Engine Timing..

[JCBoater]

Re: Engine Timing..

Yea I figured as much.

Blown head gaskets you think??

 

[Don S]

Re: Engine Timing..

It's not a head gasket causing that problem, tuliped valves, heads missing on valves, pistons not moving , causes 0 compression.
Time to pull the heads, or if you really want to know, do a leakdown test. But it sure seems like a lot of work for no return to me.
Time to pull both heads and LOOK.

 

[Bondo]

Re: Engine Timing..

Blown head gaskets you think??

Nope,........ They're too far appart.......

Bad Valves,..?? Bad, Really Bad Pistons,..??

Donno......
But I Do know that 0psi compression is Very Bad.....

 

[JCBoater]

Re: Engine Timing..

The heads are coming off later this week.

I know it does not matter, but i can not help but wonder how this could have happened.

Looking through the captains log.... On a Catalina trip the engine ran hot due to a clamp breaking off. Replaced clamp and engine ran great. Made another trip to Catalina without any problems. Made a Marina Del Rey trip no problem each trip isabout an 1.5 hour cruise. Also went out for Christmas no problems. Lastly started the engines a couple of time over the winter and had no problems.

Just wierd to me... how the engine could have gotten so damaged.

I'll update you all with the finding after the heads are removed.

 

[Don S]

Re: Engine Timing..

What was your WOT rpm when it running good? If it was too low and you were lugging the engine, look for bad valves.
Overheats, leaky exhaust, water on valves, Can cause rust on valve and keep them from moving.
Post some pictures of the cylinders and head when you get it apart. Be interesting to see, plus the pictures can explain what caused the problem to begin with.

 

[JCBoater]

Re: Engine Timing..

I will for sure post pictures. I always wondered what good is a camera on a cell phone.. I guess this will be a good use.

On a trip to catalina after the I replaced the clamp on the hose. I recorded the following.

port enigine: oil pressure 60 psi and temp of 150. At 3000 rpm oil pressure of 60 psi and temp of 162.

starboard engine (problem engine): oil pressure 50 psi and temp 140 at idle. At 3000 rpm temp 159 and oil pressure of 50 psi.

On Marina Del Rey trip i recorded the following:

At 17 MPH port engine 48 psi oil pressure and temp 160 and the STBD engine 40 psi oil pressure and 158 temp. Did not record RPM.

 

[JCBoater]

Re: Engine Timing..

--------------------------------------------------------------------------------

I will for sure post pictures. I always wondered what good is a camera on a cell phone.. I guess this will be a good use.

On a trip to catalina after the I replaced the clamp on the hose. I recorded the following.

port enigine: oil pressure 60 psi and temp of 150. At 3000 rpm oil pressure of 60 psi and temp of 162.

starboard engine (problem engine): oil pressure 50 psi and temp 140 at idle. At 3000 rpm temp 159 and oil pressure of 50 psi.

On Marina Del Rey trip i recorded the following:

At 17 MPH port engine 48 psi oil pressure and temp 160 and the STBD engine 40 psi oil pressure and 158 temp. Did not record RPM.

 

[JCBoater]

Re: Engine Timing..

Here are the pictures....

Looks like one of the valves (#7 plug position) is not seating completely. This is the same position that had a compression reading of 0 psi.

Position #1 read 0 psi too. But I do not see anything that points to why it did.

 

[Don S]

Re: Engine Timing..

Tuliped valve, kind of what I expected to see.
Lugging the engine (over propped) or lean. My guess would be lugging.
What was your WOT rpm when it ran good. before his happened

 

[JCBoater]

Re: Engine Timing..

Do not know what the WOT (wide open throttle??) rpm was, I never recorded it. But I do recall that whenever I would run the boat WOT both engines would read the same. All I have is the data that I posted. To be honest I have never heard the terms "Lugging the engine (over propped) or lean". So I would not know if the engine was doing this. And "tuliped" valve, does that mean bent? If so would that cause the 0psi readings on both #1 and #7.

 

[Don S]

Re: Engine Timing..

The WOT (Wide Open Throttle) rpm is what is used to see if the props are of the right size. The props are what determines where that rpm range will be. To much pitch and you can't get your WOT rpm and you WILL be lugging (aka overloading) your engine. The prop size and pitch is not going to be the same on every boat, even if they are exactly the same boat. Loads, altitude, weight distribution, trim all contributes to your particular boat. Trim is something you have to do constantly. It's not a " put the mark on the second line" and go type adjustment. IT moves just like the water and the load of the boat. People moving around will change how you trim the boat.
Now, to your valves. Here is a crude drawing. A normal valve seats with the valve seat, while a tuliped valve gets a cup in the valve and it will not seat in the head. What you get is ZERO compression.
Lean, just means there is not enough fuel to burn and also cool the valve. In outboards, a lean condition melts pistons and destroys engines.

Hope this helps you understand what is happening.
Sorry for the super crude drawings

 

[JCBoater]

Re: Engine Timing..

Thanks for the explanation it helps way more than you will ever know!! The drawing explain it perfectly. I think I will also have to take some boating lessons from a local captain to show me how to properly trim the boat and what to look for. I'm guessing that I have been running the boat and not had the trim tabs set to the proper angle.

Back to the zero commpression reading. It makes sense to me that the position were the valve is tuliped to read zero, but what about the other zero reading? I guess it could have a tuliled valve too and I just cannot see it as clearly as the other.

I will be pulling of the head on the other side to see why I had a reading of 100 psi. on one of the cylinders.

 

[JCBoater]

Re: Engine Timing..

I also took a look at the valve and it appears to be stuck open about a 1/4 of an inch and not tuliped. Is tuliped something that is i should be able to see?

I'm guessing that at any rate I have to have the head worked on to correct the problem, right? And possibly the other one too?

 

[Bondo]

Re: Engine Timing..

I'm guessing that at any rate I have to have the head worked on to correct the problem, right? And possibly the other one too?

Ayuh,.... They're usually done in Pairs.....

Also,.... It appears in your pictures that there's quite abit of Rust,.....

 

[JCBoater]

Re: Engine Timing..

In addition to having the heads reconditoned. Should I do something for the rust?

 

[JCBoater]

Re: Engine Timing..

Both of the heads have been reconditioned. I'm ready to put the engine together, is there anything I should check before putting the engine back together?

 

[Uraijit]

Re: Engine Timing..

If the heads are totally reconditioned, then there shouldn't be anything else to check on those. However, fresh heads on a less-than-fresh block can sometimes cause problems. If you've all of a sudden got a super tight top end, leaks in the bottom end become more apparent. Your #4 piston seemed pretty low on compression as compared to the others, but that could have been caused on the top end as well.

For future reference, if you get a low number like that on a cylinder, put a squirt of oil in that cylinder, and retest. If the compression goes up, that means that the rings are shot. If it doesn't, it means that it's most likely a top-end issue.

No way of finding that out though at this point, so no use crying over it.

Check the cylinder walls, and make sure they're all in good shape. Make sure they're nice and clean, and free of rust, nicks, gouges, or--heaven forbid--cracks. While you're at it, take a look at your cam, and make sure there aren't any flat lobes. Now's also a good time to get your intake manifold nice and clean before you put it back in. Get after the ports with some carb cleaner and a wire brush, and get as much of that carbon build-up outta there as you reasonably can.

Make sure the mating surfaces on your block are good and clean before you bolt the heads on. And be sure to use a non-metallic head-gasket when you put it all back together.

 

[fishmen111]

Re: Engine Timing..

JC, I am in no way a master like these guys, but I swear it looks like you might have a bad exhaust manifold (water mixing with the exhaust before it should) on the odd bank. The "milky oil" is water in your oil. I would get your manifolds pressure checked before you button it back up. If they are bad, water will drain back into the cylinders when you cut it off causing rust. Too much water and you will hydrolock the motor. Rust on valves prevent full closure = no compression. Just a thought.

 

[JCBoater]

Re: Engine Timing..

Hello and thank you very much for the advice!! I will follow through with all you have suggested.

Note: On the head on the side of the #4 piston there was a bent push rod and broken broken push rod. Does this change your feelings on the status of the lower end of the engine? I did not notice any cracks, gouges or nicks on the pistons or on the piston walls. However the heads of the pistons looked a little rusty (see posted pictures).

Thanks again!!

 

[fishmen111]

Re: Engine Timing..

Any marks on top of the #4 piston? If you are bending and breaking push rods, that usually indicates timing issues.