TB42 carbie getting old - poor compression - please advice
Welcome to the Nissan Patrol forum. To post a question and to see less adds on the forum then you will have to register
first. We are an easy going friendly forum so join in the conversations and feel free to ask any questions.
Become a forum sponsor for only $20 and see no adds with faster page loading times and many extras benefits.
TB42 carbie getting old - poor compression - please advice
Hi , my trusty TB42 carbie is getting old. The 1989 GQ safari has done 400k , not sure about the engine.
Over the last year or so it slowly lost its interest in climbing the steep Mountains of Warrumbungle N.P. - the engine still runs beautiful steady. A joy to listen to. No real oil loss - barely worth topping up between oil changes. But the torque going uphill is gone.
I run DUAL FUEL , 90% on Gas.
Today did a compression test and spark plug check , hope that tells it all to the specialists between you:
Cylinders from front to rear - 1 __ 6
Cyl 1: 120++ PSI , spark plug almost clean , just very slight black sooth over a very thin layer creamy brown - blue spark.
Cyl 2: 100++ PSI , spark plug almost clean , just very slight black sooth over a very thin layer creamy brown - blue spark.
Cyl 3: 120 - - PSI , spark plug very dirty , a brownish scale all over , red spark.
Cyl 4: 120 - - PSI , spark plug reasonable clean , just very slight black sooth over a very thin layer creamy brown - blue spark.
Cyl 5: 80 PSI , spark plug a little blackish - blue spark.
Cyl 1: 100 PSI , spark plug a little blackish - blue spark.
As said negligible oil use , barely worth topping up before oil change.
A small amount of coolant use. I suspect it leaves mostly via the old expansion bowl. Maybe 4 litres over 10000 km or one year for me.
I drive only medium long distance as we live 45 km from town and go there only once a week. Very very few short trips on the large property.
WHAT DO YOU SUGGEST:
Just the head a reconditioning ?
Get rid of the carbie setup and get a EFI setup ?
As said I run 90% on LP gas .
I also run on an Auto gearbox , convenient but the 3 gears are not my favorite in the mountains here.
Gas is hard on valves. One easy test to see if it is rings is to squirt a smidgen of oil (not too much )onto the cylinder wall and crank it over a few times then do another compression test. If it rises significantly the rings are shot. If not it will be a problem with a valve.
Last edited by mudnut; 21st October 2019 at 06:14 PM.