Oil Leak on SBC....please help.

[degnitz_3732]

Hello. We just bought a brand new 406 from Shafiroff and we are having problems with an oil leak. The first time we started the motor, it looked like the oil was coming off of the oil pan gasket in the rear of the motor under the crank. So we then dropped the pan, cleaned everything up and gooped it up with a sealer and bolted it back up. Well.....we tried it again last night and it still leaks. The problem is that it still looks like the leak is coming off of the oil pan but it is so hard to tell. We know that there is a possibility of it being the rear main seal, but it just doesn't look like it. If we look at the end of the crank, flywheel, and converter....there isn't any oil on any of them!!!??? If it was the rear main seal wouldn't the oil be all over the crank and flywheel????!! When we start the motor.....it takes about 15 seconds of it running and then the oil starts dribbling down the back of the oil pan. Please....if you have any suggestions or have experienced the same problem plase let me know. Thank you, Derek.

[us7race]

It isn't coming down from your oil fitting is it? I have even seen valvecovers leak in the back and run down the back of the motor down the pan. Just some idea's.

[gimmemud]

Also look at the rear of the intake,(where the intake meets the block) they are bad to leak there and it would run down the back of the block.

[signsbyesa]

if its brand new you should call the dealer back and should not have
opened it up, now they can say you made the leak, you would be amazed
at the trail an oil leak can come from, your dealer should be notified :?

[hammertime]

if its brand new you should call the dealer back and should not have
opened it up, now they can say you made the leak, you would be amazed
at the trail an oil leak can come from, your dealer should be notified :?

With my dealings from the place he got it he was SOL no matter if it went to 1000 parts on the garage floor.


My sb from them leaked like a son of a gun I put a 1 peiece fel-pro gasket on it that helped some the leak but ended up being the rear main seal. When changing it.. make sure the parts you paid for are in the motor just my past dealings with them.

[promod45]

try this first take a can of cheap primer paint and spray back of pan and up back of block , let dry then start motor and then you will see where its comming from, i have seen people put the seal on the rear main in backwards and thought it was the pan, this paint trick has help freinds of mine to find leaks, good luck..

[mopar1968]

either rear of intake or dist seal

[degnitz_3732]

Thanks for everybodys input. Needless to say we still haven't completely stopped the leak. We took the motor out last night, cleaned everything up. We have a shaft with a drill we use to get the oil primed which build oil pressure. So we did this and watched the back of the block for leaks. We found that there are three 1/4 set screws about where the camshaft is. Two of these were flush with the block, and one was sticking outwards about 1/8 inch. The one that was sticking out leaked oil when we ran the oil pump. So we then taped it and put a little sealer on it and put it all back together. We then started the car and let it run for about 15 minutes (Temp of 180). It didn't leak at first, but then the oil started thinning and it started to leak a bit in the same place as the night before. The only good thing that came out of this was that it only leaked about 6 drips while it was running, and the other night is leaked a puddle on the ground. So now we really don't know what we should do. Obviously we need to take it back out and try something. We thought about tapping the hole a little deeper, but then we have to worry about getting metal shavings in our oil. Has anyone else had any problems with these set plugs??? We have pretty much ruled out the rear main seal, because there isn't a drip of oil on the crankshaft or around the seal. It runs down from that plug and down around the crank and down the motor plate/oil pan. If you have any suggestions please let me know Also, this is a Dart 'Little M' block. Thank you, Derek.

[fla1976]

I would suspect the other two allens at the rear of the block near the cam. If one was loose, the others may not have been sealed correctly too. Does it have oil restrictors? Would also check at the cam plug (freeze plug) and see if it is leaking there. My 377 would leak at the intake manifold where it meets the block near the distributor. The problem turned out to be the manifold was poorly machined at some time, would leak at the strangest times. Used gasket in a tube to seal it.

[suicidebomb]

Make sure that the plug and hole are not threaded with different threads. ie NPT & SAE.

suicidebomb

[altune]

We had the same problem an an engine from a well known builder.
it was the rear allen next to the cam plug, use some plumbers liquid seal.
screw those in as far as they will go.
we did the same, thought it was the pan.
asked if the dydo room had any oil on the floor after our 8 pulls and they said , our dyno floor is always oil free, oh well

[degnitz_3732]

Make sure that the plug and hole are not threaded with different threads. ie NPT & SAE.

suicidebomb

I ran a 1/4 NPT tap into the hole and it seemed pretty loose even when it was completely turned into the threads?? Would and SAE thread be a straight thread? It wouldn't be tapped to 1/4 NPS (National Pipe Straight) would it????? I'm pretty confident that the plug is tapered.....but i did question if it was indeed tapped with a tapered thread. Any suggestions??

[suicidebomb]

SAE threads are straight threads. Some NPT&SAE threads are close enough to screw together, but they probably wont seal under pressure. I have seen NPT threads screwed into holes with SAE threads & vice versa. Did this answer your question? If not holler
NPT threads are a tapered thread, They are tapered 3/4 inch to the foot. I don't know why I know this but I do.


suicidebomb

[cepx111]

"I don't know why I know this but I do" thats scary dude...lol

Serioulsy if the fitting doesnt seem like it wants to tighten up , put alittle extra teflon tape on it or just toss it and try a new fitting, sometimes they get alittle carried away tapping them fittings and run it to far down the fitting which will keep it from being able to tighten up all the way. I prefer the shouldered brass set plugs over those allen ones and also I use a combination of telfon tape and pipe dope.
Goodluck, Charles

[degnitz_3732]

"I don't know why I know this but I do" thats scary dude...lol

Serioulsy if the fitting doesnt seem like it wants to tighten up , put alittle extra teflon tape on it or just toss it and try a new fitting, sometimes they get alittle carried away tapping them fittings and run it to far down the fitting which will keep it from being able to tighten up all the way. I prefer the shouldered brass set plugs over those allen ones and also I use a combination of telfon tape and pipe dope.
Goodluck, Charles

Yeah....do you think it's a possiblility that they put a straight tap in there?? If so....would you need a shouldered bolt to seal it off?? And about the teflon tape.....that is what we did the last try. We cleaned everything and tefloned it and used some sealer on it also. One more question.....can you use a brass plug in a steel block??? Thanks for everyones input. Derek

[performanceengin]

the dart little m uses 1/4 npt. on rear plugs. remove all 3 plugs, check them close or pitch snd install new ones. use pst thread sealant and tighten good. you can use steel or brass. this block has priority oil system in it and they don't recommend restricters. also check plugs to see if they may have a small hole through the center, have had that problem before..

[degnitz_3732]

So tomorrow we will be taking the transmission and converter out of the car and starting the motor so we can see exactly where the oil is coming from. Out of curiousity has anyone changed the rear seal before? Will we know if it is in backwards? We are obviously going to have our motor builder do this for us, but i'm curious how it works. I was told that you might get away with just loosening up the rear main cap???? Or will he have to take of all four caps? Is this not a good practice? Let me know if you have any suggestions.
Derek

[Racefab57]

On the rear main seal, if you change it, the seal lip has to point IN towards the frt of the motor! The other part of the rear main's seal is the dust seal Its a straight lip seal. You'll see it and tell the difference between the two lips. Long story short, the seal thats at an angle is the rear main -IT POINTS IN!!!!!!!!!!!! David. Pm me any time !

[degnitz_3732]

Well....for anyone who is curious, we think we finally have it fixed. There is another 1/4 npt plug in the bottom of the block that is on the oil filter side. So we dropped the pan and cleaned the threads out and used loctite thread sealant on all of these. Started the motor again and had it running for about 20 minutes ( got the oil temp up nice) and we couldn't see any oil coming out of anything. Basically it seems that if there was a little more time spent on sealing these plugs this would have been alot easier!! Thanks for everyones help. Derek