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Author Topic:   How do I stop oil blowby on the valve cover?
rnoswal53
Dirt Maniac

Total posts: 120
posted February 27, 2005 06:59 AM  
Well after all the advice and help from this forum, I got the car out for ten laps on playday. I loved the power and I found I don't need brakes, just let off the gas!

Anyway, my session was sort of cut short because I was losing oil out of the breathers on the valve cover. I have the breather cover on the driver side. Under the valve cover there are metal vents that cover the holes, but I put them facing down toward the exhaust side. Maybe I should point them up?

When I got done I had a lot of guys that were happy to see me in a new class, was mini stock. They all had their favorite cures for the blowby. Wrapping rags around the breather filters was a good one. I never did put any oil restrictors in the block. I am running solid lifters.

My question is, how do you guys stop or drastically slow down the blowby? A friend suggested putting fuel foam into the breather holes.

Thanks
Russ

WPP
Dirt Freak

Total posts: 451
posted February 27, 2005 07:15 AM  
Do you run akly was it cold on play day. I have also seen too much jet on akly carbs.

dirtywrench13
Dirt Freak

Total posts: 324
posted February 27, 2005 07:32 AM  
#1 put oil restricters in to keep most of the oil in the mains and rods where its needed the most!
#2 point the breathers up.

#3 try coarse steel wool in the breather tube, don't pack it in, just fill it,but try to keep it in one piece so it will pull out when you add or change oil.

hope this helps.

crwchfj10
Dirt Newbie

Total posts: 3
posted February 27, 2005 07:43 AM  
I agree with Dirty on the restictors - that "should" stop the oil blowby. I do NOT recommend the restictors if you run a roller cam - you need the oil up there to keep the springs cooled down.

rnoswal53
Dirt Maniac

Total posts: 120
posted February 27, 2005 07:44 AM  
Yeah it was semi cool, 50's and yes to the alky. I had always heard that you couldn't have too much fuel with methanol, to a point I mean, but I felt that it was too much myself. I had borrowed the carb. How could too rich a carb cause blow by out the breathers though?

Restictors?!?!?!?! was hoping to not have to pull the engine, but I kept getting different opinions with the restrictors though and just a few more leaned for not, so I didn't, maybe I should have.....****. At least I can try the steel wool without pulling the engine!

Thanks

dirtslinger66
Dirt Maniac

Total posts: 200
posted February 27, 2005 08:12 AM  
If you run a solid lifter cam you have to run the oil restrictors or it fills the valve cover with oil at high rpm

donslink1
Dirt Freak

Total posts: 318
posted February 27, 2005 08:25 AM  
It is not the solid that says you can run restricters or not. it is your rocker arms Im asuming you are running roller rockers and with a roller rocker you should run restricters if you were running stamp steel rockers you need the oil up there to cool them down.
I would turn your valve cover around and put the restricters in alls you have to do is pull the trans. a lot easyier that pulling motor

rnoswal53
Dirt Maniac

Total posts: 120
posted February 27, 2005 08:48 AM  
Well that sounds more promising. Pulling the transmission I mean. With the restictors, is it easy to put them in? Does it require cutting threads, or are the threads already there from the plugs in the oil galleries?

What do you guys think of the valve cover/breather system that puts a tube across between the valve covers up front with the breathers on that tube? It looked interesting and maybe harder for the oil to get blown out.

Yes I do have roller rockers so I guess the restrictors are a must then. Well I can do that.

Thanks

Dirt-Tracker
Dirt Maniac

Total posts: 182
posted February 27, 2005 01:37 PM  
Im not sure about chevys, I run fords. If you have to thread the holes: Take a small piece of rag and stuff the hole with the rag. Then I take my grease gun and fill the hole with grease. thread the hole then take some carb cleaner and blow out hole as good as you can then take some tweezers and pull rag out. The grease should pull out all filings that the carb cleaner didnt get. Right or wrong it seem to work for us.

donslink1
Dirt Freak

Total posts: 318
posted February 27, 2005 02:17 PM  
There are threads in there already,
there are three plugs, you have to plug the outside two leave the middle one pluged.
One plug goes right in to the distributor hole so make sure you dont go too far in and hit the distributor, you'll know if you want take out the distributor and look down the hole and you will see it sticking out if you go too far.

Istock66
unregistered Total posts: 318
posted February 27, 2005 05:13 PM           send a private message to donslink1   Edit/Delete Message   Reply w/QuoteBBBBBB
Seems like everyone is going around the real problem to me??

First off what would you do if you were running this motor in a stock rocker class, you would fix (----?----).

Sounds to me like youve got a lot of BLOWBY as in your topic heading. Rings, guides, hone job on cylinder walls all come to mind!!!

badfastjr
Dirt Maniac

Total posts: 193
posted February 27, 2005 05:59 PM  
what if hes getting too much fuel in the cylinders and part of it thats not burned is mixing with the oil, then thinning out the oil causing it to blowby........Is this a possiblity?

NOBODY
Dirt Roller

Total posts: 11
posted February 27, 2005 06:03 PM  
If you put too much alky in the motor, what doesn't get burned, will wash the rings out causing blowby.

racer17j
Dirt Forum Champ
Total posts: 5390
posted February 27, 2005 08:17 PM  
I understand the question as to, is the problem too much methanol and washing out the rings? I really don't think that it is, even though alcohol carbs run a lot more fuel than regular gas. This seems to be a more common problem than I knew about. I really think the problem is in the older oiling system used in a racing situation. I don't think the oil is controlled very well in the 350 engine if it is pushed.

My problem is that there are so many ways of addressing this problem that I am not sure of what are the best ones, other than buying an engine from Hendricks racing. If too much is pushed up to the heads and it stays there too long then I need to control that amount.

It seems that I must do what I can with what I have and if that means putting socks in the breather tubes then so be it. I think there may be better ways than that without going to extremes, but I think in the long run, it will be a solution similar to socks and restrictor tubes. I already had to put sealer on all the studs and I find that ridiculous, but necessary. Plus I don't smell any fuel in the oil and that is pretty obvious. But keep up the suggestions, I read them all and I know that there are plenty of 350's outthere that have had this problem and for the most part, have fixed them.

Thanks

sdracer12
Dirt Maniac

Total posts: 180
posted February 27, 2005 09:52 PM  
I had the same problem as you, and I finally got it fixed, maybe your setup is similar:

I had a set of the cheap stamped steel valve covers (like $29.00 from Speedway) which only had 1 baffle in the breather tubes. They always, always dripped oil.

I bought a good set of aluminum valve covers. These have 2 breather tubes on the drivers side cover, only. They also have 2 sets of baffles in each tube. I then added a small ball of BRASS scouring pad material inside the top of each tube. I run outerwears on the breathers. Now my valve covers are dry and oil-free, lol. I run a full roller motor, which is internally oil restricted by my engine builder.

The brass pads look like a whole bunch of little coils, and I found them at the local grocery store in the cleaning supplies. I figured even if a small piece found its way into the engine, the soft brass shouldn't do any damage.

Hope this helps.

rnoswal53
Dirt Maniac

Total posts: 120
posted February 28, 2005 07:16 AM  
quote:
Originally posted by sdracer12:
I had the same problem as you, and I finally got it fixed, maybe your setup is similar:

I had a set of the cheap stamped steel valve covers (like $29.00 from Speedway) which only had 1 baffle in the breather tubes. They always, always dripped oil.

I bought a good set of aluminum valve covers. These have 2 breather tubes on the drivers side cover, only. They also have 2 sets of baffles in each tube. I then added a small ball of BRASS scouring pad material inside the top of each tube. I run outerwears on the breathers. Now my valve covers are dry and oil-free, lol. I run a full roller motor, which is internally oil restricted by my engine builder.

The brass pads look like a whole bunch of little coils, and I found them at the local grocery store in the cleaning supplies. I figured even if a small piece found its way into the engine, the soft brass shouldn't do any damage.

Hope this helps.


The valve covers I am using have the two breather holes on the driver side only. I am running solid lift flat tappet lifters and aluminum roller rockers. I have had people tell me that the restrictors are needed for a full roller setup like yours but not so with my setup. It just seems that too much oil is going to the top of the heads and not draining out fast enough. I am going to pull the valve covers off and check to make sure there aren't any restrictions in the return holes, but I have heard that the stock drain holes are too small anyway. Nothing I can do about that right now.

I just need to curb the flow to the top of the heads since they don't seem to drain that well. I had a guy suggest that I put pipe cleaners in the push rod holes to slow the flow of oil. I don't understand why a lot of people say not to go with the restrictors. One guy told me that he lost 3 cams from doing that, not enough oil. This is getting frustrating.

I am sure there are more than a few of us that can't afford $10,000.00 motors, but have been able to have good reliable power and longevity with the setup similar to mine. I like the deal about the brass brillo pads. I have seen those and may give them a try.

Thanks


dluna
Dirt Freak

Total posts: 334
posted February 28, 2005 07:23 AM  
I'm not much of an engine man, but we always had some serious blow-by in our motors (wrapped the rags around the breathers) until we spent a little extra for a good set of rings. Haven't had to wrap the rags around since then.

star1modified
Dirt Maniac

Total posts: 102
posted February 28, 2005 07:47 AM  
put the restrictors in it...vent tubes(4) in the lifter valley and put 1/4 in. pipe plugs in the rest, staggered of course...thats a must on solid lift motors...

Rat Trap
Dirt Maniac

Total posts: 129
posted February 28, 2005 07:56 AM  
We had this problem last year. We bought some cleaning pads at the grocery store like the brass and steel wool pads but they were of a plastic type material instead. Worked great.

wfoondirt
Dirt Forum Champ
Total posts: 505
posted February 28, 2005 08:15 AM  
9 times out of 10 oil out the breathers is a sign piston ring blowby, usually from worn or cheap rings. Crankcase pressure is what forces the oil out not having too much oil in the valve cover. Oil restrictors were not designed to stop this, they were designed to keep oil in the pan when running stock pans. With a good racing pan you shouldn't need them and if you are running more than ~.600 lift you definately don't want them because the oil helps cool the springs. Its very easy to over fuel an alcohol motor and have it still run but it is hard on the motor. The excess alcohol causes servere cylinder wall wear and dilutes the oil.

autoshop
Dirt Freak

Total posts: 298
posted February 28, 2005 08:38 AM  
Change the valve cover beather hole placement, As with most breather hole some engineer decided to put the fill hole right over a rocker arm so thus oil can and will shoot right up the beather hole even with a baffle covering the hole,plus it makes it easier to bolt the cover down with the beather in place. Also angle the breather where it is 90* to the ground not the valve cover.If you move the breather hole either forward or backward from the rocker the problem should go away.

NJantz
Dirt Forum Champ
Total posts: 755
posted February 28, 2005 09:13 AM  
The style of foam they use for "fuel cells" works good to place in the breather tube stack. Raise your breathers up as high as you can get them on the tube. Wrap shop rags around the breathers. that's what we do. Make sure there is some sort of deflector to block oil from getting into the breather tube.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted February 28, 2005 09:27 AM  
I wouldnt put metal scouring pads of any kind in the breather. No matter how soft the brass is it still could cause problems. The plastic pads might be alright as long as they dont break down in oil. Just pull them out everynow and then to clean them.

Also the breathers are there for a reason, You need to let the motor breath if it needs it. You dont want to stop airflow completely if you need to filter out he oil then work on some sort of baffling system that wont overly restrict the airflow.

rrrrick
Dirt Maniac

Total posts: 192
posted February 28, 2005 11:39 AM  
I had that problem with some Inexpensive Valve covers.
To Cure it I welded a 1/4" fender washer inside the breather tubes about 1 1/2" down from the top at about a 45 deg angle.
This seemed to cure the the oil coming out of the breather.


NOBODY
Dirt Roller

Total posts: 11
posted February 28, 2005 03:34 PM  
I was just going off your 2nd post about how you thought that the fuel was too much. You don't have to go far, one way or the other, with alcohol. If you get too much you loose power caused from the blowby, if you get too little you melt the pistons and ring out the exhaust pipes. I run total seal rings and turn 8900 rpms in the straights, but when I was trying my engine for the first few races, I had my jets just 2 sizes too big and it caused blowby. I personaly, and do mean personaly, recomend the oil restrictors. I turn lots of rpms though and it doesn't take long to drain a pan of oil. Oh and you can wash out your rings without being able to detect it in the oil, especially if you only make a few laps and your not way-over jetted. If it does get to the point that you have exessive fuel in the oil it will scorch the bearings, and you don't want that!

stockcar5
Dirt Forum Champ
Total posts: 578
posted February 28, 2005 08:32 PM  
oil restrictors will not fix your problem. oil is metered by the lifter and pushrod. if you have oil on the top end of your motor you dont have proper drainback. all you will do by adding restrictors is shorten your valve spring life. i have used the fuel cell foam and that works well. some guys will run hose off the breathers and run them past the firewall to keep oil off the motor.

------------------
www.geocities.com/dirtstockcar5

rnoswal53
Dirt Maniac

Total posts: 120
posted March 01, 2005 07:45 PM  
Well again, there are a lot of good postings here. How about this one. I built the engine from new parts, (crank, rods and pistons) used but good from a friend. He gave me an oil pump and I just put it on. After these problems I found out it was a high volume pump. I am hearing that these can pump an unrestricted oilpan dry very quickly. Most said stock oilpump with a stronger relief spring. How does that sound?

That short time the oil light came on caused a spun rod bearing, so I have to fix that and then try the suggestions mentioned. I have a 7 quart pan with a kick out and it is baffled. I think I will go with the foam in the breather tubes and I did have the breathers pushed almost all the way down, so I will raise them up too.

I hoped to be ready for the beginning of the season, but you know, it has to be right first! How about stock pump, stronger relief spring and restrictors?

Thanks
Russ

21racer
Dirt Full Roller

Total posts: 56
posted March 01, 2005 08:02 PM  
every one else has an opinion so here is mine. i run the oil restrictors. if you are running to rich on fuel washing down cylinders oil will be diluted or milky. if you are running cheep cast piston rings you will have blowby because they do not seal as well as better rings. lastly if the oil is not excessive it wont hurt any thing just wash the motor every week. i once ran a motor that blew out a quart of oil a night finshed in the to four many times when someone looks at it in the claim area they just walk away shaking they heads saying i'm not claiming that!!!!

mdsteacher
Dirt Maniac

Total posts: 145
posted March 01, 2005 08:46 PM  
We too had a similar problem with oil blowing out of the vent tubes. Several things we did helped solve the problem. First, bought a new set of shielded breather filters and cleaned them every week. This will allow good air into the engine. Second, we closed the baffles slightly inside the vent tubes. And thirdly, we cut the vent tubes down a little to allow us to raise the breathers higher without hitting the hood. We made one change at a time until we solved the problem. We hadn't had a problem since. The engine I ran was put together very well with good parts and turned it 7500 most nights. I wouldn't ever stick anything down the breather tubes.

fast_crew
Dirt Forum Racer

Total posts: 99
posted March 02, 2005 06:46 PM  
the high volume pump shouldn't cause a problem aslong as it has the "standard" pressre spring. I wouldn't recomend the restrictors.we run a 7qt pan and only run about 61/2 qts. W/solid "flat" cam, roller rockers, high vol"std press" oil pump,no restrictors, turn 7ooo rpm. never had an oiling prob. or alot of oil out the covers. If you don't keep them clean they will start to drip alittle. we usually use old socks over the breather, and change them every week and clean the breathers every 2or 3 weeks. I would definitley check the carb jetting. Hope this helps.

James Birmingham
Dirt Full Roller

Total posts: 28
posted March 02, 2005 07:24 PM  
Gezz guys too much oil to top end for a starter. The high volume pump and no restrictors is putting to much up stairs each cover will hold 1 1/2 qts. The volume way overloads the gravity drain backs. Thats why a lot of people were installing (drilling holes into the main gallery) and oiling the cam and lifters yet installing restrictors to limit the flow to the valve covers. Man I dont know about the springs I wasnt having problems with springs sacking out not with resonable replacement cycles. The oil dilution in the oil should be pretty easy to see looks like green baby ****. Best reason to run racing type oils because of their ability to live with more fuel in them. (not the answer but helps). Man ya gotta keep the water temp up too what was it when you were practicing. In order to keep the A/F (air fuel ratio) right you almost need a O2 sensor unless you have a lot of tuning experiance.

uforacing51
Dirt Forum Champ
Total posts: 570
posted March 04, 2005 03:29 PM  
I think this is the most info I have ever seen on one post. good job

mod4
Dirt Freak

Total posts: 223
posted March 04, 2005 04:24 PM  
I've seen this a couple times and wanted to know how common it is, where somebody runs a AN fitting on the back corner of the valve cover to the oil pan to aid drainback ?
Was told it's because they wanted plenty of oil up top but the heads don't drain well enough. Don't know enough about the theories behind oil drainback and how much gets put in the heads to know, thats why I am asking.

oluf
Dirt Full Roller

Total posts: 30
posted March 04, 2005 09:04 PM  
Does anyone run the crankcase evac system that runs tubes to the header collectors, like the drag guys do?. I've seen some dyno tests on these & it seems like 15-18 hp gain was common, plus it seems it would help with the oil leakage problem. Just a thought!!

RPM08MOD
Dirt Full Roller

Total posts: 30
posted March 06, 2005 12:46 AM  
I had the same problem, tried all the tricks like foam in tubes but didn't solve the problem.After looking closer I found on the stamped steel valve covers the oil was coming from around the base of the tubes where they attach to the valve cover. I just sealed around the tube with silicon and haven't had the problem in years.

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