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Jan 28, 2014 10:58 am
Jan 28, 2014 10:58 am
Subject: 16/80 head gasket problems
16/80 head gasket problems
Dear All,
Any opinions to the following would be welcome.
After a spirited 100 mile run last September I noticed the presence of emulsion on the oil dip stick and under the oil filler cap on the rocker cover.
No oil was present when looking into the radiator cap but upon draining the engine oil you could see evidence of coolant/water.
Up until this point the car has performed faultlessly since its engine rebuild some 7,000miles ago (the block face and cylinder head face were skimmed & checked for flatness and both the head and block had been crack/pressure tested).
Open removal of the head no evidence of a blown gasket was apparent.
That said, the cylinder head inspection plate at the rear was fouling somewhat on that strange little bit of casting to the top rear of the block (see picture).
It was noticed that one or two of the new head studs had become loose and on a couple of studs the nuts had siezed so the whole stud had to be replaced.
The head and block were then cleaned a new gasket fitted, this time with wellseal on all faces (previously it had been fitted dry).
Three studs were replaced and new nuts used and all were then tightened down in sequence, 10ft lbs at a time (left for 15 minutes and then tightened down a further 10ft lbs until 40ft lbs was achieved).
It was then tightened again the following morning and the valve/tappet clearances were checked and then double checked (I set these to 8 thou always as a precaution).
A few weeks later when I had finally refitted the exhaust the car was taken for a short run.
The pick-up was sluggish and on deceleration it would POP POP POP quietly.
My initial thought was that I had not sealed the exhaust sufficiently so last Friday before the run up to Cambridge for the New Year’s Dinner I had the exhaust off and re-fitted.
The run up to Cambridge was rough, the pick-up terrible and the car would POP POP POP on acceleration and hard deceleration.
Oil pressure was good (50 – 60 psi at 50 mph, 20 psi on idle), Radiator temperatures were also normal for my car in this cold weather (60 degrees).
However, upon removal of the oil filler cap on the rocker cover, emulsion was present (could it be residue left over from before?).
A compression test was conducted yesterday and each cylinder is around 18-20psi down on the test conducted before the head gasket change.
• Before head gasket change on 1 to 6 cylinders = 122 to 118psi
• After head gasket change on 1 to 6 cylinders = 101 to 106psi
So, what to do now.
My initial thoughts are to check the valve/tappet clearances again just to make sure I did not do anything stupid.
Failing that its head off, gasket off, clean away all traces of the wellseal, check that the surfaces are flat, replace all head studs and nuts and try again (this time dry fitting the gasket with a smear of oil),
Any suggestions?
Attachments:
16/80 head gasket problems
Dear All,
Any opinions to the following would be welcome.
After a spirited 100 mile run last September I noticed the presence of emulsion on the oil dip stick and under the oil filler cap on the rocker cover.
No oil was present when looking into the radiator cap but upon draining the engine oil you could see evidence of coolant/water.
Up until this point the car has performed faultlessly since its engine rebuild some 7,000miles ago (the block face and cylinder head face were skimmed & checked for flatness and both the head and block had been crack/pressure tested).
Open removal of the head no evidence of a blown gasket was apparent.
That said, the cylinder head inspection plate at the rear was fouling somewhat on that strange little bit of casting to the top rear of the block (see picture).
It was noticed that one or two of the new head studs had become loose and on a couple of studs the nuts had siezed so the whole stud had to be replaced.
The head and block were then cleaned a new gasket fitted, this time with wellseal on all faces (previously it had been fitted dry).
Three studs were replaced and new nuts used and all were then tightened down in sequence, 10ft lbs at a time (left for 15 minutes and then tightened down a further 10ft lbs until 40ft lbs was achieved).
It was then tightened again the following morning and the valve/tappet clearances were checked and then double checked (I set these to 8 thou always as a precaution).
A few weeks later when I had finally refitted the exhaust the car was taken for a short run.
The pick-up was sluggish and on deceleration it would POP POP POP quietly.
My initial thought was that I had not sealed the exhaust sufficiently so last Friday before the run up to Cambridge for the New Year’s Dinner I had the exhaust off and re-fitted.
The run up to Cambridge was rough, the pick-up terrible and the car would POP POP POP on acceleration and hard deceleration.
Oil pressure was good (50 – 60 psi at 50 mph, 20 psi on idle), Radiator temperatures were also normal for my car in this cold weather (60 degrees).
However, upon removal of the oil filler cap on the rocker cover, emulsion was present (could it be residue left over from before?).
A compression test was conducted yesterday and each cylinder is around 18-20psi down on the test conducted before the head gasket change.
• Before head gasket change on 1 to 6 cylinders = 122 to 118psi
• After head gasket change on 1 to 6 cylinders = 101 to 106psi
So, what to do now.
My initial thoughts are to check the valve/tappet clearances again just to make sure I did not do anything stupid.
Failing that its head off, gasket off, clean away all traces of the wellseal, check that the surfaces are flat, replace all head studs and nuts and try again (this time dry fitting the gasket with a smear of oil),
Any suggestions?
Attachments: