Is it possible to morph a SJP and a EFPC?

[Horsley-Anarak]

Looks good inside. There was a bit of crud pushed to the top, but overall it looks good inside the bore and inside the jacket.

However, there is still a double blip of resistance at the top of the stroke as I turn the flywheel. Do you think that I am just feeling the magnet in the flywheel?

Looks good,could have got away without removing head, but now you know it is all clear.
Resistance could be the gearbox, is there oil in it.
Rust on the gear teeth will make it bind up a little.

H-A

[mashenden]

Yep, but I'm glad I did it none the less.

I could remove the bottom unit again (two nuts and a bolt - easy) to see if it is in the top or the bottom.

Is my magnet/flywheel theory all wet? It happens exactly at the top of the stroke, which makes me think it could be normal, but since this is my first real dive into repairing a Seagull, I don't have anything to compare it to other than the SJP which has the plate and magneto removed (no double blip resistance at all when at the top of the stroke in this case).

.

[Horsley-Anarak]

Is my magnet/flywheel theory all wet?

Hard to say, as one persons view of resistance to turning, will be different to another persons.

If it is all coming apart easily, just drop the leg off that will solve a lot of questions.

If the box is a bit tight, it is worth pulling that apart to clean it all out.

H-A

[mashenden]

Decisions, decisions...

What should I do, keeping in mind that my objective is to have a traditional looking Seagull, but with a F-N clutch? In other words, not a purist, but purist looking

The lower unit from the EFPC is in really, really good condition - dare I say "near new". However, something is not right with the top end. After removing the lower end, I can still feel something odd when the piston is at the top of its cycle that should not be there. I removed the plug on my Century 55 and found that it feels mostly smooth through a 360 degree rotation. Also the SJP is mostly smooth through a 360 degree rotation. The EFPC is smooth through about 330 degrees but something is not right for about 30 degrees - something at the top of the stroke is funky.

So with that revelation, I started to think that my best bet would be to put the old SJP top end on the EFPC lower unit. Then I thought, Hummmm the SJP is as old as I am... I wonder how good the water circulation will be. When blowing into the down tube connection, I found it was blocked solid. Now I don't know what direction to take.

Can someone comment on whether the plate and flywheel from the old SJP will fit onto the EFPC? Idea being I would put the old plate, flywheel, and points (or the CDI) on it, and get the traditional Seagull look with a clutch prop. This would mean fixing whatever is the oddity in the EFPC top end, though. It should come apart pretty easily, but it would only be worth it to me to do this if the SJP plate, flywheel etc will work on the EFPC top end.

Or I can stick with using the SJP's top end, and somehow clean out the water passages. The idea of taking it apart is less than appealing since it is 50+ years old and other bolts on this motor have proven to be impossible to remove without breaking. I am sure I would run into more challenges than I have time for.

Any suggestions on the path of least resistance?

[Horsley-Anarak]

You can mix and match those two engines, all the bits will fit.

You might not have a timing recess on CDI motor, but you can get over that.

I would strip the EFPC power head, to see what the problem is.

You can leave the flywheel on for the moment, pull the cylinder, and drop the bottom crankcase half off.

You will then be able to see if there is an obvious problem such as corrosion.

My feeling is that the crankshaft is possible bent, bore look very good in your picture, so should not be causing a problem.

I would do a total strip down and measure the crank, if nothing else looks bad.

H-A

[mashenden]

Thank you again, H-A. Good food for thought. Perhaps I bent the crank trying to get things unstuck

Please do not take this as disagreement. I am absorbing your suggestions, but given that any part will fit either engine, I have to ask...

Is there not a reasonably effective way to clean out the water passages in the SJP without opening up the motor?

It seems (to the novice ) this top end would be easier to get working if I can easily clean out the passage ways. Is that just crazy talk?

[Stelios_Rjk]

An answer from a guy that had done vast amount of experiments with chemical, electricity etc etc. (If you search you may find my attempts)
Well the answer is no. Screwdriver and hammer in a gentle way, hand-held drill and any other mechanical way is the key for crud removal from the water ways.
And of course, by eye inspection.

[Horsley-Anarak]

The only way you will clean out a cylinders water passages is to take the head off.

Perhaps you should strip both motors down and then make one good one from two, but that can be a wasteful process.

I would not give up on the EFPC, looking at the picture of the water passages, it has not done much in its life.

There are loads of bits about for these engines, so finding spares is not a problem.

H-A

[Charles uk]

Not much point in going through all this performance if your not going to do the job properly!

Strip the powerhead, to find out why it was seized, if the piston & rings are fit for purpose, & the same for the crankcase, rod & crank, it's only a Seagull not rocket science.

No one enjoys getting towed home, something I'm considered an expert in!

There are probably 10 members of this site who've been kind enough to pull me out of the s***!

[mashenden]

Not much point in going through all this performance if your not going to do the job properly! ...

Agreed, I am not looking for a short cut, just the best approach.

Clearly all are advising that the passages cannot be cleaned without taking apart the head so that puts the SJP back on the back burner because of corrosion. I'll take a look at the EFPC to see what is wrong there. It really should open right up - no corrosion.

Thank you, all - I REALLY appreciate the insight.

[mashenden]

Mystery solved. To my untrained eye, the cylinder looked great, but not all was as it appeared. After separating the crank case from the cylinder, turning the crank felt smooth as silk. Next I put the crank case and cylinder block back together and put the two bolts in but not tight. I noticed that the crank case and cylinder block wanted to separate at the top of the stroke. After a closer inspection of the cylinder bore I found a horizontal crack about where the sleeve extends beyond the cylinder. It was enough to make the piston snag at the top of the cycle. Funny (sort of)... now that I found it, I can feel it like a thorn in my shoe. It was such a clean block too.

Is there such thing as a replacement sleeve for these or am I in the market for a new block?

You can see the crack here extending from about 4 to 7 o'clock:

[Horsley-Anarak]

That is an odd one.

I have not seen one fail like that.

There is no sleeve, all all one casting.

I can not think why it would fail like that, there is no logical reason.

Now it is time to strip the other one.

There are lots of cylinders about, postage to the states could be high.

H-A

[mashenden]

You read my mind, H-A.

The SJP just became a donor. I'll use everything off the EFPC except the block, plate, and flywheel (and the brass tank 'cause that type looks better than the steel one that came on the EFPC). Not yet sure on which ignition or carb. I'll have to search this forum or ask for advise on those decisions.

The SJP's crank case came apart from the cylinder block pretty easily. It was full of what looks like sawdust. Odd??

Removing the head was a nightmare as expected. I spent two hours getting those !@%$$%!@ flat blade bolts out. A definite sign that the drug culture was alive and well in 1960 at Seagull (just kiddin'! - I suppose there was a reason for using flat blade bolts).

More of that sawdust looking stuff was the cause of the water passages being blocked. At least it cleans out pretty easily. I did not see any of the sawdust stuff in the actual chamber, so whatever it was stayed in the non-combustible areas.

Any thoughts on what caused the sawdust stuff (or why that was put in there??)?

Ta-da - One 1960, gold, 40+ block ready to be dunked in cleaner:

[Horsley-Anarak]

The sawdust type stuff is just dried out corrosion, oxide, rust.

Did it look like this.

That is the worst I have seen.

Post more pictures of your progress.

H-A

[mashenden]

Similar - mine was a bit darker and finer, but that must be what it is. I'm sure glad I didn't decide to forge ahead using that top end