Reasons for head gasket failure.
Discussion
stevieturbo said:
Boost guage in the car is mechanical. Others are map sensor based, but ive never experienced a problem in any car with their readings.
Inlet manifold/plenum is as factory 01+ car albeit with a larger TB
Nothing out of the ordinary
Ahh well, I convinced myself anyway!
stevieturbo said:
The other engine I refered to in this thread that we built has so far run a best of 11.57 @ 123mph. Hoefully with some more boost it will see very low 11's possbly 10's.
Not bad going for a true daily driven car, full weight, road tyres, and only pump fuel !!
That's pretty bloody good for anything running on pump fuel
Good to hear you've got the problem sorted - must be a huge relief!
My car overheated quite badly yesterday. The temp gauge never moved. The ECU went into Limp Home mode and din't boost at all. A lot of smoke was coming from the exhaust. Bought and fitted a new radiator today flushed the whole system through and it now boosts fine. I am however concerned if the Headgasket has gone. There isn't the usual mayonnaise type stuff in the water. I have to admit it doesn't feel like it used too but I'm thinking that may be psycholgical. P.S There is no smoke at all now. Any experiences or ideas would be greatly received. Olly
no idea what engine you have but if this is std then you're not gonna be a million miles from this even with ARP studs.
Head bolt torqueing sequence for a ej25/ej22 sohc:
C A F
E B D
<----- front of motor
1. apply a coat of engine oil to washers and bolt threads
2. tighten all bolts to 22 ft. lbs. in alphabetical sequence. then tighten all bolts to 51 ft. lbs. in alphabetical sequence.
3. back off all bolts(in sequence) by 180 degrees. back off all bolts again (in sequence) 180 degrees.
4. tighten bolts A & B to 25 ft lbs.
5. tighten bolts C,D,E and F to 11 ft. lbs.
6. tighten all bolts (in sequence) 80-90 degrees. DO NOT EXCEED 90 DEGREES
7. Further tighten all bolts (in sequence) by 80-90 degrees. BETWEEN STEPS 6&7 NO NOT EXCEED 180 degrees.
A bit more than 80lb/ft.
Head bolt torqueing sequence for a ej25/ej22 sohc:
C A F
E B D
<----- front of motor
1. apply a coat of engine oil to washers and bolt threads
2. tighten all bolts to 22 ft. lbs. in alphabetical sequence. then tighten all bolts to 51 ft. lbs. in alphabetical sequence.
3. back off all bolts(in sequence) by 180 degrees. back off all bolts again (in sequence) 180 degrees.
4. tighten bolts A & B to 25 ft lbs.
5. tighten bolts C,D,E and F to 11 ft. lbs.
6. tighten all bolts (in sequence) 80-90 degrees. DO NOT EXCEED 90 DEGREES
7. Further tighten all bolts (in sequence) by 80-90 degrees. BETWEEN STEPS 6&7 NO NOT EXCEED 180 degrees.
A bit more than 80lb/ft.
ridds said:
stevieturbo said:
They are torqued to 80lb with moly as specced by various Subaru engine builders.
That sounds like the problem to me.
I do my wheel nuts up tighter than that. Never seen a head be done up less than 150Nm.
80lb/ft is quite a lot of clamp when the stud has a fine rolled thread
Boosted.
Aye, true.
How about it did get a little warm?
That looks like quite a bit of scuffing on that cylinder. How are you listening for knock?
What was you initial ign timing for this engine? 20° doesn't sound all that retarded really Have you tried running further retarded and then bringing the ign as you feel it's safe. Don't forget to richen her up though if you do that.
Are you monitoring Exhaust gas temp
Agree with the comment about this image being Det damage.
Another thing to consider is your plug temp rating, to hot a plug and you'll destroy a tip and cause very high temps very easily. I've seen exhaust valves Tulip because of the heat and pressure caused by that. Try stepping up a range. When this has happened there has also been no other visble signs of Det on the pistons.
How about it did get a little warm?
That looks like quite a bit of scuffing on that cylinder. How are you listening for knock?
What was you initial ign timing for this engine? 20° doesn't sound all that retarded really Have you tried running further retarded and then bringing the ign as you feel it's safe. Don't forget to richen her up though if you do that.
Are you monitoring Exhaust gas temp Agree with the comment about this image being Det damage.
Another thing to consider is your plug temp rating, to hot a plug and you'll destroy a tip and cause very high temps very easily. I've seen exhaust valves Tulip because of the heat and pressure caused by that. Try stepping up a range. When this has happened there has also been no other visble signs of Det on the pistons.
Edited by ridds on Saturday 9th September 00:22
Sounds like that may not be helping really.
If it is erractic and your running at 20° a spike forward to 25° could easily induce knock events and then a jump back to 15 would cause some serious gas temps if not rich rnough although 10:1 sounds plenty rich.
Any idea of the range of the erratic spark? Take it your using a wideband Lambda on it.
If it is erractic and your running at 20° a spike forward to 25° could easily induce knock events and then a jump back to 15 would cause some serious gas temps if not rich rnough although 10:1 sounds plenty rich.
Any idea of the range of the erratic spark? Take it your using a wideband Lambda on it.
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