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Catalina 30 A4 engine

Dec 23, 2016
130
Catalina 27 Clinton CT
I have the A4 in mine. Raw water cooled . A friend put the fresh water cooling kit on his engine ( Columbia 27) and when he tries to push it, it overheats and produces steam. We ran together to Block a few years ago. I had to hand steer the whole way.
My cruising RPM was more then he could keep up with , so I just kept making large circles around him the whole trip out and back
 
Feb 6, 2019
70
None None None
Hey everyone, looking for a little insight here again. I've removed the head on the A4 and inspected the cylinder walls and valves. Lots of carbon build up and it looks like oil may have been burning?

My specific concern is... I talked to a mechanic who may be helping me out with moving and dealing with a 300lb engine... and I sent him photos and a video of the cylinders in my current A4... and his opinion is that the cylinder walls are scored and in bad shape

I couldn't feel much when I ran my fingers around. I thought this looked a bit ugly but certainly didn't look "destroyed". Note, I didn't clean the cylinder walls before recording the video or taking photos. You're seeing some water droplets and debris too.

Any thoughts here? Are the cylinder walls clearly showing signs that the rings and condition is bad? And not worth using unless it's machined?

Youtube close-up tour:

Photos attached.
 

Attachments

Oct 10, 2011
538
Tartan 34C Toms River, New Jersey
I can't tell from the pic's but I don't think the cylinder walls look scored. I think that mess is due to a head gasket leak. Just my opinion.
No way to tell unless you take the pistons out. If it were mine I would take it to a mom and pop machine shop (one that works on gas motors) they would know just by looking at it. Have them clean it up, also the crank, pistons, etc. It still will be cheaper then doing a complete motor swap unless you have a rebuilt A4 that you got cheap, and I mean real cheap.
Don't forget to check the cam while your at it.
 
Oct 10, 2011
538
Tartan 34C Toms River, New Jersey
Are the pic's you posted of the A4 you bought or is it the one in the boat? Sorry about the part in my previous post about buying a cheap A4 I forgot you already bought one.
 
Feb 6, 2019
70
None None None
No worries. These pics are from the original motor in the boat.

I'm in a bit of a fork in the road. I can either keep throwing money in to this one hoping to get compression back... or install the engine I know has good compression but unknown what other issues.

I was leaning on cleaning valves, lapping the seats, and getting it back together with a head gasket. Then test compression... if it's still poor, install the other engine.

But the mechanic's comments spooked me in to thinking this original A4 is a waste of time and money if the walls/rings are done and I have another A4.
 
May 20, 2016
2,804
Catalina 36 MK1 Everett, WA
If your going to do valves I would also recommend rings and bearings. You don’t know if low compression is valves or rings. Some of those look oily so I would suspect rings.

Cylinders didn’t look bad - a bit of glaze which removes easy.
 
Feb 6, 2019
70
None None None
Yeah part of the argument for bad rings is that it looks like it has been burning oil based on the carbon deposits. Oil blow by.

Being oily in there now could just mean someone was doing a wet compression test recently.

Since I have another A4 with good compression I'm not sure I'm willing to do rings and bearings on this one if I'm trying to take the easier path.

I could take this one out, install the other A4, and work on this one in the garage.
 
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Likes: LeslieTroyer
Nov 22, 2011
641
Ericson 26-2 San Pedro, CA
Yeah part of the argument for bad rings is that it looks like it has been burning oil based on the carbon deposits. Oil blow by.

Being oily in there now could just mean someone was doing a wet compression test recently.

Since I have another A4 with good compression I'm not sure I'm willing to do rings and bearings on this one if I'm trying to take the easier path.

I could take this one out, install the other A4, and work on this one in the garage.
Assuming I'm understanding the sequence you are suggesting....Why don't you instead work on your newly-acquired A4 in the garage and get it running there *before* you install it in the boat. Then, at the point you drop it into your boat, you'll have a running engine and a functional boat. Working on it in you garage will be easier than hunched over in the cabin.

You could then rebuild the one that is presently in your boat at your leisure and keep it for a spare.

Maybe that is what you meant, but I wasn't clear on that.
 
Feb 6, 2019
70
None None None
Maybe that is what you meant, but I wasn't clear on that.
That's a good point. I could get it running in my garage first. I'll weigh on that :)

I posted this on another forum... but not to leave anyone out, here is a running valve video:


So, I'm not sure what correct valve operation looks like on an A4... I dont have a good example of one. But aren't the valves suppose to come flush with the block when closed? These don't appear to fully shut.
 
May 20, 2016
2,804
Catalina 36 MK1 Everett, WA
Easy to adjust and check with feeler gauge - just pull portside cover. Personally I liked to run them loose so they just start “tapping”.
 
Feb 6, 2019
70
None None None
Easy to adjust and check with feeler gauge - just pull portside cover. Personally I liked to run them loose so they just start “tapping”.
My suspicion is that carbon deposits are preventing the valves from closing and that's why I have 0 compression. I don't think an adjustment would help if they're gummed up at the valve seats?
 
May 20, 2016
2,804
Catalina 36 MK1 Everett, WA
Hard to say over the starter noise, but I didn’t hear any tappet noise. If you have no clearance (held open) or excess clearance (not fully closing due to carbon) you can measure and move forward.
 
Feb 6, 2019
70
None None None
I got you now :)

Poking down there with my finger nail I can scrape gunk off the seats. They're definitely being interfered. I'll go ahead and pull the valves first to see what they look like and clean.....

I need to figure out a good way to get carbon off valve seats without ruining them. I'll try valve grinding compound
 
Oct 10, 2011
538
Tartan 34C Toms River, New Jersey
I got you now :)

Poking down there with my finger nail I can scrape gunk off the seats. They're definitely being interfered. I'll go ahead and pull the valves first to see what they look like and clean.....

I need to figure out a good way to get carbon off valve seats without ruining them. I'll try valve grinding compound
I agree with Leslie, the valves are not seating properly. Be careful when cleaning the seats. Use the lapping compound old school.
I also agree with Alan, work on the purchased one in the garage. If you can't get compression by just seating the valves.
 
Feb 6, 2019
70
None None None
Yeah I've got valve grinding compound ready to lap them.

Except my valve keepers are stuck to the retainers. I'm gently tapping and applying pressure to the valve heads... but the assembly just rises with the spring and won't break free :/

I may need to try a rubber mallet.
 
Feb 6, 2019
70
None None None
I think I've found why I've got no compression. I finally got around to cleaning up the deck... should of got to this much earlier.. but it's clear the valve seats are burnt and pitted severely. If the valves don't seal, there's no compression. Guessing they ran the engine too hot and the carbon build up gradually cooked it.

The block needs to be machined. That's likely to be cost prohibitive. May be the end of the chapter on this engine.

Anyone ever seen it this bad?
 

Attachments

Oct 10, 2011
538
Tartan 34C Toms River, New Jersey
Well Newbie I think you are right. Those valve seats look bad, I'm not sure but they look beyond machineing.
Guess you were lucky to come across the used one.
 
Apr 5, 2009
769
Catalina '88 C30 tr/bs Oak Harbor, WA
If the engine is out of the boat, you might want to run it down to your local machine shop. They can re-seat the engine to repair that. It is worth a look-see by a professional who can tell you what it would actually cost.
 
Feb 6, 2019
70
None None None
If the engine is out of the boat, you might want to run it down to your local machine shop. They can re-seat the engine to repair that. It is worth a look-see by a professional who can tell you what it would actually cost.
Ah yes- to follow up on this...

I called around to 5 or 6 machine shops this morning. Almost nobody has the equipment to machine valve seats on a flat head engine anymore. Everyone has moved on to machining valves on heads which I'm told is done on different equipment. I did get referrals to shops who could potentially do it, but they all refused the work.

They said that from their past experiences, they are highly likely to strike water due to water jacket and other corrosion.

But yes, they confirmed that this block can in theory be machined by drilling out and installing new valve seats.

I'm going to pivot to cracking the engine mounts loose today. Looks like it's coming out no matter what.