Vilhuer

Have been helping on Euro '84 S Aut's head gasket change. After lot of etc we had cambelt in place and were adjusting it to correct tension. All went smoothly for a change until we had done three adjustments getting tension to 1/3 above low limit on Kempf tool. Next measurement would have been right there in center where we wanted it. While doing two rounds to spread latest adjustments load to entire belt we ran into serious problems after one full round and then some 40-50 degrees more.

There is clearly something blocking rotation around 40 to 50 degrees after TDC. On every second round crank and cam markings had been spot on everytime. Not wanting to cause more damage by forcing we desided to backup a little and went back to TDC. Trying again gave same result, resistance gets heavy quickly between 40 and 50 after. On TDC cam markings are 180 opposite so they should still be ok.

We desided to back up even more and even stranger still laid ahead. I know it is big NO-NO to turn crank CCW when belt is on but we were desperate. Managed to turn back only 40-50 degrees before TDC and met same stiff resistance again. Now engine is stuck to this about 90 degrees wide area, 45 dergees to each side of TDC.

There is and was no water or oil (other than some lubricant applied directly to moving parts in heads before assembly) inside engine and sparkplugs are out. Shouldn't have any wires or hoses preventing belt movement. On any of the previous 15 laps there were no indications this would happen. No strange sounds or abnormal rotation resistance, just normal compression buildup four times each round. Nothing is showing through sparkplug holes other than #1 piston in TDC when crank is there also. Other pistons seem to move normally as far as we can see.

Now what the h@$$ is the problem? How it can seize like that after 15 rounds of rotation? I could understand if timing was off that pistons would hit the valves but even then they should do it under two rounds. Why it can't backup when it came through just earlier without problems? All we can think of is there must be some foreign object inside causing this. But what, were and how it got there do to this right now? Why not straight away on first round or later when engine is run first time? What makes 15th round so special? Can anyone tell us what's going on here?

What is happening on about 45 before and after TDC when cams are about 160 and 200 degrees pass their markings. I think there must be two different obstacles to be able to cause both blockages. For instance any one valve isn't opening or closing on both of these points, I think. Is this true? Any easy way to tell where each valve is at these two points? Looking for possible cause inside either head and guidance to which head pull first. Owner has fought with the gasket change long enough and understandably would like to sort current situation with least amount of work.

ErnestSw

Sounds to me like you're VERY lucky that you didn't discover the problem AFTER you started the car.
There are lots of things outside the engine that could cause the problem. Have you got the plate back on the ring gear cover? See whether a washer might be caught. Is the car in gear? Stranger things have happened. Since you're working on a non-interference engine you can turn each cam shaft independantly as well as the crank (as long as you mark them carefully) and see which one is causing the problem. Check the thrust bearing. Long shot, but who knows?

Vilhuer

True, could have been much worse.

Ring gear cover = lower bellhousing where in clutch resides on manual cars. If yes then yes, it's on. Shouldn't have anything loose in there to go between.

Gearbox is on N but changing to P and back don't help.

Is it 115% sure 10.4:1 CR Euro S is non-interference engine? If it is interference engine it could explain in theary problems we're seeing. But not in practise when valves and cams were good and all timing marks are ok. In my opinion certainly not after 15 rotations. If it's not interference, first thing to do is to remove belt and check if crank and cams move independently.

Thrust bearing should be ok as owner says he checked it before starting head removal.

ErnestSw

Vilheur,
I would ask someone with more knowledge than I have before being CERTAIN. Maybe one of the big three. My understanding is that the only time there could be interference in an 84 is if there's a carbon build up on the valves, but if the top end has been done that shouldn't be a problem.

Kevin in Atlanta

Not sure this applies to 16v, but I had a driver side chain tensioner fail on an 85 32v. The plastic that the chain would ride on spun and jammed in the chain. Felt like I had dropped something into the cylinder.

Garth S

Some quick random thoughts -

- were the cam drive gears off? - if so, were the keys reinstalled with them? If not, the cam gear/or gears would continue to move 'in-time', while the cam would begin to slip and get out of time, or simply not move! I would treat the euro 16v as if it were an interference engine at 10.4:1, especially if the head were shaved as part of the project - so if there were slippage, valve contact may be possible.
- is there a 45 deg mark on the harmonic dampner, as on the 32v cars (indicator of interference engines).
- is the distributor installed? Is the rotor moving correctly, or is its drive gear jammed?
- you mentioned 'feeling the compression build 4 times per rotation' - but the plugs were out: please clarify
- any possibility the starter drive gear became engaged in the ring gear?

Vilhuer

Cam drive gear was off only from 5-8 cam and keys should be back on if they didn't magically disappear during installation. Heads where shaved but only very little was taken off. Combustion chambers were cleaned so this should even out situation. There is no 45 mark on damnpner and I also thought this would mean it's non-interference but I'm not sure anymore. Distributor is off, hard to say if cam drive gear is moving or not but I would bet it is. Compression buildup comment just meant valve spring movement. Crank rotation resistance varied like it should because of opening and closing of valves. Starter is out and has been since heads were taken off initially. My feeling is that next step should be to leave crank at TDC, take belt off and carefully check if both cams can be rotated several times and deside what to do next according to results. Unless someone says it's interference engine?

ErnestSw

If it is an interference engine, and it sounds like it's not, turning the cams with a small wrench should be safe. You'll feel the spring tension come and go, but you shouldn't have enough leverage to damage the valves.

Vilhuer

Latest plan is to find miniature camera to be able to see inside before doing anything else. Webcam for laptop perhaps if small ones exist.

Gretch

Is the car an automatic? TT or trany ever been worked on? Crank got in-spec end play?

Jim bailey - 928 International

Is there any chance that one of the allen bolts which hold the cam housing to the head accessed by removing the cam plugs might still be inside the housing ?

Vilhuer

You have too much pressure in your supercharger Gretch to even read earlier messages? Model is on the first line of the first post, '84 S automatic meaning M28/22 engine and A28/02 4sp box. No tranny work in years.

Vilhuer

That is one possibility as one of the allen bolts is missing. Not sure from inside or under housing. It has been missing since head removal. Heads and cam housings both have been washed, machined and housings painted since then. Naturally cams, lifters and rear end plates were all off to do that. We checked both housings thoroughly before installing them back on. Couldn't find anything in them at that time. If there's something now it must have gotten there during installation and nothing went missing during it.

GlenL

Is the car in Park?

Otherwise I'd remove the belt, at least from the sprockets, and check for smooth action of the cams, oil pump and crank shaft.

One thing I did once was get the belt folded up on itself by the tensioner and it locked in place. Didn't have everything together so there was a lot of slack. Doesn't sound like your issue.

Gretch

"Aut's"= "Autmatic transmission", ok.......never mind....................