Perkins 4108 oil pan / sump removal question

[Warby12]

I'm pretty sure ours is just like yours with a hole in the crankshaft face and no locating pin on the flywheel. I remember because I had a hard time getting the flywheel back on with it's weight and the awkward angle, only to find out the five bolt holes in the flywheel only line up one way. Some careful measuring got it on.

My mistake was to use one of the drive plate bolts, screwed into the flywheel, to take its weight with a bit of rope. I'm pretty sure this is how it got bent and hence broke off inside the flywheel when screwing in for fitment of the drive plate. I hope anyway, otherwise I don't know why it broke off. I will be replacing them all anyway. I should have done a dry fit of all of the bolts first and if necessary cleaned the threads with a thread tool.

Now I know the factory way to fit the flywheel is to put a stud into the crankshaft hole first so you can hang the flywheel off it. Then you can swap the stud for a bolt.

[bongo]

Our engine also has 5 threaded holes and one unthreaded hole in the crankshaft hub. To ease putting the flywheel on I marked it before I took it off. I also purchased a couple of long grade 8 bolts of the same thread and cut off the heads, making guides out of them. I screwed them into the top two holes, then lined up one with the corresponding hole on the flywheel, and once started I rotated the flywheel slightly to line it up with the second hole. Then I just slid it into place.

I may be giving the engine a test run today, I sure hope I did the rear seal right! I hope I don’t regret not changing the oil pan gasket when I had the engine hoisted about 5 inches, (fingers crossed). Wish me luck.

[SVGreatPerhaps]

Good luck! I got to looking at it, and wouldn't the crank shaft basically fall down if I were to remove the sump pan to change the seal? Doesn't virtually the whole bottom third of the engine come down? I'm also not replacing the oil pan seal, but I thought it would be a bear of a job if the crank shaft came down?

Good idea with the bolts! We just took the handle to or manual bilge pump and put it through the middle into the crank shaft (gently) to align it long enough to get a bolt in.

Does any one know what the 6th blind whole in the crank shaft hub would be for?

[skipperpete]

The blind hole is actually for a steel locating pin or dowel, for some reason the matching hole in the flywheel was omitted in quite a lot of flywheels. No need to mark the position if the bolt spacing is assymetrical, she’ll only fit in the one position. Buy original manufacture genuine part replacements for your sheared off flywheel bolts...... these are not just good quality bolts they’re ultra high quality.
No the crank shaft won’t fall down if you take the oilpan off, its held in place by the main bearing caps ( and sundry other items)

[bongo]

Originally Posted by SVGreatPerhaps

Good luck! I got to looking at it, and wouldn't the crank shaft basically fall down if I were to remove the sump pan to change the seal? Doesn't virtually the whole bottom third of the engine come down? I'm also not replacing the oil pan seal, but I thought it would be a bear of a job if the crank shaft came down?

Good idea with the bolts! We just took the handle to or manual bilge pump and put it through the middle into the crank shaft (gently) to align it long enough to get a bolt in.

Does any one know what the 6th blind whole in the crank shaft hub would be for?

Well, I’ve got my same leak, 3 drops/minute from the lower right adaptor plate/bell housing. So, it wasn’t the rear crankshaft seal. At least I didn’t make it worse. The good news is that I renewed a lot of the bolts, did some painting, replaced the damper, which was about to launch a spring, and put in 4 new motor-mounts.
I”ve got 4“-6“ of clearance under the rear of the sump/oil pan, and a lot more under the front of the pan. (If I have to I can easily hoist the rear of the engine/tranny several more inches.) I can get to all of the screws that hold it on. But with a V-drive my engine is so far back in the hull that it is next to impossible to reach for careful cleaning and re-gasketing without standing on your head. Almost impossible to do a drip-pan as it is dripping adjacent to the shaft log with very little clearance.
Has anyone else changed out this gasket, (all 4 of them), in place, successfully? Any ideas?

[skipperpete]

It can be done in situ but the job requires a surgically methodical approach and a calmness normally only found around tibetan monks.
I just did a 4-154 sump gasket (tin can sump) with the engine inverted on the bench and that was not easy. The trick is to glue the cork to the block and into the front and rear grooves with contact adhesive and great precision... side pieces first with particular attention to the little tabs that go into and eventually under the aft and for’ard gasket grooves. Do a dummy run with the end gasket strips to avoid fumbling with glue on em. Once all the gasket is glued down and looking good, put a dab of RTV red ( or black or silver) into each of the 4 corners and a smear of the same on the oilpan and refit it to the engine.... a few long guide studs will make the pan go exactly where it needs to be.
Clean and degrease every sealing surface to perfection.
While the oil pan is down take a close look at the lube oil suction strainer. Carefully inspect the residue in the oil pan.
Oh, your’e going to need a mirror and a flashlight.
Om
Pete.

[Warby12]

Originally Posted by skipperpete

It can be done in situ but the job requires a surgically methodical approach and a calmness normally only found around tibetan monks.
I just did a 4-154 sump gasket (tin can sump) with the engine inverted on the bench and that was not easy. The trick is to glue the cork to the block and into the front and rear grooves with contact adhesive and great precision... side pieces first with particular attention to the little tabs that go into and eventually under the aft and for’ard gasket grooves. Do a dummy run with the end gasket strips to avoid fumbling with glue on em. Once all the gasket is glued down and looking good, put a dab of RTV red ( or black or silver) into each of the 4 corners and a smear of the same on the oilpan and refit it to the engine.... a few long guide studs will make the pan go exactly where it needs to be.
Clean and degrease every sealing surface to perfection.
While the oil pan is down take a close look at the lube oil suction strainer. Carefully inspect the residue in the oil pan.
Oh, your’e going to need a mirror and a flashlight.
Om
Pete.

This is such good advice Pete. Thanks for taking the time to share it. I am going to copy and file it

I have been busy swearing at the engine and while I had to have the flywheel off again, to have the broken damper plate bolt removed, I attempted the rear oil seal again (crazy I know). By the way the machine shop guy said it was definitely a dodgy bolt, not my technique. He showed me by putting a new allen key, high tensile 1/4inch bolt in quite hand tight and then hit it with a hammer another another 90 degrees around. Tight. So, I recommend new top quality bolts, they are cheap. Of course when you're fastening into aluminium with steel, I wear a nappy (diaper), aluminium is much softer.

Anyway, gearbox is back on, seems good! Test drive tomorrow.

Oil leaks? I don't want to jinx myself but...... not too bad, from 2 hours running so far.

I think, maybe, just maybe, the back of the sump pan and rear oil seal housing (not the actual seal) have a bit of a conspiracy going on. If the test tomorrow is good I will be back with more details, wish me luck and good luck to you all!


.

[skipperpete]

Well done!..
Pete.

[Warby12]

Ok well, I'm not going to brag too much 'cause it still leaks!!!! But a lot less
I think it boils down to three potential leak spots,

• The actual crankshaft seal
• the seal around the crankshaft seal housing - which part seals to the block and part seals to the oil pan
• and the oil pan seal (specially the rear end which is lower in a slanted boat installation

Now I have done an image up to explain a bit but can't upload images for some reason....




.

[Warby12]

Ok attachments working now. I've included some other pics off the backend of the engine, as it can be hard to see for many people. Sorry if the quality is not great, should have spent more time setting them up. I was going to write the whole thing up in detail but seeing as it's still 20% leaking, I'll not bore people. My attempt at sealing the oil pan was slap dash, don't follow my advice, follow skipperpete's . I do think that when you have the back seal housing off, it's worth paying particular attention to the back part of the oil pan seal and see if you can get that sealed up too. The last pic shows the squeeze out from the oil pan seal attempt. I removed the seal housing again, cleaned up all of then back surfaces really well (razor blade, acetone etc) and resealed the rear seal housing back on but it seems I took no pics. Might have been losing my sense of humour. Did my best anyway!

My leak is much better. I can only conclude it is still leaking from the exposed parts of the oil pan seal (either side of the crank seal housing) or the actual shaft seal itself (even though it is new).

Short of pulling this motor out, I will be content with it as it is. I am going to make a little bucket for the oil to drip into directly under the bell housing drain hole. That will make it easier to keep clean.

Plenty more jobs to do, sometimes you just gotta move on

[skipperpete]

Hey Warby12 , the photos turned out pretty well.
Here’s a very poor photo of another Perkins leak that I fixed before covid shutdown. The owner had previously replaced the rope seal but still had a really bad leak and thought he’d done the rope incorrectly but not wanting to enjoy the seal fitting process again he got me to do it. The seal was perfect but the gasket had moved out of position when he was messing with the seal carrier.

[Warby12]

Ah! good photo. They are finicky things aren't they? And the big problem is you don't get too many opportunities to tackle them and the only way to test it is to put it aaaaalll back together again.

Actually I was wondering if I should have tested it with the flywheel off. Then I could see what's leaking. Can you run a motor with no flywheel?

[SVGreatPerhaps]

Great pics Warby12! We didn't have the guts (or the gumption any longer) to pick up the engine to get to the oil/sump pan like you did, good on ya! We decided we will pull the engine out this offseason, take it to a friend's shop, and rebuild her. (If anyone has a guide on that, I'd love to see it!)

I don't think you can run an engine without a flywheel? When you crank the engine to start, the starter gear jumps forward into the teeth of the flywheel and gets the flywheel spinning. I don't know how you'd start the engine without getting a good crank on the flywheel? You'd need to get a good crank on the crankshaft to get it spinning by I don't know how you'd achieve that with the engine in the boat.

[Warby12]

Originally Posted by SVGreatPerhaps

Great pics Warby12! We didn't have the guts (or the gumption any longer) to pick up the engine to get to the oil/sump pan like you did, good on ya! We decided we will pull the engine out this offseason, take it to a friend's shop, and rebuild her. (If anyone has a guide on that, I'd love to see it!)

I don't think you can run an engine without a flywheel? When you crank the engine to start, the starter gear jumps forward into the teeth of the flywheel and gets the flywheel spinning. I don't know how you'd start the engine without getting a good crank on the flywheel? You'd need to get a good crank on the crankshaft to get it spinning by I don't know how you'd achieve that with the engine in the boat.

Ah you're right, what a dope I am. Surprised I can tie my shoelaces with thinking like that! Good luck with the rebuild. Take some pics?

[SVGreatPerhaps]

Too much thinking and our brain's get fried. Sounds like you deserve a break!

Yes, we will definitely document the rebuild process. I haven't done much looking yet online to see if there are any good how to videos or diy manuals, but I'll bet there's bits and pieces floating around out there of all the info we need. Hopefully we won't burn out and will put together something useful for folks.

... But now after (another) new rear main seal, flywheel bolts, new fuel injectors, and a rebuilt fuel injector pump, our engine is running like a dream!!! We might be being lulled into a false complacency, but going for a trip sounds better now than pulling out the engine!