Porting the Oil Pump hole in the block.

[inmyshadow]

Ok, I've got my 2.5 TI block torn down.

As part of my short block build up. I wanted to port match the oil pump hole to the oil pump.

Using Gary Donavan's website for an example. http://www.thedodgegarage.com/turbo_oil_pump.html

The page doesn't give much details on how to do so. I wanted to know how far down the oil hole I go. Or do I just tamper the hole so that each part matches each other.

I want to get the block at set to send off to the machine shop next monday.

later

[tryingbe]

...note that the oil pump hole is oval while the one at the surface of the block that it mates to is round... ..take a die grinder and make the one on the block match the one on the pump... ...Ed Peters swears there is a 5-6 hp gain since pump does not sap as much power due to better oil flow.....I tried it on my carb Horizon and MAYBE picked up .10...

Did you read this part?

[GLHNSLHT2]

it's apart, why not do it? I go down about an inch tapering it.

[moparzrule]

I go down about an inch tapering it.

Yup, taper/blend it back about an inch and that should do the trick.

[ATaylorRacing]

Me too.....about 2-3 hp on a carb motor.

[4 l-bodies]

I taper all the motors I build all the way to inside the oil filter cavity. Remember to do your waterpump housing too.
While your at it, chase all the threads in the block, or tell your machinist to you so.
Todd

[moparzrule]

While your at it, chase all the threads in the block, or tell your machinist to you so.
Todd

YES! I didn't do every single hole, and 2 of them that I didn't do happen to be the oil pump hole. Turns out there was crud in one of the bolt holes, so when I torqued to the 21 ftlbs it was a false torque reading and the oil pump was not truly seated against the block leaving a tiny gap. My oil pressure wouldn't go over 40 PSI after the engine warmed up.

[TurboII]

Yup, taper/blend it back about an inch and that should do the trick.

what does taper mean?

[t3rse]

cut at a very slight angle, slight ramp

[TurboII]

okay next question:
do i want to make the block whole bigger then the oil pump hole? This way the oil just flows right in instead of having a step?

[moparzrule]

Ideally you want it the exact same size! But yes if anything the block side larger.

[TurboII]

One more question:

doing this process will it effect oil pressure? harmful or helpful in way?

why did Chrysler intend to make the shapes not the same?

[turbovanman²]

One more question:

doing this process will it effect oil pressure? harmful or helpful in way?

why did Chrysler intend to make the shapes not the same?

Helpful of course it is. Imagine your taking a header down a fast river and it narrows BUT there is a couple feet of wall sticking out, you hit that and then bounce on your merry way, all smashed up. Same idea with the oil flow.

Dodge didn't do it because it costs money to port match every one so for the regular joe and his mass produced car, he won't even notice.

[moparzrule]

At stop HP levels I seriously doubt it makes any difference at all. That is why chrysler didn't bother.

[TurboII]

Helpful of course it is. Imagine your taking a heading down a fast river and it narrows BUT there is a couple feet of wall sticking out, you hit that and then bounce on your merry way, all smashed up. Same idea with the oil flow.

Dodge didn't do it because it costs money to port match every one so for the regular joe and his mass produced car, he won't even notice.

well said simon

At stop HP levels I seriously doubt it makes any difference at all. That is why chrysler didn't bother.

i figured that much.

[t3rse]

why did Chrysler intend to make the shapes not the same?

Why isn't your head ported from the factory? Why do some cars not have intercoolers? Why are they not rear wheel drive? lol

[GLHNSLHT2]

Casting and machining reasons come into play. Easier to machine a round hole with a drill than it is to stitch some complex angle with a ball end mill.

[Directconnection]

At stop HP levels I seriously doubt it makes any difference at all. That is why chrysler didn't bother.

Shouldn't matter if the car makes 150hp or 550 hp. The oil pump has no idea what the crankshaft is putting out for hp. So, to tell you the truth, on a feable 150 hp, 2 hp will make a much more noticeable difference than at 550hp.

[Directconnection]

the oil pump is drilled at an angle... so when it comes out through the flange, is why you have an oval shape vs a regular round hole drilled straight into the block.

[moparzrule]

Shouldn't matter if the car makes 150hp or 550 hp. The oil pump has no idea what the crankshaft is putting out for hp. So, to tell you the truth, on a feable 150 hp, 2 hp will make a much more noticeable difference than at 550hp.

Typically higher HP engines turn more RPM and/or have higher oil pressures. So it will make more of a difference.
But yes it's true that the actual HP doesn't really matter.