Hello all
Recently purchased a Vitesse after my 3500se was written off. Vitesse engine was in bits and in need of rebuild so I fitted my reliable se engine with the injection set up etc till the other engine gets some attention. Runs fine but now has so much crankcase pressure my valley gasket split in two on road test The engine previously had inflated the valley gasket but it had severe cylinder leakage figures so ho hum that made sense. Why would my good engine do this now? Can't find any blockage in the breather system, so I must be missing something Any ideas what I can check?
Any help appreciated as I'm new here

Have you checked the firetrap (cylinder screwed to the rocker
cover) is clear, the pipe is clear and where it enters the plenum
is clear of oil sludge? Also check the breather on the opposite
rocker (plastic cover with foam insert) cover is clear.

Though with the problem you describe, there must be more
wrong than a blocked breather system?

Cheers all so far
Am going back to look with fresh eyes tomorrow
Feel I've checked everything but will kick myself when I find what I've missed

Where can you get the small breather filter from(the little plastic thing with the foam insert!)? I tried Rimmers & they dont have any...

Oh dear
Thanks Ramon and all for you're help and advice but I have run out of checks to do
I used this engine as I said as it was in my daily driver and runs sweet as a nut, no smoke and no oil use All I did was pop it into the Vitesse with the addition of the EFI system already there. This still ran sweet and went like a rocket compared to the ol' carb set up. Unfortunately it highlights some wear in the motor which was not apparent on the carb set up
Did a compression and cylinder leakage test on this today to find out that two cylinders are in desperate shape 80% and 88% leakage via the rings or bore wear etc Mostly 170 or 160 ish PSI but one with 100lbs and one with 70lbs!! I cannot believe this engine runs like a swiss watch yet has such a terminal problem Obviously I never checked it as I know the engine runs so fine
This was to be a temporary measure while I did the original engine properly, but I expected to make it to MOT!!
Looks like I'll put things on hold till the proper motor is sorted
Thanks again to all and I'll be sticking around

Another thought - the Rover Efi system was designed for a 9.75 : 1 compression ratio.

I'm no engine expert but what is the CR of your ex carb engine and would bigger bangs generated by more fuel and air from the Efi system cause a problem??

I had the problem in my old vitesse many years ago whhen I noticed oil was collecting in the well of the front of the engine. The flame trap was smoking like a chimney and the Leyland mechanic who looked at it explained that it was too much crankcase compression which caused emissions to blow past the piston rings (sorry if I am not detailed enough). The engine was not breathing correctly.

This caused the cylinder head gasket to leak oil which collected in the well at the front of the engine. As Ramon says, you can miss that little black rubber breather pipe (the mechanic who replaced the gasket etc. didn't clean this out as I found out later!).

My old vitesse engine was a well used lump, however, with indeterminate mileage and later developed a nasty ticking tappety sound later on, despite throwing money at it!