new hp rebuild problem
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Lead Driver
Joined: Mar 2008
Posts: 7,182
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From: Near Los Angeles
new hp rebuild problem
Hey guys--
I wanted to run a bit of a mystery by you. I just finished a little project, swapping out a tired 390 in an old truck for a hp inline 300. It's a nice little engine, and should be turning close to 250 hp.
I've been driving it for only two weeks, and my oil psi is dropping. I'm only talking about when the engine is hot, coming off the freeway to a stop. In two weeks it has gone from 30 psi to 9 psi.
Today I am going to slice open the filter and see if there's anything inside. Then I am going to replace the gauge, which is a cheapo. The next step will be to drop the pan and remove and examin the new melling pump, pick up, screen, and most likely remove one of the mains just to look. I really hope it is the pump.
The engine was bored .030 over, had over size smc valves installed, crank turned .010 under, balanced.
If anyone has any advice/pointers to throw in, I'd like to hear it.
On initial start I ran it for 15 minutes at 15 rpm for the cam, on Valvoline 10/30 racing oil.
I wanted to run a bit of a mystery by you. I just finished a little project, swapping out a tired 390 in an old truck for a hp inline 300. It's a nice little engine, and should be turning close to 250 hp.
I've been driving it for only two weeks, and my oil psi is dropping. I'm only talking about when the engine is hot, coming off the freeway to a stop. In two weeks it has gone from 30 psi to 9 psi.
Today I am going to slice open the filter and see if there's anything inside. Then I am going to replace the gauge, which is a cheapo. The next step will be to drop the pan and remove and examin the new melling pump, pick up, screen, and most likely remove one of the mains just to look. I really hope it is the pump.
The engine was bored .030 over, had over size smc valves installed, crank turned .010 under, balanced.
If anyone has any advice/pointers to throw in, I'd like to hear it.
On initial start I ran it for 15 minutes at 15 rpm for the cam, on Valvoline 10/30 racing oil.
Postmaster
Joined: Jan 2009
Posts: 4,558
Likes: 2
Could just be the gauge , the hotter it is the lower the OP & some gauges are not acurate , i would change the oil & use a good filter like mobil 1 , or K&N , oil pumps usally don't go bad , a good auto meter mechanical gage will work good ... Lew
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Lead Driver
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
Thanks. That will be the first step.
Lead Driver
Joined: Mar 2004
Posts: 8,922
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Any mech. gage is ok to make sure. Sounds like it's time to open it up and see whats going on it there.
Posting Guru
Joined: Mar 2007
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Likes: 1
My opinion is, you may have gotten a faulty pump... I like melling, but the springs, can get weak in them... They may offer, a different spring for it. Maake sure the gasket didnt brake when oyu installed it, or the serface is clean.
Or
A bearing may have slipped a bit, perhaps a cam bearing would be more prone to do that... Crank bearings ussually build the guage preassure.
Did you champfer the oil passages? That is always a good idea on a fresh engine. Ussually at least done on the crank shaft...
Last but not least... What oil are you running? viscosity, and brand? If you are running a fram filter, they have been known to collapse inside...
Chances of a guage messing up are slim, enlight of the fact, your issue is happening after you get off the freeway, and it is dropping dangerously low. Viscosity, main bearings, are definatly places to look.
Or
A bearing may have slipped a bit, perhaps a cam bearing would be more prone to do that... Crank bearings ussually build the guage preassure.
Did you champfer the oil passages? That is always a good idea on a fresh engine. Ussually at least done on the crank shaft...
Last but not least... What oil are you running? viscosity, and brand? If you are running a fram filter, they have been known to collapse inside...
Chances of a guage messing up are slim, enlight of the fact, your issue is happening after you get off the freeway, and it is dropping dangerously low. Viscosity, main bearings, are definatly places to look.
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Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
During the rebuild, the mechanic had a problem with a cam bearing. He could not get the cam journal through one of the bearings, and had to 'sand' the bearing. When he told me that I took the block back to the mechinist/shop, and had them r&r that bearing. However, they too had to shave/sand that bearing. They assured me it would not be a problem.
I am using valvoline 15/40. I had originally used V. 10/30, but the pressure dropped to under 10psi off the freeway. With the 15/40 it bumped up the psi to 15 around town, but on a hot day after a freeway run, it will now drop to 10psi.
I had the cranked turned .010. When I orininally took it apart, I found the Ford bearing still in it, so I assumed the crank had never been turned. The bearing were replaced with Clevite .010 over size.
I am using valvoline 15/40. I had originally used V. 10/30, but the pressure dropped to under 10psi off the freeway. With the 15/40 it bumped up the psi to 15 around town, but on a hot day after a freeway run, it will now drop to 10psi.
I had the cranked turned .010. When I orininally took it apart, I found the Ford bearing still in it, so I assumed the crank had never been turned. The bearing were replaced with Clevite .010 over size.
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Posting Guru
Joined: Mar 2007
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Something stinks in denmark...
Sand bearings??? ah NO! original Ford bearings?? before rebuild right?
They should have champferred the oil passages... I am not buying into sanding the bearings though... Your running way to heavy of oil. maybe 10w40 in the summer, and 10w30 in the winter. With a high volume pump, you should be running about 60 to 80 warming up, 45 to 60 down the free way, and then no less then 35 or 40 when hot. I put a melling pumps in all my rebuilds. These guys say they never get below 60 psi no matter what.
Keep in mind, the guage cannot desifer between vol and pressure, so it reads presure. You really dont want a high pressure pump though... it will spin the bearings for sure.
If they did not champfer the passages, it most likely is eating up the mains. pay special attention to the rear main...
Sand bearings??? ah NO! original Ford bearings?? before rebuild right?
They should have champferred the oil passages... I am not buying into sanding the bearings though... Your running way to heavy of oil. maybe 10w40 in the summer, and 10w30 in the winter. With a high volume pump, you should be running about 60 to 80 warming up, 45 to 60 down the free way, and then no less then 35 or 40 when hot. I put a melling pumps in all my rebuilds. These guys say they never get below 60 psi no matter what.
Keep in mind, the guage cannot desifer between vol and pressure, so it reads presure. You really dont want a high pressure pump though... it will spin the bearings for sure.
If they did not champfer the passages, it most likely is eating up the mains. pay special attention to the rear main...
Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
When I pull the pan, I am going to remove one of the mains and take a look.
I am not running a high volume pump now, just a stardard Melling pump. I am considering going with one, though.
I checked the receipt from the machine shop. I don't see a charge for running the oil passages.
I am hoping it is simply a problem with either the pump, or the pick up. I reused the 40 year old pick up on the mechanics recomendation.
I will post my findings.
Something else that is really bothering me: The timing cover crank seal is leaking. I saw it leaking even before we fired up the engine, but thought it was just a spill from somewhere. My faith in this 'mechanic' is fading fast! That, like the oil pressure problem, should not happen.
I am not running a high volume pump now, just a stardard Melling pump. I am considering going with one, though.
I checked the receipt from the machine shop. I don't see a charge for running the oil passages.
I am hoping it is simply a problem with either the pump, or the pick up. I reused the 40 year old pick up on the mechanics recomendation.
I will post my findings.
Something else that is really bothering me: The timing cover crank seal is leaking. I saw it leaking even before we fired up the engine, but thought it was just a spill from somewhere. My faith in this 'mechanic' is fading fast! That, like the oil pressure problem, should not happen.
Posting Guru
Joined: Mar 2007
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at 7 psi, you risk internal failure... You are dangerously close.
ask him, if he champferred the oil passages? Not run them.
Champferr= Champ & fur 1 word. It is the machine shope terminology for opening up the holes, and deburring them. If they didnt, most likely the mains are trashed. It would be hard to believe they didnt, but then considering they are sanding bearings? anything is possible.
I was thinking about the sanding of the bearings, it kind of makes me think they messed 1 up when installing it, then they had a .010 over set, so they sanded it down. The problem with that is, There is an outer layer, then an inner layer, They would have had to sand threw the alluminum outer to the bronze inner. That aint good... When you open an engine and see that, the bearing is considered wiped.
ask him, if he champferred the oil passages? Not run them.
Champferr= Champ & fur 1 word. It is the machine shope terminology for opening up the holes, and deburring them. If they didnt, most likely the mains are trashed. It would be hard to believe they didnt, but then considering they are sanding bearings? anything is possible.
I was thinking about the sanding of the bearings, it kind of makes me think they messed 1 up when installing it, then they had a .010 over set, so they sanded it down. The problem with that is, There is an outer layer, then an inner layer, They would have had to sand threw the alluminum outer to the bronze inner. That aint good... When you open an engine and see that, the bearing is considered wiped.
Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,182
Likes: 380
From: Near Los Angeles
at 7 psi, you risk internal failure... You are dangerously close.
ask him, if he champferred the oil passages? Not run them.
Champferr= Champ & fur 1 word. It is the machine shope terminology for opening up the holes, and deburring them. If they didnt, most likely the mains are trashed. It would be hard to believe they didnt, but then considering they are sanding bearings? anything is possible.
I was thinking about the sanding of the bearings, it kind of makes me think they messed 1 up when installing it, then they had a .010 over set, so they sanded it down. The problem with that is, There is an outer layer, then an inner layer, They would have had to sand threw the alluminum outer to the bronze inner. That aint good... When you open an engine and see that, the bearing is considered wiped.
ask him, if he champferred the oil passages? Not run them.
Champferr= Champ & fur 1 word. It is the machine shope terminology for opening up the holes, and deburring them. If they didnt, most likely the mains are trashed. It would be hard to believe they didnt, but then considering they are sanding bearings? anything is possible.
I was thinking about the sanding of the bearings, it kind of makes me think they messed 1 up when installing it, then they had a .010 over set, so they sanded it down. The problem with that is, There is an outer layer, then an inner layer, They would have had to sand threw the alluminum outer to the bronze inner. That aint good... When you open an engine and see that, the bearing is considered wiped.
There is no over/under size with Cam bearings. There is a problem with the engine, that is true. I will find out when the engine is opened up. When I drop the pan I'll remove one of the mains if I don't find the problem in the pump or pick up. I'll post what I find.
Thanks.
Posting Guru
Joined: Mar 2007
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Well if that is true, I learned something here, Cam bearing reamers, I have used, resurface the block, or journal, in the event of a cam bearing being spun/failure, or debur it for the new bearing to be installed. The reamer isnt, or I have never heard of it being used on the bearing itself, but on the journal...
Posting Guru
Joined: Jan 2005
Posts: 1,299
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From: The Vieux Ford, Kansas
Reaming the bearing is normal, it is done to account for core shift or factory flaws. If your cam bearings aren't perfectly inline the cam won't go in and you can't machine the journal with out the bearing because the bearings are press fit so they would fall out if you worked the journal instead of the bearing.
-Johnboy
-Johnboy
Posting Guru
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I learned something about cam bearings today here... I didnt know this.
There are 2 types of cam bearings. 1-solid ring and 2-split ring
The "split ring bearing", needs to be deburred, or reamed, after installed
The "solid ring" bearing, is precision and erases the need to the deburring process, as it is precison made...
I have always use Clevite 77 bearings, and they are Solid ring bearings...
There are 2 types of cam bearings. 1-solid ring and 2-split ring
The "split ring bearing", needs to be deburred, or reamed, after installed
The "solid ring" bearing, is precision and erases the need to the deburring process, as it is precison made...
I have always use Clevite 77 bearings, and they are Solid ring bearings...