What shim thikness should I use to up the pressure of my LS pump to VTEC specs or maybe a bit higher even.

TIA

 

why not buy a vtec pump, just a few more bucks and i wouldnt risk 5k's for 90 bucks, just my thought.

 

If you compare the rotor and pump housing, youll see that one is thicker than the other meaning they probably have different volume rates and the pressure release spring being shimmed wont really change how it operates except when you get to max pressure/rpm...Does that make any sense?

Ive used a .020" thick shim on vtec pumps w/o any problems...

 

I already have my LS pump and ordering a VTEC one from the states (we dont have vtec engines in VENEZUELA) would be time consuming and expensive.

Nobody knows how thick they should be, ive read 1/8" but that seems like an awfull lot.

tia

 

TTT

 

1/8" inch is not very much compared to the spring length. That thing is like 5 inches long.
When you get your VTEC pump, open the covers and compare the rotors. From what I recall, the non vtec LS pump is thicker so really it should displace more volume...
I believe the shim only changes the max pressure since its the pressure relief valve...
Anyways 1/8 inch is fine. I do not think you will have any problems from it.

Just my opinion
Hows the weather down there in Venezuela anyway?

 

78 degrees all day all the time

 

.025 shim should do the job!

 

.025" seems like too little, I mean, compared to the spring length.
1/8" seems better. remember this is for an Ls oil pump, not a vtec one.

 

Beautiful weather!
You guys have beautiful women too.
Anyways I dont think theres alot of info floating around out there...
Try the smaller shim and get an oil pressure guage(if you dont have one)
Take notes on oil pressures @ idle and graph it up to redline. Then try a thicker one until you get the oil pressure you want...
BTW what are you shooting for? Are you running loose clearances or something?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PyroProblem &raquo;</TD></TR><TR><TD CLASS="quote">1/8" inch is not very much compared to the spring length. That thing is like 5 inches long.
When you get your VTEC pump, open the covers and compare the rotors. From what I recall, the non vtec LS pump is thicker so really it should displace more volume...
I believe the shim only changes the max pressure since its the pressure relief valve...
</TD></TR></TABLE>

True about the rotor thickness. So does that mean its also safe to run an early non vtec oil pump with a LSV/B20V setup?

 

From what Ive concluded, Non-vtec pumps will produce more volume and thus more pressure than vtec pumps(as long as the clearances are the same) But since VTEC needs that extra "oomph" at the end when the solenoid opens and oil locks all the rockers together, it needs a higher max pressure...
Ive never done any actual tests yet, but to me the LS (producing more volume) would be beter for race motors/looser tolerances...
I wouldnt think it would be unsafe to run an ls pump w/ a frankenstein...Just know what your oil pressures are going to be at and adjust the pressures to your clearances accordingly...Id stick to factory oil pressures no matter which pump or how loose/tight you build your engines...

 

Then again, the vtec rotor is a bit lighter since its smaller..
Every bit counts right?

 

An LS oil pump is identical with a B20b oil pump right?

 

I think the older ones were the same like 98 and below LS+B20. Sometime later on I believe they switched to the VTEC pumps on b20's. I dont know exactly when though..

 

I think B20 pumps are all 98+, meaning they are identical to vtec ones.

I have not yet finished my build as the block is getting bored for the P73 pistons, as soon as I finish Ill graph out oil pressure with a 1/8" shim to see if its suficient for vtec.

thanks a lot Pyro