Thread:

Olds 455 oil drainback.......

Ive done all the necessary mods for the oiling system on my 455. The machine shop that built my engine has now stepped up to finishing my heads and wants to know what thread size i want for the oil drainback to the pan... He was gonna go with a 1/4 npt but im not sure if thats big enough. I know hotboat did an article on this procedure in one of its magazines but i dont have access to it.

Does anyone know what thread size can be used, 1/4 just doesnt seem large enough to me for some reason. Any addition information or pictures of this procedure done would be great.

Look at this photo what size does this look like???

get rid of the olds..............

That's odd they have one oil drain back going up to the other side of the engine instead of down...

Get ahold of TIMINATOR, he's probably the guy that wrote the article in HotBoat.

My buddies has -8 hose and fittings, has the Mondello return kit. He too has a return on each side running to the pan. That crossover would not work too well for oil return, it's only gravity pulling the oil to the pan.

Originally Posted by sleekcrafter

My buddies has -8 hose and fittings, has the Mondello return kit. He too has a return on each side running to the pan. That crossover would not work too well for oil return, it's only gravity pulling the oil to the pan.

yea i dont plan on using the crossover, im gonna have 2 returns to the pan... that setup doesnt look towork very well especially with the routing of the lines. Happen to know what size threads the -8 fittings are?

Originally Posted by matt1840

... Happen to know what size threads the -8 fittings are?

A copy and paiste from Luckie Stiff who stole it off another site.

"
AN Fittings


"AN" (Army Navy) Sizes were established by the aerospace industry. The measurements represent the O.D. (outside diameter) of rigid metal tubes.
Basically, dash sizes are the numerators of fractions with a denominator of 16.

EXAMPLE:

-6 is equal to 6/16 in. which is equal to 3/8 in.
-8 is equal to 8/16 in. which is equal to 1/2 in.

In the examples above, a -6 AN fitting would work with a pipe that has a 3/8 in. O.D. A -8 AN fitting would be used with 1/2 in. O.D. pipe.

Here's a simple chart, just in case you don't want to do the math.

-02 AN is equal to 1/8 in.
-03 AN is equal to 3/16 in.
-04 AN is equal to 1/4 in.
-05 AN is equal to 5/16 in.
-06 AN is equal to 3/8 in.
-08 AN is equal to 1/2 in.
-10 AN is equal to 5/8 in.
-12 AN is equal to 3/4 in.
-14 AN is equal to 7/8 in.
-16 AN is equal to 1 in.
-20 AN is equal to 1 1/4 in.
-24 AN is equal to 1 1/2 in.
-32 AN is equal to 2 in.



The most commonly used fittings are adapters. These adapters connect an AN fitting to a pipe thread fitting. Most fuel pumps, regulators, and canister type fuel filters, come with pipe thread inlet/outlet ports. In order to use braided line, the ports need to be changed to a AN type of fitting. This is when a "pipe to AN adapter" is needed."

Originally Posted by hotrod56cars

Get ahold of TIMINATOR, he is the guy that wrote the article in HotBoat.

use a 1/2 pipe to 8AN adapter.

Originally Posted by fleetimus

Contrary to your opinions, I never had one problem with oil. It worked fine.

1/4" in the heads and -6AN lines

fleet your running and olds motor?? with youbeing so quiet in the olds discussions i figured you were runnin one of those dime a dozen motors

I just got off the phone with tim (timinator) and he gave me LOADS of information on the olds 455. Now ive just gotta find the correct issue of hotboat and ill be on my way to spankin all you bowties on the water

My first boat had an Olds. Once I learned to keep it under 5K, I never had a problem. I am running a BBC in the TX-19.

Originally Posted by fleetimus

My first boat had an Olds. Once I learned to keep it under 5K, I never had a problem. I am running a BBC in the TX-19.

Thats gonna be the hard part.... Keepin my foot out of it!

I got ahold of tim over at tuf enuf.. WOW that guy is FULL of information on the olds. I was on the phone for damn near 35-40 minutes and i still wasnt done picking his brain. I got the june 06 hotboat mag thanks to Sharpy THANKS BROTHA!!

Originally Posted by matt1840

Thats gonna be the hard part.... Keepin my foot out of it!

Get one of those dime a dozen motors...and you wouldn't have to think about it.