I really need some input on this one. I searched but only found one post reguarding tight bearing clearances. I currently have a B18A1 block which Im prepping for use with a B16 head. I want a reliable street motor and dont really see the need to rev over 7500k. I have a set of ACL main bearings which measure

Main 1 .0010
Main 2 .0012
Main 3 .0012
Main 4 .0012
Main 5 .0010

These measurements were plastigauged using 10W30 oil on the main bolts at 56lbs final torque for all maincaps as per the factory guidlines (B18A1/B1).

I know alot of people generally try to target .0015 for OEM bearings. I realize the rule of thumb is tighter=longer life/less power, looser=more power/shorter life.
Is anyone here running there clearances this tight? If so, how high do you normally rev and what weight oil do you use? I live in Florida so I,ve always used 10w40 on my motors but I've heard that you should run a 20W-30W oil on the intial break-in so I wanted to get some opinions.

 

Anyone?

 

Bearing clearance should not affect power in any way if the right lubricant is used. Insights use 0W-20 oil which is like water, with insanely tight bearing clearances. They are so tight, even the slightest variation in the rod or crank itself can cause damage to the bearing shell.

If you do plan to do this, use a thinner oil, 5W-30 at MOST. I would suggest 0W-30 to start. (it is hard to find in some places) And see what your pressures are. If your pressures are too low when its hot you may need a thicker weight.

The reason a lot of people aim for OEM specs is because they try to follow factory standards, and by doing this your treading away from that path, so those standards no longer apply. Just remember oil clearances and viscosity are for the most part proportional.

Using thick oils for engines that do not call for them will starve those components. I had a guy come to me saying his power steering pump was pumping oil out of the reservoir on cold days. Turns out the moron put 75W-140 gear oil in the pump, and it emulsified out of the reservoir. Needless to say he needed a new pump as well. The vanes "welded" themselves to the carrier, and made the Ford Power Steering Pump noise.

Any whoever told you larger bearing clearances are for more power/less life, tell that to Detroit Diesel. The bearing clearances on the Detroit Series 60 are around .007" and they see a million miles and change.

 

try a set of proper honda bearings to get the correct clearences. if those measurements are correct i think they are a little too tight.

 

yeah def. on the tight side.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowcivic2k &raquo;</TD></TR><TR><TD CLASS="quote">Bearing clearance should not affect power in any way if the right lubricant is used. Insights use 0W-20 oil which is like water, with insanely tight bearing clearances. They are so tight, even the slightest variation in the rod or crank itself can cause damage to the bearing shell.

If you do plan to do this, use a thinner oil, 5W-30 at MOST. I would suggest 0W-30 to start. (it is hard to find in some places) And see what your pressures are. If your pressures are too low when its hot you may need a thicker weight.

The reason a lot of people aim for OEM specs is because they try to follow factory standards, and by doing this your treading away from that path, so those standards no longer apply. Just remember oil clearances and viscosity are for the most part proportional.

Using thick oils for engines that do not call for them will starve those components. I had a guy come to me saying his power steering pump was pumping oil out of the reservoir on cold days. Turns out the moron put 75W-140 gear oil in the pump, and it emulsified out of the reservoir. Needless to say he needed a new pump as well. The vanes "welded" themselves to the carrier, and made the Ford Power Steering Pump noise.

Any whoever told you larger bearing clearances are for more power/less life, tell that to Detroit Diesel. The bearing clearances on the Detroit Series 60 are around .007" and they see a million miles and change.

</TD></TR></TABLE>


Alright, so if I choose to keep the bearing clearances I should also use a thinner weight oil (understandable), then what weight oil would you recommend for the intial start-up/break-in?


Modified by DC_Legacy at 9:50 AM 2/4/2008


Modified by DC_Legacy at 2:21 PM 2/4/2008

 

Use the oil that the engine will use for the rest of its life, if not thinner initially. This ensures that oil gets in every crack and crevice possible, and prevents the most initial wear. NEVER use a thicker oil on a dry engine. The pump will not pump the right volume of oil at too high a pressure initially, which will starve the components, and possibly ruin the pump and bearings.

If you do use thinner oil on break-in, let it idle for a few minutes, and check the pressures. Normal oil pressure range is around 60-70psi when the oil is cold at fast idle and will drop as the oil warms, around 20-25psi at hot idle fully warm, and at least 50psi at 3000rpm with the engine warm. If your pressures abnormally deviate, try a thicker/thinner oil to raise/lower the pressure to spec.

The hand full of engines I've rebuilt get this treatment. Some people even go a step further by using a hand pump to fill the engine cavities with oil manually through the oil filter port or pressure switch port.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowcivic2k &raquo;</TD></TR><TR><TD CLASS="quote">Use the oil that the engine will use for the rest of its life, if not thinner initially. This ensures that oil gets in every crack and crevice possible, and prevents the most initial wear. NEVER use a thicker oil on a dry engine. The pump will not pump the right volume of oil at too high a pressure initially, which will starve the components, and possibly ruin the pump and bearings.

If you do use thinner oil on break-in, let it idle for a few minutes, and check the pressures. Normal oil pressure range is around 60-70psi when the oil is cold at fast idle and will drop as the oil warms, around 20-25psi at hot idle fully warm, and at least 50psi at 3000rpm with the engine warm. If your pressures abnormally deviate, try a thicker/thinner oil to raise/lower the pressure to spec.

The hand full of engines I've rebuilt get this treatment. Some people even go a step further by using a hand pump to fill the engine cavities with oil manually through the oil filter port or pressure switch port.</TD></TR></TABLE>

Thanks! will do.

 

at first i use the cheapest 5w20 oil.. for the first 3 oil changes... then i go to my normal use synthetic 10w.30 ... =D ..hope this helps.. heres a link that might help u a lil too... =D from here... hey... my first post after like uuuuuuuuuuuuuuuuu..lol


https://honda-tech.com/zerothread/1676914



Modified by gsrcrazy at 3:47 AM 4/16/2008

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gsrcrazy &raquo;</TD></TR><TR><TD CLASS="quote">at first i use the cheapest 5w20 oil.. for the first 3 oil changes... then i go to my normal use synthetic 10w.30 ... =D ..hope this helps.. heres a link that might help u a lil too... =D from here... hey... my first post after like uuuuuuuuuuuuuuuuu..lol


https://honda-tech.com/zerothread/1676914

Modified by gsrcrazy at 3:47 AM 4/16/2008</TD></TR></TABLE>

Thanks!, Yeah thats what I did. Im still using conventional 5W30 however I got a much bigger problem reguarding coolant leaking into my oil .

 

uh oh... could be bad head gasket.. warped head... or possibly deck...