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Spitfire 76 Spit 1500 almost there

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Billy_Bob

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So I have been working on my wife's Spit for the last couple of days...and I gotta tell ya, that little 4 banger has more "Umph" than I would of expected. Although....I was not able to get it completely right....
New plugs, gapped to .025, new filters, (air and fuel), fresh oil, timing set, checked plug wires, (Odd set), and now it runs ALOT better than when we got it. BUT!...(there is always a catch), it still has a kind of "misfire" sputter between 2000 and 3000 RPMs. Below and above....pulls nice and runs smooth.

Old plugs showed it is running VERY rich...although the front plug wasn't coated as much as the other three.

I haven't gotten into the carb yet but the PO said he had adjusted it as best as he could but he didn't spend alot of time on it. (Original Carb) I don't have the carb adjusting tool, (YET!), so I decided it was best to leave it alone as it is running, so I didn't want to mess it up. And it does have oil in it as well.

Thoughts? Tips? Tricks? Rants?

Thanks everyone!
 
My 1st thought is that maybe you should recheck the valves. If the plugs are showing uneven amounts of gunk on them, then the valves may not all be set right.

You already said the carbs running really rich right now, so an adjustment to that should solve the lot.

Have you done a combustion chamber compression test?
 
Nope...No pressure check....yet. I will go across the road and borrow the neighbors gauge.

As for the valves....now I regularly check and adjust them on my motorcycle and my ATV's.... How difficult is it to do on the Spit?

Engine isn't much bigger than that of my bike so.... :laugh:
 
The valves are easy to do. Remember the rule of nine.

Try to find one of the new silicone gaskets for the valve cover.
 
billspit said:
The valves are easy to do. Remember the rule of nine.

Try to find one of the new silicone gaskets for the valve cover.
Click to expand...


OK...I will admit that this is my first, (or actually HER first), British car.... I have always played with American muscle cars and trucks.

Rule of 9? Ummm Is there another "Rule of 9" other than the mathematical one? Or is there some way to apply it here that I am missing? :crazyeyes: :confuse:
 
Billy_Bob said:
As for the valves..... How difficult is it to do on the Spit?
Click to expand...

Lets put it this way, Air cooled VW's and ATV's are harder. Nothing different about the procedure, just Spits are easier to get to and work on. Don't forget to check it twice, and don't be forceful... but you already know that :smile:
 
OH! Quick side note here... don't forget to remove the negative side from the battery! I actually had an old VW start on me once from cranking the engine by hand... Maybe that's what I get for adjusting valves while the engine is still hot... but that's when I was always told is the best time to do it.
 
pjsmetana said:
I actually had an old VW start on me once from cranking the engine by hand... Maybe that's what I get for adjusting valves while the engine is still hot... but that's when I was always told is the best time to do it.
Click to expand...

Um if it was an aircooled VW the manual is very clear that they are to be adjusted COLD. In fact virtually EVERY spec for valve lash is to the best of my knowledge with the engine at room temp. If you adjust them to the spec with the engine hot they will be way to loose and clack away since they will be way to loose.
 
Well....Valves checked out...no adjustments there. New plug wires arrived today...I will put them in when I get home. At least I can get rid of the one wire that doesn't have much of a boot left on the plug end.
And in the process.....I started poking around...Hmmmm Where does this vaccuum line go that is piched and taped off? I also looked real quick at the cold air valve in the end of the air cleaner, tube thingy. Could the "extra" vaccuum line that is taped off go to that? There is a line next to the blocked one that is for the vaccuum advance on the distb. But this one is just terminated.
 
It could be part of the emission tubing. There is a vent tube from the gas tank that goes to the charcoal canister. On mine it was pinched off and when I ran for a while the car would just die and not start for a half hour or so. No vent to the gas tank so vacuum would build up and cut off fuel flow. Pop the gas cap and it would start.
 
70herald said:
Um if it was an aircooled VW the manual is very clear that they are to be adjusted COLD.
Click to expand...

Pfft, Manuals... I followed the teachings of a grandfather. Granted, he was known to be wrong from time to time... Like that time he went to jump the Rail Bug... "Oh I'm sure it will fit between those trees before I land!"
 
eejay56 said:
It could be part of the emission tubing. There is a vent tube from the gas tank that goes to the charcoal canister. On mine it was pinched off and when I ran for a while the car would just die and not start for a half hour or so. No vent to the gas tank so vacuum would build up and cut off fuel flow. Pop the gas cap and it would start.
Click to expand...

This is definately a vaccuum line. Can't really tell where it comes from tho. Is is mounted on a bracket about 2 inches in from the cold air valve. it is mounted on the bracket next to an identical line that goes to the distributor.
 
Well the new plug wires are in...and I must say it did improve...BUT!!...That stinking "chug" is still there..only not as much. Seems to only be between 2000 and 2500 RPMs. I am thinking of going back to the timing and spend more time on that to see how it does. I turned the Distb Clockwise and the rpms came up, but then I stopped cause I didn't want to have the car idle so high...(The Homer in me just went DOH!) Guess I should let it come up then turn down the idle screw.

So anything else I should look at if that doesn't clear it up?

How tough is it to adjust the carb? I know I need to get the "special tool", (to go along with my "Special" helmet), to make the adjustments... Just haven't done that before on this type of carb. Or should I just roll it into a shop and let them deal with it?
 
You should spring for a timing light. The book says 10 BTDC@800 RPM. Most people find that it will run better advanced from that. Start there and advance 2 degrees (adjusting idle as needed), drive it to test, rinse, repeat until you find the sweet spot. Too much advance can be harmful if you start to get predetonation(pinging). I run my(not stock)78 at 16 degrees. Can't help you with the mystery hose, mine is desmogged and has only the one line carb to dist. A vacuum leak can cause problems so you should get to the bottom of that. And do adjust valves cold.
 
Its funny you should say that...I was just thinking....Wait! I have a timing light! Sitting in a box buried in the back of my tool room. Guess it's time to start digging!.

(It's been a rough week.) :nonod: :rolleyes: :crazy:
 
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