Merc MPI V6, cracking timing covers **UPDATE**

[achris]

Hi all,

I have a 2006 Mercruiser V6 MPI.

4 months ago I noticed oil in the boat bilge. I located the source as the front of the engine. I pulled the engine and removed the cast ali sump, expecting it to be a sump gasket problem. What I found was a cracked (plastic) timing cover. I replaced the cover and refitted the engine. It lasted 30 hours before I found oil on the sump again. Engine pulled, another cracked cover.

I checked the sump and it appears to be putting a slightly higher pressure in one place (where the cracks are starting).

My question is: Has anyone else had this problem with a V6 with the plastic timing cover, or am I all alone in the universe?

Any input welcome.

Chris........

 

[JustJason]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Interesting achris (and good to see you back!)

I think boat-tech and Don S. are the only guys here with access to the most current up to date TSB's.

I know that you know what your doing so obviously I'm not going to give you any advice, i'll only throw out a question to you.

Since you have to replace the cover again, is there any reason why can't throw a tin one on there?

 

[Don S]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Chris, do you have a cast aluminum oil pan or stamped steel pan? Haven't heard of any problems, either with Mercruiser or Volvo, and they are the same engine.

Jason, the steel and plastic timing chain covers are not interchangable.

 

[JustJason]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Jason, the steel and plastic timing chain covers are not interchangable

Didn't know that and now duley noted and uploaded to the brain for future reference.

Is it a change in the block or the bolt hole pattern? Just curious.

 

[Fun Times]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

I did not see anything in the service bulletins either.

When did you actually buy this engine?

(FYI) (OW617679) this engine is not registered with MerCruiser.

Where you ever offered an extended warranty?

 

[achris]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Hi Guys (and thanks for all the responses),

Engine purchased Oct 16 2006, from a authorized Mercruiser dealer (in Australia), and is registered with Mercury Australia. I have the card and service log book sent out by Mercury.

Sump is cast ali (hasn't changed since the first post ).

Was not offered an extended warranty. (maybe no such animal in Oz).

The second timing cover was slightly different to the original, I had to drive the dowel pins into the block before mounting up the cover. The sump and second cover are back with the original dealer (who also supplied the second cover for me and I gave the original) awaiting a response from Mercury. I was just putting this out here to see if it's a bigger problem or mine is an isolated case.

Cheers,


Chris........

 

[Fishermark]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

I checked the sump and it appears to be putting a slightly higher pressure in one place (where the cracks are starting).

I don't have an answer, but do have a question. What exactly do you mean by the statement above?

 

[achris]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

I don't have an answer, but do have a question. What exactly do you mean by the statement above?

I ran my finger around the front section of the sump gasket, while it was on the sump, where it meets the timing cover, and you can feel a definitely high spot on one side, the side that crack on the timing cover starts from. The guys at the dealership I bought the engine from, and hence the dealer I'm going though to talk to Mercury, also agreed that it felt wrong. You can even see the non-symmetry (is that a word?).

Hope that's clearer....

Chris.......

 

[Fishermark]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

You can even see the non-symmetry (is that a word?).

Sounds like a good enough descriptive word to me.

It seems to me, that if the "deformity" in the pan is bad enough that you can visually see it - AND it happens to correspond to where the crack starts.... then you've found the answer.

 

[Rustychain]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Since you have to replace the cover again, is there any reason why can't throw a tin one on there?

FWIW.
The tin cover has 10 bolts and the plastic cover only has 6 bolts. Blocks cast after about 1996 only have 6 bolt holes.
Also, the plastic cover has hole for mounting crankshaft position sensor. Tin cover does not.

 

[achris]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Latest update.....

Went back to my friendly dealer and he had pulled the sump of another engine he had there. We saw a definite difference in the sumps.

Here's where it will get messy. Because the engine is out of warranty, despite the fact that it is quite obvious that the fault is a casting flaw and was there from the factory, Merc are playing hard ball and are refusing to cover it....

Chris......

 

[superpop]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

So is the casting flaw in the block or the oil pan. If it is the pan, are you sure your pan is installed correctly? I suppose if the pan was shifted forward a hair it would cause this not flat surface for the timing cover to try and compensate for. I am guessing that you are torquing the timing cover bolts to try and seal up the gap, and thus stressing the cover. May be a case of loosening the cover to see if it moves at all in any direction other than up and down, like I said it may just be on their **** eyed. Otherwise a new oil pan may be in order. Hopefully you do not have to pull the motor to swap out pans. The pan is pretty easy to R&R though if you have good access to the motor. Fel Pro also makes a pretty nice gasket kit for this motor that includes 4 clips that hold the pan and gasket in place loosely until you get some of the bolts in, makes it a one person job.

 

[achris]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Engine's already out. Can't remove the oil pan without removing the engine (unless I cut a big hole in the bottom of the boat ).

Timing cover.... It's plastic and the bolts are in rubber inserts and have shoulders, can't be over tightened or mounted 'cocked'. The oil pan is on locater bolts at the rear and can't be mounted anywhere but exactly. The casting flaw is the oil pan, so yes, a new one is required.

Had to pull the engine because in order to get the sump off I needed to remove, the starter motor, the MPI fuel pump system, the engine flywheel cover and all those silly little water hoses for the 'single point draining system'. That's one system that may get 'forgotten' when it comes time to re-assemble .

Chris......
(engine was only 4 months out of warranty when the fault manifest the first time )

 

[Bondo]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

The casting flaw is the oil pan, so yes, a new one is required.

Ayuh,... So is it long, or short, or cracked or What,..??

Just curious, I've got a Bud with the 4.3L w/ a cast sump...

 

[JustJason]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Any chance you can throw up some pictures if you get some time?

 

[achris]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Ayuh,... So is it long, or short, or cracked or What,..??

Just curious, I've got a Bud with the 4.3L w/ a cast sump...

It's just a slightly raised area (over a length of about 1 inch) that presses just a little too hard on the timing cover. The spot it pushes on (on the timing cover) has no structural strength, so would be very prone to breakage. The raised area isn't a step, it's like it should have been machined, but it's not a machined surface, it's a raw, untouched, casting. See picture....

 

[Bondo]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Ayuh,... I know you've got a New motor,+ shouldn't have to reengineer it,...
But,...
A couple strokes of a flat file oughta flatten that .040 shouldn't it,..??

I mean, it's your Boatin' season,... Are ya gonna hang out on shore waiting for parts,..
Or, fix it,+ go Divin',..??

 

[achris]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Ayuh,... I know you've got a New motor,+ shouldn't have to reengineer it,...
But,...
A couple strokes of a flat file oughta flatten that .040 shouldn't it,..??

I mean, it's your Boatin' season,... Are ya gonna hang out on shore waiting for parts,..
Or, fix it,+ go Divin',..??

Ayuh, Fixing it this weekend....

(We don't have a 'boating season', weather's so good here we boat all year round.... )

Cheers.....

 

[Bondo]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

(We don't have a 'boating season', weather's so good here we boat all year round.... )

Ayuh,... But you can't walk on water, like I can around here right now.....

 

[Willyclay]

Re: Merc MPI V6, cracking timing covers

Re: Merc MPI V6, cracking timing covers

Ayuh, Fixing it this weekend. Cheers.....

Anything to report?