ANY TIPS?

[roddy]

Hello Bill

I may have missed the beginning of your saga, but was it just uneven running and difficulty with the carbs?   Was the water system pressurising and expanding off lots of water?   If not, it may not be the head gasket.   Could be that the front carb was running very lean and has burned valves in cylinders 1 and 2.   You didn't say if putting oil into the bores made any difference to the compression pressures.   If it didn't, then that tends to indicate valves.   Of course my earlier comment about gasket failure allowing compression to escape into the adjoining bore still applies.   Depends how cleanly the gasket separates from the faces on what can be diagnosed with eyesight.   Let me know if copious amounts of water was expanding off, as there can be various reasons for the cause, which can lead to local overheating and gasket failure?   Also, has the oil in the sump started to get a milky opaque colour to it - indicates that water is in the oil - if a gasket has failed and the water system is pressurising, when you switch off the engine, the water pressure flows back through the gasket flaw and into the bore and runs down into the sump....

Regards - Roddy

[nistri]

Light score marks on the tensioner pad are OK. Andrea

[roddy]

Sorry to bombard you with more information, but it is all designed to help you (and others?).   When refitting the cylinder head onto the block it is quite difficult to keep the gasket in place (it wants to slip down the block face), locate and hold the head in place, and feed the chain through the head aperture whilst still keeping it tight on the crank chainwheel.   From an engineering suppliers or DIY supermarket, get a length of 8mm threaded rod.   Cut two lengths about 1" longer than a cylinder head bolt.   Screw in the two lengths into the block first.   This then gives you a pilot for holding the gasket in place, locating the head, and letting you re-tie the string to hold the ends of chain in place.   You will be aware that 2 of the cylinder head bolts have a slightly thicker diameter shank, and these are the two bolts to fix in first to correctly locate the head and gasket on to the block.  Now unscrew and remove the two pilot rods and fit in the remaining bolts.   Torque in stages and in order.   The W/M gives the location of the 'thicker' bolts and the tightening order.   Of course, all the tappings into the block should have been clean and free of grit/oil/etc. first.

Regards - Roddy   

[bill]

Back again, will take some pics once the weather brightens up. I was talking to my brother in law last night and said when I have went this far why dont I take out the pistons, to check them. It sounds scary to me but he has a point.
Can this be done with the engine in the car, and its it complicated?
Thank you.
Bil..

[ncundy]

I'm not sure what you would gain other than seeing the condition of the bearings. You haven't said what you think the problem is but I take it that you think it is either gasket or valves?

[Philm]

If you are going as far as taking the pistons out you are getting close to a full rebuild as you would probably want to replace rings and bearings. You will need to remove the sump to get to the rod bolts. How many miles has the car/engine done?

[bill]

Hi Neil, I was just going to take out he pistons to see what state they are in, and if that is the reason for the low compression.(rings)
I have had two mechanics look at the head gasket and they cannot see any problems with it. Tomorrow I am going to strip the head and see what the valves are like.
Will keep you informed.
Bill.

[bill]

Hi Phil, I think the has done around 70,000 this is begining to be a mystery, hope it can be sorted.
Thank You.
Bill.

[ncundy]

I'm not sure checking the pistons will shed any light on the problem. It may be the rings are worn (or broken, misaligned etc) but it is far more likely to be bore wear if that is problem and highly unlikely to be a problem with the pistons. Now you have the head off you can measure the bores with a dti. Even if it is the rings (which I would consider unlikely) you are better advised to have the block at least re-honed before putting new ones in. If it is bore wear then you will need a re-bore and next size pistons.

It's a shame you haven't been able to isolate the problem before taking the head off, but TBH now you have the head off I would get it sorted and re-fit it to see if that solves the problem. If it does fix it then you've saved yourself the hassle of unnecessarily taking the pistons out (and in doing this you will have to get a new sump gasket, remove the oil pick up (new gasket), and run the risk of breaking the existing rings if you re-fit them). If it doesn't you know where to look next and you've not really lost anything apart from a bit of time.

The other approach is that touched on by Phil - you are half way to an engine rebuild. 70k is a good mileage for an engine and I suspect it is less broken and more just tired  - so remove it and do a full rebuild (and if you are into a re-bore and new pistons it won't cost much more anyway - especially if you can do most of it yourself).

[bill]

Hi Neil,thank you for your reply you have a good point, I think I will go down your first road, if it does not work, out comes the engine. It does not seem a big job to remove it.  Taking the head to the machine shop tomorrow to have the valves done and ask them to tidy up the ports. one thing puzzling me was why were some of the bolts coverd in sludge and some bone dry?
Thank you once more for your time.
Cheers to all.
Bill.

[ncundy]

Not sure about the bolts.

If you get the chance I would measure the bores before you put the head back. The details are below and you can tell if it is an A or B class because there will be a stamp next to the cylinder on the block top deck. That will give a clue of where you stand.

All the best

[davidwheeler]

If you do go to the total rebuild remember that you do not take the engine out of the car, you take the car off the engine.  It is much easier to undo the four bolts holding the subframe to the car and lift the car off the unit than to wriggle the engine off the gearbox in the car.  With the engine/gearbox/subframe unit on the garage floor things are so much easier to get at and you can also check the subframe which may well have holes it it and also clean up the engine bay, repair the steering box, check the brake lines etc. etc..   I have done it both ways and find taking the lot out much the easier route.  You just need a stout beam, a piece of 3x4 to go across the engine bay and a decent block and tackle.
David

[davidwheeler]

Go back to page three for full instructions!
David