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-   -   another milkshake question??????? (https://www.offshoreonly.com/forums/general-q/209423-another-milkshake-question.html)

lake speed 05-23-2009 06:09 PM

another milkshake question???????
 
Here is the situation. new 640ci bbc, dart block heads and intake. the short block was brand new and the heads were off my other motor with no previous issues. first the pushrods I had were too short and it was keeping some of the valves open upon the initial start up. I pulled the plugs out and 1 of them has water and oil on it. could it just be reversion from the exhaust valve not closing? I did a leak down and it was at 3-5%. across all 8 cylinders and with the motor being brand new and the rings still not being seated I think that these are great #s I could understand if the plug was wet with just water but the milkshake has me concerned. the headers are cmi's and were also on my other motor with no issues. what do you guys think? intake leak? BTW I am using cometic head gaskets and the cam is on a 114 lobe centerline. Also the oil in the pan had a little water in it but it was far from milkshaked??????? help??????? I cant keep spending money for nothing lol.

Vinny P 05-23-2009 07:31 PM

I can not give you an answer as to what is causing your problems. I can say for sure that I have never heard of pushrods being soo short, as to be able to hold the valves open and cause reversion issues. Proper length push rods are essential for correct rocker arm and valve train geometry. Your problems may be reversion. What are your exact cam specs. 114* centerline , meaning I.L.C. is not really important. Maybe you mean 114* lobe seperation? Is it possible for you to seal off your cooling system and pressurize it like an automotive system? That will tell you if the engine is sealed tight. If it is, the problem most likely is reversion or a header leak.

lake speed 05-23-2009 08:36 PM


Originally Posted by Vinny P (Post 2871830)
I can not give you an answer as to what is causing your problems. I can say for sure that I have never heard of pushrods being soo short, as to be able to hold the valves open and cause reversion issues. Proper length push rods are essential for correct rocker arm and valve train geometry. Your problems may be reversion. What are your exact cam specs. 114* centerline , meaning I.L.C. is not really important. Maybe you mean 114* lobe seperation? Is it possible for you to seal off your cooling system and pressurize it like an automotive system? That will tell you if the engine is sealed tight. If it is, the problem most likely is reversion or a header leak.

yes it meant to say 114 lobe seperation. what I am trying to say about the push rod deal is when I tried to do the leak down I had to back the rocker arms all the way off because it was leaking out of the exhaust with as little as 1/4 of a turn pre load on the polylock. the push rods were allowing the rocker arm to make contact with the poly lock therefor when I was trying to pre load the lifter it was actually opening the valve at the same time. I am putting the correct pushrods in the motor and I wll try it again. my concern is why the oil and water on the plug if its reversion? wouldn't it just have water on the plug. Could it be a leaking intake gasket? the headers were fine on my other motor 2 weeks ago.

Vinny P 05-24-2009 05:04 AM

I still dont follow your push rod issues, but in any case, you need the correct length in there. If your issue is reversion, water generally backs up into the cylinder, then squeezes past the rings and into the oil pan. From there, it makes a mess of everything. Including causing the exhaust valves to get brittle. Do a search here. You will see countelss threads on it. 114* lobe seperation is not too tight, but the duration has alot to do with it as well. For instance, my cam is a solid roller, 114* lobe seperation, 244* and 256* duration @ .050" . CMI headers on a N.A. 540 . This cam sucked water back @ idle speeds. I went to full dry tails to solve the problem.

lake speed 05-24-2009 10:13 AM


Originally Posted by Vinny P (Post 2871946)
I still dont follow your push rod issues, but in any case, you need the correct length in there. If your issue is reversion, water generally backs up into the cylinder, then squeezes past the rings and into the oil pan. From there, it makes a mess of everything. Including causing the exhaust valves to get brittle. Do a search here. You will see countelss threads on it. 114* lobe seperation is not too tight, but the duration has alot to do with it as well. For instance, my cam is a solid roller, 114* lobe seperation, 244* and 256* duration @ .050" . CMI headers on a N.A. 540 . This cam sucked water back @ idle speeds. I went to full dry tails to solve the problem.

The push rods were too short. short enough that when you tried to preload the lifter it would actually open the valve. I have the correct length pushrods now. I am just hoping this is the problem. The water is injected at the end of my tail pipes but I am sure it could still suck some water in if the exhaust valve was open on an intake stroke. the cam is 244* intake 256* exhaust* @.050"

Vinny P 05-24-2009 11:54 AM

Now I understand. I never thought of that possibility. They must have been reallllllly short. Looks like your cam is very similiar to mine. As I said, mine sucked back water from the standrad CMI tails. Be careful with it.

lake speed 05-24-2009 12:15 PM


Originally Posted by Vinny P (Post 2872065)
Now I understand. I never thought of that possibility. They must have been reallllllly short. Looks like your cam is very similar to mine. As I said, mine sucked back water from the standrad CMI tails. Be careful with it.

The pushrods that I had were 8.250 and 9.250 the pushrods that I have to replace them with are 8.650 and 9.650. I thought that the shorter ones would work since I had to use a .300" taller lifter but it turns out the lifter body is taller but the plunger sits deeper down in the lifter body so instead of needing a shorter pushrod I need a longer one. I am about tired on messing with this thing:lolhit: btw the cam I had in the other motor was about the same spec wise it just had a little less lift. I never noticed any signs of water in the cylinders? my tail pipes are only wet at the tip so maybe thats why.

lake speed 05-24-2009 12:34 PM

man I just read this thread http://www.offshoreonly.com/forums/g...ater-leak.html I hope this isnt the problem. I doubt it is because I seem to have more of a problem with the water getting into the combustion chamber and less in the oil pan. there is some reaching the oil pan but I dont think its much? besides I have the dart 360 heads and I believe that they are different than the pro 1's?


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