CD-11 power head overhaul

[Stickler]

Hi everyone, I recently removed my powerhead to change the impeller, and while the lower unit is off decided to do a reseal on it as well. I removed the head and exhaust cover and there is alot of carbon built up everywhere and very thick,also the cylinder walls are varnished but in good shape,so i figure they could use a light hone to remove the glaze.So i realize this will require the powerhead to be completely torn down and have a few questions, i ordered a engine gasket kit from Antique Outboard which comes with every powerhead gasket needed.
My first question is , besides gaskets, what else would i require to do the job right,bearings,crank seals etc?

2)what would be a good cleaner to use to clean the power head case properly and with out damaging the aluminum, but remove the carbon accumulation and clean the water jacket?

Thanks in advance to all that reply.

 

[HighTrim]

Re: CD-11 power head overhaul

You are going all the way are ya! lol


Well the top of the crank just has an oil slinger, no seal there. The bottom is the carbon seal assembly on top of the drive shaft, so easily maintained there while you have the gearcase down.

Regarding bearings and such, judgement call once you have it opened up. How did it run before? What was the compression pre tear down? You will need some 3M 847 to reaseal the crank halves.

When honing, you usually re ring, but measure the end gap of your old rings inside the bore, they may be fine. Before tearing it all apart, take pics along the way if you have never done it, and dont forget to mark the rod ends to keep them together and orientated. They are matched with the rods, and cannot be mixed up. I mark them with a sharpie across where they meet with a T and B so I know what cylinder they are for, and which way the cap goes. Mark both cylinders with a T and B as well. You may think you will remember all of this, but trust me, things happen and you quickly forget. I do anyways.

Engine Tuner or Sea Foam is meant to remove carbon build up and works well. Other guys use oven cleaner. There are a few ways to attack it. Get most off manually to start, then clean from there.

Just a thought, if all was fine, you very well may want to leave well enough alone. Sometimes you cause more harm than good opening things up. Just something to think about. You can still clean it up, and regasket without splitting the crank halves.

 

[Stickler]

Re: CD-11 power head overhaul

The compression test showed T=100psi B=101, It ran only when started at wot and as soon as you throttled down it would die, so i rebuilt the carb,all new ignition system,resealing lower unit,and now figure why not reseal the powerhead, im going to restore the motor and dont want to later regret not opening it up and giving it a good cleaning,i have a good amount of experience in automotive engine overhauls and am comfortable with all the tools and measurements that need to be checked, iv just never worked on anything this old, so experience in what troubles i may encounter or should look out for is limited any helpful tips and advice from anyone who has done this before would be appreciated.

 

[HighTrim]

Re: CD-11 power head overhaul

Wow that is incredible for a CD, I dont know if I have ever had one that high....must be a low hours motor good score.

Your ring end gap should be .005 to .015"
The piston to cylinder wall should be between .0013 to .0025"
The CD bore is 1.938"

I would take some measurements first after cleaning to determine the route you need to take. Of course too, run the bore scope down the cylinder to ensure you are not out of round.

I take my powerheads right down when I hone them by soda blasting to clean them up, then rebuild.

This one was just honed/blasted and ready for rebuild.

 

[HighTrim]

Re: CD-11 power head overhaul

Also when rebuilding the following torque measurements will apply:

Connecting Rod Bolts 60-66 inch/lbs
Crankcase to cylinder 60-84 inch/lbs
Cylinder Head 60-84 inch/lbs
Exhaust Cover 24-36 inch/lbs
Flywheel nut 40-45 ft/lbs
Intake Manifold 24-36 inch/lbs

 

[Stickler]

Re: CD-11 power head overhaul

Wow, nice work, when you soda blast ,do you hit everything, it looks like the bearing surface and pistons were done as well, do you do a pre clean before soda blasting?any tips on soda blasting in general,does it remove alot of material?
Iwas also wondering what type of hone you use, and would you recommend polishing the crank journals as well? and during reassembly do you just use 2 stroke oil to lube all bearing surfaces.
thanks for sharing your experience and knowledge, its always appreciated.

 

[HighTrim]

Re: CD-11 power head overhaul

I hit everything with the soda. It is not real abrasive, so is good for this. The pistons were acid dipped, then cleaned. You dont NEED to preclean before blasting, but if you are using a blasting cabinet all the gunk will clog your gun if you dont. If you are using an outdoor blasting machine, no need to get it real clean first. This is just done on motors I am painting of course. I dont blast them if Im not painting the powerhead.

I have been using a rigid hone. The dingleberry hones are good, but they hide any problems, and you need a specific one for the bore size. The rigid hones will show a problem, and can be used on a variety of motors.

I use assembly grease (Lubriplate 105 as that is what i have) when assembling. It helps hold the needles in place and such as well.

Cleanliness is next to godliness as they say. Just keep a clean table, take your time, and have fun. As I said, take the time to label things as you remove them. It is best to try to get the same pistons in the same bore, and the same rings in the same grooves if you are reusing them. Thats what they say anyways. Im not so sure what difference it makes if you hone anyways myself. You may need rings anyways, but wont know till you measure them.

I do polish the journals. Some dont need much, some need alot. Get strips of emory cloth. Princess auto sells rolls of it for cheap. You will need to cut it in half along the length to fit in the journal as it is double the width you need. Get them nice and polished.

Dont put the piston is backwards! Bought a motor like that before with the sweeps facing the intake instead of exhaust. Iwonder why it didnt run well, lol.

 

[Stickler]

Re: CD-11 power head overhaul

When you reinstall the pistons,do you dip the pistons in oil before installing, like on a automotive engine rebuild. The only thing i dont have is a soda blaster, is it something expensive to invest in, or should i just get someone else to do it, as im planning to repaint motor as well.

 

[HighTrim]

Re: CD-11 power head overhaul

If it is a one time thing, too much probably to invest in. I used to use a grafitti removal company to do my blasting before I bought a cabinet. Alot of them use baking soda. They did it outdoors, no cabinet, so I wouldnt even have to really clean it all that well.

There are other ways to strip it as well. Blasting is just the technique I personally prefer.

Alot of guys dont stip it right down to bare metal either, as long as it is very clean, it isnt totally necessary.

Use a lighter coat, I wouldnt dip them per se. Just use your finger and coat everything. Then be sure to take the time to break it in afterwards.

 

[Stickler]

Re: CD-11 power head overhaul

In your experience would you personally open the powerhead case if the power head had good compression and was just really dirty, and if not what would be the best way to clean without splitting the case, and still get a good satisfactory cleaning,im still on the fence on which way i want to go.
Thanks again,Stickler

 

[HighTrim]

Re: CD-11 power head overhaul

With compression like that, I would leave well enough alone. Sometimes you open a whole can of worms that didnt need opening if you know what I mean. I only open the ones that need it. But I can understand where you are coming from. Been there.

Some oven cleaner, OMC Engine Tuner, or the like, a few small tooth brushes, compessed air, and some other tools should get the job done.

Be sure to dress the head before reinstalling it.

 

[Rick.]

Re: CD-11 power head overhaul

Hi Stickler. Sounds like you are hard at it. Are you planning on painting the power head either way? Tried to get a re-seal kit at my NAPA store and he said none in Canada and it would take 6 to 8 weeks to get one. So I bought one from Iboats. Rick.