hello ! Aircooled 81 engine rebuild 2.0 cu

[jamiesgoingcampin]

I've not driven my van much , it's been a restoration project , carbs were running Rich and the engine was burning a lot of oil , so engine out , stripped down , valves worn , guides worn , heat exchangers melted inside , go to order new valves and guides , and the cylinder heads have a different ratio of size there 18.00 cc cylinder heads with a bigger intake valves and bigger exsaust valves but the ratio of differance between the two means the heads might tend to overheat , ? Has anyone had any experience of 1800 heads on a 2.0 engine ,recipe for disaster also the od of the guides are massive , heads not cracked tho thanks for any advice ,

[bigherb]

Only the early AP 1.8 had larger valves 41mm in and 34mm ex against the later AP & CU 39.3 in 33mm ex.
The heat exchangers use different port mountings oval for 1.8 square for CU, round port heat exchangers don't fit CU engine fan housings.

[jamiesgoingcampin]

Ok thanks ,I'm going to try and upload some pictures to try and explain , thank you