Sea Water and Oil - How Much is Too Much for an Engine (2QM20)!

[Jim Cate]

Originally Posted by GILow

Actually, most of us are wondering why she married YOU.

for my charm, lad, for my charm...

Jim

[GILow]

Originally Posted by Jim Cate

for my charm, lad, for my charm...



Jim

So many ways to go with this one... but I will be strong.

Back to Wottie’s reciprocating rust rotator... is it going yet?

And did I miss something? I thought the seawater had come in via the cam shaft driven pump? (One reason I much prefer the belt driven, stand-alone sort). Did a minor rebuild of an early Volvo Penta petrol donk for dad after that seal failed. It turned out that Volvo made the pump shaft out of mild steel. WTF!? Had one turned up out of stainless for chicken feed, not sure why they didn’t do the same when they built the rotten thing.

[Wotname]

Originally Posted by GILow

.......I thought the seawater had come in via the cam shaft driven pump? ..........

Never proven and the picture below of the camshaft that turns the RW pump suggests this wasn't the point of entry but the jury is still out.

Initially the PO thought it must have been a blown head gasket and arranged for a mechanic to do a compression test. The mechanic couldn't remove the injectors so that test never eventuated. The PO then bought another 2QM20 and the mechanics fitted it. The engine then sat under a house for quite awhile. Then I bought it ($50). The RW pump was off the engine and in parts although not all the parts were present.

By then it had no compression - I pulled the head and could not find any issue with the head gasket. The valves were badly pitted and the rings were stuck. I made the assumption the leak must have been the water pump">raw water pump in the light of no other evidence. However once the engine was pulled down, there asn't been any smoking gun re the water ingress.

Maybe it was the head gasket? Or the RW pump? The pressure testing between the water side and the oil side described upthread suggests the cast iron and the liners seals were OK.

Note, the PO didn't get the engine into this state, it was a PPO who did that and scammed the PO.

[GILow]

Originally Posted by Wotname

Never proven and the picture below of the camshaft that turns the RW pump suggests this wasn't the point of entry but the jury is still out.

Well, you prompted me to go back and read the whole thing again, including the injector bit. I wish I’d kept count of the number of posts telling you to take it to a machine shop.

Not too late for me to add one tho...

Mate, take it to a machine shop!

Ha ha, couldn’t resist.

So, if I’ve come up to speed, this is NOT the engine for your current boat resto project?

As for the raw water pump theory, I still don’t trust it, on principle. It was the one thing I didn’t like about the new Beta but I concede that:

a) they all seem to do it this way now.
b) Beta have constructed it in a way that it should fail “safe”.

As for the MAPP gun, they are a bit of a bugger. They only JUST get pipe work hot enough to solder, and as they get older, they often fail to reach even that temperature benchmark. If I’d been on the original thread of would have mentioned this, because it has bitten me (badly) before. Certainly an oxy/acetylene job.

Looking forward to the next update.

[Wotname]

^^ Hey steady on, the injector jobbie was a win for me. They came out without any machine shop!

OK, I lost a round with the pre combustion chambers, mainly 'cause my oxy torch (and it's owner) moved out of town - can't count on some mates ()

Anyhow, if it makes you happier, the machine shop will seeing the head next week!

[GILow]

Originally Posted by Wotname

^^ Hey steady on, the injector jobbie was a win for me. They came out without any machine shop!

You do know I was joking, right?

I mean, the number of people who told me I needed a professional to install my engine was remarkable.

Of course, I’m not sure why the boat now goes backwards... but I’ll figure it out.

I’ve got a friend who has been doing up a Yanmar MA3 in his garage to stave off the boredom of Covid isolation. But he made a living performance-boosting Harleys, so he’s kinda in his comfort zone.

Still, can’t help thinking it will be putting out more like 5 HP by the time he has finished. He’s the kind of guy who designs his own camshafts. A bit hard core.

But if this one proves too far gone, let me know, he may be willing to part with the MA3(5).

[Wotname]

Originally Posted by GILow

You do know I was joking, right?

.......

As am I

[Wotname]

Originally Posted by GILow

........
So, if I’ve come up to speed, this is NOT the engine for your current boat resto project?

.........

Correct. The stalled boat restore project has a fully restored YSE8 ready to slot in once the boat is finished. Although winter is right on top us, I must get cracking on the boat (soon).

Unfortunately I don't have a hull for this 2QM20 but I expect something will turn up if the engine comes together (but I gotta keep any potential hull a secret ATM )

[Wotname]

OK....For anyone still reading, the machine shop has worked it's magic and the crankshaft and sleeves are back.

The crank journals have polished and almost all the marks are gone. It still measures with zero (measurable) wear. The engine man suggested the remaining marks are inconsequential for this heavy slow(ish) revving engine.

The sleeves initially measured with 3 thou wear. The manual states 5.9thou is the wear limit. After a rehoming, the wear is 3.5 thou (and circular) so I am happy with that. There is single vertical score line in one sleeve and I will have to live it as is. Note, the sleeves have not yet been cleaned after the going and that makes the score line easy to see. I can't measure it's depth but I can just feel it with a fingernail so I am assuming it is around 0.5+ thou. There is also some minor rust pitting at the very bottom of one sleeve and I can't see that causing any issue.

The shop managed to get the pre combustion chambers out of the head after making up a suitable shaped dolly and using oxy heat. I thought the valves were toast but the shop assured me they were recoverable and so they are regrinding the valves and the seats. The guides were fine.

Another thread on CF regarding valve springs and corrosion caused me to look closer at the existing springs and ATM I am of two minds on whether to replace them or not. Watch this space .

Next job is to make up a jig/drift/dolly to remove and refit the main bearings. They are the only remaining items left to remove.

After that, I will need to source main and big end rod end bearings, rings, maybe valve springs, pre com chamber sealing washers and a head gasket before re-assembly can begin. And oh yes, clean and repainting all exterior components before assembly. Might have to get the oil pump gasket as well as I note it is extremely thin and I am not confident of being able to make it due to it's thinness. The thinness seems to me to be critical to the pump operating correctly.

[jimbunyard]

Sooo, we don't get to put our judicial eyes on the springs?

[Wotname]

Originally Posted by jimbunyard

Sooo, we don't get to put our judicial eyes on the springs?

Stand by

Good to see someone still following the thread

[Wotname]

Originally Posted by jimbunyard

Sooo, we don't get to put our judicial eyes on the springs?

Here you go - a treat for judicial eyes (your and others )

I gotta say I hadn't really looked at these items earlier, I had chucked them into an oil bath and left them there when I pulled the head way back.

To my untrained eyes, they aren't looking great - ??????

[Wotname]

As a reminder to what it first looked like..

[Compass790]

Mines a jaundiced eye
But it just could be blind lol. Looks like one of your precom "flame nozzles"
has a bit burnt out but I dont think it matters much as I've seen one milled away in a head skim & engine still ran fine.
Journals looking pretty good.

[charliehows]

chinese proverb;"the one who says it cant be done should not interupt the one who is doing it".
If I was a betting man my money would be on this engine eventually going back for many years of useful work.