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.

Pressure test your manifolds for leaks. There are a ton of those cams running out there without dry pipes even without any issues. Personally I'd pull them and go through them.

imo,that cam with true dry exhaust should not be the cause of your milkshake.have someone do a cylinder leakage test paying xtra attention to the exhaust valves.

A few more things to throw at you in addition to things mentioned/asked above:

As a note: A leaking intake gasket from coolant port is very common on bbc's. Better gasket fit (ie: gasket you are using doesn't surround the water ports well) or sealing may be needed if this is happening.

Do you still have the factory HP500 PCV hooked up ?

Fountains sit real low in the rear. Do you have internal and/or external flappers that are still in perfect condition ?

Not sure what valve guides you have however sounds like there is a clearance issue or the bronze/magnesium/metals guides are taking a time out do to corrosion (braking down) from all the condensation.

Had those milkshakes back in the mid - late 80's and is hard on engines. That was when I learned you couldn't run a 108 lsa. Reversion wasn't discussed much then. That was trial and error days for me as well as many others.

Thanks guys for all of the advice I had stainless marine put in the new baffle that jerry uses on all of the newer pipes he makes and I also have external flappers already. I had the pcv hooked up but when I noticed the milkshake the builder put on k and n breathers. The intake gaskets that he used were felpro 1275 I wasn't real happy what I saw on the second engines looked like it could have been compromised. I bought felpro 1275s-3 this time supposed to be better.

What about the difference in water and oil temps ? Shouldn't bring up the water temps with a thermostat ? Or bring down oil temps to about 185 like merc recommends ?

imo oil temp is good but i see no reason to run a crossover in your application except for looks.if it was mine it would get a circulating pump and a 140 thermostat .

I have been thinking about going back to circulating pump. But i can't understand why for 170hrs I had no issues and now change cam which people say is fine and I have all of this reversion. I have to talk to someone else at merc tomorrow he was out sick. And I will give an update on what he says.

merc runs a circ pump&thermostat in a hp 500 for a reason,thr merc guy you are going to talk to might explain why if you ask him.

Ok so merc does not have a diffinitive answer considering I don't have a stock. Hp500. Stopped by the engine shop that did the work and he recommended a leak down and that maybe engine block deck might not be straight. I don't have a leak down tester so I was thinking of just doing a compression test on the engine stand to see if there was any irregularities.

I ran the 741 cam with stainless marine wet bravo tails, and had no reversion

You sure its not something silly like an intake leak???

Also,,,, what do you idle at in gear just out of curiosity

I am leaning towards the intake not being sealed properly. I will make sure that the intake is on perfectly. I was not happy about how tight the bolts where for the intake. Is there a specific lbs that should be put on those bolts. It runs about 650rpm at idle but I always make sure I bump up the throttles to keep rpm's up. I don't think it's cracked but Is there a way to pressure check the intake? I think I can rule out reversion now.

Stainless marines are a great set up and I use them all the time on 525's instead of tubular headers however you need to put high heat permatex on both sides of the gasket that sits between the manifold and the riser because if it isnt,100 percent sealed it will cause water to enter into the engine..Jerry from stainless will be the first one to tell you this..

Yes jerry did mention that to me. But if it was reversion then all of the cylinders on that side of the engine would have had the carbon cleaned off of them not just one right?

Good point.

Jersey also you mentioned torque on intake bolts and yes they are typically torqued to 25-30 and needs to be done in sequence and increments. Unfortunately if your bolts did loosen enough as you mentioned it's doubtful tightening and and torquing to specs would solve your problem. I thought I read that you mentioned you discovered water On top of 7 piston which I can't help but think that this problem has something to do with your exhaust. Did you pressure ck that exh manifold? If you do pull intake just follow proper procedure reinstalling. Everyone has their own technique etc which is fine as it's not rocket science however just a little tip you can follow or not. Up to you but I use a little high tac on the head surface to hold in place along with a little bead of permatex around the water passage as well on front and rear of block in place of the two gaskets supplied in some kits.

I really doubt this is your current issue though. Even with your intake bolts not being very tight after hours of use your intake has a tendency to take a set so to speak creating a vacuum like seal.

Re: I went back to your original post and did see you pressure checked exhaust. I didn't mean to question that again. Just really trying to help get your problem solved. What gen engines you have? Also you have twins correct? Your problem is just on the one engine that you had ground and replace the cam in?

do you have the cam card yet from the engine builder?

Getrdunn thank your advice. Yes the builder said that he checked the manifolds when the issues arose. Yes the intake are off both engines are on engine stands. The problem is with both engines And Both cams where replaced. Engines are 1998 gen 6. I have he cam card for the cams that are in the engines now which I posted. I forgot to get the old cam card today. But it was taken off of the 741 platform 114lsa. Ground at predator cams. But like people have said that cam which is in there now should not cause reversion with the set up I have. Thanks again guys. Chris

Just wanted to confirm the lsa on the new cams ground weren't overlooked. Sounds like they're fine though. Sometimes if an engine builder doesn't build many marine engines they simply overlook the importance of such. Btw tx pics to 231233151three
John

If you run a tstat go back to a circ pump..tstat with crossovers will overheat.

Mild thunder

What lsa you have? 114 or 112

What are the HP500 cam specs again? I knows its a 110LSA, but how much overlap does it have

Which cam has more overlap, the cam he's currently using, or the HP500 cam? Isn't overlap the issue with reversion, and not so much a specific LSA number?

In my current engines? Really would be irrelevant, as I'm running dry pipes.

In the old boat I had, the 741 crane cam with stainless marine wet bravo style tails, that cam was a 112LSA. Didn't have reversion issues.

He's running 112 also with same valve timing within a deg on opening and closing. I saw his cam card.

That's what's messed up is he's dry all the way back also so lsa isn't the problem.