Engine reassembly gotchas? Westerbeke 46

[Gary H]

Hi all,

I am doing what might be considered a "top overhaul" on my Westerbeke 46. Injectors were removed and a diesel shop replaced the nozzles and recalibrated them. I removed the head and had an engine overhaul shop take a look at it. They recommended 4 new intake valves and 8 new valve seals which took some doing to locate but have finally arrived. The shop also checked the head for cracks, machined the surface, checked valve springs, etc. While I had things apart, I flushed the coolant, replaced hoses, cleaned and painted the block and gave the heat exchanger an acid bath.

Things are looking good but now it's time to start putting stuff back together. Since calling me an engine novice would be charitable, are there any gotchas I should keep an eye out for as I reassemble?

I do have new gaskets and new copper washers for the injectors. I also have the tech manual with torque specs. So aside from this obvious stuff, what should I be wary of?

[a64pilot]

Find out if any kind of sealant should be put on your head gasket, some require it, the pure metal ones I like to use what is called "Copper coat", it comes either in a can to be brushed on or in a spray can, I prefer the spray, two coats just like paint.
Now if your head gasket is blue color and looks like it's Teflon coated, don't put anything on it, or at least check to make sure

First dry fit the head gasket to make sure you got the right one, and make sure it goes on right, sometime if the are upside down you can block some oil or coolant passages and you don't want that.

Ensure your torque wrench is close on calibration, follow torque chart exactly, I like to put a chalk mark on each bolt as I torque it so I don't miss one, your can apply torque as many time to a bolt that you want to, only issue is if you miss one, not that you torqued one twice. Usually there are at least two torque values, initial and final, but there may be three?

Adjust valves of course, easier before you install injectors, bleed fuel system, fill with coolant, leave cap off as often you will need to add more as there is an air bubble somewhere, sometime engines have procedures to remove trapped air in coolant passages. A little may flow out, then level drop, this is normal.
Just in case it doesn't start right away, I'd leave the seacock off until it starts, then open of course, it will smoke and stink as it warms up, this is normal. Look for oil pressure immediately on start up. Run until fully warmed up, look for oil in coolant water, check water level, change oil and filter. Check to see if the head is supposed to be re-torqued, some do, some never require it. I think those Teflon head gaskets never require re-torquing?
If you re-torque, re-check valve clearance, a little loose never hurt anything, but too tight burns valves.

[HappyMdRSailor]

Good info from the pilot !

One tip? Methodical... Don't rush, double check each step...

You'll do great, and venture away from novice-land with a smile...

[dwoodall]

A couple of rather generic note about torque. If you use an antiseize make sure the torque spec you are using is spec'd with antiseize. If not, you will typically require less torque if the spec is dry and you use an anti-seize. The reason is the anti-seize acts as a lubricant. I usually back off the torque spec by about 10%, but some of my motorcycle racing breathen will say 20%. I have popped bolts using anti-seize and couldn't figure out why until a friend mentioned this.

The other thing I always do on any sort of rebuild is chase the threads just to clean out all the junk that collects in the hole. Use a bottom tap (one with a flat bottom, not a pointy one) then I use a acetone and a small, round brush (the one I use is for cleaning test tubes) following chasing the threads, then blow it all out with air. Seems to work and makes assembly easier as well the torque specs much more accurate. I also prefer a dial type torque guage rather than the click type. I go in increments of 25% until everything is tight.

[Valmika]

Make sure you test your HX. I did a lot of this stuff in Feb and had everything nice and clean and pretty but I am ordering a new HX today. My old one looked good but a quick test would of told me it needed replacing. Manifold and mixing elbow are a bit easier to spot problems.

[seasick]

My reassembly gotchas always seem to be the collection of parts on the cabin sole when everything's thought to be complete.

I figure if I keep rebuilding my engine pretty soon I'll have enough spares to build a new one.

[Gary H]

Thanks to everybody for the wisdom and encouragement! Just spoke to the machine shop and the head will be ready tomorrow.

Now if I could only remember where I put all those parts...

[a64pilot]

The post about chasing the threads is spot on, go buy a tap set, just use your fingers though.
Do not wet torque anything unless it's speced to and I doubt that, wet torque is unusual.
Clean everything, don't put anything dirty back on, paint the pieces before assembly, looks better than after.
I like to use new hoses and belts if budget allows


Sent from my iPad using Cruisers Sailing Forum

[shakey doug]

Check Head Injector tubes for old copper washers lurking at bottom, might save you trying to sort a smoky cylinder

[Zach]

Keep an eye on your push rods while you re-assemble... Working on an incline like in a boat it isn't hard to have one slip out of place while you are wrenching down the rocker arm shafts.

Zach

[jimbunyard]

For the third time, chasing the head bolt threads is very important, it wouldn't be a bad idea to chase all the other threads too, if you can. Unless the manufacturer says not too (sometimes the head bolts are coated), wire brushing the head bolts themselves is also a good idea.

Being patient and methodical are equally important, a little OCD is good here.


From your first post it seems you've already gotten gaskets, and I hope you already know this, but the only other real gotcha I can think of is using original Westerbeke internal engine parts. The W46 is based on a Mitsubishi 4DQ5, you can probably save 75 percent sourcing parts from an equipment parts supplier. 300.00 for a bare head gasket just seems a little exorbitant to me....

[zboss]

Originally Posted by jimbunyard

For the third time, chasing the head bolt threads is very important, it wouldn't be a bad idea to chase all the other threads too, if you can. Unless the manufacturer says not too (sometimes the head bolts are coated), wire brushing the head bolts themselves is also a good idea.

Being patient and methodical are equally important, a little OCD is good here.


From your first post it seems you've already gotten gaskets, and I hope you already know this, but the only other real gotcha I can think of is using original Westerbeke internal engine parts. The W46 is based on a Mitsubishi 4DQ5, you can probably save 75 percent sourcing parts from an equipment parts supplier. 300.00 for a bare head gasket just seems a little exorbitant to me....

I bought a complete gasket kit for $45 from Alibaba. Shipped from China and arrived in marina in about 3 days.

[Gary H]

Thanks for the Mitsubishi tip. Fortunately, I've sourced gaskets and intake valves from aftermarket vendors supplying the 4DQ5 market.

In fact, this was the only option for the valves since Westerbeke no longer stocks them. Thanks again to Zboss for the Mitsubishi parts manual.

[HappyMdRSailor]

GARY!!!

How ya doin' bud???

In process???

[Gary H]

Well... I've reassembled but I can't get it to start. In the past, I have had some difficulty with bleeding the fuel system, but I don't think that is the culprit.