Catalina 30 Engine configuration

[Mark Millbauer]

This is a question for Catalina 30 owners with Atomic 4's.

I have a 78 Catalina 30 that I pulled a bad 12 hp Yanmar diesel out of. (Yes it came with a YS12B from the factory) As a long time Atomic 4 fan I am in the process of rebuilding an A4 to install in place of the Yanmar. Although this is not an easy swap, the only challenge I have is with engine angle and oil pan to hull clearance. My initial measurements using my mock-up engine indicate that at the approximate 7 degree angle of the prop shaft, an A4 oil pan in this C30 will only clear the bottom of the hull about 1/4" or so at it's lowest point. I'll rebuild and put the Yanmar back in it and sell it if installing the A4 requires a new prop strut and shaft log at a steeper angle.

Before going further with engine stringer modifications and sinking more machine work and parts into my A4 motor, I need to know what angle the motor is sitting at in your C30's. I would also appreciate knowing how much clearance you have under your oil pan in the area of the rear motor mounts. Any information you can provide to that end is much appreciated.

Mark

[ndutton]

If nobody responds sooner I can get you all the measurements you want tomorrow. You have hit on the most important factor in engine replacement though, the factory angle of the shaft. It's different for every type of engine. Here's a link to a discussion of the factory installation and how the engine configuration determines everything.

Isn't there a keel bolt under the engine to deal with too?

[Mark Millbauer]

Neil,

Thanks for the reply, I was hoping you would. When I first started this project I talked to Ken at Catalina and asked him if he knew if back then if the engine was aligned to the shaft or was the shaft aligned to the engine. He wasn't sure but figured the engines were aligned to the shaft, the angle already having been decided by the previously installed strut and log. I'm starting to doubt that was the case. I wish I knew someone with another C30 with an A4 in my area (Seattle) that I could inspect and measure but I don't.

The keel bolt is not a problem. It sits under what would be the forward part of the motor and given the angle and depth of the bilge, there seems to be plenty of room there. The issue seems to be under the rear mount on the port side at the lower corner of the oil pan. The corner at the bottom where the vertical side meets the horizontal bottom of the pan. If you can't see that area you may be able to get your arm under there from the the bilge access in the front or the rear of the engine and just feel for sense of how much space is there.

Placed on the shaft stub, the needle on my hardware store angle finder settles at about 7 or so degrees. If you have one you may be able to place it on the head or manifold to get a measurement.

Two other measurements that would be very helpful is the distance from the center of the flywheel cover to the forward bulkhead and the distance from the prop shaft flange to the bottom of the hull.

I know this is a lot to ask and certainly understand if you are unable to help. With engine and galley installed these are not easy measurements to make. Any help you can give is much appreciated.

[romantic comedy]

A quick thought that ran through my mind:

Sounds like you might need to elevate the engine. Would a reduction gear work for your boat? I dont remember the specifics. I guess that you already need a new prop just a thought.

[ndutton]

Mark,
I'm all over this. The flywheel forward measurement could be a problem due to zero access and zero visibility but we'll see. I can tell you for a fact the shaft/log/strut installation was as described in the link I sent. I personally did around a hundred of them, saw hundreds more over four different manufacturers.

RC,
In the Catalina 30 there is no room to elevate the engine. It sits under the dinette seat in the middle of the boat and in my case the alternator is within a hair's breadth of the underside of the seat. It's really tight height-wise in there.

I have a local sailing friend with a Catalina 30, originally A-4 powered but repowered with a Universal M25 3 cylinder diesel. Like Mark is going through, the shaft angle was determined by the A-4 so the M25 had to be aligned to suit, a case of the tail wags the dog. The finished product extends above the dinette seat by 3" at least. A large teak box was fashioned to cover it which virtually ruined the area for sitting. It's like you're a little kid again sitting on a booster seat to reach the table. It would have been far better to rebuild or replace the A-4 but some diesel snob mechanic got to him.

[Mark Millbauer]

Thank you Neil.

I looked at the specs of the A4 with reduction gear and it could indeed help out with the underneath clearance but it is definitely too long. It also would require a larger diameter prop which poses further challenges on the C30. If I can get the A4 to fit, I was planning on going with the Indigo.

I do appreciate any ideas though.

[ndutton]

OK Mark, here we go . . . .

Engine angle
As a reference I checked the boat level at the dinette seat top. It was dead nuts level. By measurement I got a shade under 8° for the engine incline, by trig it calculated at 7.71°

Flywheel cover center (sheet metal style) forward to liner = 1.125"

Centerline of the shaft coupler down to hull bottom at the Vee measured where the shaft enters the coupler = 4.75" (I think this dimension tells the story)

Port aft pan clearance to hull ≈ 1" - 1.5" estimated by finger wag

As I hinted above I have an opinion based on info in your earlier post but I'll wait until you can digest this information before commenting. Let me know if you need more.

[Nahart]

I went with the 3 blade prop from Indigo...made especially for Catalina 30's with Atomic 4. I don't remember the measurements, but it is a smaller diameter than a regular 3 bladed prop. I am very happy with the prop and I backup with more control than my old 2 blade.

[romantic comedy]

The reduction gear adds length, I understand. But you can shorten the shaft, if need be. Then the engine can fit in its proper place. You will also need a new prop from the diesel, so it would be different then the Indigo one.

If you cant raise the engine due to an engine cover, then there will always be 1/4 inch clearance underneath.

I dont know Catalinas, so maybe I am talking to the wind.

[Mark Millbauer]

Romantic,

I have to shorten the shaft any way but there just isn't room to shorten the shaft much further. The C30 already has a short shaft log to stuffing box hose and I have to cut approx. 1 5/8" off the shaft for the standard A4. The reduction gear adds another 5" to the length and if I cut that much off there just wouldn't be enough room for the length of the shaft flange hub to the face of the stuffing box.

It was a great idea and I appreciate your suggestions. Believe me, as soon as I read your post I went and looked up the A4 dimensions and compared them to the dimensions of the boat set-up.

[romantic comedy]

Mark I am out of suggestions. I wish you luck. There are some great people here. I have faith that you will succeed.

[jbsoukup]

IMHO you should rebuild the diesel and save yourself a lot of work.

[ILikeRust]

I submit that he has not yet gathered enough information to reach that conclusion yet.

[roadnsky]

I submit that he has not yet gathered enough information to reach that conclusion yet.

You read my mind Bill... +1

[Mark Millbauer]

Bill is correct. I will go to some pretty great lengths to avoid having to rebuild and put that little diesel back in it. As I stated earlier though, I do have a cut off point. It may not even be rebuildable anyway.

When I got her it had either blown a head gasket or cracked block or something as the crankcase was filled, completely filled to the top of the dipstick port with water and oil. The PO said it overheated and stopped running. That was 5 months ago. It's a raw water cooled 78 model and had been in the salt since new. When I asked the PO if he had ever given it an acid bath or even ever ran fresh water through it he said never. When I drained it and tried to turn it over by hand I could barely turn it. Even if I do get to that point and end up having to get it running either by repairing that motor or finding another one, I would not want the boat. They are just too under powered for where and how I use it.

Their are newer diesels that the boat can be adapted for but for now I remain committed to plan A. I remain optimistic for now.