Seeking rebuild advice

DGrajewski6

New Member
Joined
Apr 14, 2022
So I have 3.8l 231 V6 non turbo 87 regal, the engine has 187k+ on it. For engine oil pressure at 1600-2000 rpm’s it’s at around 20 psi on cruise. Idle is about 12 at 1000 rpms. But at stop lights when I’m in gear the pressure drops below 10 psi. I did the timing chain cover, I replaced the oil pump and the timing chain cover completely as it was a suspected leak, when primmed I verified oil coming from every rocker so I know it’s not a priming issue. I’ve had 2 mechanical oil pressure gauges in the car to make sure it’s correct. My final thoughts are to do the main bearings which i don’t think anyone wants to do. Any advice would be appreciated.
 
Depending upon the worth of the car in $$$, or to you, you might be better off driving it until it seizes.
My oil pressure is about 25psi. at 2400 rpm and about 8-10 at idle with a turbo, and that's what I plan on doing.
If you have oil coming out of the rockers you're good. :)
I assume the oil pump was set up correctly?
 
Could be the cam brgs and the mains as the main culprits.
As mentioned... Oil pump set up correctly?
Throw a shim in the pump relief and see what happens.
Not a big job to do on car.
 
So as far as the oil pump being installed if you’re referring to the gears being packed with petroleum jelly and then I did make sure I had oil coming out of all the rockers when priming it before I started the engine.
 
From how you're talking about rebuilding it, why not just run 20w-50 in it and just milk it until the crank is knocking on the door to escape.

After my car sat dead for 8 years I got sold a stock short block (fing turd was .030 crank and .020 rods after tear down) to just get the car rolling and 20w-50 was just enough to run it hard until I needed a full rebuild.
 
I meant the spec.s on pages 6A8 thru 6A11 in the service manual as linked below.
I’ll be honest I bought and installed a new pump so I didn’t have to check the specs of the old pump, I could pull it back apart to see if anything happened to the new pump


From how you're talking about rebuilding it, why not just run 20w-50 in it and just milk it until the crank is knocking on the door to escape.

After my car sat dead for 8 years I got sold a stock short block (fing turd was .030 crank and .020 rods after tear down) to just get the car rolling and 20w-50 was just enough to run it hard until I needed a full rebuild.
So I thought about upping to 10-40w, as I have 10-30w in the car right now, and I’m from New England as it’s already in the 30°s outside the car jumps up to 80-85psi on cold start, i just feel like if I up the pressure with a thicker weight I’m asking to blow the engine and the car does have bit of sentimental value as my grandfather bought it brand new off the show room floor, he turned it into a bit of a rat rod, I’m just trying to polish it
 
Melling sells an HV oil pump kit that You could install. That along with an adjustable regulator kit from TA perf would definitely beef up the low idle pressure.
On a new engine I always use a TA front cover assembly with a stock size pump in it, but the melling High volume kit is a good option for a high mileage stocker.
 
What is the condition of the timing chain?
Have you done a compression check?
If the engine has 80+ psi @30 degrees with 10w30 that's not bad.
If it's not making any interesting noises, I'd run it.🙂
 
"I’ll be honest I bought and installed a new pump so I didn’t have to check the specs of the old pump, I could pull it back apart to see if anything happened to the new pump"
The suggestion is to check the clearances on the new pump, not necessarily the one you took off.
However, that's a good idea, as it may give clues as to what's going on.
If the new cover and pump are "Ho Chi" specials, it's no telling what you have.
 
"I’ll be honest I bought and installed a new pump so I didn’t have to check the specs of the old pump, I could pull it back apart to see if anything happened to the new pump"
The suggestion is to check the clearances on the new pump, not necessarily the one you took off.
However, that's a good idea, as it may give clues as to what's going on.
If the new cover and pump are "Ho Chi" specials, it's no telling what you have.
I meant “pull it back apart” as in the new timing cover/oil pump to look at the new pump, however have you or any one here heard of “EngineQuest”? Out of Las Vegas, that is where I purchased the cover in hopes it would be a more quality product than rockauto but I didn’t really do my research, they use recommend silver seal PN#6573 as the front crank seal,

I think my next steps are to thicken up the oil with some STP or 10-40w if that doesn’t work then I’ll pull the timing cover and check the clearance of the oil pump, if that’s good then I’ll try a HV pump. Thanks for all the help guys.
 
I'm sure someone here may tell me I'm wrong but what I have always been told is approx. 10 psi hot for every thousand rpm and your 20 psi at cruise puts you where you should be. With that mileage though, you are bound to have some bearing wear so that is where your pressure is bleeding off some at idle. How much below 10 psi does it go? Does it turn on the "oil" light in the dash (if it is still working that is)? Did changing the front cover and oil pump up the pressure at all? There are two main areas of wear on these oil pumps and that is the area above the gears and the cover below the gears which can also warp as well as wear. Wear or excessive clearance will show up as a loss of oil pressure but with these being new items, this should not be the case here. Blueprinting the pumps by checking the clearances is something that should definitely be done on a full rebuild but with the fact the car is already running with this pump and has "correct pressure" at operating rpm's I don't think it's necessary at this point.

I've seen small block Chevy's only hold 5-7 psi at idle that have ran for ages. I know these aren't sbc and these things are notorious for low oil pressure but on a n/a, non-performance application, as long as you've got enough oil pressure that it doesn't set off the warning light and you are not having any other noises such as lifter tick or bearing knock when idling, I would say that you've got no reason to be in emergency repair mode about this. Cars don't really spend all that much time at idle, so as long as it is getting some oil to everywhere, it's not as big of an issue as people believe. When your oil pressure starts dropping off the current levels as the rpms increase or you start to get noise at idle will be the time to worry about pulling it apart. If you want to go to 10w40 now and change to 15w or 20w for the summer it shouldn't hurt anything either but may give you a little peace of mind.
 
I'm sure someone here may tell me I'm wrong but what I have always been told is approx. 10 psi hot for every thousand rpm and your 20 psi at cruise puts you where you should be. With that mileage though, you are bound to have some bearing wear so that is where your pressure is bleeding off some at idle. How much below 10 psi does it go? Does it turn on the "oil" light in the dash (if it is still working that is)? Did changing the front cover and oil pump up the pressure at all? There are two main areas of wear on these oil pumps and that is the area above the gears and the cover below the gears which can also warp as well as wear. Wear or excessive clearance will show up as a loss of oil pressure but with these being new items, this should not be the case here. Blueprinting the pumps by checking the clearances is something that should definitely be done on a full rebuild but with the fact the car is already running with this pump and has "correct pressure" at operating rpm's I don't think it's necessary at this point.

I've seen small block Chevy's only hold 5-7 psi at idle that have ran for ages. I know these aren't sbc and these things are notorious for low oil pressure but on a n/a, non-performance application, as long as you've got enough oil pressure that it doesn't set off the warning light and you are not having any other noises such as lifter tick or bearing knock when idling, I would say that you've got no reason to be in emergency repair mode about this. Cars don't really spend all that much time at idle, so as long as it is getting some oil to everywhere, it's not as big of an issue as people believe. When your oil pressure starts dropping off the current levels as the rpms increase or you start to get noise at idle will be the time to worry about pulling it apart. If you want to go to 10w40 now and change to 15w or 20w for the summer it shouldn't hurt anything either but may give you a little peace of mind.
I'm sure someone here may tell me I'm wrong but what I have always been told is approx. 10 psi hot for every thousand rpm and your 20 psi at cruise puts you where you should be. With that mileage though, you are bound to have some bearing wear so that is where your pressure is bleeding off some at idle. How much below 10 psi does it go? Does it turn on the "oil" light in the dash (if it is still working that is)? Did changing the front cover and oil pump up the pressure at all? There are two main areas of wear on these oil pumps and that is the area above the gears and the cover below the gears which can also warp as well as wear. Wear or excessive clearance will show up as a loss of oil pressure but with these being new items, this should not be the case here. Blueprinting the pumps by checking the clearances is something that should definitely be done on a full rebuild but with the fact the car is already running with this pump and has "correct pressure" at operating rpm's I don't think it's necessary at this point.

I've seen small block Chevy's only hold 5-7 psi at idle that have ran for ages. I know these aren't sbc and these things are notorious for low oil pressure but on a n/a, non-performance application, as long as you've got enough oil pressure that it doesn't set off the warning light and you are not having any other noises such as lifter tick or bearing knock when idling, I would say that you've got no reason to be in emergency repair mode about this. Cars don't really spend all that much time at idle, so as long as it is getting some oil to everywhere, it's not as big of an issue as people believe. When your oil pressure starts dropping off the current levels as the rpms increase or you start to get noise at idle will be the time to worry about pulling it apart. If you want to go to 10w40 now and change to 15w or 20w for the summer it shouldn't hurt anything either but may give you a little peace of mind.
So, at a stop light/stop sign, about 5psi, which means I probably have nothing at the rockers which terrifies me, but when it’s in neutral it has 10-12 psi I think. It’s now been a couple days since I’ve driven it, As far as the oil light, I never trust them. And it might work but I doubt it since a lot of the electrical was just cut, the car needs a rewire. I’m not quite sure what I’m gonna do but more great advice
 
Your oil pressure going that low is not terrible for a Buick, they typically go down that much at hot idle on stock gears and housing. The TA pump will fix that but it is not necessary.

You need to ask yourself if a rebuild is necessary on your motor. 187,000 miles is a lot but if its still has good compression then you should consider that.

If you are dead set on a rebuild just know it will cost you $5000 to $6000 for a bone stock rebuild. Maybe a little less but that is you doing the work. Put another $3000 ro $4000 for a shop to do it.
 
Melling sells an HV oil pump kit that You could install. That along with an adjustable regulator kit from TA perf would definitely beef up the low idle pressure.
On a new engine I always use a TA front cover assembly with a stock size pump in it, but the melling High volume kit is a good option for a high mileage stocker.
So I went ahead and I purchased the TA performance thrust/booster plate. I haven’t received it yet to actually look at it in person. I was wondering what your thoughts were on the thrust plate as I do more research, the description said it would boost engine idle but really the only benefit I see is it’s steel gears riding on steel plate instead of the aluminum oil filter adapter, if so I guess my only worry is that it’s still going to ride the same clearance and produce the same hot idle oil pressure? I’m still debating on if I should replace the the new gears with HV since technically I have great RPM oil pressure on throttle and cold start. Thanks for the help if anyone sees
 
So I went ahead and I purchased the TA performance thrust/booster plate. I haven’t received it yet to actually look at it in person. I was wondering what your thoughts were on the thrust plate as I do more research, the description said it would boost engine idle but really the only benefit I see is it’s steel gears riding on steel plate instead of the aluminum oil filter adapter, if so I guess my only worry is that it’s still going to ride the same clearance and produce the same hot idle oil pressure? I’m still debating on if I should replace the the new gears with HV since technically I have great RPM oil pressure on throttle and cold start. Thanks for the help if anyone sees
You are correct. The clearance is adjustable with the various gaskets that come with.
The HV pump kit comes with all the same stuff too, and a spacer for the longer gears.
You can also look into porting the front cover for better oil flow.
 
Melling K20IPHV is an example, hv kit with spacer and thrust plate

Some if not maybe all of the Chinese made silver seal brand front cover assemblies already have the HV gear sets in them. Is that what you have? If so a thrust plate would be the upgrade.
 
Top