[gtorich]

Interesting question.............i know i have a oil leak somewhere, oil pan/rear main seal..................really not all that bad but if i take the motor up to 5000-5800 it seems the leak is really bad...............doing a search about dip stick blowing upwards and throwing oil everywhere..................mine will move up about a 1.4 inch but no oil anywhere..................so do i have a crankshaft issue or just the normal rear main/oil pan leak.

This is gettin on my nerves fast

Rich

[Rachelsdad]

Checked your PCV valve recently? Just a random thought which came to mind thinking about pressure lifting the stick.

Edit: Another thought is whether you are actually over-filled on oil or have a blown head gasket. Both can (now that I think about it) cause pressure in the pan.

[chiphead]

An engine develops maximum cylinder pressure when running at WOT. Some of that blowby will make it past the rings and into the crankcase. On a healthy engine with a working PCV, that crankcase vapor is drawn into the intake and burned. During WOT, there is very little vacuum, so a normal amount of crankcase pressure gets vented from the valve cover breathers.

On a very worn motor or one without proper venting, or very bad detonation, the blowby will be enough to push the dipstick out, cause oil leaks or otherwise find its way out of the crankcase. My current 400 is high mile and if I run it really hard, the dipstick comes out 1/2" and there is a mist of oil on the breathers.

How many miles, how is the PCV set up and any signs of detonation near WOT?

[steve25]

Are you running the stock air cleaner assembly with the steel tube coming up out of the valve cover on one side and plumbed into the filter case?

[gtorich]

Originally Posted by steve25

Are you running the stock air cleaner assembly with the steel tube coming up out of the valve cover on one side and plumbed into the filter case?

Steve, its a 66 tripower, i have 1 breather in each valve cover.

As of the pcv valve, im on about my 6-7 one.......the cv697c, the one in the valley pan now is from Butlers. They all seem good but i try different ones just to see if any difference..............usually no difference.

The rings are gapless rings, the builder put them in last year, who knows if something isnt right with them one way or the other.

From my other post Rear main seal on 6-8-2024, would say the leak is double what your seeing on those pics, this was after hitting 5 or so grand 4-5 times.

Not sure how i want to proceed from here, had the car 25 yrs, love it, but this getting the motor rebuilt 3 times and still the same issue from the 1st build, is getting old.

Thinking of selling the car, taking a major hit money wise, but fixing it again is also taking a high money hit. Beautiful car, runs perfect except for these oil leaks...........got to think this over.

Rich

[i82much]

pcv shouldn't be doing anything at WOT. honestly oil leaks are part of the deal with old cars, just accept it. don't nitpick your way out of the hobby!! you take a close look at ANY old car at a show and you will find flaws.

[mgarblik]

There are only 2 things that can make the dipstick pop up. One is physical contact with the stick for some reason. You should see witness marks on the bottom of the stick somewhere or a bent stick. Second is excessive crankcase pressure. You stated each valve cover has a breather in it. One way to check the PCV system easily without tools is to do the "paper test". With the engine running fully warmed up, remove one breather and tape it shut with a piece of duct tape. Then get a piece of typing paper or notebook paper and cut a 3X3" square. Remove the other breather. With the engine at 1000 RPM's approx place the paper square over the hole on the removed breather. The paper should be sucked to the valve cover hole and remain there. It should not just flutter around and fall off and it certainly should not be pushed away from the valve cover. In other words, there should be a slight vacuum in the crankcase. If it fails this test, either the PCV system is not working for some reason or you have excessive blowby in the engine. Crankcase pressure just takes a marginal sealing engine like a Pontiac and makes it extra difficult to seal. A few little drips here and there just has to be considered normal on an old engine design. Obviously, an engine leaving a puddle on the ground needs to be dealt with.

[gtorich]

Hey Mike, never tried that test, will test tomorrow, looks like its gonna rain soon cant let my baby get wet...........another thing i forgot to mention i have those rubber plugs with holes drilled into them in my valve covers to keep the oil inside the covers...............could this be throwing anything off .vacuum wise.

Im hoping for the best here, but have a feeling im gonna flunk the paper test............gonna see if i can get a nos pcv valve, no idea if any of these are floating around. The pcv i have now is from butlers, one would think there selling a decent one.

Mike, i get your statement about a few drips here and there, i can see that but mine seems to drip a few drops even days later while not running.............lol, what do you consider a puddle size would be for reference.

Glad you guys are hanging in there with me on this one, very frustrating to say the least,

Rich

[gtorich]

Couple pics of what i got going here, have a hard explaining things on the puter..............maybe some of you have noticed this..........lol

Anyways pcv hose hooked up to the F-pipe behind the center carb, no other place to put it.

These are the cheapy breathers i have...................let me know if i can get better ones.

The rubber plug is the one in the v/c thought that would keep the oil inside the valve covers better, will pull out and see if that makes any difference.

Just thinking out loud here, the last two rebuilds i believe were with the gapless rings, is this my problem or just poor work done by the builder.

Im hoping some motor pops up for sale similar to what i have now, but so far seems all the motors for sale are race type.

Whats really weird about this whole deal, the dipstick is only a little down from full....................i use 6 qts

Rich

[mgarblik]

I want to make sure I understand those rubber plugs. If they are made like a sleeve with a closed bottom, that's a problem. The bottom of the rubber plug/sleeve needs to be completely open to the breather. I have seen some of those with just a razor slit in the bottom. No good. It needs to be completely open to the breather, at least on one side of the engine. As far as how much of a leak is "normal"? Of course dry is best!! But not easy to achieve. To me after taking the car out and ripping it through the gears say 4-5 times and driving it around 20-30 miles. if I park it on a piece of clean cardboard, I would not expect to see more than a quarter size stain on the cardboard. If I had a stain the size of a 1/2 dollar, I would be a little unhappy. Not very scientific, but that's my personal threshold. One of the reasons I bought a smoke machine.

[gtorich]

Originally Posted by mgarblik

I want to make sure I understand those rubber plugs. If they are made like a sleeve with a closed bottom, that's a problem. The bottom of the rubber plug/sleeve needs to be completely open to the breather. I have seen some of those with just a razor slit in the bottom. No good. It needs to be completely open to the breather, at least on one side of the engine. As far as how much of a leak is "normal"? Of course dry is best!! But not easy to achieve. To me after taking the car out and ripping it through the gears say 4-5 times and driving it around 20-30 miles. if I park it on a piece of clean cardboard, I would not expect to see more than a quarter size stain on the cardboard. If I had a stain the size of a 1/2 dollar, I would be a little unhappy. Not very scientific, but that's my personal threshold. One of the reasons I bought a smoke machine.

Mike, a few pics of what i have with that rubber plug

quarter size stain on the carboard..............damn i have a dollars worth of those after some high 5 thou runs..............not to mention, days after its still the same.

Really nothing bigger than a half dollar stain wise, but i have quite a few of those.

Are you talking about one drop after a drive..............if so im in big trouble, i get drips 2-3 days after a hard run.

Glad your hanging in there with me on this...............

Pics of the rubber grommet im talking about.

Worse case Sincero.............if i drive the car under 3500 rpm, the leaks are not all that bad..............if over 5000..............they are really bad.

I will buy a smoke machine................would be great if you could give me a # on what model you bought............

Problem with the smoke machine, say its the rear main or oil pan seal.............doesnt really matter if i have too much crankcase pressure does it.

Rich

[PunchT37]

Cut the bottom of those plugs wide open or ditch em for open versions.

PS, prolly a big part of your rear main problem.

[mgarblik]

If I am seeing the pics correctly, it looks like those are rubber plugs. Even if they have tiny holes in the bottom they can't let that big crankcase breath properly. I would cut the bottom off one of them, clean the engine bottom up and go for a drive. Problem may be solved. The PCV system can't work if outside air can't get into the crankcase and push the lighter crankcase gasses into the PCV hose and valve. Working properly, it's a loop. Outside air through the breather into the crankcase, pushing blowby gasses up into valley cover, through PCV valve, through hose, back to the intake to be burned.

[Verdoro 68]

Are your breathers pushed into the sealed rubber plugs?

[pippintook]

Hey Rich

I think for sure the rubber plug should be cut so crankcase blowby gas can escape at higher rpm. Hopefully, that is what is causing the issue.
.
I think you will find there are some guys on this forum have the same symptoms. Engine runs good and has no apparent issues and good power at lower (say under 3500-4000 RPM). But, when driven aggressively (racing, drag racing) and running at higher rpms (say 4500-5500) there is excessive crankcase blowby. Oil dip stick can get pushed out. Weeping / leaking of engine gaskets/seals - like rear main seal, oil pan gasket, front timing cover crank seal, valve cover gaskets etc.
.
All engines have some blowby. PCV system handles normal engine crankcase blowby at low rpm mostly with PCV valve connected to engine vacuum. At high rpm , for my engine (78) engine crankcase blowby is vented up passenger tube through small filter into the air cleaner. In some cases proper engine venting (PCV system) can help (cure?) some blowby issues. I think it also depends on how severe the blowby is. Drag racers can obviously see this issue a lot. As they continually run the engine at high rpm. It appears some racers may use a vacuum pump (elec? or mechanical) to help alleviate excessive crankcase pressure.
.
I had an engine (400 stroker 4.25" , stump puller cam, SD ported heads 260cfm?, headers, cast iron intake and qjet) that had moderate to severe blowby at high rpm. I first noticed when doing some drag racing/ hard driving. My oil dipstick tube was getting pushed out. I also had some oil in engine air breather. I have a tube running from passenger valve cover to engine air breather. My small air breather filter (in the air cleaner housing) was getting pretty wet with oil. I also started seeing some drips out of the rear main seal area. I started to see my oil pan gasket weep a little bit of oil and some drips from front timing cover crank seal and valve cover
gaskets weeping.
.
I tried some band aids
- header evac, did not work for me
- higher flow PCV, no real affect
- got another passenger valve cover and added a second vent and used a filter and catch can, did not really help

Through all this , I drove the car quite a few miles. My compression was always decent , like 170-180. I did a leak down test and was seeing 10-15% which is kinda marginal for fairly new engine (less than 5000 miles). My plugs looked ok. Engine had ok idle vacuum. I found the oil would get kinda sticky and turn darker quicker and maybe smelled a little bit like fuel. I seemed to go through oil quicker - though I never noticed much (any?) blue smoke coming out the tail pipe. I drove quite a few years and lived with the issue. Maybe did not beat on the engine as hard . I always parked on top of big piece of plywood so as oil dripping would not stain driveway. Maybe after having the engine like this for 3-4 years, I added an additional vent to drivers side valve cover. The normal setup on my drivers valve cover was the oil cap. I added a temp vent and hose and just vented...I think I just ran about 3-4 feet of 3/4" ID hose (with filter material) and vented to atmosphere. This seemed to help more than my other band aids - less leaking/weeping from seals and seemed like less blowby. Even through all this - engine had good power and no issues.

I am not sure on what caused my excessive high rpm blowby. Maybe for my engine, the ring seal at higher rpm was not good. Was the problem, the rings, the gapping ? the cylinder wall finish ? Bores being a bit out of spec? I have also read that you can have high rpm "ring flutter" - where rings can lose some of their sealing ability at higher rpms. Note, my stroker kit came with Mahle pistons. These Mahle pistons had oil ring cut into the piston pin area. I am not sure if the affected my issue.

Hope that helps you a bit

[gtorich]

LOL...........pippintook, when your typing gotta say your typing. thanks for that info.

Ok, did the Mike test with the one v/c holed taped shut, put the 3X3 paper on the other hole...................that was a no go, paper just fell off...............so im guessing maybe a pcv issue.

So as of now i ditched those rubber grommets and just using the regular ones with my cheapy breathers.

Only took the car up to 53-55 rpm for one shot................this pic is what i got about 5 minutes after that.

The dip stick did raise about a 1/4 inch but no oil anywhere around it.........as usual it still reads near full................wonder whats up with that.

Next pic with the two drops was about 1/2 hour later................will post a pic in the morning after sitting all night.

These drips i can live with....................the ones the other day after really beating on the car where far worse.

Guess it comes down to two things.................still too much crankcase pressure even with new rings, or bad pcv valve................will look into another pcv valve, sceen some on ebay...............old ass box but the valve looked like new which i have about 6-7 of them.

Hopefully this will help some..................question i had, are these breathers good enough, or what ones would be better to help some.

On the pics the one with a few spots are about 5 minutes after i got home.................the one with the 2 spots are a 1/2 hr later...............dont know why the one on the top was there................the reason i think your seeing more spots are i drilled some holes in the inspection plate, didnt want all that stuff near the clutch.

any more input from you guys would be great.

Rich

[gtorich]

Just for reference, i know the spots are small, not a big deal, but after yesterday on beating on the motor quite a few times, they were about 10 times that size, thats my concern, not the few small spots your seeing here..................not only were they pretty big, but after cleaning my pad 3-4 times they were still dripping 2 days later.

Rich

[67drake]

Hmmm. My valve covers have those big rubber plugs too. I know passengers side is solid at the bottom, just there for decoration. The drivers side has the breather in it like Rich’s. I never checked to see if it was open at the bottom.
If I took a picture of what my ‘69 400 pukes out onto the garage floor, you’d laugh. It actually runs out from under the car towards the floor drain if it sits long enough. One of the reasons I’m pulling my engine soon. I’ve never noticed my dipstick raising though.

[Verdoro 68]

Seems like you’re on the right track with lack of crankcase ventilation. If you’re going to keep buying and trying PCV valves, consider the ME Wagner. It’s not cheap, but it will for sure do the job.

https://mewagner.com/?p=2173

[pippintook]

When I had blowby , I think I took an old pcv valve and just cut out the middle (so valve was mostly open), this did not make much of a difference in the high rpm blowby. So, I generally just ran a stock type PCV valve. I could drive the car normal - like just cruising around and the odd moderate acceleration and afterwards oil dipstick would not move and very little dripping oil from the engine. But, as soon as I beat on the engine and drove it pretty hard I almost always had oil dipstick pop a bit and afterwards I would usually see some pretty moderate to severe oil drips on the floor. I found that not much , if any oil, actually seemed to come out the dipstick. I think I just eventually put a bolt in there. There are lots of styles of valve cover grommets. Some are open, some have a one slit or a cross slit. I had a bunch of grommets and I tried different things, like half open or drilling different holes in the bottom - nothing really seemed to have an impact on my engine's high rpm blowby. One thing I also did was stick some velcro on back of oil pan (cleaned first) and then I would stick/jam some small sponges in there - that would help with the dripping oil from back of pan / rear main seal. Periodically, I would change the sponges.