bk450 gasket on k1200RS
Turbo Mini Forums

Took the head off tonight to assess the damage. Its cylinder 2 again, right at the water gallery.

Some pics to see if anyone spots anything suspicious looking:



The bores on cylinder 2 are quite rough, not sure if this is just rust from the water or something more sinister:


All the other bores looks perfect:



This is where both cometic gaskets have failed. The block side of cylinder 2, on the inlet side:


The rest of the gasket looks fine:


You can see there has been some heat on the block on cylinder 2 here:


Close up of block and bore "damage":


head pics:

Edited by nky_84 on 25th Jun, 2014.

Maybe worth checking everything is flat, especially around the area where its failed. Any signs of det at all?

id be looking at refacing the block and head

are you data logging?
ie do you know if its had good fuel and spark?

Stop fucking about and dry deck it propper. BK450 gaskets cost £15 and you'll get rid of that un used coolant passage in the head that sits dangerously close to the fire ring.

This is not a new problem but you would be led to believe otherwise!

There I said it

Block and head will be checked when it goes into get the waterways filled etc. What signs of det should i be looking for?

Block and head will be refaced as part of the dry deck process.

As above and on previous page, dry decking is happening and very much the plan! I've not read any other examples of cars blowing gaskets at this particular point. Is that not the case?

I completely understand the advantages of the dry decking, im just not 100% sure its going to resolve this issue, or what is causing it in the first place hence the reason for posting. It will hopefully also prevent others from going down this expensive and frustrating route in future!!

refacing the block and head will probably resolve the issue, the dry decking being the icing on the cake :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I'd also be sending the injectors away for checking - after identifying that one injector mated to the cylinder that appears to always be an issue as needing particular inspection at the injector shop.

How likely is it that the block is out of shape? Is there anyway i can test this without specialist tools? If i can get away with leaving the block in situ, i could be back up and running pretty quickly. Removing the block is a much bigger task. I should be able to plug the block and fit the adapter as it stands?

I can easily get the head checked professionally. Can i assume that if the alloy head is fine, then the block should be too?

@minimole - Thats not pitting, just reflections / water droplets. The pistons look perfect, even piston 2. Its never really had prolonged running, the head gasket has stopped play after less than a minute or on boost driving each time.

@Turbodave - A duff injector could be causing cylinder 2 to run lean and cause the overheating. is that what you are saying?

The more reading im doing, the more im convinced its an airlock in the head (head is the highest point in system), which is causing the head to get way too hot on boost and its boiling what water gets there and the gasket lets go when it all gets too much.

Get it pulled out, plug the holes in the block, weld the head and have both skimmed.

it looks like one of the original plugs on the block at the front of No2 cylinder by the coolant passage is perhaps sitting a little proud, but it might just be the light

Do it right, do it once and all that...

2 years of constant abuse to 8500rpm and 100% reliability running na is looking pretty favourable right now......

On 26th Jun, 2014 nky_84 said:
Do it right, do it once and all that...

2 years of constant abuse to 8500rpm and 100% reliability running na is looking pretty favourable right now......

Edited by Sprocket on 26th Jun, 2014.

that corner of the cuttout does look remarkably like det eaten ally.

On 26th Jun, 2014 minimole23 said:

On 26th Jun, 2014 nky_84 said:
Block and head will be checked when it goes into get the waterways filled etc. What signs of det should i be looking for?

Block and head will be refaced as part of the dry deck process.

Has this bit started to melt? looks slightly pitted.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Just below the red circle seems damaged too. You can see the reflection of the damage on the cylinder wall. Unless it's all an optical illusion?

In the 13's at last!.. Just

Looks like cylinder 3 not 2 if you count 1 at the front of the engine that being the water pump end??? Looks like detonation to me too, mine looked similar but when the piston was removed the full extent of detonation could be seen down the side of the piston towards the ring lands.

sounds like you are going to have to take it out for a good once over anyway and rebuild. Like colin says get it out!!

On closer inspection and in better light, minimoles eagle eyes are correct:



I will remove the piston later in the week to inspect if there is further unseen damage, but is this still in usable condition if thats the worst of it?

Also, the exhaust valves and exhaust side of pistons are very white in colour, would this suggest further evidence of things running lean / getting very hot or is this normal?

What is also strange is that the above is piston 3, and its been blowing gaskets on 2. I guess the fire ring proximity to the water way is the weakest point and its letting go there...

I'm not an expert but I would have the piston tidied up as long as everything else is okay, making sure there are no more sharp edges or pitting left

that wont be the worst of it, i would be very supprised if it was. however long as there is no damage below the top compression ring i would be tempted to run it myself. BUT i would never let a build for a customer go out the door with a piston like that

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Plus 3 (or is it plus 4) for detonation, especially with the new picture.

As it seems predominant on one cylinder I would definately do what TD suggested, get the injectors checked.

If you ever did get the wideband installed (I think it was you struggling with the 14point7 one) then it doesn't help on a "per cylinder" basis, it can only read the average, same at a RR session, it won't show a single faulty injector.

Also, what ECU and what injection mode ??? (batch, semi-sequential or fully sequential).

The ECU may have a faulty driver or maybe the setup just isn't suitable (I wouldn't use anything other than fully sequential on a port injected engine, although I'm sure others would dis-agree....).

As for the damage, until you pull the piston(s), you won't know - there could be damage down the side and the top ring may be broken from the shock wave(s).

Schrödinger's cat - so which one am I ???

ok, will post up some pics of all the pistons once out the block. Could really do with that being the worst of the damage but luck hasnt been exactly on my side since going turbo....

Its a sprint car, so gets comparatively little abuse (length of time anyway) compared to circuit racer or even a fast road car, so im hoping that has prevented terminal piston damage.

The injectors will be getting checked yes. I've got a wideband installed, but the data logging hasnt been working and i dont have a gauge. I cross checked the read out on the laptop when it was at the rolling road and it was in the same ball park as the fancy RR sensor.

Its an SC typhoon ecu, which i believe is just "batch". I'm not changing the ECU at this stage, so if that is the primary issue then its game over for the turbo setup and im going back to NA

It won't take long to get the pistons looking like that if it's gone lean or too much ignition advance on boost.

In the 13's at last!.. Just

On 30th Jun, 2014 nky_84 said:
Its an SC typhoon ecu, which i believe is just "batch". I'm not changing the ECU at this stage, so if that is the primary issue then its game over for the turbo setup and im going back to NA

Schrödinger's cat - so which one am I ???

could it be a case that water has been getting into that cylinder causing it to run lean compared to the others?

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1/4mile in 13.2sec @ 111 terminal on 15psi