Another condenstion/ reversion problem
 

hp500's Where completely redone 7 years ago when i bought the boat from pistons to intake and cam bumping compression just a bit.
Fast forward 5 years and 160 of trouble free HRS I noticed what I thought was a little noise in the valve train. I thought something needed to be tightened up.
WRONG!! I Had the shop at my Marina take a look and they said that there was strange wear on top of the valve stems . Long story short I decided to have the top ends done so not to have bigger problems later. The builder also changed my cam. Since then I have had the froothy milkshake which I never had before plus Hanging up valves on one engine twice and the other once. Both on the port side of each engine. I only had about 15hrs on the engines when these problems started. I have crossovers no thermostat and run virtually no water temp [ 100 degrees] and 210 oil temp. My engine shop does not have an answer as to why these problems now and never before. I have read many of times on this form about raising the oil to at least 220 to burn of condensation. Now the engines are apart and I see that there was definitely water dumping into the back cylinder #7 because it has no carbon buildup on it. I recently talked to teague customer service and they informed me that I should lower my oil temp to within 40 degrees of the water temp to eliminate the condensation. Mercury marine says that Those motors originally ran at 185 oil temps. I have pressure checked the heads and exhaust [Stainless Marine ] and they are fine. I keep thinking I should go back going back to the original cam. Which was a custom ground to match the 741 to stop the reversion issue. Any help is greatly appreciated. Chris

what are the spec,s on the new cams?edit in,a exhaust valve not sealing can cause that cylinder to revert,was a cylinder leakage test done?

Plus, cold engine temps and hot combustion temps, combined with tight valve stem clearance can spell disaster, and it sounds like that happened to the OP before......and hopefully not again.

The cam is crane part# 16hr00050 grind number 234/359-2s-12 iron gear. 296/[email protected]. 234/[email protected]. 112 LSA. Like I said I pressure tested the heads and no leaks. But they loosed up the guides I think 28hundredths? I believe. On a side note the guy that did look over the heads the last time supposedly did not see anything wrong with them and only checked the spring pressure. I think he tightened the guides. Also the valves that are the worst are. #'s 3and 5.

What exhaust, short gils?

Is this the cam you have? If so, its an off the shelf cam.

http://crane.carshopinc.com/product_...d/76046/139021

I have stainless marine exhaust with pipes made from them. They checked them and no leaks detected. And yes that is the cam that's in there now. I have had half of the shops I have called on for advice say yes it could be the cam and the other half say no it's not. Just don't want to leave the cam in there and be in the same situation as last season.

are the tail pipes dry to the tip?i am asking because crane recomends dry exhaust with that cam.

Yes they are.

Water dumps out right at the end of the pipes.