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Author
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Topic: Oil pressure problem
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1trickpony
Gearhead Posts: 107
From: Escondido, Ca
Registered: Oct 2001
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posted 10-24-2001 10:43 AM
  
ya guys. I have a '69 390 in my Mach 1 that I recently had rebuilt. I have done all the oiling passage tricks to it already. I have a set of comp cams roller rockers and shafts. I only have about 2600 miles on the engine. Now to the problem. My oil pressure had been a nice steady 60 psi cold and 40 hot. The other day I pulled off the highway on my way home from work and I got stopped at a red light. I glanced over at my pressure gauge and my pressure had dropped to about 10 psi at idle 20-30 at speed. Now, I have had an issue in the past where the end plugs on the rocker shafts had fallen out. So, I pulled the valve covers and checked them, hoping that was the case again. Nope. Both end plugs were in both place on both sides. Yesterday I pulled the pan and checked the pump out. I found that the pump did not have correct tolerances, and some funky wear marks on the impeller, so I swapped it out for a new one. same problem. All of a sudden I have a low oil pressure problem. I would suspect galley plugs but they are tapped and threaded in, not to mention that if one had fallen out of the rear of the block I would see a hellacious external leak and not have any pressure at all. I pulled the distributor to see if the front galley plug may have come out internally, nope it is still in place. I pulled the filter adapter off to see if maybe the gasket had blown out and I was getting blow-by between the out and in holes. That is also not the case. I do have a remote filter and cooler set up on it with stainless steel braided hoses. I can't see it being the bearing tolerances due to the fact this is a fresh motor. I am not getting any unusual engine noises. Oh yeah I even tried 2 other gauges just to see if I had a faulty one. This morning I removed the driver side rocker cover and ran the motor. With the cover off I can hear the lifters on #5 tapping a bit. I am getting oil flow to the shafts but it is not as strong of a flow as it should be. Now, I am concerned because I know the lifters get oil before the shafts do. At this point I am stumped. I would appreciate any opinions you guys have as to what could cause this.
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steve'66
Gearhead Posts: 6352
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 10-24-2001 10:50 AM
Have you changed the oil filter yet? Is it a Fram?If that's not it, you may have spun a bearing. 
SteveW
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1trickpony
Gearhead Posts: 107
From: Escondido, Ca
Registered: Oct 2001
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posted 10-24-2001 10:53 AM
quote:
Originally posted by steve'66:
Have you changed the oil filter yet? Is it a Fram?If that's not it, you may have spun a bearing.
SteveW
Yes, I sure have. I have changed the oil 3 times since initial starup. I refuse to use a Fram filter as they are horrid. the only filters I will use are made by Wix and bought at Napa. I am thinking it is a spun bearing as well, but the big question is why would I have spun a bearing so soon on a freshly built engine? Especially after going through what I did to ensure I wouldn't have any oil problems which are so typical of an FE.
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 10-24-2001 12:42 PM
If the clearances are not 100% on an FE, they will spin bearing quite easily. I would pull the pan and check the play in the rods. Welcome to M&M by the way  ! Alex  ------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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1trickpony
Gearhead Posts: 107
From: Escondido, Ca
Registered: Oct 2001
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posted 10-24-2001 05:40 PM
quote:
Originally posted by Moneymaker:
If the clearances are not 100% on an FE, they will spin bearing quite easily. I would pull the pan and check the play in the rods. Welcome to M&M by the way ! Alex
Thanks for the welcome!
I suspect that my stock oil pan was the cause of the problem. I believe it allowed the sump to run dry for a short time which in turn damaged a main rod bearing. Probably #5 main and or #7 rod. I am pulling the pan back off on friday and will be replacing the main and rob bearings more than likely as well as installing a new oil pan/pick-up I just got from Milodon. I am just praying I did not do any damage to the crank or rods themselves and it will just be a matter of new bearings.
*crosses fingers and toes*
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n2oMike
Gearhead Posts: 1511
From: Spencer, WV
Registered: Jan 2001
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posted 10-24-2001 06:02 PM
FE engines that are run hard like plenty of bearing clearance. When you take the crank to the machine shop, have them cut it to the LOW (loose) side of the tolerance. Some machine shops stop cutting the crank as soon as it comes into the tolerance range. This often leaves the bearings too tight. Make sure they go to the low side of the "spec". Do this, get a high capacity pan, and run a good street oil... such as Mobil 1 15w50. Avoid the really thin or thick stuff. What may have happened is... some grit from the oil passage modifications might not have gotten cleaned out. This would slowly grind away at the crank and bearings. Oil filters have bypasses in them... and with a high flow of oil, only a fraction actually goes through the filter media. The thicker the oil, the more gets bypassed. For this reason, I like to break engines in on a thinner oil. The exact same thing just happened to a buddy on a 383 chevy stroker. It spun the #1 bearing after only a few hundred miles. It just barely turned in the rod. You couldn't even hear it until around 3500rpm... and at that, it just sounded like a valvetrain noise. BUT, remove the plug wire to that cylinder to take the load off, and the noise disappeared. From first inspection, it looks like the crank can be salvaged. It looks like it can be turned-out just fine. Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 10-24-2001 06:17 PM
The oil pan had nothing to do with it my friend. Mike is correct as I'm sure that I am that the clearance was too tight. You may have had a a starvation problem, but the pan was not the culprit. NHRA/IHRA stock eliminator FE's are required to use "STOCK oil pans and they turn upwards of 7500 RPM. The engines live for over a hundred or more runs. Looser clearance, a Melling HV oil pump and good oil (Mobil 1 would not be MY first or second choice)should keep you FE in good lubrication status. ------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link [This message has been edited by Moneymaker (edited 10-24-2001).]
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1trickpony
Gearhead Posts: 107
From: Escondido, Ca
Registered: Oct 2001
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posted 10-24-2001 07:21 PM
*nods*
Ok, I have to agree with you guys. I also think a bit more background info is in order. When this engine was built I specifically requested looser tolerances just for this reason. This is not the first 390 I have built. I have learned most of these lessons on the previous incarnations of this engine. I have owned this car for 13 years now and this is/was the 3rd rebuild on it. As a matter of fact I have my original block mothballed because I did not want to take a chance on ruining it. This car has run high 12's before (with Comp TA R-1's at that) even though it is really set up for road racing. I have an Edel perf on a prof built Holley 750 duel feed double pumper. My cam is a .560/.560 292/[email protected] 110 Lobe sep Comp Cams Cam with the Comp Cams roller shafts and rockers (restrictors installed in heads). 410 pistons on worked rods and crank. The heads are sporting CJ valves and it is port matched and the ports are all opened up with some compression chamber work as well. The car is lowered all the way around and the suspension is all tweaked out (ie: subframes, panard bar, gucci springs etc). I have a roll cage in her as well. Now the only reason I blame the pan in this case is not because it is a stock pan. It is because this particular pan had recently been bottomed out on some of the lovely speed bumps that inhabit the parking lots locally. This is something I hadn't realized had happened. My scattershield and bottom of the drivers side header are usually what end up hitting on anything. Of course, I take speed bumps slow and at an angle when possible but even as carefull as I am I cannot help but have something from hit from time to time as I pass over them. Now, when I noticed the oil pressure was low I looked at the pan and saw an indentation. it was pretty obvious that the distance between the pick-up and the pan had decreased. That is what I thought the whole problem was initially, was that the pick-up was restricted due to this. When I took the pan off the other day and beat the dent out of it I replaced the pump at that time. It didnt look like the pan had actually ever come in contact with the tube but that was when I noticed the wear on the impeller of the pump. Since I had the Milodon pan and pick-up on order anyways, I am going to install them in place of this beat up stock pan. I do also plan on getting an accusump(sp?) as soon as I can afford one because when I am in a long hard high g left hand turn on the track all my oil gets crammed into the upper passenger side of my engine. That is another bonus of the new pan is the baffling. I already have a windage tray installed as well. Although I do not have extra holes in it or opened up the existing ones yet. I do appreciate you guys helping me out with this. i have already learned some new stuff from reading htis forum and from you guys have said.
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Moneymaker
Administrator Posts: 19686
From: Lyons, IL, USA
Registered: May 99
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posted 10-25-2001 12:33 AM
That will do it for sure. I have seen many a dented pan sump cause oil starvation. ------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link
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Ryan Wilke
Gearhead Posts: 1450
From: Stanton, Michigan 49707
Registered: Oct 2000
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posted 10-25-2001 12:21 PM
OK guys - I'm the dummy.... How does a dented pan cause oil starvation????
1 guess: Did the dent cause the pickup to come loose from the pump and suck air at the pump? 2 guess: Did the pickup get pushed up and out of the oil level? 3 guess: Did the pan-to-pickup clearance disappear, causing the pump to cavitate? ...or did I miss it completely? Help me understand!
Thanks, Ryan [This message has been edited by Ryan Wilke (edited 11-03-2001).]
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