Melted Piston.

You had a heap of alloy welding done to that side of the head putting in the heater outlet, my tame TIG welder (with 40 years experience) recommends letting the head sit for a whole month after substantial welding before doing any surface machining, as he says it will settle and sink... that plus your detonation from having altered the cam timing would lead to the problem ... lots of people have used the Tipo head without that extra water jacket hole being an issue, so it's not that which caused the problem, the fire ring should seal up regardless.

SteveC
 
More problems.

(EDIT: all HG issues were due to ignition timing mapping - with the exception of one defective gasket)

Got the LH2.4 conversion finished. Replaced the clutch & brake masters. R&R'd the trans & took care of the sheared fork bolt that was causing by clutch problems.

Drove maybe 10 miles to check out the clutch & get gas. Started missing - could feel it at idle & power was down.

Pulled injector plugs one at a time & found #2 made little difference. Confirmed spark is present.

Pulled the plugs & did a compression test (warm engine, throttle held open) on #1 & #2.

#1 - 160psi
#2 - 55psi

No evidence of oil smoke or blowby when running.

Did a leakdown test (warm engine, plugs, expansion cap, breather, dipstick, removed) today - #1, 3, 4 are all tight, no evidence of leakage.

Valve clearances 14-16 EXH, 14-16 INT, which I think are a little tight for EXH & loose for INT on a warm motor, but not gonna be responsible for lack of compression.

Screen%20Shot%202016-04-18%20at%209.30.22%20PM_zpsoxfzvj1c.png


#2 seems to be leaking back through the intake, but it's also leaking through the dipstick / PCV. :(
 
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Redid the leakdown test, I hadn't run high enough line pressure to get meaningful values:

#1

X19_0130b.jpg


#2

X19_0130.jpg


#3

X19_0130c.jpg


#4 - the only cyl with no leakage

X19_0130a.jpg


All escaping air seems to be through the crankcase.

Removed the head.

#2 bore

X19_0292.jpg


#3 bore

7E08734E-9014-41F9-A307-8F20F1827D85_zpssgztvz06.jpg


Problem looks like the HG -

Fire rings are buggered

1b732f94-7969-403a-b56f-d9639626327b_zpshd2vitkf.jpg


Trying to determine what caused the failure this time - perhaps the lean running after installing the LH2.4 with injectors that were too small - I only drove the car literally around the block under light load, as it was clearly not running well. Perhaps that was still enough to cook the gasket.
 
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That's bad luck

That's really bad luck after all that you have been through. I suppose that this is the price one pays when experimenting with different performance options.

In terms of the engine running lean though: I don't think this should have lead to such a failure. I would have expected to hear severe pinging in any case if it were indeed so lean.

At least you will have gotten the head gasket routine down to a fine art by now :wink2:

Maybe try a Victor Reinz gasket this time?

Cheers,
Dom.
 
Gasket wasn't 'cooked' ... the thing that pushes the fire rings out like that is an uncontrolled spike in cylinder pressure... commonly known as detonation.

Might pay to pull the pistons and check the rings... it can bust those up pretty bad as well...and it hammers the big end bearings.

It does look like you might have caught it before any 'major' damage was done.

SteveC
 
In the picture of #3 bore, there's something between piston and bore at about 2:00... A trick of the light?
 
fiatfactory said:
Gasket wasn't 'cooked' ... the thing that pushes the fire rings out like that is an uncontrolled spike in cylinder pressure... commonly known as detonation.
Might pay to pull the pistons and check the rings... it can bust those up pretty bad as well...and it hammers the big end bearings.
It does look like you might have caught it before any 'major' damage was done.
SteveC
Click to expand...

Yes - thank you - I was assuming detonation from the lean condition caused by running it initially with injectors that were just too low flow. Idle AFR's were fine - but under even light throttle it was 15's - low 16's(!). I didn't drive it far or under heavy load - which is probably why further damage had not occurred. I could hear the knock, which is why I didn't drive it far until I had the larger injectors - obviously the damage was already done at that point.

I don't think I'm going to drop pistons this time. I dunno, maybe I'll change my mind before the parts get here.
 
My machine shop buddy always says that head gaskets are kinda like fuses or circuit breakers...the purposely designed and cheaper weak link that you want to fail before the damage is done to the big-$$$ items.

I was just thinking it would be nice to have a custom designed fuel rail that would use more modern o-ringed injectors rather than our current barbed ones. Would make it a lot less painful to service, eliminate failure points (too much hose and too many hose connections), and would allow a level of customization in swapping in and out injectors of differing flow rates and spray patterns.
 
I just glad I felt the miss before any more time passed.

I built my rail based on the Volvo setup - same as many others - simple rail attached to the runners on standoffs - so the whole rail and injectors can be removed in 10-15min. Welded inj. bungs to the runners that accept the later composite injectors. I have gone through four injector sizes so far - the 1600 high compression requires more fuel than I would have expected ;)
 
Got back from my C30crew "Conquer The Dragon" mini vacation last night. The Mrs. was very considerate when we went as groups on the 130 mile loop culminating in the 11mile 318 bend "tail of the dragon" section of rte 129 :)

C30_00132.jpg


C30_00134.jpg


So, I did the vacuum draw test on the cylinders today - set the Pistons all at mid stroke.

#1

X19_0175a.jpg


3
X19_0175b.jpg


4

X19_0175c.jpg


2

X19_0175.jpg


So, 2 definitely is coming out , and might as well check 1, as that holds less vac than 3&4. Could just be ring gap alignment, but need to know.

Hoping for minimal damage.

As a stress reliever, I ported the runners, and gasket matched the runner & ports.

3-4

X19_0121.jpg


1-2

X19_0121a.jpg


Cleaned out the runners back to the base of the casting line, and smoothed the run over the revised LH injector bungs.

I'm going to drop my compression closer to 10.3:1. I may be able to properly tune the timing now I have LH2.4, but it's on the edge with my 10.7:1 compression running 93 R/M2 gas that's available here.

Revisiting Steve's calculation posts (109, 113) in this thread to figure best approach to drop CR
 
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#2 piston cracks visible in the two lands between oil control ring & next one up

X19_0134.jpg


pried them out

X19_0148.jpg


#1 is fine.

Have to see if Steve has any more pistons :(
 
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I've got no more 87.0mm 0872 pistons to sell I'm afraid Hussein ...you'll have to hunt around. KS/Mahle did sell pistons individually, so you might get lucky and find a single sitting around...the other option is adapting /machining a set of taller CH pistons to suit the longer stroke 1600, or getting some forged pistons custom made.

What is the crushed thickness of the replacement head gasket you used? When did you change from the Felpro?

You static CR might be higher than what you think if the crushed thickness is under 1.5mm.... as all my calcs are based on using a Felpro headgasket on this style of build.

Broken lands are definitely a detonation issue... and judging by the shiny area next to the crack and the residue under the broken section, probably hasn't just happened, it's been like that for a while.

SteveC
 
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