Head gasket progress
Discussion
Well after about 8 hours work I have the nearside head off and I think I have found the culprit at the end of number 8 cylinder:
Here is the matching area on the block before cleaning up:
And on the cylinder head:
Looks like the gasket gave way behind the ring. It was a Rimmer's own brand one. I've started checking flatness with a sheet of glass but the head looks pretty good so far - will re-check in daylight.
Here is the matching area on the block before cleaning up:
And on the cylinder head:
Looks like the gasket gave way behind the ring. It was a Rimmer's own brand one. I've started checking flatness with a sheet of glass but the head looks pretty good so far - will re-check in daylight.
Yes the heads were off 2 years ago and I started noticing fluid burping again after about a year, which got progressively worse. Had to run the last couple of weeks on 7 cylinders ;^)
Yeah I am on ARP studs already. I think part of the problem is the folklore around installation and the need to re-torque after running the engine for a little bit. So this time I will run it up to temperature on fast idle, retorque, let it cool, retorque again, and hope job's a good'un...
Luckily the other side hasn't gone - that's a complete pain in the arris because the blower has to be removed too.
Yeah I am on ARP studs already. I think part of the problem is the folklore around installation and the need to re-torque after running the engine for a little bit. So this time I will run it up to temperature on fast idle, retorque, let it cool, retorque again, and hope job's a good'un...
Luckily the other side hasn't gone - that's a complete pain in the arris because the blower has to be removed too.
Not sure probably standard for the 3.9 North Coventry Kawasaki, albeit with thicker head gaskets (would that be about 9.75:1?)
The compression test gives about 195 when healthy, so the CR probably isn't too high.
But then there's the supercharger with 6psi of boost which should raise the effective CR to about 13.9? Although this drops off a bit at 4,500-5,200 rpm.
The compression test gives about 195 when healthy, so the CR probably isn't too high.
But then there's the supercharger with 6psi of boost which should raise the effective CR to about 13.9? Although this drops off a bit at 4,500-5,200 rpm.
Well I like cheap but I don't like nasty!
I had a look at the DPR installation notes but they don't mention the CR. So it's a bit of supposition really - I'll try and calculate it from the gasket thickness (need to find my micrometer first). I found a useful calculator to save me hurting my brain too much, here:
http://www.roversd1.nl/sd1web/capacity2.html
Plugging in my numbers gives a CR of 9.37:1 unboosted rising to - boosted - 12:1 at top RPM. And no - I don't get pinking, unless the fuel is especially dodgy.
I have checked the head for flatness and it started all under 3 thou. A bit of fettling and further cleaning has reduced this to 1.5 thou or under so there's no warping.
I developed an easy way to look for lower areas and the area which was the culprit was slightly depressed... you use a flat glass plate (check it for flatness first) and put some diluted poster paint over the head face (lying horizontal) then lay the plate on top. Press down with your finger. Any lower areas will show up darker - thicker layer of paint you see...
Before - you can see a redder area (thicker paint) where the gasket failed:
After a little very light abrasion in the areas which were "higher" - the red/pink area is much more uniform;
I've also checked the block with a straight edge just in case and all looks OK, maybe around 2 thou here and there.h
I had a look at the DPR installation notes but they don't mention the CR. So it's a bit of supposition really - I'll try and calculate it from the gasket thickness (need to find my micrometer first). I found a useful calculator to save me hurting my brain too much, here:
http://www.roversd1.nl/sd1web/capacity2.html
Plugging in my numbers gives a CR of 9.37:1 unboosted rising to - boosted - 12:1 at top RPM. And no - I don't get pinking, unless the fuel is especially dodgy.
I have checked the head for flatness and it started all under 3 thou. A bit of fettling and further cleaning has reduced this to 1.5 thou or under so there's no warping.
I developed an easy way to look for lower areas and the area which was the culprit was slightly depressed... you use a flat glass plate (check it for flatness first) and put some diluted poster paint over the head face (lying horizontal) then lay the plate on top. Press down with your finger. Any lower areas will show up darker - thicker layer of paint you see...
Before - you can see a redder area (thicker paint) where the gasket failed:
After a little very light abrasion in the areas which were "higher" - the red/pink area is much more uniform;
I've also checked the block with a straight edge just in case and all looks OK, maybe around 2 thou here and there.h
I did read somewhere a while back that the SX had a thicker gasket to reduce the CR to 9.0:1, I guess the fuel was a lower octane then so with higher octane fuels today then perhaps the CR should be a bit lower?... Maybe 10.9:1?..
When i had the heads checked for flatness on the 280i we did the same as you but the chambers were flattened off a little to prevent any detonation, It did lower the compression a little but i think when Power engineering did the Cologne 2.8 blown sierra they just used a good quality gasket and had a stage 3 pressure reg built..They also had leaded heads...My downfall was having one leaded head and one unleaded..Unbeknown to me...
I know if i had a blown car now i would go for a good ignition system....Especially on an old engine....Ziga
When i had the heads checked for flatness on the 280i we did the same as you but the chambers were flattened off a little to prevent any detonation, It did lower the compression a little but i think when Power engineering did the Cologne 2.8 blown sierra they just used a good quality gasket and had a stage 3 pressure reg built..They also had leaded heads...My downfall was having one leaded head and one unleaded..Unbeknown to me...
I know if i had a blown car now i would go for a good ignition system....Especially on an old engine....Ziga
Yeah 9.3 is a little higher than 9.0 but only 4 or 5%... Back in the day you could still get 4* so I think the octane rating was better than unleaded is now.
Yeah you're correct about the ignition the reason being that the breakdown voltage of the plug gap is maybe 45% higher, due to the higher gas pressure in there. It is also well advanced.
i am taking a break from proceedings as the manifold is out I want to fit an AFR meter bung and I have lost the sodding bung I ordered off the flea a few months ago! Derr!!!
The manifold is really easy to remove with no cylinder head in the way ;^)
Yeah you're correct about the ignition the reason being that the breakdown voltage of the plug gap is maybe 45% higher, due to the higher gas pressure in there. It is also well advanced.
i am taking a break from proceedings as the manifold is out I want to fit an AFR meter bung and I have lost the sodding bung I ordered off the flea a few months ago! Derr!!!
The manifold is really easy to remove with no cylinder head in the way ;^)
Still after all said and done 24 years later on a blown V8 with minimal modifications aint bad at all!...Just goes to show how tough that old boat engine is...There were 2 or 3 blown V6's left 20 odd years later..Most blew up...I had to have special spark plugs in Delilah, I think they were around £24 each..Normal plugs had a habit of melting when PE tested the Sierra's..If i had bought a V8 when i should of it would of probably got the S102 treatment...I have a feeling it wouldn't of cost nearly as much as the V6....I think Turbo's were better for them...The Sprintex was made for V8's even though originally they were designed to sit in the "V" they were one of the best all rounders...In a way though I'm glad i sold the S102 as Poppy would probably be dead as well now....
The book that i bought by Pat Ganahl on street supercharging is very informative on the subject...Its an interesting read indeed....
The book that i bought by Pat Ganahl on street supercharging is very informative on the subject...Its an interesting read indeed....
Found it on google books! Nice one I'll give it a read.
Yes it's done 65k in 24 years and been pretty reliable, the only problems I can put down to the original engineering are:
- the blower mount onto the left hand cylinder head bolt causes the head gasket to fail - fixed.
- the blower mount through the water pump caused the pump body to crack - fixed.
- finding the correct drive belt involved a bit of trial and error
- some idiot installed a fine pump pre-filter which caused a few issues...
and a few of the usual wedge niggles but not that many really.
Yes it's done 65k in 24 years and been pretty reliable, the only problems I can put down to the original engineering are:
- the blower mount onto the left hand cylinder head bolt causes the head gasket to fail - fixed.
- the blower mount through the water pump caused the pump body to crack - fixed.
- finding the correct drive belt involved a bit of trial and error
- some idiot installed a fine pump pre-filter which caused a few issues...
and a few of the usual wedge niggles but not that many really.
adam quantrill said:
They all look very normal with some build-up of carbon and deposits, no areas where the aly is showing through. I decoked last time I did the heads and it's built up again since then.
The one that had the leak is a bit oily I think the oil dropped into it as I lifted the head.
Which only leaves:The one that had the leak is a bit oily I think the oil dropped into it as I lifted the head.
Incorrectly specified gasket
Defective gasket
Warped head/block (which you've dealt with)
Head warping during previous gasket replacement
Head fixings stretching in service
(Have I missed any?)
Did the previous gasket fail in a similar manner?
To be fair that gasket supplied by brothers grim looks nasty...I wouldn't want that on a N/A engine let alone a blown one!...You could give these people a look, I used them for making the sealing gaskets for the pipework of the blower...They will need a template and its good to chat with them.
Ram Gaskets:
http://www.google.co.uk/url?sa=t&rct=j&q=&...
Cheers...Ziga
Ram Gaskets:
http://www.google.co.uk/url?sa=t&rct=j&q=&...
Cheers...Ziga
Cheers I already have the replacements - two row ones made by Elring Klinger (recommended by Martin). Here's a piccie (please ignore the greasy thumb prints...):
Also bear in mind that the other side is the same as the one I just took off, and there have been no problems there so far...
Also bear in mind that the other side is the same as the one I just took off, and there have been no problems there so far...
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