3.9 New Build - Carb Issues
Posted: Thu Mar 08, 2018 11:34 pm
Hi,
Although I did a top-end rebuild 8 years ago on the original 10.5:1 3.5 in my '73 P6B, the rest of the engine has been getting pretty tired since.
Top-end work at that time ended up with '89 Range Rover heads, 3.9EFi cam, JP timing set, K&N's. Still on twin HIF6...set up and dyno at Peter Burgess with BCA needles gave 146HP at the wheels, which works great for me and the occasional road use I give the car.
I've now built up and just installed a 3.9 with nearly-new 10-bolt block, Crower 50229, and Cloyes Street set from Paul at V8 Tuner. Same heads. HIF6's retained (for now?) but setting the jet heights to the book-plus-a-tad (2.5-3 turns of the screws from jets level with bridge), I couldn't get the tickover speed down below 1100 even with the screws off their stops. Suspecting air leak?....not found it yet though.
Car MOT'd OK yesterday (my usual friendly guy), but I asked him to put the probe up to check CO......1.0% ??? Does this say air-leak?
I'll get the car back up to Peter Burgess once I've got it set up somewhere near.
Thoughts on the HIF6's also welcomed!
Stan
Although I did a top-end rebuild 8 years ago on the original 10.5:1 3.5 in my '73 P6B, the rest of the engine has been getting pretty tired since.
Top-end work at that time ended up with '89 Range Rover heads, 3.9EFi cam, JP timing set, K&N's. Still on twin HIF6...set up and dyno at Peter Burgess with BCA needles gave 146HP at the wheels, which works great for me and the occasional road use I give the car.
I've now built up and just installed a 3.9 with nearly-new 10-bolt block, Crower 50229, and Cloyes Street set from Paul at V8 Tuner. Same heads. HIF6's retained (for now?) but setting the jet heights to the book-plus-a-tad (2.5-3 turns of the screws from jets level with bridge), I couldn't get the tickover speed down below 1100 even with the screws off their stops. Suspecting air leak?....not found it yet though.
Car MOT'd OK yesterday (my usual friendly guy), but I asked him to put the probe up to check CO......1.0% ??? Does this say air-leak?
I'll get the car back up to Peter Burgess once I've got it set up somewhere near.
Thoughts on the HIF6's also welcomed!
Stan