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1977 Dodge 400BB sudden oil pressure loss
01-13-2013, 05:07 AM
#31
If the new pumps have been disassembled and inspected, and appear to be fine, put one back in and see if you get the magic 3-4 weeks of normal operation. I'm betting the problem has nothing to do with the pump, but something you encounter when changing the pump. Are you putting new filters and fresh oil in every time you change the pump? What's the condition of the used oil? When the engine goes to zero oil pressure do the lifters clatter? Could there be an issue with his gauge, and the engine's been fine all along? I can't wait to hear what the problem is.
01-23-2013, 08:41 AM
#32
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Good morning Gents,
The only place local that has been able to get these pumps for me has been AZ and to my knowledge, they're all Melling pumps.
Mr.4Spd:
I have used nothing but new Wix Gold filters and fresh NAPA 10w-30 every time. The oil comes out as new as it went in; as I posted previously, you could literally eat your chili out of this oil pan because this motor is so clean. I've been using the oil in my old F-150 and Bronco because it comes out so clean.
Updates for the past week:
I borrowed a new pump from the local AZ and did a comparative of dimensions with one of the "failed" pumps. Everything was the same (+/- .01"). I put two of the mic'd pumps back in and it is getting no oil pressure whatsoever. The valve clatter is deafening. I tried my priming tool I made up to no avail now so it has to be a blockage of some type.
So, I'm pulling the engine. There's no alternative at this point. Either the previous owner dropped something into the engine that is blocking a passage or the current owner spun/partially spun a bearing being stupid. Oh well, it his dime and I warned him plenty of times.
Thanks again gents, I'll keep you informed.
-C.R.
The only place local that has been able to get these pumps for me has been AZ and to my knowledge, they're all Melling pumps.
Mr.4Spd:
I have used nothing but new Wix Gold filters and fresh NAPA 10w-30 every time. The oil comes out as new as it went in; as I posted previously, you could literally eat your chili out of this oil pan because this motor is so clean. I've been using the oil in my old F-150 and Bronco because it comes out so clean.
Updates for the past week:
I borrowed a new pump from the local AZ and did a comparative of dimensions with one of the "failed" pumps. Everything was the same (+/- .01"). I put two of the mic'd pumps back in and it is getting no oil pressure whatsoever. The valve clatter is deafening. I tried my priming tool I made up to no avail now so it has to be a blockage of some type.
So, I'm pulling the engine. There's no alternative at this point. Either the previous owner dropped something into the engine that is blocking a passage or the current owner spun/partially spun a bearing being stupid. Oh well, it his dime and I warned him plenty of times.
Thanks again gents, I'll keep you informed.
-C.R.
01-23-2013, 12:11 PM
#33
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When the pump "goes out" are you able to prime it without the filter and get oil out?
Sounds like there is something blocking the oil port somewhere in the block (near the oil pump probably) causing the pump to build enough pressure to flatten the spring. when you blocked the valve from opening it built up so much pressure it blew out the oil filter seal cause it had no where else to go since it couldnt enter the main journals if it was blocked.
I'm dealing with a 440 that suddenly lost oil pressure 10+ years ago and has been parked ever since so im really interested to know whats actually wrong here.
Sounds like there is something blocking the oil port somewhere in the block (near the oil pump probably) causing the pump to build enough pressure to flatten the spring. when you blocked the valve from opening it built up so much pressure it blew out the oil filter seal cause it had no where else to go since it couldnt enter the main journals if it was blocked.
I'm dealing with a 440 that suddenly lost oil pressure 10+ years ago and has been parked ever since so im really interested to know whats actually wrong here.
01-28-2013, 08:55 AM
#34
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Found my problem causing no oil pressure, seems the motor bent both pushrods on #3 cylinder, no idea how though. the intake lifter came out of its bore and was causing no oil pressure to get to the back of the block. Replaced the pushrods, put the lifter back in, started the engine and had 60+PSI of oil pressure at the back of the block. also changed the oil and put a new oil filter on it.
On a side note, it had a Fram PF43 oil filter on it that "according to parts stores" isnt the correct one. It was ALOT bigger than the recommended filter for it so I replaced it with a Mobile 1 version of the Fram PF43. Might have been an old racing trick to have a bigger oil filter for more capacity and less pressure drop. Dunno but obviously it works.
On a side note, it had a Fram PF43 oil filter on it that "according to parts stores" isnt the correct one. It was ALOT bigger than the recommended filter for it so I replaced it with a Mobile 1 version of the Fram PF43. Might have been an old racing trick to have a bigger oil filter for more capacity and less pressure drop. Dunno but obviously it works.
01-28-2013, 12:44 PM
#35
Seems like we missed an important piece of info !! It had a missing cyl. I think the PH43 is the one used on the later Mopars. I use the PH8 which is bigger, has more filter area Either one will work. depends on if you have the room
Last edited by TVLynn; 01-28-2013 at 12:48 PM.
01-28-2013, 12:58 PM
#36
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The guy I got the car from said it didnt rattle at all and ran good when he shut it down due to the oil pressure issue but that was 10+ years ago. yeah one cylinder was definitely not working lol.
02-18-2013, 02:15 AM
#38
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Two weeks ago I was able to get the front clip removed, then snow storms stopped work. Tomorrow, I am pulling off the valve covers and the oil pan, then the intake, and the crank caps (if I have to) to find whatever is causing my blockage.
Crashgnx: I think you are tracking what I suspect. I should find out this week if the damn snow stays away...
Crashgnx: I think you are tracking what I suspect. I should find out this week if the damn snow stays away...
05-24-2013, 03:30 PM
#39
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Found ONE of the problems, finally
Hello all, I know it's been forever BUT, my buddy finally got some budget and I finally got a chance to tear apart this 400 and guess what I found:
I think this may have been a slight problem...
What do you all think?
I'm thinking this may have contributed to the valvetrain noises and the loss of oil pressure, rough idle, etc... However, ol'boy told me neither he nor any of his employees have ever over-revved this engine. I'm calling
!
At any rate, I also found a rocker arm that did not resemble the rest of the originals.
All of this leads me to believe the original "city mechanic" replaced a rocker and Lord knows if he fished out ALL of the parts of the rocker that he replaced; I doubt it. This truck was a weed-fire truck at one time. I bet some whistle-pecker fire guy missed a shift, blew a rocker, and the city mechanic just replaced the rocker, dumped out what he found in the oil pan, put it all back together, and prayed for the best until they auctioned it off...
I also discovered that there were (3) different types of SOLID pushrods in this engine; I thought hydraulic systems used hollow pushrods, am I wrong on this year/make/model engine?
I have informed the owner that we are going to rebuild the engine. He's not arguing that fact. So, I would like to know what all of you think about mild upgrades to this motor that would improve high-altitude performance while maintaining stock reliability.
I am considering the following:
1. aluminum 4-bbl intake
2. 4 bbl carb
3. mild RV cam
4. lifter/pushrod/rocker upgrade
5. aluminum waterpump
6. performance coil
7. performance distributor
8. 9mm spark wires
Please advise what you all think about brand/model of parts.
Thanks all!
I think this may have been a slight problem...
What do you all think?
I'm thinking this may have contributed to the valvetrain noises and the loss of oil pressure, rough idle, etc... However, ol'boy told me neither he nor any of his employees have ever over-revved this engine. I'm calling
!At any rate, I also found a rocker arm that did not resemble the rest of the originals.
All of this leads me to believe the original "city mechanic" replaced a rocker and Lord knows if he fished out ALL of the parts of the rocker that he replaced; I doubt it. This truck was a weed-fire truck at one time. I bet some whistle-pecker fire guy missed a shift, blew a rocker, and the city mechanic just replaced the rocker, dumped out what he found in the oil pan, put it all back together, and prayed for the best until they auctioned it off...
I also discovered that there were (3) different types of SOLID pushrods in this engine; I thought hydraulic systems used hollow pushrods, am I wrong on this year/make/model engine?
I have informed the owner that we are going to rebuild the engine. He's not arguing that fact. So, I would like to know what all of you think about mild upgrades to this motor that would improve high-altitude performance while maintaining stock reliability.
I am considering the following:
1. aluminum 4-bbl intake
2. 4 bbl carb
3. mild RV cam
4. lifter/pushrod/rocker upgrade
5. aluminum waterpump
6. performance coil
7. performance distributor
8. 9mm spark wires
Please advise what you all think about brand/model of parts.
Thanks all!
05-29-2013, 11:27 AM
#41
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Well, honestly, I can't trust the history of the engine and I figure a new set of rings and bearings, while I have it apart this far, couldn't hurt; then we actually know what we have, instead of guessing.
I was also figuring on upgrading to better-than-stock rings and bearings while I'm in there too. However, we don't want to build a race motor, just something that will last a little longer and perform a little better up here at 9,000+ feet.
05-30-2013, 06:10 PM
#42
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Hello again all,
Sorry to be so long in responding, I just got back from 90days overseas.
Thank you all for your continued advice!
440roadrunner:
I have inspected all 5 of the failed pumps I have installed on this thing and in all 5 cases, I can't find any sign that there is anything wrong with them accept the bypass spring gets weaker over time; no metal shavings, no scoring, no heat damage, no damage whatsoever.
Worst part is, as I described in my last post, when I blocked that bypass valve, it blew the seal on the oil filter and put 2 qts on the ground within 30 seconds of startup.
I WISH I could find some metal somewhere. There's none anywhere; no simple answers :banghead:.
To try to answer everyone's questions:
- No external leaks on the pump or engine
- No damage to pump, pump gasket, pump stem O-ring (was extremely careful)
- Using mechanical oil pressure gauge
- I have not checked the dipstick length, but I have drained the oil and there was at least 5-qts in it the last time I had this issue. The engine itself has low (42,000) miles on it and fortunately has no gasket or seal leaks. Anyone know the factory length of the dipstick??
- No adapter on the oil filter. Just the pump itself.
- NOTHING in the oil pan every time I remove it. (I really wish there)
I am going to pull the pan (again x3
) this week. Fortunately I bought the good reusable rubber pan gasket...
Garys69RR:
I'm going to pull the caps and see what the bearings look like. Because, as I described in a previous post, I think I have a partially spun main bearing. The owner is an IODIOT and was giving this poor engine about 3000rpm pedal-stomps in order to "warm it up" in -10-15deegreee Colorado winter weather. I think he started to spin a main, that's all I can figure. Something seems to be moving and blocking the high-pressure side of the pump. But yet there is no noise to indicate a bad main bearing.
I will look for cracks in the oil pickup tube and bearing clearances this week.
Thank you all
Sorry to be so long in responding, I just got back from 90days overseas.
Thank you all for your continued advice!
440roadrunner:
I have inspected all 5 of the failed pumps I have installed on this thing and in all 5 cases, I can't find any sign that there is anything wrong with them accept the bypass spring gets weaker over time; no metal shavings, no scoring, no heat damage, no damage whatsoever.
Worst part is, as I described in my last post, when I blocked that bypass valve, it blew the seal on the oil filter and put 2 qts on the ground within 30 seconds of startup.
I WISH I could find some metal somewhere. There's none anywhere; no simple answers :banghead:.
To try to answer everyone's questions:
- No external leaks on the pump or engine
- No damage to pump, pump gasket, pump stem O-ring (was extremely careful)
- Using mechanical oil pressure gauge
- I have not checked the dipstick length, but I have drained the oil and there was at least 5-qts in it the last time I had this issue. The engine itself has low (42,000) miles on it and fortunately has no gasket or seal leaks. Anyone know the factory length of the dipstick??
- No adapter on the oil filter. Just the pump itself.
- NOTHING in the oil pan every time I remove it. (I really wish there)
I am going to pull the pan (again x3
) this week. Fortunately I bought the good reusable rubber pan gasket...Garys69RR:
I'm going to pull the caps and see what the bearings look like. Because, as I described in a previous post, I think I have a partially spun main bearing. The owner is an IODIOT and was giving this poor engine about 3000rpm pedal-stomps in order to "warm it up" in -10-15deegreee Colorado winter weather. I think he started to spin a main, that's all I can figure. Something seems to be moving and blocking the high-pressure side of the pump. But yet there is no noise to indicate a bad main bearing.
I will look for cracks in the oil pickup tube and bearing clearances this week.
Thank you all
About 10 years ago I had my car make a similar rattling noise in the engine area. Turned it off right away. It turned out that I spun a bearing. Hope this isn't the case here.
11-12-2014, 08:40 PM
#43
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1977 Dodge 400BB sudden oil pressure loss - solved
Tore the engine down last year and finally figured out why there was such a clatter from within. The owner had over-revved the damn thing so severely that he punched a pushrod through an intake rocker arm. Split the arm in two. One small piece of rocker arm was in an oil channel. 
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