Rebuilding the Autolite 1100

[Anonymous]

From the responses to my "Dirty Oil" post, it seems I should tackle the carb issue before I do anything else to correct my symptoms. It seems the carb is running rich.

I've attempted to adjust the choke, and the mixture screw which has had no effect except causing the car to stall during hard stops.

The engine idles fine around 700RPM.

The carb is a purchased TOMCO rebuilt.

Any suggestions?

 

[CZLN6]

Howdy Montego Man:

My only suggestion is to do a carb rebuild yourself. I'm not sure which carb you're dealing with, but all one barrels are relatively simply. Setting the float level and linkage is critical and it is important for you to understand the cause and effect of changes. A rebuild kit will have instructions and standard setting that work as designed in about 50% on the cases. We're probably the other 50% of the cases.

On a leaking carb, choke, gasket seals and gas and vacuum leaks are the biggest culperts.

Good luck.

Adios, David

 

[Anonymous]

What would be symptoms of a bad float setting? I am inclined to think that may be my culprit...

 

[mugsy]

If the float is too low, then the carb runs lean. If the float is too high, the carb would run rich.

My rule is if you rebuild a carb you should always put in a new float. They do sink. Second rule is that the float out of the box is not correct. You MUST check the level on any new float.

 

[Anonymous]

What is the procedure for adjusting the float setting? I have a rebuild kit, but I haven't opened it yet. Would the kit have those procedures or would the shop manual?

Thanks for the tips...

 

[CZLN6]

Howdy Back MontegoMan:

Open the kit and read the directions thoroughly.

Buy a can of carb cleaner. Clear a clean, well-lite place to work. Go slow and check all linkage and parts carefully when disassembling.

Most likely you have a sticking float or needle seat. Bhe needle and seat will be replaced with the kit. The float is reused. Inspect it carefully to make sure there are no leaks and that it is reusable. When reassembling make sure the float fulcrum and needle is lined up with the seat and there is no bind anywhere. Be very careful with placing the gasket. I use chapstick to help set and seat the gasket. A little is plenty.

Cleanliness IS next to Godliness in this case!. Use excessive care on reassembly. The standard setting in the kit directions is a good place to start. There is a measure in the kit. Once reassembled, on start up watch for any leaks and fix immediately.

That should get you in the ballpark.

Adios, David

 

[Anonymous]

David,

Thanks for your very helpful posts!

The handbook is excellent!

I hope the carb is my problem, sparing me from rebuilding the engine!

Jay

 

[mugsy]

Jay,

Typically floats are not included in rebuild kits. So you have to ask for it seperately when you order/buy the rebuild kit.

The rebuild kit should have instuctions on how to set the float. And "close" isn't good enough, take your time and do it right.

Hope that helps.

 

[Anonymous]

Here's a typical kit...$19.95

http://www.mustangsunlimited.com/itemdy00.asp?T1=901+01

r/
Steve-O

 

[Anonymous]

An update: I fired up the garage heaters yesterday and removed the carb from the intake. While doing so, I noticed the carb spacer was VERY LOOSE on the intake mount.

Although I still intend to rebuild the carb, would the improper seal have also caused my symptoms, or at least played a part in it the apparent rich condition?

 

[CZLN6]

Howdy MontagoMan;

Probably not. A loose carb spacer could have caused a vacuum leak, which would cause a lean condition. If you're concerned about gas in the oil, it's more likely a high float, a leaking needle seat, or a choke problem- or a combination of all.

Did you tighten up the spacer and try it? What happened?

On the dirty oil issue, if this is an old engine, ie- sitting alot, many miles, no regular maintainance, with lots of crud and varnish buildup, and you change to a modern, high detergent oil you will get a dark oil almost immediately. It will take several oil changes to get it to start cleaning up. If you suspect that this is the case, consider removing the valve cover and inspect the upper end. If you find caked on crud you are looking at the problem. If not look elsewhere. If it is cruded up the bottom end and oil pan is likely in the same condition.

While you have the valve cover off, remove and inspect the rocker assembly. Disassemble and clean it thoroughly. Clean up the whole inside of the valve cover too.

The adventure continues. Keep us posted.

Adios, David

 

[Anonymous]

David,

Thanks for the tip! And I will continue ahead with the carb rebuild looking at all those possible problem areas. The car is stored for the winter, so I am basing all my symptoms on my observations from last season's drives and until April, no way of problem solving or testing.

Here's some background on the car/engine:

It is a '68 200 block that to my knowledge, is original: C8DE 6015-B.

Interestingly, the head is stamped: C9DE-6090-R with plugged thermactor holes and what I think is a date code of: 2F29.

The car's build date is March 23, 1968 and was not a CA car, thus I am not sure why the head is a C9. Could this indicate that it was swapped at some point? March '68 seems too early for a '69 head.

The carb is a rebuilt (TOMCO) Autolite 1100 that I put on during my restoration of the car. My intent is to maintain originality, original appearance while attempting to get peak performance.

The odometer reads 73K, but I assume that is 173k. The car was a fleet order and the original owner was CARWAY LEASING CORP., so I assume it was a rental.

I have no knowledge of any major rebuild to the engine prior to my purchase. The car was only a few miles from the junk yard when I purchased her in the fall of '01. Since then I have installed new external engine accessories, distributor, rebuilt carb, new oil pump and screen and have done everything short of the internals and I have not taken off the head.

I have throughly cleaned the valve cover and the oil pan. The rocker assembly looks clean. I have also installed new valve stem seals.

Hence, I have been concerned about the dirty oil because as I began to notice the oil was also dirty, and would need to be topped off (up to a quart), the exhaust began to appear rich and no matter what I did to the carb or the distributor or how many times I timed it, it would always put out dark smoke indicating a rich condition. However, despite the apparent carb issue, I am hoping that the rings and/or head is not shot.

Any obervations or auggestions is always appreciated.

 

[CZLN6]

Howdy back:

You may need to continue doing a complete diagnostic. It is possible that you have more than one problem contributing to the dirty oil.

Sometime, very soon, you would be wise to do a cylinder pressure test. 1st dry, and the 2nd wet. For the 2nd test pour, or squirt a tea spoon of oil around the edge of the piston. The purpose is to assess the ability of the cylindeer to seal and hold pressure. The extra squirt of oil will temporarily seal the rings.

If the 1st and 2nd test are fairly high and close or similiar to each other, you have a good tight engine. Continue to look elsewhere.

If the pressure is down for both you will have to do a re-ring to fix.

If the pressure is down for the 1st and up for the 2nd you have bad ring seal.

If the pressure doesn't change from 1st to 2nd, but is widely variable from cylinder to cylinder, you have some leaking valves.

The C9 head is a '69 casting that is frequently seen on '68 model year cars. And it may not be the original head. Who knows?

Given the fleet history and miles on the engine, I'm suspious that it is cruded up inside and very worn.

Enjoy the journey.

Adios, David

 

[mugsy]

For the dirty oil there is an old trick of using ATF in the oil. But be careful and follow these precautions.

Add half to one full quart of ATF to the oil. NO MORE. ATF is a light oil with lots of detergent.

DO NOT OVER FILL THE OIL PAN. Either drain a half quart out or wait until the oil level is low.

DRIVE LESS THAN 50 MILES. You want to circulate the ATF and get the oil hot. Do do not "drive" on it. 50 miles is MAX!

DO NOT DRIVE OVER 55 MPH. By adding the ATF the regular oil has thinned out.

I have had family and friends use ATF to clean the interior of engines with good results. Just don't add to much or over fill or drive over 50 miles or 55 mph and the engine should be fine.

tanx,
Mugsy