Popped through the intake.

[Pmt133]

Seeing as the uploads are still broken, I didn't go crazy after work. Pulled the plugs. Google drive folder with files here. Interesting the difference bank 1 to bank 2. Plug 6 in particular is odd but nothing is screaming I'm broken. Just marked difference side to side.

 

[Lou C]

Are the center electrodes on #s 2 & 4 showing some rust near the base? They are right next to each other….

 

[Pmt133]

Are the center electrodes on #s 2 & 4 showing some rust near the base? They are right next to each other….

It was hard to tell honestly. I think it may just be from the fact the plugs have been in there since october 23 and the engine sat in the damp garage while I rebuilt the boat last year. Or my riser extensions are weeping. Actually no, as that would hit all 3 if it weeped.... I will also add, that is the riser/manifold side that runs warmer (alpha problems lol)

It is odd that it is only 2 and 4 though. bank 1 is evenly wet and 6 while very dry is rust free as well. Worth digging into. I notice it more on the strap if I'm being honest.

 

[Lou C]

Ok I looked at them again on my desktop compared to my phone last nite and I can see much better in detail, #s 2 & 4 look like my #s 1 & 2 when my head gaskets started to leak some years back. Your port side 1, 3, 5 cyls look very clean, by comparison. I recall the plugs in mine with the cyls that were getting water had that same orange-ish cast to the center electrode porcelain...hope it's not that actually, but if you do a compression test watch for even a small amount of water coming out of the plug hole...

 

[Pmt133]

If you do glance at 1 and 3, there is a bit of the brown on the porcelain as well but not nearly as much. I suspect I'll get to the bottom of it after some testing.

 

[Pmt133]

Compression test:

#1 125 PSI
#3 128 PSI
#5 125 PSI

#2 120 PSI
#4 125 PSI
#6 125 PSI

Low but equally low, which would make me tend to distrust the gauge more than anything. Even when it was a fresh rebuild, it had about the same compression so I'm not that worried. Also, cold engine and sitting since thursday. I will move on to a leak down test.

 

[Lou C]

Well those are very consistent, no water out of the plug holes?
I think you’ll see higher #s with a hot engine & wide open throttle. Mine was 160-170 but again might just be gauge differences….

 

[Pmt133]

Well those are very consistent, no water out of the plug holes?
I think you’ll see higher #s with a hot engine & wide open throttle. Mine was 160-170 but again might just be gauge differences….

It was a different gauge than I normally use. My matco gauge is usually 135 but it leaks down so you need two people. I borrowed my cousins horrible freight gauge and got those numbers. Throttle was open. I bet if I used a longer adapter (more in the chamber like the long reach plugs vortec heads use) it would've been a few points higher.

One other interesting thing, this engine always had a "skip" cranking. Its not like a bum cylinder skip. More like a improper starter shim skip. It does it with all the plugs out even.

 

[Lou C]

I have a Lisle gauge, every time when I've checked the compression it's always about the same. No water out of your plug holes? Just wondering about what the plugs from #s 2 & 4 looked like....
You have an inspection camera, might be good to take a look inside...

 

[cyclops222]

Starter has a definite skipping sound ? Should be a dead spot in 1 armature segment.

 

[Pmt133]

I have a Lisle gauge, every time when I've checked the compression it's always about the same. No water out of your plug holes? Just wondering about what the plugs from #s 2 & 4 looked like....
You have an inspection camera, might be good to take a look inside...

Nothing out the holes plugs stayed dry. I did dump the fuel filter... some silt in it but nothing crazy. Looks mostly like remnant glass from the tank being in the garage... no water there either. Going to start a leakdown.

 

[Scott06]

It was a different gauge than I normally use. My matco gauge is usually 135 but it leaks down so you need two people. I borrowed my cousins horrible freight gauge and got those numbers. Throttle was open. I bet if I used a longer adapter (more in the chamber like the long reach plugs vortec heads use) it would've been a few points higher.

One other interesting thing, this engine always had a "skip" cranking. Its not like a bum cylinder skip. More like a improper starter shim skip. It does it with all the plugs out even.

125 is good enough to run, and very even. seen much worse variation run just fine. As long as the plug seals the length of reach wont matter -Dont over think it

 

[Pmt133]

So my inspection camera doesn't fit in the plug hole. What I can see with a flashlight and naked eye is tops of pistons when rolled over and nice crosshatched bores. Pistons don't appear "washed".

 

[Pmt133]

125 is good enough to run, and very even. seen much worse variation run just fine. As long as the plug seals the length of reach wont matter -Dont over think it

And it runs well. Pushes my sled of a boat to 44mph give or take and is snappy. Not reading into it!

 

[Pmt133]

Leakdown results:
#1 4%
#3 3%
#5 3%

#2 20%
#4 7%
#6 6%

And the majority of the air is present in the crank case. You can hear some through the exhaust outside as well. So I'd say cylinder 2 is questionable.

 

[Pmt133]

I hunted down my small inspection camera. While not high quality, it paints a picture of what the bores look like.

 

[Lou C]

Interesting, the one thing that jumps out at me is some rust on a valve in cyl #5, but that might be nothing, and a bit of scoring in some of the cyls, again, if blow-by is normal might be nothing.
This was a re-man engine correct? How many thou was it re-bored?

 

[Pmt133]

Interesting, the one thing that jumps out at me is some rust on a valve in cyl #5, but that might be nothing, and a bit of scoring in some of the cyls, again, if blow-by is normal might be nothing.
This was a re-man engine correct? How many thou was it re-bored?

My machinist had to take it .060 over.

There is some rust on the exhaust valve on 2 as well if you look. The dark spot on piston 2 is also interesting but may just be carbon. I really got nothing. For only 60 hours on a fresh rebuild, #2 is off for sure.

 

[Lou C]

What might be interesting is to do a cylinder balance test. See how much the RPM drops while disconnecting one plug wire at a time…..with insulated pliers of course

 

[Pmt133]

What might be interesting is to do a cylinder balance test. See how much the RPM drops while disconnecting one plug wire at a time…..with insulated pliers of course

I have those.