View Full Version : Dr Det
Taking the head off my car in a couple of hours. Will be uploading some pictures later. 10 points for who ever spots the det 1st.
So took the head off, this is where it failed on the gasket. On cylinder number 1.
No cracked liners, or any det dints on the head itself. Usual cracks on valve seats but that is all. Not sure why this has happened still, i cant say that it definately had fuel there. because i dont recollect looking at my afr gauge because it is second nature. But any way heres pictures. Opinions welcome.
http://www.rtoc.org/boards/picture.php?albumid=1567&pictureid=7197
Both angles of cylinder 1
http://www.rtoc.org/boards/picture.php?albumid=1567&pictureid=7198
http://www.rtoc.org/boards/picture.php?albumid=1567&pictureid=7199
Then a quick shot of the block.
http://www.rtoc.org/boards/picture.php?albumid=1567&pictureid=7200
lovely that one josh piston comps ok? deffo didnt lean out?
Pistons are fine mate. I've never done a compression test and the only thing I can put this down to is leaning out. Cause everything else is sound...
Dave Reed
30-09-2012, 16:42
Looking at the pics it almost looks like all the cylinders where seek g some water (te clean parts)
Will have run lean, it only takes a split second.. I take it your running the updated head bolts?
Dave Reed
30-09-2012, 16:44
To add it's almost always either 4 or 1 that go, it's due to the shape of the inlet tracket (ie end 2 to see fuel last)
I didn't put the head bolts in previously dave, but I have ordered fresh ones with the gasket kit. May well have leaned out, like I said I'm not sure. Hmmm.
May well have leaned out, like I said I'm not sure. Hmmm.most do the hg this way somehow, i recon it leaned out are ya piston comps ok
It's definatly leaned off, I spotted what Dave has and it looks like all the pistons have seen some coolant,
We were in fifth gear side by side doing a few comparison tests, you lump breaths very well high up the revs thats why it wants to keep on making power. High up the revs in fifth gear and your really loading the motor.
He also mentioned to.me that some of the headbolts felt very easy to undo, I would be tempted to get the head checked for flatness, or at least get a decent straight edge and some feeler blades on it. It didn't overheat ot anything and chances are it will be fine, you just don't want to bolt it all back up and the same thing happen 100 Miles later.
this is often the issue, it will fuel for a blip in fourth on the rollers, and most probaby in fifth. You need a beefed up FPR to keep the bowle full;)
Dave Reed
30-09-2012, 18:54
I wouldn't worry too much, if you had the standard bolts in there that's where the problem lies.. They are a stretch type bolt and have done what they say on the tin, hence probably why all the cylinders have seen water.
Get some of the cap head bolts from the RTOC shop, think there about £8 and it won't happen again. Well, the head gasket wont go anyway, it'll be a liner next :laugh::laugh:
The bolts that came out were the cap head 12.9's
That's why I was wondering about the headbolts being different in terms of tightness, maybe they weren't tourqed up correctly and the head has lifted slightly. Hard to tell without actually laying eyes on it.
Either way a new gasket and bolts should see it right:agree:
Tony Walker
30-09-2012, 19:35
The clean section on the pistons looks to be on all the inlet valves? maybe running rich on idle part throttle keeping those areas clean?
It did have a 135 main in when he bought it, so thats not a bad shout, was silly rich on part throttle.
Dave Reed
30-09-2012, 19:52
The clean section on the pistons looks to be on all the inlet valves? maybe running rich on idle part throttle keeping those areas clean?
Could be, as I say it's hard to tell with pics.. No1 has defo had water in it though.
Yeah new bolts & gasket, make sure all the bolt holes are clear of any water etc, it's always a good idea to put a little copper grease or similar on the new head bolts too.
steer from the rear
30-09-2012, 20:00
third picture in, just a quick one how does that vertical score mark feel in the bore with your fingernail??????
They all feel smooth as a baby's arse buddy.
Tony Walker
30-09-2012, 20:04
yeah it has scored alittle and definetly had water in the 1st cylinder where the gaskets gone, difficult to say why its gone :S hows the head look around that area?
Well the head looks fine, feels smooth to touch. May get it skimmed or at least checked properly incase it's warped at all.
The gasket has gone because of det, in the first pic you can see little dents in the fire ring, this is caused by detonation.
The mark looks like it might just be coolant on the side of the liner.
Tony Walker
30-09-2012, 20:09
no pitting or scratches across the ring sealing area?
No, it's in good condition as far as I can see.
The det has weakened the fire ring and caused the gasket to go across the water jacket, usually the first place they go.
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