Rebuild step 1

[thatch]

"On second thought"

After looking at bearing failure causes on several additional websites and thumbing through even more repair manuals, I am tending to agree with Hanley and Russ that this is more likely a case of bearing failure caused by extreme engine lugging. Recently another A4 owner who posted bearing pictures with similar pitting marks, was also experiencing an inability to reach decent cruising rpm's, which would also tend to support this theory. Although Acid corrosion does look similar, the higher wear pattern on the portions of the bearing shells toward the center of the engine might very well indicate a "flexing" of the crankshaft. Ironically, the better the tune of the motor, the more this situation would be prone to happen.
Tom

[P30inbuffalo]

Lugging wormtrails

Thanks to all of you for your analysis. I in my limited experience am thinking that this was caused ultimately by the engine lugging- the lugging caused minute cracks in the bearing which then were eroded by the presumed excessive acidity, along those crack/fatigue lines.

I was concerned there might be another mechanical condition in the engine that needed to be addressed, not wanting to go to all the trouble of rebuilding and then miss something.

Another question- where would I find all the measurement specs for the engine to compare against what we measure? I wasnt seeing them in the Moyer manual.

Jim

[ArtJ]

There is another manual for the atomic 4 which may have the specs you
are looking for by Robert Staton "Service and repair manual for the atomic 4"

[ArtJ]

Also found this link by Hess which does give specification details

http://www.cncphotoalbum.com/atomic4/atomic4specs.htm

[ILikeRust]

update:
Wow! I just found an even better site.
http://www.agkits.com/bearing-failure-analysis.aspx

The damage on mine looks exactly like this pic:

[P30inbuffalo]

Status of your rebuild?

Hey Bill, did you have specific engine issues like lugging or low power? I'm curious as your bearing breakdown is very similar. How's your rebuild going? Have you determined the wear on your crankshaft and bores and whether you will be upsizing rings/bearings?

[ILikeRust]

I bought my boat in August - during the survey, the surveyor noted that the engine never got above about 1700 rpm cruising at WOT. The seller said he had had a professional mechanic check the timing and everything, and that it had always run that way since he had it (he had it about 8 years).

I said it probably was the propeller and the surveyor agreed that I should check that out.

I'm planning on biting the bullet and buying the Indigo prop.

[P30inbuffalo]

Oil filter

I'm thinking it makes complete sense to add an oil filter system like the kit for sale through MMI. Does anyone have experience doing this? A former auto mechanic friend of mine was in disbelief when I told him the engine had no oil filter.

[ILikeRust]

Oh, and no, I have not yet put a mic on the bearings or cylinders. Visually, they appear pretty much perfect. They also feel pretty much perfect to the touch - no discernable ridges, wear or scoring anywhere, so I'm optimistic.

I'm working on contacting local engine shops who will be able to properly get a measurement of the cylinder bores and crank journals. Once I get those numbers, then I'll have a better idea of how to proceed. But for now, I'm thinking I'm probably going to be able to get away with just giving they cylinders a light honing and installing the standard piston rings and crank bearings.

[P30inbuffalo]

Re-wiring

Like many others here it seems pulling the engine inevitably leads to a host of related projects which make a lot of sense to do at the same time, to the extent that funds and energy permit.
My engine compartment is a complete mess of in-line fuses and electrical taped splices and crisscrossed hanging wires. I have been reading up on some of the basics like wire and connectors. I am in a freshwater environment so corrosion isnt as big an issue as it is for a lot of you. However I think it still makes sense to use tinned wire and double crimp connectors when I redo the wiring. If nothing else it would be nice to have the satisfaction of knowing something was done "properly". (The problem is trying to learn enough starting from near zero, with limited time available, to be able to hit the mark close to "properly". And when its smarter to NOT attempt something! I am inclined to attempt more than I can handle)

Has anyone found a source for small quantities of tinned wire (25ft?) and quality connectors? A lot of the sites I have checked out have 100 ft as a minimum.
Any thoughts on some do's and dont's?

Thanks

[sastanley]

Has anyone found a source for small quantities of tinned wire (25ft?) and quality connectors? A lot of the sites I have checked out have 100 ft as a minimum.
Any thoughts on some do's and dont's?

Thanks

Jim,

genuniedealz.com - no minimums as far as I know and free shipping.

I used them when I re-did my mast wiring and I am building a shopping list for the rest of the boat now too.

They have an e-bay store too, but their prices are the same no matter where you shop.

Since Moyer sponsors this forum, I should mention they also have ABYC compliant re-wiring kits available too.

[ILikeRust]

My engine compartment is a complete mess of in-line fuses and electrical taped splices and crisscrossed hanging wires.

I don't know what you mean - here is my engine compartment - a veritable paragon of organization...

[ndutton]

In my recent engine rewire I prefabricated a harness using the attached drawing. Note that the drawing has features specific to my installation so there may be wiring shown that's not necessary for others. I made measurements as to lengths from connection to connection and scribbled them on the drawing as a layout tool. I drove nails into my workbench top to use as measurement posts and off I went. The junctions shown were soldered and insulated with shrink tube. I finished it up by encasing the whole thing in split loom.

Blasphemy Alert!!

I did not use tinned wire. The proper colors are tough enough to find in reasonable lengths untinned and I figured the original untinned harness worked fine for over thirty years, why wouldn't I expect another thirty years out of the new harness?

[Kelly]

I'm so glad you blasphemed before I had to run that gauntlet. I too go the non-tinned route and pay particular attention to proper crimping and heat shrinking.

This is certainly good practice for increasing connection viability and assuages my conscience...

[P30inbuffalo]

To tin or not to tin, that is the question

I'm so glad you blasphemed before I had to run that gauntlet. I too go the non-tinned route and pay particular attention to proper crimping and heat shrinking.

This is certainly good practice for increasing connection viability and assuages my conscience...

Maybe tinned wire is overkill here on Lake Erie?