Old Cylinder Head Removal

Guys,

These are the photos of the cylinder head and engine block, soon after removal of the head.
Some of the photos and cropped and uploaded to the forum & the other's in the google photos with the links.
They are uncropped and in it's original high resolution and size.
For the most part, the failure of the gasket was due to head bolts coming loose. It was too easy to
undo more than half of the head bolts. I remember re-torquing the head bolts few days later after I replaced the head and the head gasket. But, if I have retorqued the bolts few months later, I could've possibly averted this drama and keep the head and gasket fair bit longer. But, a good lesson learnt to check the torque of the headbolts at least once a year, I reckon.

I have few questions if you guys can help with some ideas and explanations.

1)Can you suggest few less harmful ways to remove the soot from the piston crowns (& perhaps wall of the bore)?

2)I couldn't see a massive buildup of soot(my estimation, which may be incorrect) from what I see on the piston crown and cylinder head. So, how did I produce massive compression(180-190psi) when I did the compression test on all the cylinders last time???!!! Compression tester is accurate. Again, I am not 100% certain there is a need for a thick soot buildup for the compression to shoot up by 20psi or so(normal should be around 170psi, which it was last year).
Also, considering the head bolts were loose, compression should have been low.

Thanx

These are the high resolution photos in google photos.


https://photos.google.com/share/AF1Q...9iQjI1cDIydnJB

https://photos.google.com/share/AF1Q...AxekZyRTRZczVn

https://photos.google.com/share/AF1Q...dFNkFRUEdOM3pn

https://photos.google.com/share/AF1Q...tNRjdlX0JvSmdn

https://photos.google.com/share/AF1Q...VxX3puZ3ZMYkdn

https://photos.google.com/share/AF1Q...NsYUo0YzVhbzVR

https://photos.google.com/share/AF1Q...RycC1ZdlJsRU9n

https://photos.google.com/share/AF1Q...V1RkVkM1hXck1B

https://photos.google.com/share/AF1Q...I4bGN1Z2xxRmhR

https://photos.google.com/share/AF1Q...kxa3NtOHhKZld3

https://photos.google.com/share/AF1Q...VrRVlxY3ViT29B

Any chance you guys can speculate on the reasons for higher compression?

Compression tester is accurate & I didn't squirt any oil into the combustion chamber.
I didn't think the carbon build up was bad enough to cause a hike in compression from 170 last year to 190 this year.

Head bolts were loose.

Examining head, gasket and block says there is only one spot that was leaking water into the
combustion chamber from the gasket. That is near the cylinder 6. The rest appear to be ok with
any water leakage from water passages to the combustion chamber.

Fire ring of the gasket on the cylinder 1 is broken(severed) unlike the rest of the fire rings.

Most of the fire rings have bit of rust on them indicating they were loose and compromised.

Everything points to a lower compression, but I was getting higher compression.

I feel like I need to understand it before putting everything back together with a reconditioned head and new gasket.

Any ideas are appreciated.
Thanx

As a guess, the head repair gunk dissolved over time, and filled the gaps.

Quote:

---

Originally Posted by mudnut

As a guess, the head repair gunk dissolved over time, and filled the gaps.

---

The Steel Seal gunk most certainly filled and blocked the water passages on the head surface, and yeah the guess makes sense,
assuming some of the sodium silicate still circulating around with the coolant. Over the years it has been through several coolant changes. So, I reckon the blockage was from the previous run of sodium silicate. Another issue with the theory is that only one
combustion chamber was water compromised. The rest appear to be fine, as far as coolant getting into the combustion chambers(see pictures).

@mudski, you know a bit about engines by working at home and selling parts, don't you?
May I borrow you brain for a microsecond and hear some of your speculations? :)

Come on guys, I don't care what kinda wild theories you have.
There always some good behind all kinda theories.

I'm calorie starved and my brain only functions at fraction of it's previous capacity.
So, hearing thoughts from other brains most certainly will give me a boost for regeneration. :D

@mb, @MudRunnerTD, @garett, @billyj, @Alitis007, @growler2058, @Kimbo63, @4bye4, @NissanGQ4.2, @PeeBee, @the evil twin,
(sorry, it I missed any other experts).

May I hear what your brain tells you? , but please have a quick look at the description and photos.

Sorry DOM, don't have a clue.

Me neither, sorry Dom mate.

did you do one test with the throttle wide open and the other closed?. tester had a bad day ( that time of the month?) liquid in the cylinders. doesn't look like a lot of carbon...

only thought re the high compression is was one a hot reading vs cold? the more important qustion is why did the gasket fail in hte first place, the way the failed fire ring is pushed back looks a little like detonation, how much timing are you running? or are the mixtures lean

Quote:

---

Originally Posted by garett

did you do one test with the throttle wide open and the other closed?. tester had a bad day ( that time of the month?) liquid in the cylinders. doesn't look like a lot of carbon...

---

Yeah mate, but it was running rich(on petrol) and building up soot in no time when I was testing it.
I decided it was due to stuffed up carby, but now I think otherwise.

I did the test with WOT, but not sure what you meant by "the other"!!!

Thanx


P.S. Ok, my bad. I got it. You meant one test with WOT & other with throttle closed.
I didn't do a compression test with throttle closed at all!
What is the reason for that?
Since I always warmed up the engine before compression test, chokes flaps are fully opened while I was testing the compression.

Only thing I can think of that made a difference is that I replaced the stock starter motor with a Skyline one. The Skyline starter had more grunt for some reason and always turned faster. Not sure whether that affects the compression reading?!! The number of cranks were kept the same. I allowed the piston to go through all four strokes and was watching the compression jump with each stroke.

Quote:

---

Originally Posted by billyj

only thought re the high compression is was one a hot reading vs cold? the more important qustion is why did the gasket fail in hte first place, the way the failed fire ring is pushed back looks a little like detonation, how much timing are you running? or are the mixtures lean

---

Thanx for the reply mate.

In petrol the mixture was super rich and I was able to adjust it intermittently, but went back to be rich again, so I decided it was due to carby quirks & gave up until I get hold of a good carby that I know is good for sure. Running fine with LPG and AFR gauge was showing the mixture(15 ish), which was where I wanted LPG mixture.

I warmed up the engine before doing the compression test(always). So, I reckon it must be something else.
I'm pretty sure the compression tester is accurate enough 'cos it shows the compression of the bike engine, mower, etc etc the same as it showed last year.

Yeah, there was detonation going on previously while I had the spare dizzy on it(which had stuffed vacuum advance diaphragm that I only detected much later). I ran the spare dizzy for months. So I believe there was some detonation and damage.
The pushed back fire ring(cylinder 6) is the one with water jacket leaking into the cylinder. The one with the fire ring severed is the cylinder 1.

I ran 15 BTDC 'cos it was on LPG most of the time. Mixture was rich(with petrol) definitely, and I couldn't fix it and didn't run on petrol for that reason(other than occasional few minutes to see if I can fix it by fiddling with carby mixture screw(using the AFR gauge).

No doubt loose head bolts is one of the reasons for the head gasket failure.
I reckon these el cheapo Burson aftermarket gaskets(paid $60 for it) need some TLC
months after installation. Probably needed retorquing months after installation.
Obviously occasional detonation didn't help.

Sorry Dom not my strong suit mate. George Alitis007 would be your guy

Sorry mate over my head.

Maybe a conversion, a couple more cylinders???


Sent from my A1601 using Tapatalk