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Donziweasel
08-01-2006, 06:03 PM
As I continue to try and set up my Classic 16 for high altitutde (between 5000 and 7000 ft), a freind who has a lot of experience at high altitude settings, suggested that I advance the timing on my 5.7L mercruiser from 8 DTDC to 12-13 DTDC. Any input anyone?

mrfixxall
08-01-2006, 06:40 PM
You will move your rpm band down (more low end torque) and loose on the big end,also it may detonate and pound the valves out ot the head...

My suggestion leave it alone and rejet for your altitude....

MOP
08-01-2006, 07:15 PM
All ignition packs are not equal!!! Always set you timing at top time, 32 degrees is good you may be able to push it to 36 but that is pushing it and scary. I have seen 32 degrees with base timing showing anywhere from 7 to 11, if you have a pack the reads low on the bottom but goes higher on top all of what Mr Fixit says can happen.

Phil

Donziweasel
08-01-2006, 07:20 PM
This is not the only person who has mentioned advancing the timing at this altitude. I am down 17-20% of my hp and down 700 rpm's. By the way, anyone ever replace a 5.7L with a 300 Mag MPI. The fuel injection could really help with the altitude changes. Any problems with this conversion?

mrfixxall
08-01-2006, 08:04 PM
This is not the only person who has mentioned advancing the timing at this altitude. I am down 17-20% of my hp and down 700 rpm's. By the way, anyone ever replace a 5.7L with a 300 Mag MPI. The fuel injection could really help with the altitude changes. Any problems with this conversion?

Talk to DonCig,i think he has a complete 350magefi forsale still..i think he wanted 2500 for the complete pkg...

p.s. in reguards to jetting,,one of my cust moved to cali with his hallett and had the same problem your having..he didnt have enuff air to consume the fuel he was putting through his engine..he flew me out their i brought my jet kit and walla i rejetted his carb and regained the 400 rpm he lost.