+- Austinsevenfriends (https://www.austinsevenfriends.co.uk/forum)
+-- Forum: Austin Seven Friends Forum (https://www.austinsevenfriends.co.uk/forum/forumdisplay.php?fid=1)
+--- Forum: Forum chat... (https://www.austinsevenfriends.co.uk/forum/forumdisplay.php?fid=14)
+--- Thread: Blown Head Gasket? (/showthread.php?tid=2680)
Pages:
1
2
Blown Head Gasket? - Mark McKibbin - 21-04-2019
The stud between 3 and 4 is weeping very black oily gunge as per picture I assume its blown from a cylinder to the stud?
RE: Blown Head Gasket? - David Stepney - 21-04-2019
I have had a similar problem with FG 8659 recently, but on the stud between Nos 1 and 2 cylinder. The car was running well otherwise. I checked he nut on the stud in question and found it was barely finger tight! So I checked all the nuts and made sure they were down to 25 ft/lbs and carried on motoring on the basis of "If it ain't broke, don't fix it!"
RE: Blown Head Gasket? - David Witton - 21-04-2019
Mark this is more indicative of a cracked block around the centre stud usually between cylinders 2 or 3 or even both. The block’s weak area in my opinion.
RE: Blown Head Gasket? - Greig Smith - 21-04-2019
Mark the real culprit is your painter, if the head was black you wouldn't notice the oil.... Jokes aside this is wicking up the stud from the cylinder which means you have a weak spot at the gasket. What David says could be your problem.
Pull the nut and washer off, clean around the stud, scratch the paint off the pedestal (Paint deforms under load and gives you a false torque reading), apply a bit of sealer to the washer on both sides as well as to the thread and underneath the nut and then fit & torque to 25lbs, leave to cure and then go for a test drive.
The sealer will stop the oily stuff wicking up, but won't cure the underlying problem
Aye
Greig
RE: Blown Head Gasket? - David Stepney - 21-04-2019
On FG all the compression felt about the same when cranking it over and the tickover is nice and even. if your car ticks over nicely then unlikely to be a head gasket problem. C/A head gaskets are very forgiving. just make sure everything is tightened down.
RE: Blown Head Gasket? - Hedd_Jones - 21-04-2019
I do like the 'Empire Blue' cylinder head.
Father had a 1931 Singer 10. The base model with a sidevalve engine rather than the usual over
head cam job. The rolling chassis was a very deep blue with black wheels and coachwork as original. It must have been very smart
RE: Blown Head Gasket? - Mark McKibbin - 22-04-2019
David S, I have checked the nut tightness and they are still at 20 ft/lb however is it meant to be 25 ft/lb?
Greig, I have done as you suggested and will give it a day before taking it out for a test drive, I am rather attached to the blue head so maybe I should look for Blue oil to go with it?
David W, I hope you are wrong, the oil in the sump is very clean and this stuff on the head is very black so hoping it's from the combustion chamber, but will check when I pull it down to put my shiny new crank in during our winter (soon).
Hedd, for some reason I like to paint my engines blue not really sure why. Empire Blue does sound like a good colonial colour!
RE: Blown Head Gasket? - Bob Culver - 22-04-2019
The 25 lbft figure always seems high to me. It is far greater than usual recommendation for 45 tsi HT bolts. A broken stud is a saga. Excessive pressure distorts valve seats. Is it the cause of the block cracking? Did Austin ever suggest a figure?
RE: Blown Head Gasket? - David Witton - 22-04-2019
Mark, FWIW, in my case, the engine still ran like a train, it just got messy around the head as you are experiencing. No need to be downhearted just yet.
RE: Blown Head Gasket? - Chris KC - 22-04-2019
My two-penn'orth: Paint has two effects on bolted joints
1. It can act as a lubricant under the joint face; this means that for a given applied torque the axial clamp force may be higher. However I don't imagine blue paint is significantly different from black in this regard!
2. If applied thickly, the joint may relax after a period of time as the paint layer compresses, reducing the axial clamp force. For this reason it's always wise to retighten such joints after a short period of time.
I routinely apply 20lbft to head joints, on occasions have gone up to 22lbft, but never higher.