oil consumption

[midlife]

The PCV, for it to work correctly, needs a vacuum source outside of the valve cover. If I understand your post correctly, you actually drove the car vice revving it in the driveway. Since there was no difference between the two conditions (PCV in and out), there's something amiss with that system.

Does the PCV itself rattle when shaken (not stirred *G*)? Is there a source of vacuum on the hose to the PCV? I agree that the PCV can be overwhelmed with splashed oil, but first one has to rule out the other conditions.

 

[cjstaci]

When I have the PCV installed, yes it has a vacuum source to the intake manifold. When I removed the pcv, I blocked off the vacuum source. Either way, the engine continued to use oil.

With the PCV removed, there should be some pressure in the crankcase, especially at higher rpm's. The fact that some combustion pressure goes past the rings should create a positive crankcase pressure. I tried to test it by blocking one the hole in one valve cover while using a vacuum/pressure gauge on the other valve cover. The gauge showed no reading at all. So I think the crankcase pressure is escaping somewhere, and I think that somewhere may be the valley side of the intake manifold. I just haven't seen any proof positive evidence of the intake being at fault. I feel like I am missing something, just don't know what it is yet.

 

[4Vforever]

Auto transmission? Maybe sucking some trans fluid into the intake via the modulator. Just one more to cross off the list. These problems can do your head in but you'll get it in the end.

 

[cjstaci]

Good thought, but it's a 4spd,

I think I might try another intake manifold. If that doesn't help, then I will put a borescope in the valve cover when it's running so I can see how much oil is present. If that doesn't seem to a problem then I will pull the engine, tear it down, One way or another I will find out what the problem is.

 

[basstrix]

When I have the PCV installed, yes it has a vacuum source to the intake manifold. When I removed the pcv, I blocked off the vacuum source. Either way, the engine continued to use oil.

With the PCV removed, there should be some pressure in the crankcase, especially at higher rpm's. The fact that some combustion pressure goes past the rings should create a positive crankcase pressure. I tried to test it by blocking one the hole in one valve cover while using a vacuum/pressure gauge on the other valve cover. The gauge showed no reading at all. So I think the crankcase pressure is escaping somewhere, and I think that somewhere may be the valley side of the intake manifold. I just haven't seen any proof positive evidence of the intake being at fault. I feel like I am missing something, just don't know what it is yet.

Did you also plug the dipstick tube?

 

[4Vforever]

Good thought, but it's a 4spd,

I think I might try another intake manifold. If that doesn't help, then I will put a borescope in the valve cover when it's running so I can see how much oil is present. If that doesn't seem to a problem then I will pull the engine, tear it down, One way or another I will find out what the problem is.

Well that crosses off the auto trans idea, lol. I don't think the HV oil pump is the culprit as this was happening before then. It really can only be PCV set up, intake manifold not sealing properly by either not enough crush on the gasket or the mating surfaces are not parallel to each other, as mentioned casting fault in the intake, too much oil in the top end and going down past the guides or the rings aren't bedded in. As you said the leak down test was good and blow by isn't there then the rings not bedding can be eliminated, positive stop seals are in that category as well if they are quality pieces, so it only leaves the others as the culprits. Before pulling it apart I'd do your idea with the bore scope or the cut top rocker cover as was mentioned previously. It just a frustrating game of elimination.

 

[cjstaci]

Good catch on the dipstick. I missed that.

I was looking at the intake gaskets today, the intakes machine marks are on the gaskets, it looks like they were sealed. I also checked the angles on the manifold and heads, they both are 45*. Although the intake has been my main suspicion, I am just not seeing any evidence of it.

I looked in the intake ports and I could see a small puddle of oil around each of the intake valves. The oil in the ports could be from reversion as opposed to where the intake mates.

I don't think it's from the PCV, if it were, there should oil in the intake manifold. When I removed the pcv and blocked the vacuum line, it didn't make any difference.

I've never been at such a loss to find a problem, this is driving me crazy.

 

[mjlan]

If there was no evidence of oil getting past the gaskets I would vote for the valve stems being submerged in oil due to the pump putting out more oil to the top end than the drain back holes in the heads. The vacuum of the engine running then draws in the oil...

 

[c9zx]

Which ring set did you use? Those with TG, TL, TSG, or TSL in the part number are not recommended for street use. T or TS are recommended for street use. Just a thought. Chuck

 

[Jeff73Mach1]

Replace the high volume oil pump with a standard volume pump or drill the heads and oil pan for fittings and run external oil return lines.

 

[cjstaci]

The rings are TS1.

Regarding HV pumps, correct me if I am wrong, but if the clearances are stock, it should raise the pressure. The flow should only increase if the clearances are larger. Higher flow should equal lower pressure. I am not sure if the holes in the push rods are larger than stock, I doubt they are. They are comp cams 3/8" chrome moly, I would have to look up the part numbers.

The oil pressure is 40 psi idling @800 rpm and 60 @ cruise.

I think at this point, I should re-install the intake, run the engine and stick a camera in the valve cover to see how much oil is in there. If it is in fact flooding the valve guide area that could definitely be the problem. The bad thing is if I have to change the oil pump, that's a pain considering the deep pan and headers. I'll probably have to pull the engine. Too bad they didn't use a removable crossmember like the earlier Mustangs have.

 

[cjstaci]

Here is a video of it running.

 

[Jeff73Mach1]

Sounds good, has good numbers, how much oil are you losing? It might be one of those issues to ignore.

 

[73pony]

It sounds great, idle is nice, seems to respond to throttle quite nicely. I am surprised that there wasn't any blue smoke from the tailpipes given that you mentioned the black on the plugs, and the oil you see oil sitting inside the intake ports and around the valves. Just weird, I would think you would be seeing some blue smoke.

 

[basstrix]

Sweet ride!

 

[cjstaci]

I do see a light amount of blue smoke at idle, hard to notice but it's there. It is fouling plugs, otherwise I probably would ignore it.

One other thing I was thinking I could check, is to remove a couple valve springs and check that the guides/seals haven't developed a problem. If they are okay, then I will re install everything, run it, check the valve cover with a camera to see how much oil is in there. If that doesn't seem to be an issue then I'll just run it for a while and see what happens. Maybe it's possible that the oil rings haven't seated and just needs more run time, although I have never had an issue like that before. There is only about 150 miles on it so far. I don't know, I am just reaching at this point. If I have to pull the engine, then I am going to bore it and put a stoker set up in it, probably should have done that in the first place.

So far, I feel I have eliminated the PCV system, and the intake gasket. That leaves guides/seals, or rings.

 

[basstrix]

You had some questions in a prior post regarding the HV pump so I'll give you some fluid dynamics based input. Flow through a fixed orifice is proportional to delta-p (change in pressure) across said orifice (there are most definitely limitations to this statement, but in the flow regime we're talking about, that is the case). So, if you now have more oil pressure than before the rebuild, you also have more flow. The fixed orifice comment relates to your comment about maintaining the same clearances. Same pressure, same clearances = same flow. The bottom line is, if you added a HV pump but didn't restrict flow to the top end, you'll get more oil up top. That doesn't mean your problem is due to excess oil up top, but it puts it on the list as something to verify. Flooding the valve stems with oil will result in an increase in consumption vs the usual splash that takes place.

I've also heard of oil consumption through the rocker stud holes...I've never experienced it and not sure what the path for oil is into the cylinder....speculating, I'd say that someone bored the holes for studs too deep....with CJ heads, there would be no reason to mess with this, so I don't see this as a possibility...wanted to mention it anyway just in case.

 

[basstrix]

Also...when you ran without PCV, how long did you run it (I asked this before but don't recall a response....forgive me if you already answered)? You need to drive it around for at least a half an hour to get a clear signal of whether or not it made a change.....when you said it only has 150 miles on it, it made me think that you may not have given it enough time w/o PCV to make a clear call.

 

[cjstaci]

I initially ran the engine with open breathers, no pcv. It wasn't until I noticed oil on the plugs that I hooked up the pcv. I even hooked up a catch can. Also, I couldn't find oil tracing up the vacuum fitting. The intake manifold only had oil about 1" up in to the runners and the ports on the heads were completely wet.

Regarding the rocker studs, they don't protrude into the intake ports like the P51's and SCJ's. They a blind holes.

I hope your right and maybe it's too much oil at top. If that's the case, do they make push rods that have smaller orifice's. Just asking because if I have to change the pump, then I have pull the engine, fun fun fun, nothing like doing things twice.

 

[basstrix]

Yep, I know the rocker stud holes don't protrude into the ports on the iron heads...which is why I speculated that someone would have to have bored the holes too deep for that to be a path for oil. My comment wasn't at all clear. I have not worked with the P51's or the Ford Motorsport SCJ's and wasn't aware that they do...but that explains why I've read about that particular path.

When I was a kid, I rebuilt an XR500 motorcycle engine....I put the 2nd piston ring on upside down...it ran fine but smoked really bad. Let's hope that's not the case here....lots of oil on the rings can make compression numbers look good. I don't have any experience with a leakdown setup so I can't comment on how that would be affected by an upside down ring.