Instead of firing my new engine today, I will be chasing a leak. This is a 400 block with Edelbrock heads. Everything is new. The head gaskets are Mr. Gasket Ultraseal. Torqued with ARP fasteners and retorqued after sitting a couple days. It drips pretty good from the head/block interface at the back of the block about 1 inch from the intake manifold on the driver side.

What strikes me as odd is that is started dripping even before I had the radiator topped off, without any pressure in the system. Something is way wrong here. Is there something about the Eddy heads that requires something special? Are the Mr Gasket Ultraseals problematic?

Found something in a pdf about putting an 1/8" bead of sealer along the end sealing surfaces and long the bottom of the intake ports. I am not a fan of sealer on the mating surfaces so I might have overlooked that... Does everyone do that on the Eddy heads(apply sealer)?

Did you check to make sure your dowel pins weren't going to be keeping the head from mating flat? Sometimes they can be too long or the head holes not deep enough.

You shouldn't need sealer on a BB head gasket to seal coolant. Oil, yes, at the intake mating corners. My first thought was the dowel is too tall on that end. If not that, (assuming the block deck and head are flat) a head gasket that was damaged during the install maybe.

Brian

I have always sprayed my gaskets with VHT Copper right before install but
you have a problem that I doubt this would fix. Be sure to tell us the problem and good luck.

Identify the problem accurately and fix that, don't patch it

Apples to oranges but, I experienced the same thing on a smallblock, with the MP gskts, which were the red material Victor / McCord.

Are you sure it isn't the soft plug in the back of the head? but I would go with the dowel to tall or boogerd up not allowing the head to seat

I replaced the dowels. I know they weren't deformed and I am pretty certain they are not too long. There isn't a plug in the back of the head. I will get the head off in the morning. I keep coming back to this statement from the Edelbrock install instructions:

Apply a continuous 1/8” bead of automotive RTV silicone sealer to end
sealing surfaces on block and along bottom of intake ports on cylinder head. Also, apply a thin bead of sealer around intake ports on cylinder head
and gasket.

They are talking about the intake and end rails on the block, not the deck surface. Never had a BB Mopar leak water from the deck if assembled properly. As stated, either the dowel pin is long or the gasket is bad. Dont assume the dowel holes in the head are drilled to the proper depth just because the heads are new. Always something with aftermarket parts.

Always and I mean always place a head on the block BEFORE putting a head gasket on it to assemble the engine or you may crack the head if the dowel isn't in the block deep enough and bottoms out in the head. Ask me how I know. Also if the head has been surfaced take a round file to the dowel hole to remove the ridge left from machining.

OK I have the head off. The gasket looks fine. It measures .042 pretty uniformly along the entire length instead if the advertised compressed thickness of .038". The ARP bolts are the right size and don't bottom out. The were all at the proper torque.

The dowel pins are fine. Not too large or too long.

The head and deck are flat according to my Starrett straight edge. The was not enough room to surface the deck but two machine shops said they were fine.

A bit of a mystery.

I have some Fel-pro 8519PT1 head gaskets to put on. Any ideas before I just try a different gasket? Of course the other question is whether or not to do anything on the right side.

Check to see if the holes that hold the intake on go into the water jacket. If they do you should use some teflon tape or at least pipe dope on the manifold bolts when you put it back together.

Take your time to figure out EXACTLY why it was leaking coolant Don't do this twice Good luck

Thanks, I still can't explain what happened. I put the head on without a gasket and I couldn't get a .005 feeler gauge in anywhere. So I put the head on with the new gasket and pressure tested the cooling system. It held pretty well. Leaked down a little after 10-15 minutes, which it about what I expect from leakage at the cap.

I think I will put a scope in the plug holes on the other side and see if the cylinders have any coolant in them

Did you torque the bolts with the proper lube? The thickness of the gaskets says that you were light on the torque values. If you used the lower ARP torque specs with engine oil on the threads, instead of the ARP thread lube, you could have created a low torque condition.

With everything RIGHT spray your gaskets both sides with VHT copper and get them on.

Copper Coat is your friend. If I put a dry head gasket on it will leak.

I've never had a PT Fel Pro head gasket leak by putting it on with no extra coatings, never I do use copper coat on all the beaded steel head gaskest I use That or silver paint
OP, how smooth or course is the finnish on your heads and deck surfaces? Can you feel the finish if you drag your finger nails across them? If so, there to course

Cab,
I've had this problem before
The casting of the block is a little off
I had to put a bead of silicone around the large water hole on the block (Large triangle water port on the block)
Good luck!
Big

I fixed the left head gasket, filled it with water and put 7 pounds of pressure in the system. The left head seems fine. The right started to leak from the back of the head just like the left. So I changed that gasket too. Both show no signs of leakage now.

I still can't explain what happened. Neither gasket showed signs of compression yet I know both were torqued to specs, twice and still had plenty of ARP lube on the bolts.

Cab, the finish on the mating surfaces is smooth.

I'm pretty confident, but the real test will be when I fire it. It's all ready, just need to prime it again and put the dist back in. Hopefully Tuesday if my helper doesn't have too much homework.

you might pump it up to 15 & WO water/coolant is the best for no contamination if it does leak & has to come apart again (hopefully not). it'll take longer to pump up air than water since as you know water ain't compressible but better be safe than sorry. (going thru the cooling system from Hell myself/same deal) & still ain't solved it

I did pump it up with air first, then with water when it looked good. I did hold off on the antifreeze in case I have to drain the block again. If it survives the start up, I will drain some water and add antifreeze.

perfect plan, you have it covered dead on but I am wondering why you didn't go higher on the psi check

I meant to say 7 pounds with air and around 12-14 pounds with water. Just too much pumping with air only.

We fired it up tonight. Started right up with no leaks or bad noises. Seems to run good. I noticed the TTI headers don't quite clear the idler arm so I will have to do something there

I hope I can get it out on the road before it snows.

My ARP instructions said to torque to 60 lbs with aluminum heads and ARP lube. I think that is not enough. I went 70 lbs with the new gaskets. That said, I won't be using any Mr Gasket head gaskets in the future.


Thanks everyone