dipstick calibration

Julian West · 05-18-05, 06:22 AM

Does anyone have an opinion on the best way to calibrate a dipstick after a sump swap?

I've fitted one of Armandos GT40 oil pans & am not sure how much oil to fill it with??

ISTR there was a thread about this a while ago, but can't find it anywhere????

Any advice greatly appreciated!

Peter D · 05-18-05, 08:46 AM

Julian, I had the same problem & got a mate to measure his setup (same stock "camel hump" Mustang sump as mine. He measured 160mm from the top of oil to the swaged shoulder on the dipstick holder.

However, with different sumps, dipstick locations, dipstick angles, etc, it is probably not much help with your new sump.

Somewhere out there, somebody must know an "absolute" oil level for an SB 302 - I guess that a useful benchmark would be a distance below the sump gasket. Armed with this & some school trig, it should be easy to work out the level on dipsticks located at any height or angle in the side of the sump.

Anybody got any clues ?

Kind Regards,

Peter D.

Kalun D · 05-23-05, 04:22 PM

This may not be scientific and I'm not a professional engine builder but here goes.

The pan I modified from a stock mustang pan measures about 6" deep, or 6" from crank centerline to car/ pan bottom.
This doesn't leave much room for variance of the oil level so the oil level is less than 1/2" away from touching the crankshaft. It can't touch the crank obviously.

So the furthest intrusion of the crank is marked on the pan, then the oil (or water) is then poured into the pan while it's off the engine to a point close to the crank position and that quantity of liquid is measured. Mark this fluid level, then install the dipstick and by measurement correspond a mark on it, then subtract a quart and make another mark on the dipstick for your low level.. I think 6 qts or more is a good amount to shoot for, 7 or 8 max with a wet sump, any less than 5 and you need extensions on your pan.

Or once you've measured the amount of quarts you can just assemble everything, fill with that many quarts and mark your dipstick that way. I used a generic dipstick from Summit that was way too long so I cut off the part that was marked and made my own marks. The quart distance between the upper and lower marks isn't always the same depending on the shape of the oil reservoir in the pan.

Don't forget that a dry oil filter takes almost a quart to fill and make sure everything is level during the whole process.

Kalun D · 05-23-05, 04:37 PM

""somebody must know an "absolute" oil level for an SB 302 - I guess that a useful benchmark would be a distance below the sump gasket.""

I'm estimating this is about 3" minimum, since my pan is already bolted. The crank centerline is at the sump bolting surface. What's the largest radius of the crank? Take that and add a 1/2". Add 6 or 7 qts., measure and if you're not past that, that's your level.

Or... call Armandos, they can probably give you an amount, pour it in and mark the dipstick.

BenL · 05-23-05, 05:08 PM

I don't know if this would work (I never tried something like this), but it seems reasonable to me.

With the pan off, cut a piece of cardboard to fit inside the pan at the location where the dipstick comes down into the pan. Cut out a curved bit to make an allowance for the crank.

Hold the cardboard under the engine and decide where the max level for the oil should be (somewhere below the path of the crank and above the pickup). Once you have that level, mark it on the piece of cardboard. Then transfer that mark to the oil pan. With the top of the pan level (or at the same angle as the engine), fill oil pan with water to the max line. Then subtract one quart of water and add another mark to the oil pan for the fill line. Drain the pan, and transfer the fill mark to the cardboard. Draw two horizontal lines across the cardboard at the max and fill marks. Insert the dipstick into to the engine and transfer the fill and max lines from the cardboard on to the dipstick.

After cutting the cardboard to match the shape of the oilpan, you might want to attach tab on each side of the top of the piece of cardboard to keep the top of the cardboard level with the bottom of the engine.

If you still have the original dipstick, you could start by transfering the original max line from the dipstick onto the piece of cardboard (since the crank hasn't changed, the max line is probably still valid, though the fill line might have changed).

Julian West · 05-24-05, 05:39 AM

If you still have the original dipstick, you could start by transfering the original max line from the dipstick onto the piece of cardboard (since the crank hasn't changed, the max line is probably still valid, though the fill line might have changed).

[/ QUOTE ]

Ben,

You've got me thinking now.... The *new* dipstick would end up being identical to the *old* one... it's just the quantity of oil required to reach the correct level that has (possibly) changed...!! The level should remain the same...

Does this sound right???

BenL · 05-24-05, 11:56 AM

[ QUOTE ]
You've got me thinking now.... The *new* dipstick would end up being identical to the *old* one... it's just the quantity of oil required to reach the correct level that has (possibly) changed...!! The level should remain the same...

Does this sound right???

[/ QUOTE ]
My guess is that it would depend upon the shape of the oil pan between the level of the max and fill lines. If it's the same, then you can probably use the same dipstick marks.

Ian Anderson · 05-24-05, 12:36 PM

Ben

I would consider your statement to be correct. Thinking about it from the top hole that the dip stick goes through - lenght of dip stick from there to top level of oil should remain a constant. So if your dip stick "sits" on the seal at the top then this level should be correct - The lower level could change if you want to calibrate for a quart or whatever but surely most people now have a large container and top up until the max level is reached.

Sorry can't resist
Blond walks into a parts department and asks for a new dip stick - needs to be longer than this she says as this doesn't reach the oil!

Oh well at least I apologised first

Ian

Peter D · 05-28-05, 08:58 AM

A mate of mine bought a new "High Energy" oil pan which had a "correct" oil volume specified for the standard sbf. When he did a preliminary test fill with water, the distance from the "oil" level to the sump gasket was 3.75".

This lines up fairly well with Kalun's estimate of 3"+.

I put a simple spreadsheet together which takes inputs of :

- Oil level to sump gasket level
- Height of dipstick entry above sump gasket
- Angle of dipstick

The output is the length of dipstick from point of entry to the oil level.

The following is a pic of the s/s with some rough numbers inserted - if any one wants a working version, just pm me.

Kind Regards,

Peter D.

Peter D · 05-28-05, 09:02 AM

Well so much for my skills at generating a pic from a spreadsheet - can't read a damn thing !

I'll have 1 more go.

Peter D.

BenL · 05-28-05, 01:31 PM

[ QUOTE ]
Well so much for my skills at generating a pic from a spreadsheet - can't read a damn thing !

[/ QUOTE ]
The image is quite readable. To view the full size image, click on the blue word "Attachment" in the bar above your message (or if your web browser allows it, right click on the image and select "View Image" (works with Mozilla browsers)).

Peter D · 05-30-05, 12:05 AM

Thanks Ben - I learn something new every day !!

Kind Regards,

Peter D.

Julian West · 05-31-05, 07:54 AM

FWIW, here's a picture I took with the sump off. It would indicate that a 'high' level of about3" below the sump mounting face would be pretty close.

What do you gents think?

Peter D · 05-31-05, 08:06 AM

Yep, 3" looks like its about right.

Peter D.

Peter D · 06-18-05, 07:43 AM

Another question about dipsticks - mine is hopeless (an adaptation from a 302 Falcon / Fairlane setup which the previous (unmentionable) engine builder cut short & stuck in so that it comes out in between the header tubes). Net result is a burnt/melted blob of yellow plastic where the dipstick handle used to be !!

Does anyone have any good ideas on what would be the best tube/stick assembly to start with, & how to mount it so as to keep away from the header tubes ?

Kind Regards,

Peter D.

Colin CJ D · 06-19-05, 02:11 AM

Peter, I use a Lokar flexible dipstick (like this one) that I anchored on the fiberglass deck just below where the roll bar stay meets the frame. Works really well.
Colin

Peter D · 06-19-05, 04:24 AM

Thanks Colin - that looks perfect - solves the access/routing problem & no plastic handle to melt !

Kind Regards,

Peter D.

**patbarry** · 07-01-05, 11:36 PM

Just to chime in late, the stock oil pan that came out of my engine shows 4.25 inches from the top with 4 quarts of water and 4.0 inches from the top with 5 quarts of water.

Peter D · 07-02-05, 01:09 AM

I got the Lokar dipstick from Summit racing the other day & it is now fitted much like Colin's one - much neater - thanks again Colin.

The interesting thing is that if you buy the one designed for LHS block-entry for the s/b 302 (Part # ED-5004), it is already calibrated for the correct oil levels relative to the crank - so regardless of which sump you have, you just keep filling until the level is right on the dipstick.

Kind Regards,

Peter D.