Rebuilt 360, excessive oil consumption

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oldwirebender

oldwirebender

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I got this engine running about a month ago. I put about 300 miles on it when last night I had to add the first quart of oil. I thought it would get better when it is broke-in. Today I took it on a trip to Edinburgh, 120 miles one way. It ran great on the way down, 60 psi oil pressure at 60 mph. I don't think I drove it hard. Kept it under 70 with no hard acceleration. On the way back I drove about 20 miles when I noticed the oil pressure dropping. Next exit I stopped at a truck stop and checked the oil, nothing on the dipstick. It took 2 qts to top it off. When I got almost home, I noticed the oil pressure getting erratic. 2 qts low again. I pulled the spark plugs. The plugs on the passenger side were very fouled, especially #8. The driver's side weren't nearly as bad. The engine is a 360 .030 over, forged flat top pistons, stock heads, Crane de265 cam, air gap manifold with a Holley 600 cfm carb. Any comments?

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Plugs don't look bad. Sure there is not a leak? Sometimes the bottom of the intake manifold leaks oil in to the ports. That would be the most likely place. Who rebuilt the motor. Any chance a ring was put on upside down?

Something is wrong for sure, intake manifolds can leak due to a bad gasket, even cracks in the aluminum.
 
Ironworker? Did you do the engine or buy it this way?Could be bored too big,oil rings not oriented opposite.Any noise?cold does it rattle until it warms up?Was it cleaned good after it was honed?oil pressure come back good after you refill it or does it continually go down?Throw me a bone.
 
intake gasket or valve stem seals on the passenger side head is where I would start AFTER I do a compression check. What are the odds of you installing the rings wrong on 4 pistons on the same bank of the engine but getting them all correct on the other bank. Slim to none. With the engine running spray some carb cleaner on the manifold where it mates with the cylinder head and see if the idle changes, if it does you found your problem. If it don't you might wanna look at you valve stem seals.
 
mtandrews said:
intake gasket or valve stem seals on the passenger side head is where I would start AFTER I do a compression check. What are the odds of you installing the rings wrong on 4 pistons on the same bank of the engine but getting them all correct on the other bank. Slim to none. With the engine running spray some carb cleaner on the manifold where it mates with the cylinder head and see if the idle changes, if it does you found your problem. If it don't you might wanna look at you valve stem seals.
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Well sometimes just the bottom of the intake manifold leaks. Look in front of the intake flange and see if there is any gap towards the bottom of the flange.

Sometimes the intake gasket splits on one port, why I like using Fel-Pro steel core print-o-seal gasket . http://www.summitracing.com/parts/FPP-1213S-3/

Once the intake is pulled, you can look for oil in the intake ports. Its really a common problem on many makes of motors.
 
I've had engines with plugs look tons worse than those not use much oil. Sounds to me there's a leak somewhere. Does it smoke down the highway? If it did in fact use the amount of oil you say it did it would be leaving a trail of blue smoke.
 
A little more information, when driving down the road, I can not see any smoke, but when I "punch it" a good bit of blue-black smoke rolls out of the passenger side. And this is only after driving at a steady rate for a time. As for the plugs, the fouling got worse toward the back of the engine. The #8 was by far the worst. It was the first one I took out, and it was almost completely shorted out. I chipped a lot of the crud off of it before taking the pics. As soon as I get time, I am going to run a compression test.
 
Also, no I did not build this engine myself,(maybe I should have). It was built by an experienced person who specializes in small block Mopars.
 
You need to do a compression test and then find a local guy who can do a leak-down. Things it could be: leaking intake gasket, broekn rings, poor ring seal due to finish or dirt, bad guides in the heads.
 
moper said:
You need to do a compression test and then find a local guy who can do a leak-down. Things it could be: leaking intake gasket, broekn rings, poor ring seal due to finish or dirt, bad guides in the heads.
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My vote is either the first or last choice of what Moper listed, but to me, the first is very likely. I had a similar problem for a while, about a quart in 500 miles or less. I pulled the intake and found cyl number six port was oily and the intake gasket was slightly cracked. Replaced the gasket and the problem was solved.

Do you see any blue smoke coming out of either of the pipes during decelleration after jumping on it? This is a sign of a possible intake gasket issue.

Do a compression check, if possible, first.
 
Just finished a compression test. Here are the results. The first number is the dry check, the second number is wet.
1: 150, 160
2: 155, 160
3: 155, 160
4: 160, 170
5: 150, 160
6: 150, 160
7: 150, 160
8: 110, 120
 
I know you don't want to hear this but that is bad news

Number 8 cylinder has a problem and its not your intake gasket or the valve guilds. I would say rings but why so low wet also? Something is wrong with the 8 either the rings, cylinder walls, piston. I heard of pistons or rings in sets not being all the same size.

This hobby can be more of a pain in the butt than enjoyment I am finding out :angry7:
 
no. 8 has an issue.

but how are you breaking it in exactly, are you varying the rpm at cruise, or just keeping it steady?
you need to vary the rpm/speed every couple minutes or so.jmo

what kind of bore finish?

what primary jet size and pv are running?

and does the valve cover have a baffle to keep direct splash from the pcv?
 
Looks like 8 didnt seat for some reason. Do you have power brakes?
 
1wild&crazyguy said:
no. 8 has an issue.

but how are you breaking it in exactly, are you varying the rpm at cruise, or just keeping it steady?
you need to vary the rpm/speed every couple minutes or so.jmo

what kind of bore finish?

what primary jet size and pv are running?

and does the valve cover have a baffle to keep direct splash from the pcv?
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Yeah but why only one cylinder not sealing? Rings can go on upside down. That would be my guess yet I heard of the wrong size rings-pistons in a lot. I never seen it but heard from builders it can happen.

Regardless, the head and oil pan need to come off and the piston pulled out and see what is wrong. If the rings are on upside down you may get away with just new rings and no honing. Means the crank can stay put. Yeah its a lot of labor. Like I said I'm getting brunt out on hot rodding
 
Well upside down rings can cause heavy oil burning. Plus the ring on the inside has a taper to force the rings to the walls, if the ring is upside down it might not be forced against the wall enough on the compression stroke.

But yeah we are just guessing.
 
Sorry to hijack the thread, but ya got me interested.

Which way is correct for piston ring installation?

The instructions that came with the Speed Pro rings for my Stroker have them pictured one way, yet the book that I bought on Engine Blueprinting has them pictured the other way.

The instructions clearly show that the notch is to be oriented towards the bottom of the piston. The top ring on the right is the proper illustration.

The book shows the notch on the upper side, towards the top of the piston.

Of course, I didn't notice this little tidbit until after the pistons were installed. :angry7: I do not want to have to tear it apart. But at least I don't have the heads on yet.

Please tell me I'm good to go. :toothy10:

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You are going to need to pull that slug out. There is no since guessing what happened to the rings.

The oil ring is really what controls oil so that is probably were the problem lies. Since we are guessing I would say that the oil ring expander is "overlapped" and not "butted". The top two rings are compression rings and that is their intended purpose.

Chuck
 
I agree with Chuck. I think the corrugated portion of the oil ring setup got overlapped instead of butted, which is not putting the pressure on the oil rings that it should.

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Pulled intake today. All ports had an oily sheen. Tops of the intake valves were heavily carboned. The intake gasket bead was compressed on top, but, hardly at all on the bottom. I took a picture of the gasket at the #5 and #7 ports. You can see the bead is nearly intact on the bottom. What caused this? It was that Chinese intake I bought off of E-bay. It's NOT going back on. My engine builder is sending me an iron manifold to try. He is hoping the low compression on #8 may be caused by carbon buildup. He also said to go to a #72 jet on my carb. He thought it was running a little lean. Are we having fun yet?](*,)

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You are running lean beause of the vacuum leak from the intake not being sealed. Wait on the jet change until you can get the intake seal fixed.


Chuck
 
When you pulled the intake did all the bolts seem tight? As long as the heads weren't angle milled the intake should seal up square. Only reason not to do so is it's cut wrong. Do you have an angle finder to check the angles?
 
It's been a while, so I thought I would update everybody what I found. I pulled the Chinese crosswind style intake and put on an iron intake off of a '71 340.
I immediately saw an improvement in the power and idle quality. I put in a can of Seafoam in the tank for the next three fill-ups. after that, I ran a dry compression check. all cylinders were in the 150-155 psi range. the car is a joy to drive. Now with winter just around the corner I can move on to the next projects- headliner, and front end rebuild. thanks for all your help and opinions!
 
So the intake was machined at the wrong angle, say was it used off e bay cause that would make a lot of sense for someone to sell it...and not mention the problem.

bummer
 
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