fuel issue

sammaw@bellsout · Apr 30, 2008

Hi Guys,
I think I have sorted out the igintion on the SIV, but am puzzled by a lack of fuel to the engine. The carb is getting a good gas supply, to the point of overflow thru the manifold drain, but the plugs are dry with no firing. There seems to be good suction thru the carb air intake and I dont see any apparent vacuum leaks.

I would be grateful for any suggestions

64beam · May 1, 2008

Hi Sam,

If your fuel supply is OK and there seems to be good suction, it sounds like your timing is out. Try readjusting the timing as it sounds like it is not firing at the correct point.

Good luck, Robin.

Chazbeam · May 1, 2008

compresion?

During my learning curve on my alpine i learned a few good lessons the hard way and discovered that the valves need to be checked for proper clearance. if they are not seating well you get week compression on idle and startup especially when hot as the expansion is very marked on these engines. this will not draw gas into cylinders well. but your problem may be more around spark. check out your firing order and point gap as well as the resister to your coil. i had mine go bad recently. also check that the condenser inside the distributer is OK. if this shorts you will get no spark. a test light can reveal wether you have voltage to the coil and if the distributer is working. also a timing light can easily be used to test spark.
hope that helps best of luck
Chaz

Chazbeam · May 1, 2008

flooding?

Also i had a flooding problem when i did not have the ignition and valves correct. you know that anxious pumping the peddle too much just floods it out and the mixture is way too strong to get it going. On mine i found one short pump and then 1/4 throttle opening starts it every time. but still with all the setting correct it cant wait to start.

best
chaz

sammaw@bellsout · May 1, 2008

Thanks for your help. We went thru the ignition side and are satisfied with the timing settings and the strength of the spark. It just doesn't seem to be getting fuel. The plug is dry after many attempts to start, with no gas smell on it. I even got my nose close enough to the plug hole to sniff the cylinder, just couldn't smell any. Also tried ether. Could something be "cruded" up in the manifold. It has been over 5 years since this car has run.

Thanks guys

sunbeam74 · May 1, 2008

Which carbs are these?

Steve

dannym · May 1, 2008

Sam,
You have mud dauber wasps in your part of the world? I bought a tractor years ago that the mud daubers had built a nest in the carb venturi, completely sealing it off. There was a second one up in the manifold that I could never see, but knew it was there because of the dirt I washed out with the hose. It had also set for a number of years. This was a bit difficult to find. Alternately, I suggest you spray a small amount of starting fluid into the carbs while a helper cranks the engine. Take care not to flood it with ether as its a bit hard on the engine. If it's a fuel issue, it should start or at least try to. This is the only way I can make my daughters Alfa run, but I will eventually get that dang fuel injection system sorted out.
Good luck,
Danny

Bill Blue · May 1, 2008

Mud daubers? I had that thought, but discarded it when I realized he said he had suction at the carb and gasoline running running out of the intake manifold.

Sam, when is gasoline running out of the carbs into the manifold? Is it from choking? Pumping the accelerator? Running out of the carbs all the time?

Nice little mystery.

Bill

sammaw@bellsout · May 1, 2008

I like the mud dauber idea, nature fights back, but it did have a filter attached and looks clear down the throats (weber DGR).

I did try different combinations of throttle pumping, choking, yelling, cussing, praying, begging, etc trying to get it to hit, and noticed the fuel running out when I got out of the car to stare down the disagreeable engine.

One thing I have noticed is that the valves seem to have a lot of play in the closed position. I am wondering if the valves may not be opening enough to let the fuel/air mix in. I know you are supposed to set the valves while the engine is hot, but if I adjusted them while its cold, would use a different feeler gauge setting, since I am not compensating for heat expansion?

Thanks for your ideas

Bill Blue · May 1, 2008

If you set the cold valve lash to specification, it should be good enough to get it started. Specification plus 2 thou should be very close to correct after the engine warms up.

Does the single carb manifold have a drain?
Bill

sammaw@bellsout · May 1, 2008

yes, it has a drain. I think the manifold is the same one that the solex used. It has been discussed in some other threads on the board.

Chazbeam · May 2, 2008

compression check?

Hi. wow wasps? I never would of got that one right!
Pardon my nieve atempts at help. it seems you all are very knowlagable with the sunbeams. But I was thinking about this mystery a bit more and because you said the fuel was in the manifold yet not cylinders i thought maybe you have a stuck open float valve.
It would explain why the manifold gets too much gas with the pump just sqwerting it in. A posibility?. Also i mentioned firing order. when i put mine back together i had that wrong after a few attempts to start her i realized it. I had similar symptoms. And a compression checker would take some guess work out of the valves idea.

anyway i wish you luck.

Chaz

sammaw@bellsout · May 3, 2008

update

I think I know why I was not getting anything to fire. I decided to pull the head, and first noticed the bolts released easy, too easy. I thought it would be tough to get the head off, but a couple of yanks and an open hand karate chop later it lifted off. The #1 cylnder was full of gunk, looked like dehyrated anti freeze. I got the fear, you know, the one you get when seeing money blowing away in the wind. But I dont think all is too bad, as the gasket came right off without to much effort. The water channels looked pretty good, the gasket was not blown. I turned the head over and noticed that it had been machined in the past, but what a rough surface. You could catch your finger nails in it with the ridges.

My opinion is that the head was never torqued down properly and water(steam) was passing right by the gasket into the cylinders. I am amazed it ran the last time it ran. Must be a tough little engine. The cylinders loked ok, no rust, smooth to the touch.

It will be taken to a shop tomorrow to be cleaned and magnafluxed to rule out a crack.
I intend to go ahead with rings and bearings since I have gone this far.

A couple of questions though, the curved water passages on the head were a little rough around the edges, but did not look extended or deformed. Is this ok?
There seems to be plenty of room to plane the surface again, to smooth it, but should I dictate how many mils to remove or is this a machinist decision?

As always, thanks for your input.

Sam

V_Mad · May 3, 2008

If its been standing, the valve seats could have corroded, and may not be sealing, and there will be little or no compression. Check this while the head is off by inverting it, then putting some fluid in the chambers to see if it leaks out.

Bill Blue · May 3, 2008

In a situation like this, where you are not trying to increase compression ratio, just tell the machinist to clean it up. If he has an I.Q. over 50, he will remove the smallest amount possible. He should be able to inspect the head and give you an estimate how much will need to be removed.

Bill

lemansvk · May 3, 2008

From your description if catching your nails in the surface grooves, this is far too rough. Downunder, machinists recognise a term 'surface grind' which means cleaning up the surface with minimal removal of material (as distinct from 'shaving' it).

Standard, unground heads have two "quarter moon" recesses on one side of the head face - if there is no evidence of these, the head has been ground a fair bit in the past and you will want to have the minimum of material removed this time, to avoid increasing compression ratio too much. Of course if you do the well known "Vizard" modification this will counter the removal of surface material.

The crescent shaped water passages typically have some corrosion - a good way to see if they are OK is to check them against the corresponding holes in a head gasket.

Cheers, Vic

sammaw@bellsout said:
I turned the head over and noticed that it had been machined in the past, but what a rough surface. You could catch your finger nails in it with the ridges.

I intend to go ahead with rings and bearings since I have gone this far.

A couple of questions though, the curved water passages on the head were a little rough around the edges, but did not look extended or deformed. Is this ok?
There seems to be plenty of room to plane the surface again, to smooth it, but should I dictate how many mils to remove or is this a machinist decision?

As always, thanks for your input.

Sam