Some people are prolly gonna say obvious stuff in here but i already know so whatever.

ok my last motor used acl bearings all the way across ls vtec. everything was fine made 515.

I did the same thing this time with acl all the way accross. The main bearings were at around .035 which is the loose end of the clearance range being .038, keep in my im still experimenting as an engine builder so dont say, WTF ARE YOU THINKING!!

We tuned the other night and made over 600whp and the car is fast ****. Everything runs great. Im just not satisfied with the engine "noises" at idle and around 2k ish with no load, theres the faint sound like a rattling main bearing or something, kinda like a ultra faint clacking sound knocking sound, anything over about 2k and it sounds like a normal motor and any type of REAL load at 2k it doesnt make the sound. I cant tell if its just the motor being on the loose end of the spectrum or if maybe one of the main or rod bearings got distorted. I know we never detonated once and it doesnt make any insane noises or obvious noises and doesnt skip a beat. Im thinking about going ahead and swapping all the rod bearings to brown to close down the clearance and same with the main bearings. What my real question is, how much does the clearance change going to the next thickest(smallest) bearing. say a main was .035, what would it be if i go to a brown bearing which is the next tightest one. Ive done this before with the rods and i know its possible with the bearings while the motor is in the car. just trying to see if i need to go one or 2 sizes down, cause i know its all across the loose end of the range. its an ls block by the way. thanks for any input. please no lamers with the bullshit responses.

 

The problem with running so much main clearance is that when the block warms up it gets even bigger.At idle the oil pump isn't making enough volume to support the crank and rods.Your loosing so much pressure thru the mains that the rods aren't getting enough oil at idle.You may get away with the big clearance with a dry sump or external pump.
Glenn

 

yeah because whatever is faintly rattling only does it at idle and about 1500 and light throttle. I havnt decided what im going to do yet. I need to drive it some more. how do those other oil pumps work, i didnt think they were legal for nhra events in the SFWD categories.

 

i think im gonna stick some browns in the rods. b20 uses the same bearing measurements dont they, so green ones for the b20 are the same as for the b18?? I need to know cause i dont have an acura dealership local.

 

What does the oil pressure look like? 0.0038" is HUGE!! Why not something more in the range of stock--say a bit above stock like 0.0022-0.0025"?

 

what grade or engine oil you running?

you might want to try some thick oil and see if the noise goes away....

 

i dont know what my oil pressure is. Im gonna go down in size on the rods, and if i can weasel the main bearings out with the crank still in im going to go down in size on those too. Its an art, but it can be done.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by non-VTEC &raquo;</TD></TR><TR><TD CLASS="quote">what grade or engine oil you running?

you might want to try some thick oil and see if the noise goes away....</TD></TR></TABLE>

20w50 is what i run

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SPOOLINmatt &raquo;</TD></TR><TR><TD CLASS="quote">yeah because whatever is faintly rattling only does it at idle and about 1500 and light throttle. I havnt decided what im going to do yet. I need to drive it some more. how do those other oil pumps work, i didnt think they were legal for nhra events in the SFWD categories. </TD></TR></TABLE>

Might want to look into shimming that oil pump for extra pressure.


How did you get the main clearances that lose? What kind of ACLs are you using?

 

I don't have any experience building a Honda motor to take upwards of 600 hp. What do they usually set the clearances at when expecting that much power?

 

ACL RACE BEARINGS

and ive heard of shimming the oil pump but i have no CLUE how to do it. ID like to since im going to check my bearing clearances anyways, not like that would be THAT much more work at the same time.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d16dcoe45 &raquo;</TD></TR><TR><TD CLASS="quote">I don't have any experience building a Honda motor to take upwards of 600 hp. What do they usually set the clearances at when expecting that much power?</TD></TR></TABLE>

usually on the loose side but i think im to loose.

 

i ordered brown rods today, im going to stick them in tomorrow and clearance them out and see what up.