Looking for advice on an Atomic 4 repair / replacement

[infy]

I'm on another forum asking some questions and I'm getting some great help there. They also pointed me to this community which is focused on the Atomic 4 and I figured this would be a great resource to help me make some decisions too.

The backstory.. I purchased a 78' Catalina 30 at rock bottom price mainly due to the condition of the gas A4 raw water cooled engine. The previous owner had a mechanic take a look at it and after diagnostics the mechanic basically pointed them to Moyer Marine with quotes for a new engine. So, pretty bad news. Sounds like they determined the block is a write-off.

By the looks of it.. They did *not* take the head off and I don't believe they inspected cylinder walls, gaskets, or valves. I've attached the inspection report... but the short story is:

Cylinder #1 has 0 compression
Cylinder #2 has 30%
Cylinder #3 has 50%
Cylinder #4 has 50%



At worst case, this is a ~$10,000 repower project. Unless I can save the current engine.. or find a replacement used engine.

Plan A:
My current conclusion is that there's still a chance this is only a top-end problem and the block, rings, and etc is OK. But I won't know until I disassemble it.

Photos:



Plan B:
Meanwhile, I've began looking for a replacement engine and I've found a potential candidate. I'm told it ran a month ago, has about 550 hours on it, fresh water cooled, and came out of a Catalina 27. But it looks like it belongs in a dust pan. I don't see any deep corrosion, but everything is covered in surface rust. I'm going to check it out on Sunday and if it looks promising, I'll buy it. It's not on a test stand... but I plan to try and convince the owner to allow me to hotwire the starter with some jump leads to a battery to crank and do a compression test. At minimum I could turn it over by hand and make sure it's not seized.

Photos:



Right now I'm trying to figure out the best way to hotwire or evaluate an A4 on the back of a truck bed.

Any thoughts/suggestions on the overall strategy? Or insights to the pattern on the original A4?

[Tim]

I would do some more testing before shopping for a new motor. It is much more likely that you have a stuck valve than a cracked block. Take the valve cover off and look for broken valve stem or broken valve spring and turn the motor by hand or starter and see is all the valves are moving.

[ndutton]

A two stage cooling system pressure test will tell you if an engine is viable or scrap metal.

• Stage 1 - Test the entire system excluding the water pump. If it holds pressure, you're good. If not, proceed to . . . .
• Stage 2 - Test the manifold separately. If it doesn't hold pressure, good. The manifold is easily replaceable. If it holds pressure, the block must be considered junk.

This testing protocol is not 100% conclusive but close enough for a quick assessment.

I purchased a 78' Catalina 30 at rock bottom price mainly due to the condition of the gas A4 raw water cooled engine

That means there should be some budget left for engine work and whatever else is needed. Where did that $10K repower figure come from? Are you including a professional Rolls Royce mechanic to do the work?

I would go ahead and look at the engine for sale today and make the sale contingent on the aforementioned pressure test as well as the tests you mentioned. For the right price it could be a great source of spare parts at the least.

[Dave Neptune]

Check the above and note that the compression figures could be a simple valve adjustment or just sticky valves. This is especially so if it has set for a long time.

I have often seen low compression numbers go away after the engine is started and ran for a bit. This will often shake the valves and rings loose.

My ole A-4 had far worse numbers and it ran for 34 more years for me and it is running now for the new owner, keep the faith.

I'd try a bit of "spray" oil into the cylinders and let them soak for a day or two and give the engine a spin on the starter once in a while. Then try starting and it may take some "motor crack" (starting fluid). Also add some MMO or my favorite some 2-stroke oil to the gas at about 100:1 for some oil to get delivered to the valve stems. I have seen and experienced this working far more often than not.

Can it be confirmed that the compression check was done with the throttle and choke wide open?

Dave Neptune

[infy]

Originally Posted by Dave Neptune

Check the above and note that the compression figures could be a simple valve adjustment or just sticky valves. This is especially so if it has set for a long time.

I have often seen low compression numbers go away after the engine is started and ran for a bit. This will often shake the valves and rings loose.

My ole A-4 had far worse numbers and it ran for 34 more years for me and it is running now for the new owner, keep the faith.

I'd try a bit of "spray" oil into the cylinders and let them soak for a day or two and give the engine a spin on the starter once in a while. Then try starting and it may take some "motor crack" (starting fluid). Also add some MMO or my favorite some 2-stroke oil to the gas at about 100:1 for some oil to get delivered to the valve stems. I have seen and experienced this working far more often than not.

Can it be confirmed that the compression check was done with the throttle and choke wide open?

Dave Neptune

I'm not in touch with the mechanic who completed the original inspection. So I'm not sure what procedures they followed for the compression test.

But I do know that they were unable to start the engine at all. It would turn over, but that was it.

Great tips on the valves! I'll remove the valve cover and take some photos... Looks like a few things need to come off first... carb.. and fuel pump.

[Dave Neptune]

With the cover plate off you will be able to "see" if the valves are sticking and also be able to work any loose if need be.

Dave Neptune

[infy]

Originally Posted by ndutton

A two stage cooling system pressure test will tell you if an engine is viable or scrap metal.

• Stage 1 - Test the entire system excluding the water pump. If it holds pressure, you're good. If not, proceed to . . . .
• Stage 2 - Test the manifold separately. If it doesn't hold pressure, good. The manifold is easily replaceable. If it holds pressure, the block must be considered junk.

This testing protocol is not 100% conclusive but close enough for a quick assessment.

I'll read up on this. I've done many compression tests but never a cooling pressure test.

Originally Posted by ndutton

That means there should be some budget left for engine work and whatever else is needed. Where did that $10K repower figure come from? Are you including a professional Rolls Royce mechanic to do the work?

Got 3 mechanics to quote the project. They used Moyer Marine to price replacement engines. Roughly $6,000 for a new engine and $3,000 for old A4 removal, shipping, and complete installation.

A perfectly good Catalina 30 with a running motor can be found for roughly $10k in this area so there's only so much I can justify before I'm in too deep.

[ndutton]

Originally Posted by infy

Got 3 mechanics to quote the project. They used Moyer Marine to price replacement engines. Roughly $6,000 for a new engine and $3,000 for old A4 removal, shipping, and complete installation.

Sounds to me like these three mechanics each expect $2500 for one day's work.

[infy]

No kidding. I don't see what the big deal is. It's 8 bolts, prop shaft, exhaust, water intake, and wiring harness. Lego kits are more complicated. But I don't know. Maybe there are gotchas.

I just spent the day at the marina. Confirmed compression us abysmal. 10 psi, 30 psi... this block may be a lost cause after all.

I may take it apart to satisfy my curiosity as to what happened to this tired donkey. At least the weight off will make it lighter for removal.

[infy]

Originally Posted by Tim

I would do some more testing before shopping for a new motor. It is much more likely that you have a stuck valve than a cracked block. Take the valve cover off and look for broken valve stem or broken valve spring and turn the motor by hand or starter and see is all the valves are moving.

Agreed - I'd want to wait and see what a disassembly reveals. But it's not very expensive and could be a good investment for parts or a spare. The trick will be properly evaluating the condition without having the ability to start it.