Engine out - can of worms opened?

[Donald360]

I have taken the cylinder heads off my 1.9 DG with the intention of fixing a low compression problem by fitting two replacement heads. Now the heads are off I have a couple of different problems to sort out. Firstly, it turns out that the low compression seems to have been due to a broken piston ring and not, as I originally thought, a burnt valve. The next wee problem is that I now have two small sheared off bolts sticking out of the thermostat housing with no intention of coming out, the steel seems to have permanently bonded to the alloy. Just to make things even better, I also accidentally bent one of the new cylinder head sealing rings.

So, a couple of requests for information. Is it possible to buy a single set of piston rings? I really don't want to buy a whole set (a) pretty expensive, and (b) I had already removed and resealed the two liners on the other side (a pig of a job) and have no wish to disturb them again. Similarly, is it possible to buy just a single cylinder head sealing ring (the metal one)? Again I don't want to have to buy a whole gasket set. Finally has anyone any tips on removing these broken bolts from the thermostat housing. I was wondering how difficult to drill and re-tap the holes or should I just try and source a good second hand one?

I'm having to do this on a budget, so would appreciate any thoughts on this.
Cheers
Donald.

[ELVIS]

thermostat studs can be carefully drilled and retapped

[Donald360]

I have reassembled one side of the engine and I am now having second thoughts that this might not have been the best action. I have now received a set of new piston rings in order to replace the broken one on the other side. My question now is, is it ok to just replace the piston rings on the one side or should I dismantle the other side again and replace the rings on all four cylinders? If I do this, can I re-use the gaskets/seals or would I have to buy new ones? Hope this is clear enough, I'm starting to confuse myself here...

Cheers
Donald.

[New Kentish Campers]

I would have thought that if the compressions were good on the other cylinders then there's not much to gain in replacing the rings to those cylinders. Surely its all about having good compression on all cylinders.

Gaskets, etc shouldn't be reused; even if they work at first, there's a good chance they will let you down later, probably when you in the middle of nowhere at 2.30 in the morning..

Doug.

[Red Westie]

What is technically correct and what is actually the best course of action may well be two different things here. Technicalled all the rings should be replaced but then as a result all four bores would need glaze busting and if badly worn, any wear ridge removing (unless the top ring is 'stepped').
My feeling is that replacing just the one ring maybe the best option in this case unless you are happy to carry out more extensive repairs.
The other point here is that you don't know yet what damage may have been done by the broken ring.
Lets hope you can get away with just replacing the one ring or set of rings and the bore isn't badly scored.

Martin

[Donald360]

The liner that had the broken ring looks pretty good, in fact all four liners looked in good nick. I think I will opt for the simplest option and only replace the one ring.

Thanks,
Donald.

[Red Westie]

Give the bore a bit of a deglaze to help the ring bed in....even it it's just with wet n dry and a bit of white spirit (in circles not done the bore), better than nothing.

Martin

[Donald360]

Ended up replacing the three rings on number 1 & 2 cylinders. All put back together and looking good. I'm slightly worried that I might have set the tappet clearances wrong. I assumed that the timing mark on the crankshaft pulley needs to be at the top for tdc on cyl 1, etc. I then tightened up the adjuster until there was no gap and then 2 further turns. Fingers crossed but hey, what's the worst that can happen

All I need now is a few new bolts for the exhaust and it can go back into the van. Looking forward to starting her up.

Donald.

[Aidan]

preload 1 and 1/4 to 1 and 1/2 turns on worn engine seems to be better than 2 which is fine when everything is new

[Donald360]

Thanks for the tip, I shall back off me tappets an half turn or so.

[toomanytoys]

or just touching until its been running a bit.. then I'd suggest only 1/2 a turn on.. 2 turns is far too much IMHO..

[Mocki]

or just touching until its been running a bit.. then I'd suggest only 1/2 a turn on.. 2 turns is far too much IMHO..

agreed.
2 turns is too much.

[Donald360]

Re-did them to one and a half turns. Haven't got to testing it yet as I need to pick up a new oil filter before I fill her up with oil and then water. Do you think I should re-do them a bit less? Engine had done about 160k miles as far as I know.

Donald.

[Donald360]

Engine now back in place. Filled her with oil. Put all the engine bay wiring back where it was before (or so I thought). Turned the engine over and was met with a puff of smoke from wiring... oops! Now I'm scratching my head trying to figure out where its all gone wrong. Engine turns over ok, but no spark so I'm thinking its the coil or the wiring to the coil that has been put back wrong. The wire that melted seems to be the one that goes to the carb heaters. Now trying to match the existing wiring to the Haynes diagrams

Might need a bit of help here I'm thinking. I'll keep you posted.

Donald.