Ford 302 engine oil dipstick - 1995 OMC Cobra, Ford 302, VolvoSX

I may put what the manual says and monitor oil pressure to ensure I’m not getting oil aeration. It’s been running fine for years with my current approach.

On the GM engines the automotive location for the dipstick was on the starboard side of the block and when these systems for the tube that connects to the pan are used the hole for the dipstick is filled with a rubber plug. On then it’s possible to add an automotive style dipstick; not sure if you could do that with the Ford engines…..

Lou C said:

On the GM engines the automotive location for the dipstick was on the starboard side of the block and when these systems for the tube that connects to the pan are used the hole for the dipstick is filled with a rubber plug. On then it’s possible to add an automotive style dipstick; not sure if you could do that with the Ford engines…..

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Thanks Lou, Since realising the dimples on my stick are where oil level should come to if I put in the quantity that's correct according to the manual I'm happy just filling to the dimples. As you know, the engine is relatively newly rebuilt, it doesn't seem to use or lose any oil between changes anyway.

The thing that got me wondering again about oil levels is when I first used the boat on the sea a month ago, up until then I'd only used it on a river and lake. I launched into calm water in a tidal estuary and let the engine run a few minutes to warm up and check gauges etc before heading out to sea. Heading out to sea there was some chop at the mouth of the estuary, hit a wave at around the same time I was putting power on causing the bow to rise up probably higher than it's risen on the river or lakes. I was watching the oil pressure gauge when the bow came up, pressure dropped to zero then immediately up to way high, bounced like this very quickly just a couple of times... This was a bit alarming in the dangerous stretch of fast flowing choppy water, I very quickly throttled down but I think oil pressure was back to normal even before I'd throttled down. The oil pressure reading stayed around normal the rest of the time, it never bounced like that again but did seem a bit low after first slowing down after half an hour on the plane. All this got me thinking again about how much oil the book says it should take and how I'd put in less than that to not go far above the safe area on the stick. After that trip on the sea I pumped out the straight 4 or 4.5 quarts of straight 30 oil, changed the filter and refilled with 6 quarts of 20/50. Only been on the river since but oil pressure seems a bit higher all the time now, even on returning to idle after being on the plane, and I suspect if I'd had the 6 quarts of 20/50 in it at the time the bow came up in the estuary oil pressure would've remained normal then too. I think the engine didn't get oil for a split second due to the smaller quantity sloshing away from the oil pickup tube when the bow came up.

Higher oil pressure is also likely due to the heavier weight oil. I see ~ 15PSI more pressure at idle after a hard run with 10W40 synthetic than I did with SAE30 conventional break in oil.

kd4pbs said:

Higher oil pressure is also likely due to the heavier weight oil. I see ~ 15PSI more pressure at idle after a hard run with 10W40 synthetic than I did with SAE30 conventional break in oil.

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I agree, I ran it with 20/50 last year and oil pressure after a hard run was higher than with the straight 30, even when I only had 4 / 4.5 quarts in it in both cases. But with more of the 20/50 in pressure seems to stay higher after a hard run than it did with the smaller amount of 20/50 last year. No doubt in my mind my oil pressure stays higher after a hard run with 4.5 quarts of 20/50 in it than with 4.5 quarts of straight 30 in it but I think it stays even higher with 6 quarts of 20/50 in it. Maybe the extra oil keeps the oil a bit cooler?

kd4pbs said:

10W40 synthetic

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Is that fully or semi synthetic?

I think I used to see a much wider range of oils than seem to be available now. These days it seems most stuff is 0/30, 5/30 synthetic, even some 10/40 semi is labelled as 'classic', then there's the really old stuff like 20/50 mineral and straight 30 or 40. Think I used to see a wider range including 10/40 synthetic.

Here it’s driven by government mandates for fuel economy but none of the oils that are for fuel economy are adequate for inboard marine engines under constant load. The ones I’d use are 20/50, or the Mercruiser/Quicksilver 25/40 or their best which is the 25/50 syn blend. The 20/50 is much cheaper. If you do an oil analysis you’ll see if it holds up in your use.

Lpgc said:

Is that fully or semi synthetic?

I think I used to see a much wider range of oils than seem to be available now. These days it seems most stuff is 0/30, 5/30 synthetic, even some 10/40 semi is labelled as 'classic', then there's the really old stuff like 20/50 mineral and straight 30 or 40. Think I used to see a wider range including 10/40 synthetic.

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10W40 synthetic. Rotella T6. Thankfully the EPA has yet to really ruin diesel engine oil, and while it's more expensive, there's no reason I have found to not use it in a non-catalyst gasoline engine.
Yeah - I imagine the pressure is related to a lower temperature due to more oil. There would be virtually unmeasurable pressure increase due to a higher static level causing the pump to have more head due to not having to pump as high above the reservoir of oil.