How to make her purr. Compression, ignition, carbs and idle questions

XK-Engine
#1

New to the forum. Have read a lot. See a lot of experience here. I have a number of questions. My 1960 MK9 idles rough and is lacking power. Left exhaust pipe is inconsistent, right pipe smooth.

  1. Compression 1-6= 90,138,105,115,130,140. Should I have valves ground?
  2. clearances 1-6 intake, exhaust = .006, .015; .004, .008; .005, .011; no clearance, .004; .002, .007; .004, .008 I will adjust clearances, but are they out so much as to effect running?
  3. Ignition. I have original looking wires, cap, and points, rotor, coil and Champion N5C plugs. I set the point gap and timing. I am thinking of replacing parts for reliability, such as Pertronix ignition, new cap, coil, wires and plugs. I read a way-too-long post of advantages. I want reliability and eliminate potential problems. I still have positive ground. Recommendations?
  4. HD6 Carbs. I put in a Facet Cube FEP42SV electronic fuel pump with filter because the old pumps crapped out. The PO put in a fuel cell due to rusty tanks. I put in new fuel, replaced the filter and cleaned screens, blew out carb jet and float valve. Set float level and adjusted jet housing even with the bridge. Checked butterfly sync, and equal intake flow. Started the motor and adjusted by tach and sound according to SU, Jaguar, and Kenneth Ball . Still poor idle and inconsistent flow from left tail pipe. What am I missing?.
    The motor has 49,000 miles on it. At 46K, the cylinders were honed, new oversize pistons put in and new gaskets and seals. I believe the engine can run as intended with the right care. I want her to run down the highway at 70-75 MPH. How can I get that to happen?
#2

When clearances are that out of whack, yes, it will lead to weak/uneven running.

Once adjusted, you then need to see why the compression is that low. Do a wet/dry test.

Lastly, welcome!

#3

Item 1 & 2
Firstly adjust ALL those valves, ESPECIALLY exhaust #1 and #3, that’s why your compression is low in those two cylinders, and why your car is running rough.
#1 exhaust valve will burn out if you leave it.
#2 inlet must be tapping to high heaven,
Oh yes , welcome.

#4

Welcome to our group. Watch a YouTube video on the operation of a vacuum gauge as a matter of education. It’s a much overlooked bit of kit but ideal for our dinosaurs. Can diagnose multiple faults from sticking valves to late ignition timing. Some of us are big fans. Agree with the other guys as well. Paul.

1 Like
#5

TIMING
GAS
ELECTRONIC IGNITION
NGK SPARK PLUGS
This will help you get there…
good luck
gtjoey1314

#6

Not before the mechanicals have been sorted.

1 Like
#7

do what is essential first, do what is relatively easy next…do "upgrade swap last…That means essential is adjust valves- confirm cam alignment, re-check fuel delivery, Next do the Easy which is replace plug wires (for wires…tho.a problem…if you will use distributor you want no resistance wire set, but if you use the EI module then you will need the resistance wires they recommend) , replace spark plugs, yes the NGK…as they have a wider heat range in a given plug ) and in my opinion do points-condenser-check vac , unit on the original distributor… set timing,…all before a swap to an electronic…so as to get it running nicely first. If all is fine…why swap now? Then Recheck compression and vacuum. Nic

#8

Nic, I think your route sounds best. It seems like the small benefits that may be gained by immediately putting in a EI are minimal. I am adjusting valves now and will just put in a set of NGK plugs for now. I know how to set points and timing. I have a 1960 MK9 3.8L with 9:1 compression. Glenn’s repair and tune up guide calls for Champion N5 with a .025 gap. Cross references call for NGK B5ES or B6ES. What would be your recommendation?

#9

The NGK B5ES is a step “hotter” than the B6ES. .I would install the 6… You don’t want too hot. NGK have a bit wider range within one plug than do Champion. you seem able in the valve adjust…(but there is a fine article-narrative of it in the archives…) .It usually ends up with two adjustments…but maybe you will be the lucky ONE.