Blown head gasket (again!)

[Bee]

If I were you I think I would remove the stats and the pressure cap and refill the system squeezing the hoses to hopefully work some air out, run the engine for a good length of time topping up as necessary and see what happens, is your water pump ok? impeller still got vanes?, bits of vanes blocking pipes? this saves stripping the thing down and will tell you something, it is sometimes not obvious from an old gasket if it was leaking, if no problems start putting a stat back then another then if still ok the pressure cap then if ok go to the pub, if it`s not start looking for cracks etc. good luck.

[Gibbo]

The new bolt is not pre-stretcted until you fit it and tighten it up it then stretches.

 

It's not pre-stretched then surely?

 

These came into use when due to the use of more slippery greases being used on nuts and bolts torque reading became unrealiable.

 

Er, slippery greases make torque reading more reliable, not less reliable, or even "unreliable".

[simon&jan]

 

 

 

 

Er, slippery greases make torque reading more reliable, not less reliable, or even "unreliable".

 

 

I allways put a small amount of grease on headbolts to get a smooth torque down , spoken to a few engine builders i know and they agree, so wot do other people do ???

 

The other thing about stretchbolts is they could bottom out before pulling head down and clamping gasket , torque wrench says click and bolts are tight enough but put no.pressure on gasket

Edited December 6, 2012 by simon&jan

[bizzard]

Its all about jerks!. A touch of light oil on the threads and Morris stern tube grease is nice and slippery under the heads to help prevent torque spanner jerks, as you can be just on the point of a jerk with the torque gauge showing the set torque setting but the bolt is actually a little under torqued. The bolt can also give a sudden last extra big jerk that can suddenly jerk the bolt way over the desired tightness and its not good to slacken them off a bit.

It goes without saying too that its very important to adhere to the correct tightening sequence of these bolts or nuts as laid down in the engines workshop manual, usually tightening commences from the middle area of the head and works outwards following a particular pattern.

[simon&jan]

Know wot you mean about jerks , like the same ones who told me never to oil or grease threads when i replied to a thread about heli coils , the same jerks can rip them out !!

[bizzard]

Know wot you mean about jerks , like the same ones who told me never to oil or grease threads when i replied to a thread about heli coils , the same jerks can rip them out !!

Yes there's lots of jerking jerks out there.

[simon&jan]

[larkshall]

For starters BMC engines need re-torquing at between 20-30 hours runtime. New bolts or studs should have been used at rebuild point. These must be checked for overall length and fit before final fitting. There was always a debate about pattern v original head gaskets, I don't know which you used. Some swear by a pure copper gasket rather than a copper composite gasket. I have used both which have worked. Oh when you checked and found a warped head, did you check the block face?.

 

Cooling system, this needs pressure testing, beg steal or borrow a pump and gauge. Oh and as someone has said marine installations are a lash-up at best. I would be very careful in checking for any airlocks during the fill procedure. Just like some cars are notorious for this where the heater matrix is higher than the engine. The thermostats should be removed and tested in hot water for operation, you need to find if they are opening, and indeed closing at the right temperatures. As others have said check they are the right way round !. (The coil part always faces in the direction of flow).

 

At the moment, I'm not sure your head gasket has indeed failed, but I would consider a compression test. I would re-torque the head a.s.a.p.

[Titan]

I concur with Krusty.

My vetus gasket went, replaced using the same bolts, went again.

Even had the strange things with the water, header tank filling and the pressure still there the next morning.

 

Asked Vetus, they said about the bolts.

Used new bolts and no more trouble. Over 6 months now.

Good luck.

 

 

Yup I also guess perhaps if bolts are used they may be of the stretch type, although a bodge i have overcome this at the side of the road by removing one bolt at a time and fitting thick penny washers to accomodate . Just a thought ??

[IdealStandard]

I'm just catching up on all of these posts and all makes very interesting reading. There are lots of good suggestions and things to think about.

 

I re-torqued the head bolts, but they were pretty much bang on anyway and hadn't de-torqued at all really. I re-adjusted the valve clearances and then did all I could to bleed the coolant system. There are no bleed points on the skin tank (that I can see) and I wiggled all the pipes and kept the engine filler open until it was good and warm.

 

I've started the engine twice since doing this and now there is white smoke as the engine is turning over from the starter, and for the first few minutes until the engine is warm. It has also been a bit tricky to start, kicking in and then backing off and then taking properly second time.

 

The coolant system worked fine.

 

I am planning to email Shanks about their advice on replacing head bolts and trying to get some more advice from people who know my engine (few and far between!)

 

I really appreciate everyone's thoughts.

 

I concur with Krusty.

My vetus gasket went, replaced using the same bolts, went again.

Even had the strange things with the water, header tank filling and the pressure still there the next morning.

 

Asked Vetus, they said about the bolts.

Used new bolts and no more trouble. Over 6 months now.

Good luck.

 

Can you clarify whether you changed the bolts and the head gasket after it went again, or just the bolts?

[ROBDEN]

I'm just catching up on all of these posts and all makes very interesting reading. There are lots of good suggestions and things to think about.

 

I re-torqued the head bolts, but they were pretty much bang on anyway and hadn't de-torqued at all really. I re-adjusted the valve clearances and then did all I could to bleed the coolant system. There are no bleed points on the skin tank (that I can see) and I wiggled all the pipes and kept the engine filler open until it was good and warm.

 

I've started the engine twice since doing this and now there is white smoke as the engine is turning over from the starter, and for the first few minutes until the engine is warm. It has also been a bit tricky to start, kicking in and then backing off and then taking properly second time.

 

The coolant system worked fine.

 

I am planning to email Shanks about their advice on replacing head bolts and trying to get some more advice from people who know my engine (few and far between!)

 

I really appreciate everyone's thoughts.

 

 

 

Can you clarify whether you changed the bolts and the head gasket after it went again, or just the bolts?

 

 

 

Yes I changed the gasket as well as the bolts...just to be sure.

[IdealStandard]

Had a tricky day yesterday on the river Avon into Bristol (went over the weir at Hanham, which was fun!). There were some hairy moments when I had to full throttle and the engine got a pretty hard workout.

 

I kept checking things and the coolant was all working fine.

 

There is now some milky white oil on the dipstick and plenty on the rocker cover cap. There is also some oil around the rocker cover case bolts which has pushed through. I think this is probably engine breathing again, although it isn;t pushing back past the dipstick like before.

 

Definitely going to have it apart before too long and get it pressure tested and rebuild with new bolts.

[larkshall]

Had a tricky day yesterday on the river Avon into Bristol (went over the weir at Hanham, which was fun!). There were some hairy moments when I had to full throttle and the engine got a pretty hard workout.

 

I kept checking things and the coolant was all working fine.

 

There is now some milky white oil on the dipstick and plenty on the rocker cover cap. There is also some oil around the rocker cover case bolts which has pushed through. I think this is probably engine breathing again, although it isn;t pushing back past the dipstick like before.

 

Definitely going to have it apart before too long and get it pressure tested and rebuild with new bolts.

 

 

Milky white on dipstick means water in oil....

[IdealStandard]

Milky white on dipstick means water in oil....

 

I know. It's what I had been looking out for as the answer to 'maybe it's just condensation' or 'no it's definitely the head gasket' debate.

[RLWP]

Had a tricky day yesterday on the river Avon into Bristol (went over the weir at Hanham, which was fun!). There were some hairy moments when I had to full throttle and the engine got a pretty hard workout.

 

<snip>

 

There is now some milky white oil on the dipstick and plenty on the rocker cover cap.

 

<snip>

 

Milky white oil on the dipstick and in the rocker is an emulsion of oil and water. It seems to collect in lightly worked petrol engines, the solution is to go and get the engine hot by working it hard.

 

Like running at full throttle on a river

 

I'm afraid that emulsion in the oil after hard work doesn't sound good

 

By any chance, have you got a water cooled oil cooler on the engine (not the gearbox)?

 

Richard

Edited December 16, 2012 by RLWP

[IdealStandard]

No water cooled oil cooler.

 

Also, if it helps, the engine manual is here:

http://www.barrus.co.uk/pdfs/Shanks_04_Owners_Manual.pdf

 

I'm now currently safe and sound and in a position where I can get round to doing something about the issues. Next step is to take the head off, have it pressure tested and examined and take it from there I reckon. Every day I spend on the engine is one day I miss on fitting out the interior, which makes things frustratingly slow.

 

Thanks again for all the advice.

[MtB]

Had a tricky day yesterday on the river Avon into Bristol (went over the weir at Hanham, which was fun!).

 

Blimey!!

 

Was this due to engine trouble or did you not notice the lock...?

 

Seriously though, why?

 

 

MtB

[IdealStandard]

Blimey!!

 

Was this due to engine trouble or did you not notice the lock...?

 

Seriously though, why?

 

 

MtB

 

Lock is silted up and will be for the forseeable. They reckon on late January. http://www.waterscape.com/things-to-do/boating/stoppage/detail/7543/Hanham+Lock+1

 

I can't afford to be on the river trying to do this engine work as any tricky situations would require a working engine.

 

The Hanham lock keeper suggested waiting until a spring tide and cruising over the weir. I am now safe and sound in Bristol harbour, only problem is that there's no way out again until they sort out the lock (late Jan possibly) or going back over again at a high spring tide.

 

The tide was so high, and coupled with the recent rain I probably could have gone over the lock.

[smileypete]

I know. It's what I had been looking out for as the answer to 'maybe it's just condensation' or 'no it's definitely the head gasket' debate.

Could also be a breather problem and/or some blow by/poor compression, might be worth a read of these links:

 

http://www.reds-headers.com/html/red_s_engine_talk_38.html

http://www.mgb-stuff.org.uk/enginetext.htm

 

cheers, Pete.

~smpt~

[IdealStandard]

Could also be a breather problem and/or some blow by/poor compression, might be worth a read of these links:

 

http://www.reds-headers.com/html/red_s_engine_talk_38.html

http://www.mgb-stuff.org.uk/enginetext.htm

 

cheers, Pete.

~smpt~

 

Good reading that. The only problem with doing any of that is:

 

If there is visible coolant in the oil, or the oil drained from the pan is milky or what we sometimes call "mayonnaise", the compression tests I describe here may not be needed to find your underlying overheating or low performance problem. These are also signs of a leaking head gasket, a cracked head or a cracked block, requiring a teardown and possibly rebuild on the engine. 37-48 water pumps can fail, leaking coolant into the crankcase causing water in the oil also.

 

the way I see it I'll have to strip and have the head tested anyway really. The only really scary thing would be a cracked block, but I've been told that this would normally present me with a fair amount of smoke.

[smileypete]

Good reading that. The only problem with doing any of that is:

 

 

 

the way I see it I'll have to strip and have the head tested anyway really. The only really scary thing would be a cracked block, but I've been told that this would normally present me with a fair amount of smoke.

Well the usual way to diagnose problems like this is:

 

List possible problems in order of likelihood

Devise tests to categorically rule out each possible problem

Don't overlook there may be more than one problem

 

So I wouldn't go 'all in' on one possible diagnosis/problem (which it does sounds like you might be doing). But I quite liked this test mentioned above:

 

There are other ways to check for combustion gases in the coolant. One is to warm the engine up, take off the fan belt, restart the engine, and watch the coolant in the top tank for air bubbles upon sudden throttle opening. Of course you shouldn't run your engine very long without the water pumps turning.

 

cheers, Pete.

~smpt~

[Justme]

Car garages have testers that can sniff or even dip test the coolant for combustion.

 

Almost 100% effective diagnosis of a combustion to coolant leak.

[MtB]

Car garages have testers that can sniff or even dip test the coolant for combustion.

 

Almost 100% effective diagnosis of a combustion to coolant leak.

 

Indeed. The garage that maintains my vehicles does a reagent type test on a sample of coolant to determine with certainty if combustion gases are leaking into the coolant circuit. Would be well worth Googling and buying the kit for this, I'd suggest. This will at least narrow down the possibilities.

 

MtB

[IdealStandard]

Well the usual way to diagnose problems like this is:

 

List possible problems in order of likelihood

Devise tests to categorically rule out each possible problem

Don't overlook there may be more than one problem

 

So I wouldn't go 'all in' on one possible diagnosis/problem (which it does sounds like you might be doing). But I quite liked this test mentioned above:

 

 

 

Very good point. I need to get a bit more systematic.

 

So what you're saying is that a combustion in the coolant means that it is DEFINITELY a head gasket as opposed to the coolant getting into the oil another way?

 

Would a cracked cylinder head also show up positive results for combustion gases?

[Justme]

Depends where the leak / crack / gasket failure is & which 2 systems it breaches.