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08-21-2012, 09:46 PM | #1 |
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Oil pressure dropping on right turns
Last year I had an engine rebuilt with all the "good stuff", balanced, full pressure, insert bearings, etc... About a week ago I added an oil pressure gauge and tach under the speedometer. I've noticed that on a sharp right turn, the oil pressure drops from 35 psi to under 10 psi. Has anyone had a similar problem and how did you get around it? On my Lotus, I had to make a baffled trap door pan and run a quart over. Seems a little overkill on a Model A. I don't have to be going fast for this to happen. As soom as the oil sloshes to the left side the pressure goes away.
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08-21-2012, 10:17 PM | #2 |
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Re: Oil pressure dropping on right turns
fordgarage:
Good thought but I get dizzy if I only turn in one direction! Thanks Dick |
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08-21-2012, 10:19 PM | #3 |
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Re: Oil pressure dropping on right turns
nice one fordgarage! two wrongs don't make a right, but three lefts do!
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08-21-2012, 11:08 PM | #4 |
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Re: Oil pressure dropping on right turns
Is the oil on the full mark of the dipstick? Maybe you are turning too quickly, Elliot Ness wasn't after you was he?
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08-21-2012, 11:32 PM | #5 |
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Re: Oil pressure dropping on right turns
when you turn right, the momentum would carry the oil to the left side of the oil pan. The oil pump is on the right side. So it would make sense. I don't think it's anything to worry about. Your engine won't starve of oil if you make a right turn.
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08-22-2012, 06:08 AM | #6 |
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Re: Oil pressure dropping on right turns
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08-22-2012, 06:21 AM | #7 |
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Re: Oil pressure dropping on right turns
Drop the pan and install a baffle in the sump of the pan that is hinged.
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08-22-2012, 07:07 AM | #8 |
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Re: Oil pressure dropping on right turns
Thanks, I am going to add another quart first. This is a full pressure system so there is no oil in the chamber to run down into the mains. I don't have to make a fast turn at all. If that doesn't work I will probably make a hinged baffled pan as I did on my other car. AND three positives don't make a negative? Yea, yea, yea.
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08-22-2012, 09:28 AM | #9 |
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Re: Oil pressure dropping on right turns
Add the trap door, as Brent suggested, or build a road race pan. Dick, your engine
pressurized, 35 pounds? |
08-22-2012, 10:10 AM | #10 |
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Re: Oil pressure dropping on right turns
Yes, It has a new high capacity pump with a built in 35 psi relief valve. I wonder if I would still need the original tray or if that may be keeping the oil from returning as quickly as possible? Anybody have plans for a road race pan?
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08-22-2012, 10:10 AM | #11 |
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Re: Oil pressure dropping on right turns
i have had the same problem . my motor has a "v8" pump . on rt turns it will lose most of the oil pressure . i have installed one way gates (as in race cars) but still does it . the problem with mine is the v8 pump is higher than the stock pump was . next time i drop the pan , i am going to build a lower pick-up . for now i just go a lil slower on rt turns ... hope this helps .............
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08-22-2012, 11:14 AM | #12 |
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Re: Oil pressure dropping on right turns
Dick,
I have built pans on and off since the mid 70s, not hard just time consuming for a proper job. Look on line/ebay at road race pans for images inside the pans. The gates, trap doors, are made from piano hinge(light weight, 20 gauge), with welding rod for the hinge rods. The gate opens no more than 45 degrees, and move very freely. Dudley |
08-22-2012, 12:37 PM | #13 |
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Re: Oil pressure dropping on right turns
I think that Urb Stair went in to this in detail in the secrets of speed journal in the ninties. On a sharp right turn the oil is pulled away from the pump. He constructed a baffle around the pump and recommended running seven quarts of oil. I tried running seven quarts of oil in an unmodified engine. Without special rear main seal it doesn't work well. The coupe left a trail of oil when run with seven quarts. I figured I was better off running five quarts and not having to appologize for the leaks.
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08-22-2012, 04:31 PM | #14 | |
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Re: Oil pressure dropping on right turns
Quote:
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08-22-2012, 04:49 PM | #15 |
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Re: Oil pressure dropping on right turns
Is this the baffle that is being described?
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08-22-2012, 04:58 PM | #16 |
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Re: Oil pressure dropping on right turns
That '31 baffle keeps the dipper tray full on hard lefts, necessary if you do not have a cross-drilled crank. It does nothing to address the problem described. You need a lower baffle in the sump, a relocated pickup point, or a pivoting pickup to keep the pump fed constantly.
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08-22-2012, 07:34 PM | #17 |
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Re: Oil pressure dropping on right turns
MikeK:
I'm not sure what is in there, I was only saying the chamber is not full like a regular "A" engine. The bulk of the oil has to come from the pressure system. Dick |
08-23-2012, 09:50 AM | #18 |
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Re: Oil pressure dropping on right turns
L-head ngines that are not designed for hydraulic lifters generally have no organized oiling system for the valves. Cam/lifter area is continually splashed by oil departing the reciprocating and rotating parts, upstairs gets some splash and lots of oil fog.
In a Ford flathead V8, leaving out a minor baffle in the valley floor will generally cause oil burning...suggesting that stock non-system is feeding the stems all they can handle. |
08-23-2012, 10:26 AM | #19 | |
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Re: Oil pressure dropping on right turns
Quote:
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08-23-2012, 03:01 PM | #20 |
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Re: Oil pressure dropping on right turns
Yes! That would permit oil mist from the crankcase to flood the chamber. Something that is NOT happening on an A that has been converted to pressure. Adding those large holes would be an excellent idea.
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08-23-2012, 09:41 PM | #21 |
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Re: Oil pressure dropping on right turns
The holes are something to think about if I ever have the engine apart again. I would think it would be a job to get all the chips out if I tried to do it in place. I am going to have to talk with the builder and find out exactly what he did in there - or pull the side cover off and look.
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08-23-2012, 10:11 PM | #22 |
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Re: Oil pressure dropping on right turns
Years ago,I built up an"A"block with a 33 C crank fitted with 1-11/16" mains & heavy steel front & centre main caps.I used a special oil pump with 8BA gears& pressure relief valve.It ran about 50#oil pressure with a drilled C S.I had also drilled several 5/8"holes in bottom of valve chamber.I used NO dipper tray & it ran great & did not drop oil pressure when making RH turns.I was also running an original 2-port Riley & large zenith updraft on it.Wish I had kept it as it was around 80 HP.
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04-28-2014, 09:37 AM | #23 |
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Re: Oil pressure dropping on right turns
I know this post is a little late, however, I just finished making a trap door baffled oil pan. I put it in about two weeks ago. There is no dipper tray as the engine has a full pressure system. I am using the Stipe oil pump. I got the starting ideas for this from Jim Brierley's book.
On the trip to Hellertown last Saturday, I could not see any drop in pressure no matter how hard I went around right corners or the highway exit ramps. Thanks to all who have posted suggestions to me. Thanks Dick
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1965 Lotus Elan S2 1930 Model A Sport Coupe Last edited by bettlesr; 04-28-2014 at 09:38 AM. Reason: spelling |
04-28-2014, 10:04 AM | #24 |
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Re: Oil pressure dropping on right turns
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04-28-2014, 10:08 AM | #25 |
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Re: Oil pressure dropping on right turns
Buy Jim Briarley's book, Bangars and me.
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04-28-2014, 10:28 AM | #26 |
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Re: Oil pressure dropping on right turns
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It's different, overseas, you would be in trouble ! MIKE (mikeburch) |
04-28-2014, 01:58 PM | #27 |
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Re: Oil pressure dropping on right turns
Hey Dick,
Thanks for the great follow up and pic , better late than never...they say ! Yeah, I agree that Jim B book has done a lot to help people in this 'hobby' ! I'm wondering, after reading entire thread, never said whether you had a dipper tray or not ? It you did not have a dipper tray when problem existed, I could easily see why problem. When pressurized , dipper tray can be left and inch sized holes drilled in tray to allow quick draining of oil to bottom of pan..then no problem. That's what I did successfully, without trap door system necessary. I would use trap doors if racing tho.. There are also adventages to leaving original tray with inch holes drilled. BTW...I bought one of original stipe oil pumps for my B...pricey, but GOOD ! Pay for quality !! |
04-28-2014, 02:21 PM | #28 |
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Re: Oil pressure dropping on right turns
Hardtimes:
It had the dipper tray when I first had the engine built and yes, the problem did exist. Ora at Schwalms put 1/2" holes around the edges of the tray. With the trap door baffles I had to remove it. When I was racing my Lotus, I not only had to run a baffled pan but also had to run it 1 qt. over full. So, when I built this, I went all the way this time. The dippers on the rods were effectivly plugged with the full width insert bearings.
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04-28-2014, 03:08 PM | #29 | |
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Re: Oil pressure dropping on right turns
Quote:
I'm going to use modified V8 flathead pump this time. I'm thinking of making sump pickup device CLOSE to pan bottom with screen. I've seen other 'varieties' for A/B pan baffle systems. Yours looks a bit different, but nice work ! Maybe copy it,eh |
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04-28-2014, 03:51 PM | #30 |
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Re: Oil pressure dropping on right turns
hardtimes:
If you need them, I have the cad drawings of the pieces I made. They required some trimming to fit the exact shape of the pan but they are close. I used 3" long pieces of 3" ss piano hinges. There is about .050 clearance below the doors so the pan drains properly when changing the oil. I also removed the hinge pin and replaced it with a thinner piece of ss wire bent it the ends to limit the hinge to swing a max of 45°.
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04-28-2014, 05:20 PM | #31 |
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Re: Oil pressure dropping on right turns
Right Mike, look at a Model T, 2 1/2" holes and no pump to begin with. There has to be some oil in the chamber or the guides will soon wear out and the valves will be really noisy. I fixed one for Pete on here that was done exactly as you describe and the guides were all worn with 2 worn our .070. Talk about some noise .
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04-29-2014, 02:23 AM | #32 | |
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Re: Oil pressure dropping on right turns
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04-29-2014, 07:02 AM | #33 |
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Re: Oil pressure dropping on right turns
My A does exactly the same thing. When cold, the low pressure lasts MUCH longer than when the engine is hot. My theory is that the pump is filling the valve chamber and the thicker oil (15W-40) takes longer to run through the overflow tube and back to the pan so the effective level at the pump is lower. When the engine is hot, it lasts only a few seconds. When cold, it can last a minute or so after a significant turn. I TRY to let the engine warm a bit before driving off... or take it VERY easy on right turns until it's warmed.
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04-29-2014, 10:39 AM | #34 |
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Re: Oil pressure dropping on right turns
I have found that the dipper tray stops the oil from surging away from the pump better than anything, because there is nowhere for the oil to "go", as long as you keep the oil level topped up properly, and keep your dipper tray in, you should have no problem.
I built a strong Model B engine with Miller OHV head, Dan Price pump, drilled crank, and ran it at 50psi with an adjustable blow-off valve. Had real headache with oil pressure cutting out on bends, specially when cold. I had tried to get clever with swinging doors and baffles. An oldtimer persuaded me to put dipper tray back in with a half inch hole drilled in each dipper groove for oil drain-back, and I never had another problem. IMO the extra volume pumps will pump alot of oil out of the pan on start up, specially when cold, and the oil sits up in the block. Why do you wait an minute to check the dip stick when you ve just run the engine? So oil level must be kept up to the top mark! Tom. |
04-29-2014, 12:35 PM | #35 |
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Re: Oil pressure dropping on right turns
The drop in pressure was noticed mostly when the car had been run for over 1/2 hour and was totally warmed up. As mentioned before, there were 1/2" holes around the tray.
The notch around the oil pump opening was for the pressure relief valve on the Stipe pump
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1965 Lotus Elan S2 1930 Model A Sport Coupe Last edited by bettlesr; 04-29-2014 at 12:36 PM. Reason: Added last sentence |
04-29-2014, 01:01 PM | #36 | |
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Re: Oil pressure dropping on right turns
Quote:
Hm, thanks for this picture. Those 'holes' are not what I was talking when mentioned previously. One inch holes in 'bottom' of each dip area is what I was saying. That drops all oil quickly to bottom as opposed to what is there. It worked for me on the present B in my '30 with stipe pump. Unless I'm missing something, do not see how those small holes in those locations...will help. Last edited by hardtimes; 04-29-2014 at 01:06 PM. Reason: ,,,,,,,,, |
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04-29-2014, 01:13 PM | #37 |
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Re: Oil pressure dropping on right turns
hardtimes:
As I had the problem with them there, NO, they didn't help. The original pan on my old engine had 1/4" holes in the dipper area with a stock oiling system. They really didn't help. Got about 5 highway miles before the babbit parted company with the rods and mains. Should have dropped the pan before we ran it on the street! Interesting thing, when I put it back together, I used plastigauge to check the clearances and found the plastigauge had dented the babbit more then the plastigauge was squished. I guess it was a soft alloy. That engine had been rebuilt pre-1950. Last registration was 1952.
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