The 100 Forum

I'm in the home stretch assembling my fancy schmancy 100 motor with DW alloy sump. DW advised oil capacity is the same as stock, but I would need to cut off my dipstick and make new marks. Now I'm wishing I'd asked some followup questions like "Howcome?" "How much?" and "Where do I put the new marks?" Anyone been down this road who could advise?

Thanks,

Craig

Craig,

I have dealt with similar issues but with BBC marine engines. I do have some initial questions.
First, if I remember correctly, the DW pan is a little shallower than stock, correct?
Second, is the lower sump the same length, shorter or longer than a stock pan?
Finally, is the pan on the engine with engine in car or still on an engine stand?

Thanks Craig, good questions. Sump is on the motor, in the car. Easy enough to remove it and loud capacity and calibrate dipstick, just thought I might run into someone here

Hit the trigger too soon in previous post. Was hoping to run into someone here who has Denis Welch sump and knows oil capacity.

Craig

Craig,

I don't have a DW alloy oil pan, I don't even have a 100, but your problem should be easy enough to solve. Pour half the required volume of oil into the motor, mark that as half way point on the dipstick, next pour the rest of the required volume of oil in except for one quart, mark that as one quart low, the add the rest of the oil , that's your top mark. You can add more marks(1/4, 3/4)if you wish but the most important marks are full and a quart low.

Thanks Kevin, good plan, will follow once I figure out the oil capacity.

Craig

Craig, no need to drop the pan. The DW pan, while shallower than OE pan appears to have a sump that is several inches longer than OE. Volume may well be in the same ballpark. The big issue is that a stock dipstick will not register correctly.

Most important rule is to not fill to a level that is closer to the crank than stock. Doing so will likely get the crank into the oil causing aeration.

I took some measurements related to the dipstick on mine today. With stock stick and stock pan, the distance from the "Full" mark up to the top of the dipstick tube is 10 inches with dipstick hitting bottom of pan. That means that with your shallower pan, the dipstick will not go all the way in to allow the "Full" mark to be in the correct location relative to the crankshaft. So, pull the dipstick and measure 10 inches up from full and mark the stick with a Sharpie. Reinstall and mark the stick right at top of dipstick tube. Remove stick and measure distance between these two marks. Now measure DOWN the stick from "Full" and mark the stick again. You may want to use a bit of paint or White-out as the oil will likely wash away Sharpie ink. That line is your new "full" mark. You are now ready to see how much oil it takes to get to the new full mark OR to see how high up the stick the standard oil fill quantity gets you. You may want to stop a quart or two short and crank the engine with ignition disabled so that the filter gets filled. Let the engine sit to allow for any drain back. It is, up to you to decide whether to stop at 8 quarts or go all the way to the new "full" mark.

Once you have done this and decided which level you want to use, you can trim the end of the dipstick until the "full" mark coincides with your chosen oil quantity/level.

Thanks Craig, I like it. Took me a couple of times reading to get your meaning (my issue, not yours) but the light went on. We are attempting to maintain the distance from the top of the dipstick tube to the level of the oil in the sump, right? Once I get that, and mark the dipstick I can add oil to get to that point. When oil begins to show on the dipstick, I'll keep track of how much it goes up per quart, then measure back down that distance from the full mark for new "quart low" mark.

Much appreciated,

Craig

Hi Craig , I have recently fitted an alloy sump and after careful measuring of the oil quantity , 7.5 litres
I now use the low mark on the dipstick as the full level . very simple and very lucky !
I did have problems with the gasket clearance , resulting in 140 psi oil pressure which was sorted out , see an earlier post.

I may be missing something but since the full line on the stock dipstick is where, in a perfect world, you want to run your oil level; Isn't this just as simple as seeing how much the dipstick is sitting above the top of the tube when it hits the bottom of the DW sump and cutting that amount off the bottom of the stick? Fill the sump to the full mark and you would avoid crank aeration and have the maximum amount of oil you can have, giving the standard clearance from the crank. Measure what you put in to get there and you know your capacity.

---

Jon Robbins
1956 BN2
(Do it all youself, you'll be glad you did)

Jon: I think you are right, just a matter of shortening the dipstick by the additional amount it sticks out of the top of the tube, BUT, I wasn't sure if the DW sump with its' baffling and different shape might have a little lower (or higher) level than the stock one. Seems safe enough though to keep the distance from the top of the dipstick tube to the top of the oil in the sump the same as with a stock sump. I did inquire and was told the oil capacity is the same as stock, but it was good to have that confirmed here as these are the guys who sold me a plastic fan that collides with their damper which has the TDC mark about 40 degrees away from the little arrow on the timing cover when the motor is at TDC. This is my first attempt assembling a 100 motor with mostly aftermarket rotating and reciprocating parts. Still will be tempting if the sump happens to be off the motor again to pour oil in and see what it takes to fill it.

Hi Craig, I fitted a Denis Welch alloy sump to my 100 but did not have a problem with the dipstick length (I’m getting worried now and will make a check), mind you the dipstick did foul one of the baffles which I had to cut the let the dipstick go fully to the bottom of the sump. Cheers Eric