. I never once touched the bottem end of the motor. The way it left the factory is the way it was
Turn the idle up to at least 750,even my bone stock 300 with 80,000 miles on it's 5.7 hot idles at 49 psi with the idle turned up to 750. Something was whacked with your 5.7 if your truck only idled with 22 psi,i'd guess either the pick-up screen was close to being plugged or the o-ring on the pick-up tube wasn't sealing properly,as i know of lots of 5.7's and not one of them idles with that low of oil pressure. Even with the 550/600 stock idle rpm,most of them still idle in the mid 30 or higher range even with 5W-20 in the crankcase

Yeah I just checked my rod bearing clearances and something from the factory was definitely different because I put standard bearings in it and the clearance is like .003 and they are standard bearings which is ridiculous way too lose it is a 2009 pretty bad year for the economy so it's got parts that shouldn't be on it like the axles I couldn't find an axle shaft for it got all different kinds and none of them were right. Was bought with 15,000miles.

 

[Malthael]

Yeah I just checked my rod bearing clearances and something from the factory was definitely different because I put standard bearings in it and the clearance is like .003 and they are standard bearings which is ridiculous way too lose it is a 2009 pretty bad year for the economy so it's got parts that shouldn't be on it like the axles I couldn't find an axle shaft for it got all different kinds and none of them were right. Was bought with 15,000miles.

Whenever I would floor it I'd hit 55psi of oil pressure hot