KR issues

I bought a 2nd hand Kr engine (without proof of running ) and got it fitted in my Mk1 Cabby.
Engine is fitted with twin 45's upon first startup the cooling system was bled, went down last night and coolant system was empty. Refilled and bled and noticed oil pressure light was flashing so I hooked up my VDO oil pressure gauge as a backup. When warm the car read 2 bar, the coolant system seemed to build up way too much pressure and then the oil pressure dropped to 0 on my VDO followed by the expansion cap venting the coolant all over the floor.

Anyone have any suggestions? I think I may need to source a new engine, would I be better off finding another KR or going ABF?

Taking the events literally, it seems you have (at least) 2 problems:

- dumping the coolant
- no oil pressure

The no oil pressure could be something as simple as a poor connection or loose wire. You'd need to be starved of oil or the oil pump fail, to go quickly from having pressure to no pressure. Obviously there's a number of things to check out there.

Venting the coolant - could be many things, eg cap not fitted right, not bled properly, overfull, etc etc. Or it could be head gasket failure.

Just to add, it might be the oil cooler too - if that fails internally, then oil and coolant will mix - what's the oil and remaining water like, does it look like there's cross contamination - if so, suspect the oil cooler or head gasket failure.

Here's a starting point but there's lots of other things to check:

- check for oil in the water
- check for water in the oil
- check to see if you've lost any oil (low on the dipstick)
- compression check - you don't even need a gauge, you can hear if there's a big difference in the compression between cylinders just by turning it over on the starter.

I think I can rule out the wiring to the sensor as the VDO was fitted after the dash warning light (sender and gauge both known good items) also the oil pressure senders in the engine are new both high and low.

The oil on the dipstick looks very clean and no apparent level loss. Again no emulsification under the oil cap.
Unfortunately no water left in expansion bottle to check for cross contamination.

I think I will need to get my hands on a compression tester to get an accurate reading.

Can you force the coolant around the engine and back into the expansion tank? (When there is water in it obviousy) is it just the cap it is coming from? 

Cheers for the replies. Managed to conduct a pressure test which resulted in 175 psi across all 4 cylinders (dry) didn't bother with the wet test as deemed this to be acceptable.
Noticed the top end was very noisy while cranking and decided to pop the rocker cover off. To my surprise it was very dry. Looks like the oil pump has failed and is not circulating around the engine which would account for very low pressure.

I'll pull the belt and run the intermediate pulley to confirm but I believe it's new engine time.