Excel/Barefoot 454 oil pressure drops after 4k RPM |
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dave12gauge
Newbie Joined: April-06-2015 Location: California Status: Offline Points: 34 |
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Posted: June-07-2018 at 2:49am |
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1991 Excel with a rebuilt 454 with high volume oil pump running 20w-50. Does anybody notice that after 20-30 seconds at 4000 rpm or more your oil pressure gets erratic. Oil pressure is a solid 70psi and then it will drop to as low as 30, then back up to 50, back to 30ish. Just bounces around but will not go back to 70 until I get off the throttle. Electric gauge and mechanical gauge in two different ports on the block. It happened with the oil in the middle of the two marks on the dipstick and just above full on the dipstick. My guess is the oil is staying in the top of the motor and its sucking up some air with the sump being almost dry. The water was almost glass so the motor was staying nice and level.
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dave12gauge
Newbie Joined: April-06-2015 Location: California Status: Offline Points: 34 |
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Sorry, can't figure out how to change topic to "Engine Repair". Can someone move it for me. Thank you
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Did it have the same pump before the rebuild?? Sounds like it is starving for oil
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Keep it as original as YOU want it
1978 Mustang (modified) |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Verify the pressure with mechanical gage before tearing engine apart.
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10652 |
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Read what he said in post number 1
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21109 |
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Mark iv or gen 5? Which 2 ports are you using? I think you’re saying that both electrical and mechanical gauges agree 100% of the time?
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10652 |
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It looks to me like you rebuilt the engine in 2016, meaning it ran all last season so has it always had this issue since the rebuild or is this something that just started happening recently?
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4232 |
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Not sure why you went with a high volume oil pump, stock pump should move all the oil you need. I'm wondering if the high volume pump coupled with the 20W50 oil is pumping all the oil from the pan to the top end, and not draining back fast enough. This is a known problem in other older V8's, not normally a problem in 454's as far as I know.
Could be a problem with the oil pickup as well, for some reason not pulling oil once a quart or two is pumped out of the pan. |
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'63 American Skier - '98 Sport Nautique
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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I’m wondering if it might be one of a few things;
1) pickup tube too close to bottom of pan (starves) 1a) pickup too far from the pan—leaving too much behind 2) Windage issue (froth from crankshaft) 3) drainage back to pan slower than pump pickup Why not pull pan and see what’s going on? I know—no fun pulling engine mid-season—but there may even be some gasket goop on the screen. Hope it’s something simple and easy to fix!!! |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3327 |
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Thats a lot of work
how about putting in more oil and see if it improves, thats a 4 dollar 5 minute test |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4232 |
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He said he has the problem with the level a bit over full, so I don't think adding more would be a good idea, would possibly cause Peter's #2 above, windage, might froth up the oil. This is assuming the right dipstick is in place.
I agree, lot of work! I think before pulling the engine I'd do an oil change and go to 10W30, maybe even (dare I say it!) 5W30 given he has solid oil pressure. For the price of a change it might prove if it's a drainback issue or not. |
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'63 American Skier - '98 Sport Nautique
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tryathlete
Platinum Member Joined: April-19-2013 Location: Lake Villa, IL Status: Offline Points: 1797 |
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I really like this idea! |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Think he needs to answer the question of "when did this start". Adding more oil can open a new can of worms. Such as aeration due to the crankshaft journals whipping the extra oil airborne. (Hense the value of windage trays in the pan) High volume pumps are OK if you prepare the block and heads for them. That means de-burring the oil return passages and painting all the insides with Glyptal electrical insulating paint. That speeds the rate of oil return to the pan. Also high volume pans, but that may not be an option here. If he gets back and answers the question above then we will know more. Need more info. Kinda like telling the Doctor that your foot hurts, failed to tell him you dropped a brick on it!! |
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Keep it as original as YOU want it
1978 Mustang (modified) |
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KENO
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Riley
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From reading Ken's article, it sounds like the pick up clearance could be too tight. I've read a lot of stuff during the past few years regarding HV pumps on Ford engines and it's a bit like discussions about oil brand, weight or ZDDP.
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dave12gauge
Newbie Joined: April-06-2015 Location: California Status: Offline Points: 34 |
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I was afraid if my first post was seven pages long nobody would read it. Here it goes. Engine was rebuilt by a machine shop with years in the business and millions of $ in equipment. 2016 was rebuilt with standard volume oil pump, he had the cam recut (I didn't notice much difference from stock), bumped up the compression to about 9.0 ratio. Mid summer my low oil pressure light would come on at idle. He said it must be a bad oil pump.
2017 season had a new high dollar high volume oil pump. High RPM my oil pressure would dip to 10 PSI and bounce around. Ran the boat for the rest of the season but I would not go over 3000 rpm and oil pressure was always good. (Before assembly, I did see the cam broke in nice and the crosshatching still looked good. He also pulled a rod and main so I could see and it was smooth and bearings were not worn. He said only one bearing had one slight line in it and the rest were perfect). 2018 Pulled motor again and he found the cam bearing installed were a manufacture defect (thats what I was told). He found this by pressurizing the block without the oil pan. So he installed new cam bearings and re-pressure tested and was able to see all the oil dripping evenly throughout the motor. The motor I gave him was a running motor. I never really ran the motor at full throttle for very long, so I don't know if this oil pressure bouncing around happened in the old motor. I suspect not, because this is a barefoot boat and I would guess that it should run at high rpm for a long time. From your comments it doesn't look like your motors do this. I even told him that the high volume oil pump might do this because of last year bouncing around, but he said if I want the standard oil pump back in it he wouldn't warranty it. Im glad the cam bearings are fixed, but I still can't run the motor the way it was designed 28 years ago. I used to know what motor is was, but I forgot. Mark IV I think. Oil temp about 210 at the pan and oil filter but I did get it as hot a 235 at the pan and filter. Electric gauge is in its normal spot above the oil filter. My mechanical gauge is T from the back of the motor where the Oil pressure switch for fuel pump safety (I believe that what that switch does). The hose was bleed. Water temp 160. Hot idle in neutral about 24psi. I did ask each time they had the motor apart about the pick up distance from the pan and I was told it was good. A 30 viscosity oil has me a little worried because of hot idle oil pressure. (in gear idle is about 20psi). He built the motor on the fat side of the tolerance. He also told me to run 20W-50. Long story long, your BBC oil pressure does not bounce around? Next stop is to talk with the builder again and tell him that your guys boats do not do this. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21109 |
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I would prefer to see mechanical pressure measured elsewhere in the oiling system- back in the filter area (if it indeed is a mark iv, I am not as familiar with the gen5 oiling), the pressure reading can be affected by the bypass valve actuation (ie you may only be seeing oil pressure in a certain path, which is NOT the same as total pressure).
Do you have a remote oil filter mount or anything else that would change the set up of the oiling system? Is the original stock adapter (with 11psi bypass) still in place? Something is amiss but not necessarily a bottom end/ oiling /clearance problem. |
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63 Skier
Grand Poobah Joined: October-06-2006 Location: Concord, NH Status: Offline Points: 4232 |
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I'd also say I think the low oil pressure at idle does not necessarily mean a bad pump. You really only need 10-15 psi at idle to be healthy, as long as the pressure rises quickly as you add throttle. So I have a feeling you could have run with the stock oil pump which wasn't giving you the high rpm drop without any problem, assuming at idle it wasn't dropping to below 10 psi.
I run a 454 in a jet boat. Oil pressure is rock solid running 20W50 Valvoline VR1. Idle is 30 psi or more, tops out I think around 60 psi. The only time I saw a high speed pressure drop was when I ran more than a quart low, it eats a bit of oil and I let it go too long without checking. I'd add this is a healthy but somewhat tired engine at this point. Bottom line - 454's are durable engines that don't tend to have oiling problems. You should be able to run it at WOT for a bit, or 4000 rpm continuous, with no drop of oil pressure. Not bashing your rebuilder, but an oil pressure problem on a freshly rebuilt engine should be his problem, not yours. |
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'63 American Skier - '98 Sport Nautique
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Not comfortable with what is being said here. Bearing defect?? Sounds more like installation defect. (ie: oil holes not lined up) 24psi at hot idle does not scare me Stick with 20W50 oil.. Was the stock oil pump tested?? Likely not Pickup clearance is OK *** what is OK?? |
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Keep it as original as YOU want it
1978 Mustang (modified) |
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dave12gauge
Newbie Joined: April-06-2015 Location: California Status: Offline Points: 34 |
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Oil filter is on the block with no remote or cooler adapter. Not sure is the stock adapter with 11 psi bypass is still in place.
As far as the oil pressure gauges are concerned, they are both doing the same thing so I'm not real confident putting a gauge in a third location would show anything different. Last year and this year I can drive around under 3500 rpm and everything looks going and both gauges doing the same thing. 4000 rpm or 4600 rpm oil pressure is nice and solid and steady then it just drops at about 20 seconds into high rpm. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21109 |
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2 pressure readings in the same spot confirm you are measuring correctly. But they don’t confirm you are measuring the correct thing.
Either your high rpm oil pressure isn’t really 10psi or you have big time problems. If it is bi-modal, then something isn’t quite what it seems. It sounds like your bpv may be in actuation, a measurement elsewhere in the oil system would confirm. There are several oil galley plugs further up the side of the block. |
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dave12gauge
Newbie Joined: April-06-2015 Location: California Status: Offline Points: 34 |
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I'm with you about the bearing defect. Oil pump probably was not tested and he did not tell me. Concerning the hot idle oil pressure, I would think my pressure would go to the teens with 30 viscosity oil, probably would be ok but thats up to the builder.
'Not bashing your rebuilder, but an oil pressure problem on a freshly rebuilt engine should be his problem, not yours." my thoughts exactly. In the end, I think the motor will have to come out again. Can I run the engine with the transmission in neutral at 4000 plus rpm on the trailer without hurting anything? Would like to see if it still happens with the motor still. Does anybody have a picture of the inside of the oil pan? Also, can someone post a picture of the outside of the pan. Just want to confirm that my pan wasn't changed at some point. |
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tryathlete
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Ha! Good thinking. If the oil pressure is read back of the 11PSI relief it would bounce. |
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tryathlete
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Engine goes back to the builder in my book. It’s acting screwy and it ain’t your fault.
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dave12gauge
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The electric gauge is in the stock port near the oil filter. Mechanical gauge is out of a port on the block near the distributor. What would be the best spot to have another gauge? |
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oldcuda
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Think the spacing on the pickup is to close to pan. The high volume pump would be a bit longer making it necessary to readjust pickup. That pump requires the pickup be a little higher from pan. Stock would be 1/4 -3/8" now I would be comfortable with 1/2" checked with modeling clay or steal some of the kids play dough. Make sure the pickup is tacked.in place.
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TRBenj
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Believe the dizzy oiling plug is gen5/6, not Mark iv. |
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dave12gauge
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Talked with builder and he is going to try to get a camera up into pan. He said the pickup tube is 3/8" from the bottom. He is going to take the boat to the lake and try to figure it out. Maybe he is just going to the lake to pull the plug. It is a Gen5 motor.
I still would like a picture of an oil pan just so I know that mine was not changed and should have the correct windage plates/ baffles. |
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dave12gauge
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Was there a baffle welded to the bottom of your 454 oil pan? (My windage plate is still bolted to bottom of block.)
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KENO
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Here's a picture of the baffle from a thread here on CCF a while back.
It's been a while since I could see the inside of mine but that sure looks familiar |
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