67 L71 ,low oil pressure at idle

[Dave C.]

Some of you may have seen my thread from the last couple of days over on the forum, just thought I would bring it over here for any last minute suggestions, before I begin pulling the motor back out.
Long story as short as possible: L71 , fresh last year, installed, losing coolant due to leakage at the hardened exhaust seats. Fixed with irontite , drove for the summer no problems. Pulled motor in the fall , installed correct rec. port, cc. Heads, finish reinstall three days ago. Fire it up, runs awesome, second day notice drop in oil pressure, ( 3-4 psi at idle, 25 max) change oil to 20-50, new wix filter, slightly better but not much. Pull pan, change out oil pump to high volume, change oil back to 10-30, 60 psi cold, back down to 3 or 4 at idle hot. Cut open first oil filter took it to my local engine shop, full of magnetic material as well as copper, ( #*%+^}%)
is there any point in looking into it any further, or should I just resign myself to the fact that the motor has to come apart?
the real kicker is that I was getting her to leave next Friday for California, to be judged at the so cal meet on April 8th, it would have been the first NCRS event I have ever attended.

[Enzo C.]

Re: 67 L71 ,low oil pressure at idle

Hi Dave, I think that the particals in the pan and filter are definitely evidence of failure ... I would pull it and take it apart... There will be other NCRS events like the Regional in September in Canada... Your car looks great. Good luck and keep us posted

[Dave C.]

Re: 67 L71 ,low oil pressure at idle

Thanks , Enzo ,you are probably right, sure was looking forward to some time on the coast highway, though!

[Joe R.]

Re: 67 L71 ,low oil pressure at idle

Hi Dave,

What kind of oil are you using? By that I mean which API category? I'm guessing maybe you're not using CJ-4 and the cam is flattened. Did you try measuring lift on all 8 intake and all 8 exhaust valves? That would tell you for sure. But regardless, I agree that the engine has to come apart.

Joe

[Dave C.]

Re: 67 L71 ,low oil pressure at idle

Joe I was still using Joe Gibbs break in oil, I think it has the zinc additive for the cam. Someone did suggest to check the lift and that is what I will do before I actually start to remove the engine.

thanks,

dave

[Timothy B.]

Re: 67 L71 ,low oil pressure at idle

Dave,

I would not bend over that fender any more than necessary. Get the motor out and start over, you will never be happy until you do.

[Patrick B.]

Re: 67 L71 ,low oil pressure at idle

Since you have had the oil pan off before, I would remove the pan again and inspect the main and rod bearings before removing the engine. Since you used Joe Gibbs break-in oil and ran it a whole summer with normal oil pressure, it is not obvious that the cam failed or why it should have failed. With the pan off you can see if the bearings are torn up. That would explain the low oil pressure and give you a solid reason to pull the engine. However, what would you do differently breaking in the engine after another rebuild?

[Joe R.]

Re: 67 L71 ,low oil pressure at idle

With that much metal inside the engine I would pull and vat it until I was sure all the particles have been removed. IF you put a band-aid on it you will experience this problem again. Don't take a chance that you will regret again.
If you used break-in oil also use some moly lube recommend for the camshaft. Also a can of chevy break-in lube with the oil would be recommended if I was building the engine.
Also, I would recommend you interview another engine machine shop before you begin again!

JR

[Dave C.]

Re: 67 L71 ,low oil pressure at idle

Thanks for the advise guys, I suppose I could pull the pan and check the mains, but I am starting to get my head around the fact that the motor is going to have to come out. As much as I am trying to keep this thing stock, maybe a roller cam this time, I do not want to go though this again!

[Joe L.]

Re: 67 L71 ,low oil pressure at idle

Some of you may have seen my thread from the last couple of days over on the forum, just thought I would bring it over here for any last minute suggestions, before I begin pulling the motor back out.
Long story as short as possible: L71 , fresh last year, installed, losing coolant due to leakage at the hardened exhaust seats. Fixed with irontite , drove for the summer no problems. Pulled motor in the fall , installed correct rec. port, cc. Heads, finish reinstall three days ago. Fire it up, runs awesome, second day notice drop in oil pressure, ( 3-4 psi at idle, 25 max) change oil to 20-50, new wix filter, slightly better but not much. Pull pan, change out oil pump to high volume, change oil back to 10-30, 60 psi cold, back down to 3 or 4 at idle hot. Cut open first oil filter took it to my local engine shop, full of magnetic material as well as copper, ( #*%+^}%)
is there any point in looking into it any further, or should I just resign myself to the fact that the motor has to come apart?
the real kicker is that I was getting her to leave next Friday for California, to be judged at the so cal meet on April 8th, it would have been the first NCRS event I have ever attended.

Dave------


I hope you didn't have hardened valve seats installed in the new heads. Doing this represents a risk (which was realized in your first set of heads) and a significant cost for virtually no real benefit.

[Dave C.]

Re: 67 L71 ,low oil pressure at idle

Thanks Joe, I managed to find a nice set of unmolested heads, and I did not install hardened seats

[David S.]

Re: 67 L71 ,low oil pressure at idle

Make sure the lifter bores are honed after the engine is cleaned. If the lifters can't rotate it will wipe the cam lobe off in short order.

[Dave C.]

Re: 67 L71 ,low oil pressure at idle

Thanks David, will do!