The V8 Owners Forum -

Have seen foriegn items that have found there way into a engine and litteraly get passed from pot to pot moving in and out of inlet valves and as bits get broken off pistons ect the damage increases.Have to agree with Gav the damage looks very servere and why are some pistons untouched?When engine put back together make sure inlet manifold fully cleaned out.
Cheers John.

Foreign objects are another possibility but usually they leave marks everywhere in the chamber, including valves.

There was definately no debris anywhere prior to fitting heads, and engine just ran at it's normal temp - could actually tick over all day at 80 degrees with fans on.
When I left it ticking over fans were on and temp was below 80 all the time - never seen an engine do this before without running on the road.

Pete

Here's some comparison pics of the 3 heads I have.
I measured depth of all 3 heads and they seemed the same (ruler), but would have to measure more accurately to be 100%

Casting Number of 'Vitesse' head



Casting number of my spare SD1 head




The 3 heads - Vitesse, SD1 and P6 - left to right






Vitesse and SD1 head - note combustion chamber difference







SD1 and P6 head - similar combustion chambers:



Close ups of combustion chambers:

Vitesse





SD1





P6





I think that the 'Vitesse' heads had a much smaller combustion chamber, causing massive detonation, but then, why not on all cylinders. Engine was never overheated and wasn't driven - still a mystery to me.
I'm going to build up a spare SD1 engine I have, use the new valves and springs from the damaged head, and the cam from the P6 engine and see how that goes - unless someone has another suggestion.

Pete

The heads with the damage are interesting. The squish at the top and bottome of the chambers is free of carbon yet the bowl of the chamber is black. I've seen bike engines that run such a tight piston to head clearance that carbon can't form in the squish area, is this the case with this do you think?

I've seen bike engines that run such a tight piston to head clearance that carbon can't form in the squish area, is this the case with this do you think?

Quite correct !

Just a thought - what inlet manifold do you have?
It might just be coincidence .. but .. with a standard or converted rover inlet manifold, wouldn't pots 1 and 4 be fed from the same side of the manifold? How's the damage to the other head? middle 2 pots?

minorv8 wrote:

I've seen bike engines that run such a tight piston to head clearance that carbon can't form in the squish area, is this the case with this do you think?

Quite correct !

Which leads me to the question, how is this happening with a rover v8?

There should be loads of clearance in that area!

It's a converted SD1 inlet - a well executed job whoever did it - I preferred this to the offy one that I had.
I haven't taken off the other head yet - too pissed off, but I reckon 1 pot is damaged due to 1 spark plug electrode being flattened. I'll post pics when I do.
Mate suggested I fit a small block chevy in place of a Rover mill, but I'm half way through the build of a Cleveland powered Minor, so will persevere with a Rover in this one.

Pete

its definitely all a bit odd, one of the damaged chambers is virtually carbon free by the looks of it while the others are fairly sooted up.

Are the valve seats still in place?

If they moved there would be debris that would cause that damage

Ian

I'll take the valves out tomorrow - never thought of that one.
Could easily make this thread into a competition - winner gets the engine

Pete

Is it me or do those valves look recessed into the heads? is there a bit of valve resession going on with the lack of lead in the petrol ? john

These heads have been run for a total time of 1 hour to produce this damage. They were slightly surfaced, had the valve seats recut (3 angle by well known company up here), and had new valves and springs fitted. I also fitted a set of almost new rocker shafts and rockers (got them years ago).The car did about 1 mile on the road when I was testing it, remaining time was ticking over with a few blips of the throttle.
It ran perfectly well before I put these heads on
You can see why I was upset.

Pete

thats proper gutting looking at that