Motor question

[ericcarr2000]

Ok. I have a major delima. I have been battling trying to get ahold of the engine builder of my motor that has just 4 hours on it out of California, by the name of California engines. I know by now that I pretty much got shafted on the deal due to the fact that they will not answer the phones and I even tried to send a certified letter no luck? The problem that I had was the motor was mixing water with the oil the surveyor said That when he went to where the boat was the mechanic told him the reason being is because the camshaft was allowing water to mix through the exhaust valves due to the Cam being too big. So now I have this motor it's completely tore down and not sure what to do any suggestions? I thought about sending it back into a machine shop locally in having it checked for cracks & if all is good just starting the rebuild process over by myself what do you think?

 

[alldodge]

the camshaft was allowing water to mix through the exhaust valves due to the Cam being too big

If this is happening then its called reversion. This is caused mostly by a high lift cam with quite a bit of valve over lap. If this is the case the exhaust needs to be changed so the water mixes with the exhaust further away from the manifold. Without getting way into this issue yet, can you reconfirm what motor you were sold? What was the HP claim and I will assume this is with standard Merc style exhaust manifold and elbow.

 

[Bt Doctur]

Do you know the cam number? the motor is .................

 

[Scott Danforth]

agreed, if the cam is wrong for the exhaust, it will suck water back thru the exhaust (reversion). for a stock center manifold and riser elbow, about 268 degree for a flat cam and 270 for a roller is all you can get away with. for a long elbow that exits at the transom you can go more duration.

if this is the motor in your Sundancer 250, being a 1990 you should have a Mark IV block which is flat tappet unless it was upgraded to roller lifters. so about 268 degree duration should be max on the cam with stock exhaust.

 

[Bondo]

That when he went to where the boat was the mechanic told him the reason being is because the camshaft was allowing water to mix through the exhaust valves due to the Cam being too big. So now I have this motor it's completely tore down and not sure what to do any suggestions? I thought about sending it back into a machine shop locally in having it checked for cracks & if all is good just starting the rebuild process over by myself what do you think?

Ayuh,..... I think I'm wonderin' why seein's you've paid so many engine builders/ surveyors/ mechanics to this point,....
Why do you think yer gonna do any better,..??

I'd send all yer parts to yer local machine shop, have 'em check all the parts over for fit, finish, 'n proper application,....
Then have Them assemble at least the Long Block assembly, or the complete marine bob-tail motor,.....

After that, you can decide to drop it in yerself, or have yer boat mechanic put it back together,....

Assemblin' a dependable long block is not for a typical Diy'er,....
It's a science that demands accurate measurements, many times over,....

If yer willin' to throw a few extra bucks at it,... have a full balance job done before it's assembled,....

 

[mxcobra]

because its tore down now first thing I would check for is cracks in the manifolds, heads, and block, then I would re seal everything-correctly. get a new cam within the limits theese guys are talkin. that should work...