Ask a Car Mechanic and Get Answers to Your Car Questions ASAP
hi, my name is XXXXX XXXXX i'll be happy to help you with today.
as you might imagine its been a while since i worked on a spitfire lol
please tell me about the carburetion (for the life of me cant figure out how to spell that lol)
a big 2 barrel, 2 i barrels?
anyway how about a big vacuum leak near cyls 3 and 4?
This is a Zenith Stronberg CD150 - single carb.
What could cause the vacuum leak?
sorry i was distracted by the picture.
very pretty car.
i guess in one sense a 1 barrel simplifies it.
so one and two plug color is ok and 3 and 4 are white?
If it ran it would be even better. I have changed much of the rubber things and now have new tires and a new rear spring and rear shocks and sway bar bushing in the front.
Let me go look at the older plugs, just a minute
ok, if i'm with you this all started with a carb rebuild?
i'm still thinking vacuum leak.
spray carb or brake clean all over the intake manifold but not in the carb, any change?
No the other way around
ok, so you rebuilt the carb in an attempted repair?
1342 on the firing order right?
I did replace the diaphram in the carburator with a new one.
bad intake manifold gasket between 3 and 4.
does it have air injection, god i hope not lol
Yes I did. I got an old carb so I could understand how it really went together and replaced the diaphram and cleaned the piston in the carb
thank god on the air injection.
so to summarize its running on 1 and 2 but not 3 and 4
so as long as the firing order is ok its fuel
try the carb clean deal, how are the brakes?
where does the vacuum line for the brake booster connect to the intake manifold?
Yes on 1 and 2 based on pulling the spark plug wires.
you get what i'm driving at.
gotta love this remote diagnosis.
the brakes work fine.
just to be sure 1342 right?
I do not believe there is any vacuum assist on the breaks
The firing order is 1, 4, 3, 2 actaually.
wow, no vacuum assist, must go better than it stops.
Photos of the distributor on other web sites are the same as the one in my car.
well i just looked it up, humor me try 1342
what have you got to lose.
i'll double check while you do that.
I have to press hard on the breaks,
it is 1, 3 4, 2 clock wize with the #1 in the 10:00 position
Also in this car if I remove the oil filler cap I can see the valve tappets and using the timing light wiht the cap off the valve tappets are all the way up, so closed when the spark is firing.
That is for the #4 cylinder
double checked 1342 looks right.
humor me, swap 3 and 4.
looking into the brakes/vacuum issue.
looks like you have an external vacuum brake booster, similar to the mercedes 190 sl.
its not between the master cylinder and brake pedal as on most cars
so, heres what i think, you either have a firing order issue 3 and 4 or a big vacuum leak at the rear of you intake manifold.
nothing else makes much sense.
what do you think?
so where are you anyway?
beautiful car by the way, did i mention that? lol
I am in No California.
How do I determine if I have a vacuum leak in the intake manifold.
spray carburetor cleaner or starting fluid all over the intake manifold near 3 and 4 if the rpm changes you've got a vacuum leak.
look for any hoses pipes etc that connect near the rear of the intake manifold, disconnect and plug or pinch off.
so, are you 100 percent sure on the firing order??
I have to try that in the morning as it is 11 here and will make too much noise. If the engin changes then I have to change the gasket.
The fireing order is as i described, Is it possible to add a photo so that you could help me verify?
11 hear to i'm in morro bay,
really humor me, swap 3 and 4.
vacuum leak beyond that.
cant think of anything else.
if i do you'll be the 2nd to know.
get some sleep.
talk to you tomorrow.
Gary, I will try these in the morning. I have attached an image of the distributor firing order - front of engin #1 to the left
great picture, you had me going at first with the oil filler cap in the rear lol
can you send a picture of the intake manifold?
OK, so I finally got back to the Spitfire 1500 with the apparent ignition issue.
I used carb cleaner on at the junction of the intake manifold and the engine block and the sound clearly changes. If I swap 3 and 4 there is not change in sound or behavior nor does the carb cleaner have an effect.
I guess then I have an intake manifold leak.
Guess I will try and tighten down the manifold bolts to mfg spec torque.
tightening it down probably wont help.
as you know english engines are notorious for poor mating surfaces.
your best bet is to remove the manifold and make your own gasket using rtv silicone or equivalent.
i think your good to go.
please take a moment to rate my seervice.
may the force be with you.
You are correct the bolts were no where near the 25 lbf feet of the spec and it did not help. It needs a new gasket as using the carb cleaner still makes a change.
I will try to make my own and if not then get a performance intake manifold gasket on the internet.
You have been very helpful. Tahank you an I will rate your service execelletn