Mark V - X 420G 1948 - 1970

MKV 3.8ltr engine timing and Lucas distributor.

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Old 02-11-2017, 07:07 PM
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Default MKV 3.8ltr engine timing and Lucas distributor.

Hello everyone.
Can anyone supply me any info, or links to info on the full tune up of engine.( timing, valve set and dizzy timing)
The firing order is, from flywheel end (No1) 153624.
I don't have any info on valve location.
I have used the exhaust ports as the valve location, (which can not necessarily be correct).
Valve location IMO is as follows.
NO1 NO2 NO3 NO4 NO5 NO6 cylinders ( NO1 being at the Flywheel End).
E I I E I E E I E I I E. Exh 0.015" Inlet 0.012"
I have set the valves using the 'on the rock' setup. Being No6 cyl valves on the rock, set valves on No1. No1 'on the rock', set No 6 valves. Then 2 and 5 and 3 and 4 cylinders.

I am also after any detailed info on the Lucas Distributor model DVX H6A Type GC.42
I have the points gap 0.012" and limited info on the micrometer adjustment for retard/ advance timing.
In the manual it reads as follows.
It is necessary to set correctly the ignition timing at the distributor before tuning the carburettors. Since if retarded or advanced too far, the setting of the carburettors will be affected.
Test the car on the road, and when the engine has reached normal operating temperature, set the fixed setting of the ignition timing on distributor so that , with the micrometer adjustment is in the neutral position, that is, with the datum line is on the zero mark, the engine just shows tendency to 'pink' on under full throttle under load at 1500 to 2000rpm, in top gear.
Where is the Zero line taken from, the alloy housing? There is retard and advance marked on the adjuster at the base of the 'dizzy cap'. I have attached some photos, hope these upload OK.
Cheers for now Rusty.
 
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Old 02-11-2017, 07:11 PM
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Default Its a 3.5ltr engine, pushrod type Not a 3.8ltr

Ooops incorrect engine size in title, 3.5ltr early pushrod type
 
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Old 02-26-2017, 07:50 PM
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Since I don't see an answer, I'll step out on the limb. I used to work at a Jag shop in the early 90s and we had a couple of these come through the door. I looked up the parts for points, etc. and the #s are the same for MK1 and 120. I would sync the carbs as close as I can before start up. Then, I would try .015 on the points and TDC 0deg on timing. Points then could be moved to the MK1 and 120 set of .025 if .015 does not help. I would not move timing from 0 unless you feel it is low after tuning carbs. Then feel the timing by feel and hearing. Most of that era were not advanced, just on 0deg TDC. Good luck! Larry
 
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Old 02-27-2017, 03:29 AM
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Cheers for the reply Jagfixer, I have just kitted the carbies, and new plugs and the like.
There is no timing marks on this 'ole donk', so will find TDC No.6 the old fashion way, nothing like a good challenge.
I have just finished overhauling the brake system, ohh thats another story.
Thanks again. Regards Rusty.
 
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Old 02-28-2017, 01:46 AM
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Default MKV 3.5ltr engine timing and Lucas distributor.

Cheers Jagfixer.
I will carry out a test and tune/ trial and see what outcomes I obtain. The car has sat for 5+ years so have had to do some required maintenance prior to fine tuning etc.
I have just finished with the brakes, that's another story! I will let you know what transpires. Thanks again Rusty.
 

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