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Blown head gasket[s].
Posted: Sat Feb 11, 2006 12:13 pm
by wanderinstar
Where to start?
Suppose this started last June with bypass hose going, and head getting very hot. Limped homeand changed bypass hose. Problem sorted or so I thought.
Engine started using about 3 pt of water to 7mls. No visible water leaks and no steam from exhaust. Changed head, ran about a month and head gasket went between 3+4. Stripped all down checked head with level, OK. cleaned everything and rebuilt. About a month, to 6 weeks same again. Blown between 3+4. This time changed head. Lasted about 2 months, this time blew between 1+2. Fitted skimmed head, pulled all studs, checked block, all [appeared ] OK. Rebuilt for another 2 months and guess what . Its gone again.
Am getting desperate and running out of ideas. Spoke to a bloke at Minisport and he said that 92 deg stat wouldnt be helping. Surely that wont be the problem, I,m just trying to keep warm in winter.
Any ideas greatly received.
Ian.
Posted: Sat Feb 11, 2006 12:15 pm
by johnm
Stupid thought but do you torque the head bolts down in the book defined sequence and do you retorque them a couple of weeks later??
Posted: Sat Feb 11, 2006 12:17 pm
by wanderinstar
Yep. Done that, tightened to 40 then retorqued to 45.
Posted: Sat Feb 11, 2006 1:21 pm
by chickenjohn
Why 45??? its supposed to be 40.
Did you make sure you thoroughly cleaned the faces of head and block of any trace of old gasket, rust or other gunk??
other than that you might need to get the clock skimmed ;(
Posted: Sat Feb 11, 2006 3:01 pm
by wanderinstar
Torqued it to 40 after changing first two gaskets, thought 45 may stop it from going again. But obviously it didnt. Yes did clean all surfaces off.
Ian.
blown
Posted: Sat Feb 11, 2006 3:30 pm
by Willie
It certainly looks as though the block is warped,assuming that your replacement head is not warped! I think that 92 thermostat is too high.
It can also be useful to lightly countersink all of the head stud holes after removing the studs as they can get pulled up over the years. If you have the
late type heater and want to keep warm in winter then disconnect the fresh
air intake pipe from the heater unit under the dash and block it up, The
heater will then recirculate air from inside the car and warm up very much
better. I am running like this in a convertible and am perfectly comfortable
all winter on a standard thermostat.
Posted: Sun Feb 12, 2006 10:43 am
by bmcecosse
Sorry to hear the gasket has gone again. The stat should be just fine. Where did it blow this time Ian ? But I do think the time has come to get that spare engine in the car - with the MG cam. Torque to 45 ft lbs is correct - in fact Minis are now torqued to 50, but 45 will be fine. Did you fit the thick washers under the head nuts ? If you are determined to have another go with this head - pull all the studs out, clean the top face and check it carefully for any low sections using a steel rule with a light behind it.
Posted: Sun Feb 12, 2006 7:09 pm
by wanderinstar
Hi Roy,
It blew between 3 + 4 again. Cleaned block off and there is 1.5 thou under a straight edge at narrowest point between cylinders. Will tighten it down to 50ft/lbs this time and see how long that lasts.
Have sown the seed with SWMBO re doing spare engine up, will probably start next w/end.
Ian.
Posted: Sun Feb 12, 2006 7:33 pm
by Pyoor_Kate
50lbft?! Eeek.
Um, with my Ital engine, which is *meant* to be tightened to 55lbft, I found that the threads were stripping on the nuts and studs at 50. In the end there's a couple of Morris 1098 nuts and studs (*thankyou Nikki*) which meant I could actually get my engine back together, but they really were quite definately not happy at 50 (you know that "I can't do this up anymore, because I can feel it's started to strip, but it should hold as long as I don't fiddle with it" feeling?).
You may find that you end up stripping the threads... at one or other end of the stud.
Posted: Mon Feb 13, 2006 11:18 am
by KirstMin
Pyoor_Kate wrote:50lbft?! Eeek.
Um, with my Ital engine, which is *meant* to be tightened to 55lbft, I found that the threads were stripping on the nuts and studs at 50.
Hiya, I didn't have any probs at all with 55lbft on my Ital block. I guess it depends on the condition of said unit. That said, I dont see how giving it more welly will prevent the problem and I wouldn't go higher than the recommended torque.
I know this might seem basic but how are you doing the torquing? With a modern head gasket (not asbestos) you should torque and then run the engine up to warm and then torque again (you easily notice the need to torque after running up to temp). Then dont torque again - no need after 500 miles as per book.
Posted: Mon Feb 13, 2006 11:25 am
by rayofleamington
But I do think the time has come to get that spare engine in the car
seconded!
Posted: Mon Feb 13, 2006 1:45 pm
by Kevin
Hope you have not had the bad luck to get some of those poor quality head gaskets that were floating around a while ago, I still prefer to use copper ones as they seem far more reliable.
Posted: Tue Feb 14, 2006 8:07 pm
by wanderinstar
Kevin.
When you say copper gaskets, do you mean solid copper or faced with copper.
Ian.
Posted: Wed Feb 15, 2006 12:23 pm
by KirstMin
it's the performance ones with the copper rings exposed on the head side isn't it?
Posted: Wed Feb 15, 2006 7:19 pm
by bmcecosse
You could make your own the 'old way' - from a sheet of copper!
Posted: Thu Feb 16, 2006 11:38 am
by ianselva
There are quite a few supplier of cut to pattern solid copper gaskets, however you shouldn't ever need one my racer ran with standard Copper-asbestos ( or whatever the current replacement is) with a compression ratio of 13:1 and never blew. It's more about having a flat face on the head and block and no work-around will work for long.
Posted: Thu Feb 16, 2006 4:19 pm
by KirstMin
ianselva wrote:It's more about having a flat face on the head and block and no work-around will work for long.
Good point. Unless the gaskets are from a faulty batch or you know you have put the head on incorrectly then its unlikely to be gasket related and eventually, no matter how tight you get those bolts or how good the gasket is, it WILL blow again. Best bet is to get the faces sorted.
Posted: Fri Feb 17, 2006 8:49 pm
by bmcecosse
Easier said than done!
Posted: Fri Feb 17, 2006 11:44 pm
by bigginger
I've just read in P classics that modern non asbestos gaskets will fail quickly if they come into contact with water, and some folk run the engine with no water in it to warm them up and "melt the varnish" and ensure a good seal. I dunno - but worth trying? No idea if this applies to Mog head gaskets, mind

Posted: Sat Feb 18, 2006 12:27 am
by Cam
Just use a good quality copper one and don't rely on those other cheapos.