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Spitfire 6 shaky when stopped and holding brakes


chrysler49

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I have a 1949 Windsor with the fluid drive transmission. The car runs pretty well and is in excellent cosmetic condition. It has sat for a couple of years and i've just got it out and have been driving it over the past couple weeks. The car seems to shake when sitting at stop signs or just when I am stopped and holding the brakes. It will idle okay, doesn't die, but the shaking has me a little worried. I've made sure it has plenty of oil but have not checked the transmission fluid. Could it possibly be low on tranny fluid and be wanting jump out of gear when i'm holding the brakes?

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Could be an number of things, as keiser31 says plugs or wires could give you an ignition fault; bad carb idle mixture settings will also do it; and then there is the more expensive, sticky valve, due to sitting around which will do it.

Best start with spark plugs, remove them one at a time and see if they are clean or gummed up, does one have more deposits or different color deposits than the others? if so you have at least identified the problem area.

If the plug(s) are black and sooty this usually points to a carb mixture problem, if they are oily then you may have an issue with rings or valve guides.

Wtih the engine running, put your head under the hood at night, or find a dark corner of the shed, and look for blue flashes from the ignition wires or plugs, this is an indication of ignition component breakdown; replace wires or plugs as appropriate ( if you are in the shed keep proper ventilation in the area)

If no faults are found with the above, perhaps a cylinder compression test is required to establish the leaky / stuck valve issue.

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Here is one of my plugs. The rest of the plugs look identical. To me they appear to be worn, and as far as I know they could easily be 15 years old but i'm not 100% on that; I do know they are older. They don't appear to be too white from too much heat, at least to me anyway, but looking at the condition of these would you guys think it could be my rough idle problem? And does anyone think they appear more than just worn? I had someone confirm it had a slight misfire issue. I'll more than likely just change out all of the plugs to be safe anyway.

Sorry for the picture quality. The ipod I used to take the pics doesn't have the most impressive camera quality and the file sizes were too big with the digital camera.

post-76827-143138584458_thumb.jpg

post-76827-143138584464_thumb.jpg

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OK my first reaction is that the plug in right hand picture is black and sooty compared with the other, to me this indicates that plug is not firing or has been exposed to an excessively rich mixture.

If more than one plug is like that then I would lean towards a mixture problem, if only one plug is like that then I would think the plug, the plug lead or distributor cap have a problem.

The easiest way forward is to change all the plugs, particularly if they are old. Remember which cylinder the black sooty plug came from so as to investigate further if the problem still exists after installing new plugs.

Keep us posted :)

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Sounds like a miss to me. With the engine running pull the plug wires off one at a time. When you get one that does not make it run worse, that one has a miss. Check if the plugs are firing.

If it is not a misfire it may be a bad cylinder. DO a compression test to find out. That is if the miss is regular and always the same cylinders.

Might just be time for a tuneup. If you are old enough to miss Ed Sullivan you know what a tuneup is ha ha

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Guest Harold Phillips

One other thing to check is points, if out of adjustment could also be a cause of miss

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I did go ahead and buy all new plugs. If it still has an issue now i'll work down the line on what could be the problem. As I pulled each plug I had planned on gapping the new ones according to what the old ones were set to, but I did come across something. Four of six plugs are gapped at around .27, but then one is gapped at .30 and another at almost .35. I'm guessing this could have something to do with my issue, and still the fact the all the plugs are quite old. Does anyone know the correct plug gapping for a 49 windsor spitfire? I have my manual on order but it hasn't arrived yet.

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Dont get too fixated on plug gap, being out .005 or so will not be significant at idle. Install the new plugs, run it and post the results.

Working progressively through the information provided will ultimately solve the problem.

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Does it have a vacum leak? If it has vacum wipers the hose maybe perished or there could be a vacum leak around the base of the carb. Carefully spray some WD40 around the bottom of the carb while it is idling and if it speeds up that is your problem

It could also be sticky valves. A dose of MMO down the carb while it is running and some in the tank will certainly help the engine if it has been sitting for a while.

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