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Perkins M20 - Head removed and this is what I found

7K views 28 replies 9 participants last post by  chowdan 
#1 ·
Well i finally got time to really dig into the perkins M20 thats on my boat.

The engine wont turn over via the nut on the crankshaft even with the injectors removed. I had flooded the injector holes with PB Blaster for 2-3 weeks and was still unable to get it to turn over.

I decided that yesterday was the time to tear it apart and see what it looks like on the inside. I pulled rocker cover, rocker arms, and the head off, and I now know why the engine wont turn over....


I've cleaned out all the gunk for the most part and filled the cylinders with a mixture of WD40, PBBlaster and Liquid Wrench. Hopefully we can salvage the engine soon!
 

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#10 ·
:puke
Ewww. that's disgusting.

I've seen this one video of a guy who took his engine apart and found a similar mess. Just slide show of pictures.

YANMAR - 2GM20. 2cil. Reconstruction - YouTube

So likely it can be cleaned up and brought back. Did water get into the cylinders?

Good luck on that project.
That's a serious pro rebuild, maybe that's obvious but that level of work is almost impossible to achieve onboard by the DYI. Impressive none the less.
 
#3 ·
If this was water in the cylinder for a long time it will be tough to make turn without flipping the engine and removing the big end caps. Sometimes ,if pistons are not TDC, a BIT of tapping with a wood block on piston top will jar the stuck rings ,then on to phase 2. Be careful to not damage the journals with the conrod bolts.as you tap each rod with a wood dowl and hammer.May have to remove ridge so rings can pass without breaking the lands. Then hone,new rings,and shells and bob's yer unc. IF engine hydrauliked the last time it ran, bent rods are possible
 
#4 ·
Wow that yanmar rebuild was impressive.

No clue if it was hydrolocked. Everyone I've contacted that owned the boat doesn't seem to know why happened. One bought it and 'it was like this' and another sold it and 'it was running perfectly'.

That said, could be hydrolocked, no clue wtf that sludge was though. I think it was salt, but am not 100% sure. To me, it felt more like puss...

On a flip note, I got 5 of the 6 valves moving free in the cylinder head. Final valve is still pretty stuck so its going to soak overnight. I might go get some ATF and acetone if its still stuck by tomorrow afternoon.
 
#11 ·
Was the Boat in the water during this time frame? and was the seacock open. It has been well lamented but even if used regularly and with the water valve left open, its important to close it when not used for extended periods. A very small leak around the water pump will do this damage in short order. Find the cause and fix it or it will happen again.
 
#7 ·
I think at this stage that would be the least of his worries! I think I would try Kroil or the atf/acitone. WD40 is totally next to useless, and I have not had much better luck with PB Blaster. I have had good luck with liquid wrench and excellent results for Kroil. I keep the Kroil in a cup holder behind the nav station!
 
#8 ·
I definitely will agree. I do not have any concerns about seals being damaged. Mainly because those can be replaced, yes it may be difficult, but i feel it is a lot more work just trying to revive the engine.

I will have to say though WD40 works like ass, liquid wrench and PBBlaster also IMO work like ass but liquid wrench does work to an extent. It was because of liquid wrench i got the valves in the head to free up, not wd40.

I will be switching away from all of these products to ATF/Acetone mixture in the next 3 days when the weekend starts though.

That said, does anyone know of a tractor that uses the Perkins 103-6 engine? I can't find ANYTHING regarding tractors using this engine. All of the engines in tractors that run perkins of this age seem to be running a 4 cylinder, however the 103-6(M20) is a 3 cylinder.
 
#13 ·
That's interesting! I do not know if the m20 has sleeves. I believe it does not.
@albrazzi - I am not sure if the boat was in the water. One owner said it was running another said it wasn't. I do not know what happened to the engine or how it got seized. That white gunk I think could also be a fungus as it was 100% crystallized material
 
#14 ·
Sounds like your open and inspect will go deeper. Piston service anyway. I'm sure you will get lots of advice on next steps. Beta seems to be the recommendation for repowers, Yanmar too of course, but I like what I've read on Beta. If you choose that path of course.
 
#15 ·
Unfortunately repowering is not an option. Cost of repowering is far beyond what i am willing to spend. If it comes to the point where this is not repairable, the engine is getting completely removed and we'll continue to putt putt around with the outboard that is present.

Not planning on keeping the boat with me for more than 5 years before I upgrade to something larger. Would much rather save the 8-12k and put it towards something that is a bit b igger and ready to go more offshore than this one
 
#16 ·
How about a little history.. did you buy this boat with the seized engine? Anyway.. seems you have the skills if you already have the beast apart. in for a penny....
 
#17 ·
Boat was bought with the engine in this state. Its a Bristol 27, 1976. The previous own told us he has no clue what happened with the engine so he just stuck with using the outboard. He said he never liked inboard diesels due to the fact that "they always break and smell up the boat".

For the reason of the inboard not running, we agreed on the purchase price of $3k. It's outboard is fully functional, it had 2 sets of mains, 2 sets of jibs a brand new spinnaker and a storm jib in decent condition. The chainplates are being replaced, the standing rigging will be replaced in middle of summer or winter depending on finances.

As for the inboard, i called the owner(owner 2) who originally installed the engine. He installed it brand new back in 1993, sold the boat in 2003 for $13k. The engine ran perfect still when he sold it. The owner(owner 3) that bought it had called owner 2 and told him she was selling the boat because the engine had seized due to a loss of oil while being ran. She sold the boat for pennies on the dollar due to the engine problem. The guy who bought(owner 4) it from owner 3, apparently 'fixed' the seized engine as owner 2 saw in his port getting fuel in 2009. Owner 2 went to the boat and talked with owner 4, owner 4 said that he just had to add oil to the engine and replace the filters and it fired right up. There was no signs of oil leaks or any problems.
That was the last owner 2 had heard about the boat or saw it.

The owner that we bought it from(owner 5) said he has no clue what happened and never really cared due to the preferred use of the outboard.

All that said, atleast i have some background on the engine. Not enough to exactly know what happened to it. I've never see something like that inside the cylinder before. I do have a feeling that the engine was flooded via exhaust, however thats just a hunch, not anything else. The reason i have that feeling is due to the exhaust elbow is incredibly rusted, however its rusted on the outside. This could also be due to the fact that we intake seawater, and pump out through exhaust.

I have no experience with diesels, in fact this is the first engine that i've pulled the head from. If i appear to have the experience, then maybe thats a good thing, or could be bad. Its a learning process for me by all accounts. I'm a determined soul, not just to fix this engine, but to gain more knowledge. In the industry that I work in(software), learning is a constant process and is something i do on a daily basis. Being a self taught programmer, I do feel that being able to figure out and understand and fix this diesel engine is just something i am bound to do.
 
#19 ·
That is some history Dan! thanks. Do it. you clearly have the skills and those you don't have can be obtained from here and diesel friendly machine shops.
 
#20 ·
Thanks everyone! Definitely will be a slow process in restoring it due to funds, but over time we'll get this engine purring again!

I was at the boat over the weekend and it was still frozen. Added some ATF to all the cylinders. Hopefully that will soak in and I'll get some movement during the next weekend!
 
#21 ·
Heres some photos of the cylinder head when i pulled it off. I have cleaned it up since pulling and have freed 5 of the 6 valves. Ill grab some photos of it cleaned up when i get a chance.

Still need to clean up all the gunk thats built up inside though and free up the final valve.

The final valve that is stuck is completely a goner and need replacing, and in fact they all might need replacing
 

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#22 ·
Wow! That's even worse than how my head looked when I pulled it.

Hopefully you can get it back to running condition. Once cleaned up to your level, a machine shop to do a hot tank cleaning and smooth out the valve side surface would be a good idea. I did that myself for my head and it turned out great.
 
#23 ·
How much did the hot tank and smoothing cost?

I'm considering about having it done, but at the same time, the cost of which to get the engine online is already outside of my budget right now i think.

If i can get the engine out and the lower end dropped, I'll be able to determine how bad of a state and exactly what needs replacing and will be able to better understand how much its going to cost me in terms of buying of new parts.
 
#24 ·
It ended up costing me only $72.25 at a small automotive machine shop attached to a NAPA store, so away from marina shops. I expected it would be closer to $100 but glad it was lower. Took a couple days to do as they were busy working on other engines.

I did my own cleaning before hand. The attached picture with the valves show how it looked after I cleaned and lapped the valves, and the other picture is after I got it from the machine shop.
It's for a Yanmar 2GM.
 

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#26 ·
Tadiesels has 2 unused 103/6 industrial units, It would give you a cost comparison vs extensive rebuild. I bought a new m30 when I repowered. One thing I learned, at least for my m30 is that it has no zinc protection in the raw water/heat exchanger. I added an inline unit. It would be prudent to check that system as well before proceeding. Best wishes!
 
#27 ·
Yeah i was looking at the 103-6 from TAdiesel. I just dont have $2.5k + shipping to throw at this!

If i did, i would be purchasing one to replace my current engine. I still need to go through and try to figure exactly what i'm looking at paying in terms of cost for overhaul/rebuild.
 
#28 ·
No matter what you do be sure to service the vented loop and be sure the cooling system functions properly. that's a lot of moisture in that motor. It could have hydro-locked first if so who knows the damage. Forgive me if this has been covered. Head aside, the rings are shot then there's over-boreing and bearings and the rest of the system. Before paying for anything consider the whole job.
 
#29 ·
Yeah, I want to pull the engine out and tear it apart to see how bad everything is. Once torn apart ill be able to then figure out what it will cost me. If its going to cost close to $2k to rebuild and get running again in just parts and everything else, then ill just start saving the cash and purchase one from TADiesel and hope that it doesn't go out of stock by mid summer.
 
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