<VV> Corsa update - compression and temperature

[Guus de Haan]

Really a story for diehard engine guys ;-))

Follow up on the compression test of last week. After installing  
(new) points (I wanted to rule out problems with the Ignitor) and  
cleaning the spark plugs the car ran pretty decent again. Took it for  
a drive but it ran hot again very soon. Even at low speeds like 40/50  
mph it runs at 400F. Contrary to a "normal"  water cooled car with  
heat problems the temperature goes quickly down again if you just  
leave it idling. My guess is it could idle all day and never run hot.  
It's definitely connected to higher revs.

Just out of curiosity I also measured the compression again with the  
engine hot. Almost burned my fingers removing the spark plugs so hot  
it was. The whole engine compartment gets incredibly hot. You can  
hardly touch anything in there after the engine has run for a while.  
Even the spare tire rim was hot when I took it out.

The hot values are as expected lower but with almost the same spread.  
Cylinder 1 is also lower now.
Cylinder		Cold	Hot (all psi)
1			174		133
2			138		123
3			160		152
4			145		141
5			160		152
6			145		138

I think that the only real problem is the car running hot. If I keep  
it low the car runs good. The shrouding is all in place, spark plug  
boots are there and the seal is in place.

So what can make an engine run hot on higher revs?
I think two things could be wrong.

Option 1
Valve timing.
How can one check if the hydraulic lifters have collapsed? If I had  
adjusted them like that this woud result in solid lifter wouldn't it?  
Can valves that are adjusted to tight make a car run hot? (I mean  
really hot!)

Option 2
Distributor trouble
Like I mentioned before the distributor is the only (main) part  
that's not rebuild. I've timed it at 20-24 degrees at 850 rpm like  
the manual suggested. How can I check if the centrifugal and pressure  
retard are working correct? I looked at the manual and at 2000 rpm  
the pressure retard should retard the time. If it doesn't and the  
timing stays at 20-24 degrees would that make an engine run hot?

There's only one big BUT concerning this retard thing. There's an  
Safeguard retard unit on this car. This unit can electronically  
retard the timing if detonation (pining) occurs. The display however  
shows very little action of the unit. At least it doesn't act in the  
range the car is already running hot. Only when I really boost it the  
Safeguard takes over every now and then. Nice unit btw.

The Air/Fuel ratio indicator on the Safeguard also give an almost  
perfect ratio (13-14) while driving. Only running a little lean on  
acceleration but quickly becoming normal again. That's why I rule out  
fuel problems.

First I could adjust the valves again. But then I would like to know  
how I can detect one or more collapsed lifters. With the distributor  
probably the best option would be to ship it to Dale Mgt for a  
rebuild but I would like to be sure if that's really necessary and if  
it's really the reason the engine runs hot.

What else could cause it? Opinions welcomed.

Sorry for the long post. The good news is that tonight I took it for  
a nice drive through the woods nearby. As long as you keep the revs  
down you would never know it has a problem ;-)

Regards,

Guus de Haan
The Netherlands
'65 Corsa Turbo-Charged Cvt