106 1.1 Tu With No/ Low Compression

[leon 1.9 0]

Ok, a friend told me he was doing his head gasket as he thought it had gone on his 106 1.1.

 

Apparently it had been running ok, but then just wouldn't start properly. If you turned it over it made an awful noise and they said that if it did start it would only fire on 2.

 

So we pulled the head off (couldn't get it off at first until we found we'd left one of the head bolts still partly in ) but looking over the gasket it looked ok, no signs of a failure?!?

 

The pistons will move slightly in their bores, so there's a possibility that the rings are shot, and the outter two cylinders had normal looking spark plugs and much less coking, so I believe its the middle two that had no compression.

 

After looking at this topic http://forum.205gtidrivers.com/index.php?s...00746&st=10 I also remembered that I could easily turn the engine over with no problem off the cam sprocket when the head & belt were still on (bad practice, I know, but it was so easy I was suprised). Now I'm thinking this means there was pretty much no compression at all, so I'm starting to think that maybe the belt had slipped (looks ok though) or the valves weren't closing?

 

So any advice? Should you be able to move the pistons side-to-side in the liners at all? How much play can you get away with? Can you check the valves are sealing somehow?

 

Cheers

 

Leon

[RossD 43]

Valves not seating properly like you say, or the possibility that the liners have been disturbed when the gasket was done the first time around and are now not sealing properly.

 

The pistons will move slightly in their bores, but only very slightly. Any more than negligable movement shows wear.

[leon 1.9 0]

Suspect the bores are worn, but as three of the pistons all had roughly the same amount of 'wiggle' (technical terms here see) and one of those three was still firing, then I'm not sure thats the real problem.

 

The head hasn't gone back on yet, I was just wondering if there is any way I could check the valves are seating properly. Was no real sign of oil-burning smoke so I'm pretty sure the stem seals are fine, but that doesn't rule out the actual valves not closing. Can I adjust the clearances with the head off by just turning the cam pulley?

 

The engine hasn't been locked in position yet, we just made sure that the liners didn't move once the head was lifted off. The liners look pretty square and don't appear to have moved. There was a fair bit of oil in the inlet so I think it was breathing through the vents quite heavily, but not TOO bad.

 

The car was a freebie for this lad so he doesn't want to spend too much more cash on it, he's already got a gasket kit so I think the plan will be just bang it back together will new gasket, headbolts etc and see if it'll go.

 

edit: just to say don't think the gasket has ever been done before or the head ever come off, so doubt the liners have previously been disturbed.

Edited March 23, 2009 by leon 1.9

[Anthony 1,000]

The head hasn't gone back on yet, I was just wondering if there is any way I could check the valves are seating properly. Was no real sign of oil-burning smoke so I'm pretty sure the stem seals are fine, but that doesn't rule out the actual valves not closing. Can I adjust the clearances with the head off by just turning the cam pulley?

Lap the valves back in with a little grinding paste - a bent valve will stick out like a sore thumb.

 

Haynes gives a good guide to checking the valve clearances - it's very easy on TU's, just requiring a set of feeler guages, a flatblade screwdriver, and a 13mm ring spanner from memory.

 

Has the owner ever seen the engine run, or did he buy it as a non-runner with a failed headgasket? If it's been seriously overheated, then it could have toasted the rings/lands on it, which results in next to no compression. Otherwise, are you sure that it was timed up correctly when the head was refitted and the cambelt put back on, as a few teeth out would give you low compression...

[leon 1.9 0]

The engine has run happily for at least a year during the time I've know it, but as the car has been passed between various friends it hasn't been particularly well cared for.

 

No temperature gauge on it (only a warning light, if it works...), but its not known to have been very heavily overheated, the reason they suspected head gasket was that it went from running ok to refusing to even start. Its definitely got poor compression as I could turn it easily by hand with the plugs in, head on etc.

 

Didn't explain it very well, but its never had the head removed & refitted or even the belt changed for as long as I've known it, this is the first time the head has been off to do the gasket, and we have yet to put it back together after taking the head off.

 

I'll see if I can scrounge some grinding paste from here at work somewhere to lap in the valves again, and recheck the clearances after.

 

The valves all looked straight when I took a quick glance, but as there was oil all over the head once it was off I didn't get a good look. When its cleaned up I'll check. Suspecting that they're just not seating properly now.

[sub205 5]

even with low compression, the engine will run smoothly most of the time. had a broken pistonring in an xu9 several years ago, the engine ran fine but sounded like a diesel in idle ;-)

[leon 1.9 0]

Cheers for the reply, but she was fixed ages ago! We refitted the head, timed it up, I did a quick check of the valve clearances and tweaked them, and she fired first time.

 

The liners are clearly worn, but its not worth the effort of stripping it down, I think the total cost for the work we did was about £30.

 

ITs had a knocking driveshaft for about a year and it still hasn't gone, no matter what the lad does to it (2nd at 60 mph by mistake the other day) he just can't kill it!