440 crank bearing clearances?

[moper]

Factory specs are fine for factory-type expected usage. If they weren’t Mopars wouldn’t be known for their engines. That being said... for more spirited driving or racing you want more space in there, both for oil flow to cool the parts and in case parts deform under use. I’m not sure you are on the same page with your machinist in regard to measuring. The sizes can be presented a couple ways: in thousandths (.***), or in ten thousandths (.xxxx). So “ three thou” is .003, and “thirty ten thousandths” (.0030) are the same thing. In your above post, “three thou” is fine. .0003 (three ten thousandths) is not.

 

[Auggie56]

Factory specs are fine for factory-type expected usage. If they weren’t Mopars wouldn’t be known for their engines. That being said... for more spirited driving or racing you want more space in there, both for oil flow to cool the parts and in case parts deform under use. I’m not sure you are on the same page with your machinist in regard to measuring. The sizes can be presented a couple ways: in thousandths (.***), or in ten thousandths (.xxxx). So “ three thou” is .003, and “thirty ten thousandths” (.0030) are the same thing. In your above post, “three thou” is fine. .0003 (three ten thousandths) is not.

I think I got frisky with the zeros just looked again and yes your right the measurement is .003 So you think it's OK at .003? The mains were .003 so I shimmed them with .003 brass shim stock which gave me .006. Still, haven't approached the rod bearings.

Many thanks

 

[73HEMI_RR_GTX]

I think I got frisky with the zeros just looked again and yes your right the measurement is .003 So you think it's OK at .003? The mains were .003 so I shimmed them with .003 brass shim stock which gave me .006. Still, haven't approached the rod bearings.

Many thanks

.0025 - .003 is perfect for a hi- performance engine. I would also run a Hi- volume oil pump and a six quart oil pan.

 

[RJRENTON]

I think I got frisky with the zeros just looked again and yes your right the measurement is .003 So you think it's OK at .003? The mains were .003 so I shimmed them with .003 brass shim stock which gave me .006. Still, haven't approached the rod bearings.

Many thanks

Augie,
I've used 0.002" - 0.0025" for both mains and rod bearings, Clevite 77 tri-metal bearings for both, with ARP bolts and rod cap screws and nuts using a HIGH VOLUME PUMP with Mobil One 10W-30 and one pint of ZDDP, a 6 qt pan, windage tray. The main bearings are full groove so the rod bearings get oiled for 360° of crankshaft rotation. My pressures are 75#-80# cold and 70#-75# hot at 3000 RPM and 55#-60# @ 1100 RPM idle. This is what works for me.
Exact bearing clearances are best measured with outside mikes for O.D. journal diameters and bore snap gauges for I.D. main bore and rod bore (with bearings installed and caps torqued to specs), with the differences being the clearances. Just my opinion of course.
BOB RENTON

 

[Cranky]

Augie,
I've used 0.002" - 0.0025" for both mains and rod bearings, Clevite 77 tri-metal bearings for both, with ARP bolts and rod cap screws and nuts using a HIGH VOLUME PUMP with Mobil One 10W-30 and one pint of ZDDP, a 6 qt pan, windage tray. The main bearings are full groove so the rod bearings get oiled for 360° of crankshaft rotation. My pressures are 75#-80# cold and 70#-75# hot at 3000 RPM and 55#-60# @ 1100 RPM idle. This is what works for me.
Exact bearing clearances are best measured with outside mikes for O.D. journal diameters and bore snap gauges for I.D. main bore and rod bore (with bearings installed and caps torqued to specs), with the differences being the clearances. Just my opinion of course.
BOB RENTON

I used inside mics for checking bearings. Got a better feel than using snap gauges....then mic the inside mic with an OD mic.

 

[RJRENTON]

I used inside mics for checking bearings. Got a better feel than using snap gauges....then mic the inside mic with an OD mic.

True.....I guess it depends on the "feel" of the snap gauge drag and if its "square" to the bore. I should probably purchase a set of I.D. mics to double check my initial measurement. Either method is superior to "plastigage" but if that's all that is available, it's better than nothing...
BOB RENTON

 

[Auggie56]

Factory specs are fine for factory-type expected usage. If they weren’t Mopars wouldn’t be known for their engines. That being said... for more spirited driving or racing you want more space in there, both for oil flow to cool the parts and in case parts deform under use. I’m not sure you are on the same page with your machinist in regard to measuring. The sizes can be presented a couple ways: in thousandths (.***), or in ten thousandths (.xxxx). So “ three thou” is .003, and “thirty ten thousandths” (.0030) are the same thing. In your above post, “three thou” is fine. .0003 (three ten thousandths) is not.

Many thanks.

 

[Cranky]

True.....I guess it depends on the "feel" of the snap gauge drag and if its "square" to the bore. I should probably purchase a set of I.D. mics to double check my initial measurement. Either method is superior to "plastigage" but if that's all that is available, it's better than nothing...
BOB RENTON

Never did like to drag a snap gauge in a bearing....plus I usually got a couple of tenths difference with them vs using an inside mic. And if plastigage is fresh it's not bad but once it gets old, it hardens up some.

 

[RJRENTON]

Never did like to drag a snap gauge in a bearing....plus I usually got a couple of tenths difference with them vs using an inside mic. And if plastigage is fresh it's not bad but once it gets old, it hardens up some.

Good point....ive always used a a little lubricant (oil) on the bearing surfaces, but I.D. mics would prevent or reduce the possibility of bearing scratches on the friction surfaces.
BOB RENTON

 

[Challenger340]

Boy.... things could get really long-winded on this subject about Bearing Clearances Vrs 'applications'.

.0025" Vertical on a "P' Bearing just ain't the same .0025" Vertical on an 'H' Bearing.....
Don't believe me ?
GO measure Bearing Clrc at 45* from Vertical on a 'P' Bearing Vrs and 'H' Bearing.
SEE ?

Side Clrc on the Rods in pairs ?

No matter,
just shoot for .0025" on the Rods and closer to .003" on the Mains for street stuff.

Some food for thought though if you are headed Racing/Competition especially with the cheaper Stroker Cranks?
Crank runout or 'Bend'.... they ALL have it !
#4 Main Cap wallop and the crappy 'as delivered' $150. Stroker Crank Balance Jobs = JOKE !

 

[dvw]

Put enough power through your stuff to make the crank act as a jump rope? You may want to move clearance up to .004+. But as stated general rule .001/ inch of journal diameter is pretty safe. A few .000x either way isnt going to kill it. Unless you are starting tight already or are looking for every edge you can get.
Doug

 

[dcala84141]

Not to change the subject, but does anybody have any ideas why when my motor sits for an hour, when I start it up I have no oil pressure for a few seconds, longer when it sits for a few days, I had a Mellon hi volume oil pump, but put back the stock pump seemed to help, but still a lag time for oil pressure. Oil pressure is 70 to 80lbs. When running. I called my engine builder, Mellon, Hugh’s engine, Porter performance, etc. no one could come up with an answer. I did put a 1/2 oil pick up, but no other oil passage mods.
Any ideas?
P.S. some told me to add a switch on ignition and crank over the engine to build oil pressure

 

[moper]

Drain back is your issue from the sound of it, and that’s more a function of your filter, overall condition of the block, and the oil’s viscosity hot.
I’d change the filter to a high quality like a Wix Blue or Gold and see what that does. Maybe try a grade or two thicker than what you run if the filter doesn’t help. I’d say if it comes up with the cranking it’s fine- if it fires a runs and then comes up it’s a problem. If it’s still a problem get an Accusump accumulator for it to pre-oil before you turn it over.

 

[dcala84141]

Yes Oil is definately bleeding down. I had a wix oil filter, changed it out for a STP filter because half the size of the wix filter. Engine is a stroked 383 pushing 550hp. I asked engine builder to mag. The block before all the work was done, so I assume block checked out OK. 5w 50 is currently in it
Roller cam, lifters and rockers
Should I try 10-30 weight oil?

 

[moper]

I don’t think it’s a case of damage missed in the building stages. If he’s making 550hp out of a 383 the basics should be covered. What oil are you running? How are you seeing that there’s no pressure? How long does it take to come up?

you responded while was apparently... lol

were the lifter bores bushed? What are the clearances? It’s a synthetic oil, right? Also have you verified what you’re seeing with a diagnostic quality oil pressure gage?

 

[dcala84141]

5w50 racing oil, mechanical oil pressure guage no oil pressure for about 2 seconds upon startup little longer if engine sits for a few days. Engine does make noise for those 2 seconds, but then no noise ( sounds like lifter rattle) when oil pressure comes up

Frustrating

 

[moper]

Solid roller? Lifter bores bushed?

 

[dcala84141]

Solid roller? Lifter bores bushed?

Hydraulic rollers
Lifter bores not bushed

 

[moper]

Guessing it’s lifters bleeding down, either their due to their design or other factors. It’s not a lower end issue and I don’t consider it a “damaging” deal. It’s irritating but my suggestions would be you can try another brand of lifter, verify the preload is right, try a little heavier oil, or stick an accumulator on it to pre-oil. Or live with it. If it’s fine after 2 seconds there’s not much that can be done.

 

[dcala84141]

Hey
Thanks for help and suggestions
U maybe rite about the lifters the more I think about it. Differently sounds like lifter bleed down
I think they are from comp cams
Bill