Tuning the carbs and eventually timing Jag 420
#1
Tuning the carbs and eventually timing Jag 420
Hello,
So I have finally had some life out of the engine, it fires up, but then dies quickly.
I have rebuilt the carbs and cleaned up the distributor.
It seems like there are too many possible adjustments to get this dialed in.
I was able to set the point gap, which sounds like nothing, but I had to rotate the engine by hand pulling on a fan belt to get the points to the fully open position.
I have not moved anything related to the advancing and retarding the timing. I do not want to touch that until the car engine runs.
I am thinking that the starter carb needs some type of adjustment.
I also think the mixture setting and low speed adjustment need tuning too.
There is also the linkage screw that needs to be set.
Right now I can not tell if it stops running because of too much or too little fuel.
Also not sure how the vacuum figures into getting it going.
Also if there are any wires that could contribute to this issue.
So it starts. I can push slowly the accelerator , it might accelerate a bit, then die.
If anyone has a sort of step by step procedure to recommend, I am open to that.
Thanks
Jimmy
So I have finally had some life out of the engine, it fires up, but then dies quickly.
I have rebuilt the carbs and cleaned up the distributor.
It seems like there are too many possible adjustments to get this dialed in.
I was able to set the point gap, which sounds like nothing, but I had to rotate the engine by hand pulling on a fan belt to get the points to the fully open position.
I have not moved anything related to the advancing and retarding the timing. I do not want to touch that until the car engine runs.
I am thinking that the starter carb needs some type of adjustment.
I also think the mixture setting and low speed adjustment need tuning too.
There is also the linkage screw that needs to be set.
Right now I can not tell if it stops running because of too much or too little fuel.
Also not sure how the vacuum figures into getting it going.
Also if there are any wires that could contribute to this issue.
So it starts. I can push slowly the accelerator , it might accelerate a bit, then die.
If anyone has a sort of step by step procedure to recommend, I am open to that.
Thanks
Jimmy
#2
i would turn on the ignition and note if the fuel pump was working or not, although i suspect it is or otherwise the engine would be unlikely to start at all. and then i would remove a floatbowl lid or two and visually inspect for gasoline. there are other ways to do this BTW that don't necessitate removal of the lids.
and the fact that it starts would indicate to me that the starting carb was probably not the problem, although it could be. if the starting carb is not working you should be able to keep it running on a summer's day by revving the engine until you see the temp needle move off it's resting mark though.
i would also be interested in how many times it would start and then stop and the interval between the start and stop and the quality of running when it did start.
the pistons in the SU's could be stuck too. and if so, there would be little enrichening on acceleration and could stall the engine...maybe. although you'd think that if the accelerator was pressed slowly enough it wouldn't make much difference.
i doubt if it's a very serious problem and others should have more and probably better ideas as to what to do.
and the fact that it starts would indicate to me that the starting carb was probably not the problem, although it could be. if the starting carb is not working you should be able to keep it running on a summer's day by revving the engine until you see the temp needle move off it's resting mark though.
i would also be interested in how many times it would start and then stop and the interval between the start and stop and the quality of running when it did start.
the pistons in the SU's could be stuck too. and if so, there would be little enrichening on acceleration and could stall the engine...maybe. although you'd think that if the accelerator was pressed slowly enough it wouldn't make much difference.
i doubt if it's a very serious problem and others should have more and probably better ideas as to what to do.
#3
Join Date: Nov 2012
Location: Joyner, Queensland, Australia
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Disconnect one of the fuel lines to a float bowl and make sure that there is a solid flow (into a container.)
If it is just a miniscule trickle then there is possibly a partially blocked fuel filter, damaged fuel line or a fuel pump not doing its job.
A miniscule trickle allows fuel to build up in the float bowl and engine starting but cannot keep filling the float bowl as it empties and the engine dies.
I have just been through this in a MK2 where some previous owner put an extra in line filter where the hard line exits into the engine bay. It was really blocked!
If it is just a miniscule trickle then there is possibly a partially blocked fuel filter, damaged fuel line or a fuel pump not doing its job.
A miniscule trickle allows fuel to build up in the float bowl and engine starting but cannot keep filling the float bowl as it empties and the engine dies.
I have just been through this in a MK2 where some previous owner put an extra in line filter where the hard line exits into the engine bay. It was really blocked!
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Schmitty (09-22-2024)
#4
Thanks to both of you.
I will be checking the fuel supply as you both suggested.
In the meanwhile, I discovered a large oil leak as I try to start the engine.
Need to look at that first as it is making a mess.
Regarding the fuel pumps, they look rather new, and I was surprised that they still worked.
I do not have a fuel filter installed, only the glass jar, maybe some bits have got into the carbs.
Picking up the filter next week.
Reminding myself, it is the journey that is the fun!!
Jimmy
I will be checking the fuel supply as you both suggested.
In the meanwhile, I discovered a large oil leak as I try to start the engine.
Need to look at that first as it is making a mess.
Regarding the fuel pumps, they look rather new, and I was surprised that they still worked.
I do not have a fuel filter installed, only the glass jar, maybe some bits have got into the carbs.
Picking up the filter next week.
Reminding myself, it is the journey that is the fun!!
Jimmy
#6
i think you'll find, when setting the points gap, that removing all the spark plugs first will make life a lot easier...for two reasons.
if turning the engine with the starter, the engine will be less likely to stop at the same rotational position each time. increasing, dramatically, the chances of it stopping at a convenient location. and if turning the engine by hand, it will make it much easier to do it if using the fan.
if turning the engine with the starter, the engine will be less likely to stop at the same rotational position each time. increasing, dramatically, the chances of it stopping at a convenient location. and if turning the engine by hand, it will make it much easier to do it if using the fan.
Last edited by hueyhoolihan; 09-22-2024 at 09:02 AM.
#7
i think you'll find, when setting the points gap, that removing all the spark plugs first will make life a lot easier...for two reasons.
if turning the engine with the starter, the engine will be less likely to stop at the same rotational position each time. increasing, dramatically, the chances of it stopping at a convenient location. and if turning the engine by hand, it will make it much, easier to turn the engine with the fan.
if turning the engine with the starter, the engine will be less likely to stop at the same rotational position each time. increasing, dramatically, the chances of it stopping at a convenient location. and if turning the engine by hand, it will make it much, easier to turn the engine with the fan.
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#8
#9
Good grief, setting the point gap by turning the engine via the fan blades... ouch! You need one of these:
Amazon.com: Performance Tool W80586 Heavy Duty Remote Starter for Car and Truck Engines with Push-Button Switch and 5-ft Wire Leads , Black : Performance Tool: Automotive
Amazon.com: Performance Tool W80586 Heavy Duty Remote Starter for Car and Truck Engines with Push-Button Switch and 5-ft Wire Leads , Black : Performance Tool: Automotive
#10
Problem with this on the Mk2 and S Type the gap between the crank bolt and the back of the radiator is tight and unless you can find a really thin socket and bar you will struggle. I have a ring spanner with an off set head that goes on quite nicely.
#11
#12
Hello all,
To those of you who added comments to getting the points to line up on the high point, you are all correct.
Using the starter for me, it never landed on the right spot.
I did remove all the spark plugs, and with the loose fan belt it was easy to rotate into the right position.
And in no way can you get a common tool onto the crank shaft bolt.
I ramble on here!! lets move on....
To those of you who added comments to getting the points to line up on the high point, you are all correct.
Using the starter for me, it never landed on the right spot.
I did remove all the spark plugs, and with the loose fan belt it was easy to rotate into the right position.
And in no way can you get a common tool onto the crank shaft bolt.
I ramble on here!! lets move on....
#13
So now the bigger problem is the Oil Leak.
Seems to come out fast when engine starts. And it appears to leak between the motor and the transmission.
I am stopping for now. I will have to investigate next weekend for the source of the oil leak. Not liking what I expect to find out.
Also I think I have covid, so I am feeling rather sick.
Cheers
Jimmy
Seems to come out fast when engine starts. And it appears to leak between the motor and the transmission.
I am stopping for now. I will have to investigate next weekend for the source of the oil leak. Not liking what I expect to find out.
Also I think I have covid, so I am feeling rather sick.
Cheers
Jimmy
#14
Could be a rear main leak, or it could be the cam oil feed lines, those are at the rear of the engine. The rear main seal is a rope seal, and if the car has been sitting for a very long time it will leak. They usually leak less when the engine gets running and is hot and has some driving time on it. As the seals dry out, the do shrink a bit. Unless it's massive, I wouldn't worry about the leak too much right now. If it is in fact the crank seal, that's a lot of work to replace.
Last edited by Jagboi64; 09-22-2024 at 03:53 PM.
#16
#18
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Glyn M Ruck (09-23-2024)
#20
Join Date: Nov 2012
Location: Joyner, Queensland, Australia
Posts: 979
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No
I can't see the feed line in your pages.
It most likely will be in an exploded diagram of the cylinder head.
It is a solid line which exits on the left-hand side of the cylinder block close to the rear and then goes up to bolt on to the rear of the cylinder head in two places.
It feeds oil to the camshafts. It is notorious for oil leaks.
I can't see the feed line in your pages.
It most likely will be in an exploded diagram of the cylinder head.
It is a solid line which exits on the left-hand side of the cylinder block close to the rear and then goes up to bolt on to the rear of the cylinder head in two places.
It feeds oil to the camshafts. It is notorious for oil leaks.
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Peter3442 (09-24-2024)