lake speed

Here is the situation. I have a new motor its a 638" bbc, dart block, intake and heads. the headers are cmi split tops. the cam is from comp but it was a teage specific cam. the specs on the cam are 258* intake 266* exhaust* @.050" on a 114 lobe seperation. the headers have no drop at the tail pipes and the are injected at the tips. the problem is is that I keep mixing water and oil. I pressure checked the block it checks out ok so at 40 psi I have no loss of pressure. the headers check out ok at 35 psi but the 1,3,5,7 cylinder side of the motor has water in all 4 header tubes after running it at idle for a few minutes. there is no water in the other header. I am sure that the water in the oil is coming from the exhaust but why would only one side of the motor have reversion? the tail pipe on this side is the longer of the 2 if that matters. HELP!!!!! I am out of ideas and patience.

getrdunn

iTrader: (7)

It doesn't make sense to me just being on the one side if it was to be reversion. You certain everything is plumbed properly?

lake speed

well too be perfectly honest no I am not. the boat is actually at a shop and I have been there working on it so I can get it done lol. how could the cooling system be being improperly plumbed cause these symptoms?

rssteiny

Are you sure the intake is sealed good

PatriYacht

Seems unlikely that the intake would put water in all 4 intake ports. Thats a pretty mild cam to revert water from dry tailpipes. I'm voting for a problem above the joint in the exhaust. If you are certain that there are no leaks in any of the pipes, than it must be reversion. In that case, have some spacers made to raise the collectors and tailpipes and get some downward angle.

lake speed

maybe I wasnt clear. there is water in all 4 header tubes but only on one side???????? the other side has no water in the header tubes. the oil actually looks like it is getting worse every time its changed. the headers were tested with the tops on them with no psi loss. I have not tested the tail pipes but they are dry to the tip.

Raylar

From what I read here it does not seem possible or probable that only one side of this engine would expierence reversion. I have seen horizontal exhaust systems (no drop down angle) have water lay in the tubes and get sucked back into a normally aspirated engine with a mild cam, but it should be happening on both sides of the engine.
I would take another look at the head gasket seal on that side. My expierence with 600 plus cubic inch big blocks means bore sizes of 4.600" or larger and that leaves so little head gasket around some parts of the head you could be looking at water coming from one or more cylinders getting out the exhaust, up to the header horizontal and being pulled into the other cylinders on that side of the engine. Just a thought but if you've thoroughly check out the headers and tips for leaks then the water is got to be coming from somewhere on that side of the engine.

Best Regards,
Ray @ Raylar

lake speed

here is a little more info and a slight recap of the situation.
the leak down was 3 to 5% across all 8 cylinders. the compression test shows 170-180#s. I did dump the water overboard this afternoon and it still has water in the oil. I pulled the intake and it is concentrated at the front corners of the intake to the point that it looks like an actual milkshake. its very thick in the 2 corners. I cant see why a pressure test wouldn't reveal an intake leak but I believe thats what it is. I also pulled the heads off and the head bolts were no longer torqued to what I had them. the short bolts were as loose as 60 pounds and the long bolts were averaging 70-75 pounds. I believe that the head bolts may be a little long they are arp bolts but the dart block has blind holes. I am thinking that the heads will torque when the cometics are new but when the settle in I believe that the head bolts are bottoming out before I can get crush on the gaskets. I ordered new cometics, new intake gaskets and new head bolts that are specific to the dart heads. whats different about the bolts I dont know but they are different. my theory as simple as it may sound is that the heads are lifting allowing the compression to push water into the front corner of the intake. sound plausible? The reason I think this is because it doesn't present itself when checking with psi it only does it when its running. 170-180 pounds of cylinder pressure its certainly enough to push water out of a non seated gasket I think???? thanks for all the input guys.I am about to throw in the towel lol. I am over 15k into this new motor and its never been in the water.

getrdunn

iTrader: (7)

I feel bad for your situation and sicereley hope the best for you and solve your problem soon. Just another thought though after thinking about this a little more. I'm not for sure what exhaust you have however is it possible when pressure checking them they check out fine under room temps but is it possible also that at over 1,100 degree exhaust temps a crack might/could expand and allow the reversion and even transfer to the other cylinders on the same side.

I really feel this is an exhaust issue. Do you have any other exhaust available to test even if it is only on the bad side. Even if you have to use flex tubing to get it out the transom.

With all the test and process of elimination you have done I am completely baffled. I wish you the best of luck and if anything else comes to mind I'll pass it on for what ever it's worth.

Stay tuned,
John

lake speed

well I changed the head gaskets and the intake gaskets and guess what......the first 10 minutes the oil was perfect so I changed it and ran it again for 10 minutes and it milked the oil. the only changes between the two 10 minute sessions is that The timing was changed and the idle was lowered to 1000 rpm's. I am out of ideas and patience. anyone have any other suggestions?