My brother has a 1979 Dodge custom p/u with a tired 318. It has blow by so bad that the air filter got oil soaked and stopped letting air flow through it, so it pumps oil into the air filter housing and is covered in oil. I ran a bottle of amsoil engine cleaner through it (which I got for free from a guy at work)and it helped a little bit but its still bad. I have 5 quarts of trop artic 10w40 in it now, I may put a catch can in it but its so bad that the can would probably fill within 100 miles. It runs fairly well, doesnt miss, and it does not have to pass emissions. So any suggestions short of a trip to the machinist would be appreciated.
Bad blow by in my dodge 318 V8 any suggestions
- Thread starter hotrat
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Tough engine probably rings and a valve job.
Good luck.
Good luck.
I'd clean up the PCV valve and line, run the cheapest 15w-40 or 20w-50 I could find and run'er! Maybe rigging up a big catch can for the breather line wouldn't be a bad idea, or route the breather line thru the aircleaner cover so it goes right into the carb instead of on the filter.
G/luck
Joel
G/luck
Joel
This would be a good case for 20W-50 or straight 40.
Go to a junk yard and find another 318 that runs better. You should be able to get one for under 300.
An ARx treatment may clean out the ring packs so that they seal, and not burn oil.
They need to be free and clean for the cyl. pressure to force them outwards and seal.
They need to be free and clean for the cyl. pressure to force them outwards and seal.
Could it hurt any to try a sea foam soak (start with warm engine, let sit overnight with plugs loosely installed to minimize eveaporation), with also trying some through a vac line? It seems that a piston soak by pouring some through the spark plug hole just cleans the piston tops, but I'd figure some to also seep past the rings - also be sure to turn the engine with the starter prior to reinstalling the plugs to get most of the liquid out to help prevent hydrolocking. be mindful of spark emissions from the distributor while doing this (ground a plug that's attached to the min high-tension lead from the coil if the charge must be dumped - i think I remember someone saying that some newer electronic units require discharge to prevent damage..don't understand quite why unless it's such a high voltage it could jump somewhere from around the coil - seen this with a different step-up transformer I've used in experiments).
Like others have mentioned, you may want to also try running one weight up, or perhaps a straight weight if it seems to blow-by the most when going through the warm-up cycle.
A friend of mine had a situation where oil fouled his tractor's air filter after I did an oil and filter change - appearently the oil level as read on the dipstick shouldn't be above the half-way mark in the mettering area. Has the fill level changed at all since before this became appearent?
Like others have mentioned, you may want to also try running one weight up, or perhaps a straight weight if it seems to blow-by the most when going through the warm-up cycle.
A friend of mine had a situation where oil fouled his tractor's air filter after I did an oil and filter change - appearently the oil level as read on the dipstick shouldn't be above the half-way mark in the mettering area. Has the fill level changed at all since before this became appearent?
I second the recommendations for ARX and a heavyweight oil.
I had a 318 years ago that developed terrible blow-by very rapidly. Turns out it had put a pushrod through one of the rocker arms. Long shot, but you might want to pull the valve covers and check that everything is where it's supposed to be.
Do the words "Hey, that thing got a HEMI ??" mean anything.
P.B.
P.B.
Ignore all the above posts untill you've replaced the Crankcase vent canister on other valve cover from PVC valve!!!
Back when these were 2-3 year old vehicles you could buy them with "bad" engines at 50-60K, change canister and run them another 200K before real blowby started.
Bob
Back when these were 2-3 year old vehicles you could buy them with "bad" engines at 50-60K, change canister and run them another 200K before real blowby started.
Bob
Joel
Line to air cleaner housing connects to cannister on valve cover oposite PVC valve. That's how oil gets into breather.
Bob
Bob
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I'll second or third the Auto-Rx attempt and the plug out piston soaks. You've got nothing to lose. Same with the checking the PCV system.
What's your emissions environment in your PNW state
What's your emissions environment in your PNW state
HOTRAT DO NOT give up the ship!Well..... what I MEAN IS...start engine and let it idle.Remove the PCV valve from the rocker cover.If this part of the PCV system is operating correctly the air passing thru the valve will cause a hissing noise,and a strong vacuum can be felt if you put your finger on the exposed end of the PCV valve.If not, determine if the valve is plugged or defective,and that the hose and the lower carburetor port that the hose goes to are not plugged.Its a problem of this sort that then causes oil to end up in the air cleaner housing.How?IF the other stuff is clogged the engine suction will then cause reverse flow thru the "canister" as per Bob.The cannister is actually a very crude longlife? air filter for the PCV System.Its kinda counter intuitive because it draws UNFILTERED air FROM the AIR CLEANER ASSEMBLY when the other side is functioning.Next, re install the PCV valve and remove the crankcase inlet cleaner(ie the previously mentioned cannister). Take a piece of stiff paper and hold it over the rocker cover opening where that filter mounts.Give it a momentfor crankcase pressure to reduce.The paper should then be sucked tightly against the the rocker arm opening.If not repeat step one or replace the PCV valve.From what you described odds are in less time than it takes to type this you will be squared away.As far as the "air inlet cleaner goes unless its unserviceable clean it out and lightly reoil it.Hope this helps Bob and Joe are both right - its Mopar PCV related.
Haven't worked on one in a while, but canister used to be cheap enough to just throw away.
Bob
Bob
Ah.....air is drawn OUT of the crank case through the PCV valve and line.
Air goes IN to the crank case through the opposite valve cover, through the canister......
Clean....or replace the canister.....and as mentioned.....verify that you have the airflow through the crank case.
The PCV system is removing nasty stuff that you want to get out of there.
That is the case for ANY engine.
The AutoRx is certainly worth a try....it DOES clean things up and should help.
Another possibility is using a different oil that has a lower evaporation rate.
Also, one could reroute the air source INTO the canister from a source OTHER than the air filter "box".
The only time that one would expect oil vapor to come into the filter area from the crankcase canister would be when you shut down the hot engine......and it sits.
Also, oil vapor could enter the air filter area from the PCV line after the engine is shut down.....as there is no airflow through the filter area into the intake manifold / carborator.....so the warm air will rise.
A catch can on the PCV line is another good idea that you mentioned.
Air goes IN to the crank case through the opposite valve cover, through the canister......
Clean....or replace the canister.....and as mentioned.....verify that you have the airflow through the crank case.
The PCV system is removing nasty stuff that you want to get out of there.
That is the case for ANY engine.
The AutoRx is certainly worth a try....it DOES clean things up and should help.
Another possibility is using a different oil that has a lower evaporation rate.
Also, one could reroute the air source INTO the canister from a source OTHER than the air filter "box".
The only time that one would expect oil vapor to come into the filter area from the crankcase canister would be when you shut down the hot engine......and it sits.
Also, oil vapor could enter the air filter area from the PCV line after the engine is shut down.....as there is no airflow through the filter area into the intake manifold / carborator.....so the warm air will rise.
A catch can on the PCV line is another good idea that you mentioned.
Thanks for all the suggestions, I checked the canister and sure enough it was bad, so I tossed it and got a new one on there, no more oil in the filter housing. Thanks for the old school MOPAR knowledge Bob and Joe, now theres another 318 on the road. PS, Papa Bear "This things got a wedge" and its mighty 2 barrel is breathing again.
Kestas
Staff member
If needed, the dealers sell pcv vavles especially for high blowby engines.
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