To rebuild or not to rebuild.

[dlnrunner]

I recently became the proud owner of a Pathfinder Marine 1.6 VW Diesel. I have started cleaning the motor up for fresh paint, and I find myself removing more and more items from the motor.
I don't know a lot about the life of the motor, but it does have 3500 hrs on it. The timing belt was brand new looking, but very tight. I know for sure that I am looking at the valve clearance and replacing hoses and thermostat.
Any thoughts on what items to replace while the motors on the stand?
Should I get into a full rebuild, or throw it in the boat and cross my fingers?
The motor spun well, and the valves look great. I haven't popped the injectors off to check compression yet though.

[vanbcguy]

Oil seals are a no-brainer. Valve stem seals and valve guides would be worth checking on if you are planning to pull the head. A good quality fresh water pump would be wise.

Check the intermediate shaft bearings, the outer one in particular. They are often damaged by an overly tight timing belt and can cause low oil pressure.

If the compression is good I wouldn't bother with a full rebuild personally, unless this is going in to something you intend to run for at least the next 10 years.

Sent from my XT1097 using Tapatalk

[air-cooled or diesel]

if you can, after other checks, maintenance, can get it started on stand, another good thing to check that will tell you alot is oil pressure(that is after compression test). 

[dlnrunner]

I started getting into thing, and I noticed that there was a lot of sludge in the cooling system. It was white, but more of a Crisco consistency, and not mixed at all with the coolant. It seemed more of an oxidation than oil in the coolant system.
I am going to replace all accessible gaskets, waterpump and the intermediate shaft bearings and seals (front only). I am on the fence on a new oil pump.

After pulling of the valve cover, the valves look brand new.

For me to pull the boat from the water costs about $400, which is the main driving force of making me lean towards a rebuild. Most of what I have hear about though is the issues with broken timing belts.

Does anybody have a spare intermediate shaft pulley by chance?

[air-cooled or diesel]

yea i think id want some kind, perhaps strong coolant flush. it doesnt have any kind of heater core right?

After pulling of the valve cover, the valves look brand new.

huh? and how did you see any part of a valve, cam and lifters may look ok, well enough, i suppose.

pm sent.

[dlnrunner]

yea i think id want some kind, perhaps strong coolant flush. it doesnt have any kind of heater core right?

After pulling of the valve cover, the valves look brand new.

huh? and how did you see any part of a valve, cam and lifters may look ok, well enough, i suppose.

It has a heat exchanger in the exhaust manifold, I pulled it out, and it looks like its in good shape.
I may have misspoken about the valves. The top of the head cam assembly looked nice and clean.
Thanks for the input.

[air-cooled or diesel]

id get the tool and loosen slack/tension on belt 1st, turn motor over 2x, like in timing post first to make sure your still in tolerance, because a lot of change in belt tension changes timing, so make sure.

or pull valve cover and re-measure timing w/feelers, add dial and check, dont forget everytime 2x over on crank and re-check, etc.

[Toby]

This clearly a case of having too much time on your hands. The first thing that you should have done is lit the motor off. Before cleaning, before painting, before anything. Then you have some idea what you are dealing with. Right now you could be putting lipstick on a pig!

Before you go any further with ANYTHING light the motor off.

FWIW, nobody on the outside can match what the factory does when they manufacture these motors. "Rebuilding" one, usually means just an overhaul. A rebuild means that every working surface is NEW: reground crank and cam, rebuilt rods, new bore job and pistons, new oil pump, valves springs, guides, etc, etc, etc. $$$$

Just doing rings and bearings and maybe a valve job is a HUGE step BACKWARD in a good motor.

Get it running, verify oil pressure and no obvious knocks, etc. THEN check the compression.

FWIW oil pumps almost NEVER go bad except when they get FODed. That is when broken pieces of the motor get sucked up by the oil pump as the motor is disintegrating. I have been inside of hundreds of bad motors of all kinds and I have never seen an oil pump fail on its own. I have seen them smashed by big heavy chunks of cast iron and steel. I have seen broken gears and rotors when they choke on debris. I have never seen one as the primary failure. If you think about it, the oil pump is the first thing to get oil and the last to lose it. By the time it fails the motor is only minutes or seconds from the scrap pile.

CAVEAT: There are things like some Subarus and SAABs that have such marginal oil pumps that tiny amounts of bearing wear will cause low oil pressure, but these are well known and a new pump never cures the problem. A bigger oil pump does however.

So when somebody tells you "the oil pump failed", it means they ran it out of oil.

[air-cooled or diesel]

I am on the fence on a new oil pump.

what about current oil pump, a few simple measurements will tell you,, and from what your telling us you dont currently have a problem, unless theres additional circumstances. aside from above scathing post.

[ORCoaster]

IF-
I recently became the proud owner of a Paathfinder Marine 1.6 VW Diesel.

I would have run it first to determine if it started, ran and performed to my needs. 

Then I would have checked some of the items you are considering.  Timing belt, timing itself, Oil pressure, compression and only then would I have a short or long list of items to attend to.

It sounds like that you decided to make it pretty first with the cleaning and such.  Only upon putting a wrench to it did it start to occur to you that something mechanical might be wrong with it.  Wrenches have a mystic power to do that, so ignore that desire.

With 3500 hrs on it you have to figure this was a worn engine, break that down to driving it 60 mph for all those hours.  210,000 miles right.  But Marine work is more about setting the throttle and letting it run, at least on the ocean I live next too.  So it makes me think that the timing belt you are looking at might be a replacement not original.  The boat owners I know take better care of their boat engines than the ones in their trucks or cars.

Now that you have it in some state of parts clean them up, reassemble and test the pressure in the cylinders, check the timing to spec, and then run it and do the other tests for oil, water temp and overall performance. 

You may very well have a winner there.  Take care of it and I bet you get another 3500 hrs out of it.

[dlnrunner]

This clearly a case of having too much time on your hands. The first thing that you should have done is lit the motor off. Before cleaning, before painting, before anything. Then you have some idea what you are dealing with. Right now you could be putting lipstick on a pig!

Before you go any further with ANYTHING light the motor off.

I am married with children, wrenching on things in the garage is never a waste of time for me at this point. Lip stick on a pig...... every now and then its OK to play dress up.

I agree I should have fired this thing off, I was just uncomfortable with how tight the timing belt was, and how it was brand new. I decided to check the timing before doing anything else and just couldn't wait for the timing tools to come in.

I will get her back together with some fresh gaskets, a new fresh waterpump, check the valve clearance, and see how she does. I will update the post when I get there.

Also to clarify, I was asking if I should just go ahead with a rebuild, to include the machine and head work. I would never just replace barring and rings.

Thanks all.