Post by p5andrew on Oct 22, 2020 14:48:30 GMT
I undertook a complete bottom end rebuild of my engine earlier this year - reground crank/re-bored/uprated oil pump/new camshaft bearings etc., 9.35:1 pistons.
I am now planning to replace my original P5B heads, which have worn valve guides, valve stems and the usual absence of efficient valve stem seals as a result of which oil consumption is very significant. I have acquired a pair of completely rebuilt heads from a 3.9 which of course give me slightly larger valves and better breathing. Additionally, the heads have been fitted with new seats which are fine for unleaded (not that I have had any problems with the original seats on my heads). The new heads also have top hat seals to all valve stems. I also plan to replace the timing chain and gears while everything is apart. I have two questions;
1. While it is all apart I have been wondering whether to replace the camshaft and followers with a mildly uprated profile. My current camshaft has done very little work and is as-new as are the followers so wear is not an issue. What do others think? Is it worth it? If so, which profile? I do not have the slightest interest in increased high end performance. An increase in low-mid range torque would, however, be welcome. And most importantly, I do not wish to change anything which might have an adverse effect on smooth running.
2. Should I consider changing the carburetor needles to suit the improved breathing of the new heads and/or the change in camshaft? They are currently standard and I only rebuilt the carbs 3500 miles/6 months ago so all is as-new.
As always I would be very interested to know everyone's thoughts on this!
Andrew
I am now planning to replace my original P5B heads, which have worn valve guides, valve stems and the usual absence of efficient valve stem seals as a result of which oil consumption is very significant. I have acquired a pair of completely rebuilt heads from a 3.9 which of course give me slightly larger valves and better breathing. Additionally, the heads have been fitted with new seats which are fine for unleaded (not that I have had any problems with the original seats on my heads). The new heads also have top hat seals to all valve stems. I also plan to replace the timing chain and gears while everything is apart. I have two questions;
1. While it is all apart I have been wondering whether to replace the camshaft and followers with a mildly uprated profile. My current camshaft has done very little work and is as-new as are the followers so wear is not an issue. What do others think? Is it worth it? If so, which profile? I do not have the slightest interest in increased high end performance. An increase in low-mid range torque would, however, be welcome. And most importantly, I do not wish to change anything which might have an adverse effect on smooth running.
2. Should I consider changing the carburetor needles to suit the improved breathing of the new heads and/or the change in camshaft? They are currently standard and I only rebuilt the carbs 3500 miles/6 months ago so all is as-new.
As always I would be very interested to know everyone's thoughts on this!
Andrew
