All Small Six My 200 l6 engine is a hodgepodge...can this affect performance?

[bmbm40]

You will get a lot of good advice on what to get for replacement but one option to consider is getting a rebuilt and custom curved DSII from a member on here, wsa111, who is very qualified to provide that and guide you through balance of parts selection for your complete ignition system. Additionally there are many carb choices for better performance such as the Rochester small base 2bbl which will require some modification but very doable. You will very likely need alterations to accelerator pedal linkage and a compatible air cleaner. The Rochester is going to be available used for rebuild or purchase from a rebuilder. I have attached a link here for general info:

https://www.jalopyjournal.com/forum/threads/rochester-2bbl-large-base-vs-small-base-dims.181649/

Somewhere on here is a post with pics describing fitting the Rochester to your carb base. I'll see if I can find it.

And consider that the cfm on the Rochester is 280 and your stock carb may have been 185 cfm. But if your head is a 1970 it has a larger log than what was on the 1966 200 1240cc vs 1100cc. Changes like this will probably require tuning skills but old cars require that usually. Any corrections on this from anyone are appreciated.

 

[My66Mustang]

Hi, you have the early LOM distributor. The easy way to tell is the flatter pancake style vacuum advance. I enlarged the pictures and it looks like the breaker plate is covered with metal filings. If the bushing is disintegrating you have a big problem. That oil port has maybe not been serviced in a long time. grab the rotor and try to move the distributor shaft. If the shaft can wobble the dwell will be all over the place and that can explain poor performance. Now I would decide on a distributor upgrade. Good luck

So it's definitely incompatible, and sounds like it's on its last leg. Very valuable information thank you. The shaft does move freely back and forth without any hesitation, no wobbling, no noises, seems like it "works" but only in its moving parts. *adds distributor to parts list*

"If the bushing is disintegrating you have a big problem."

........w-what would be that big problem?

 

[My66Mustang]

I like the screw in type better than the ones with rubber tips, less room for error. I’m surprised nobody mentioned the ground wire,, it’s toast!
Get with Bill at Ambler Race- in the vendor section. He can get you set up with a quality distributor curved properly for your car. I think he’s got $50 off right now

Ok I'll send him a message!

 

[My66Mustang]

Same guy. Bill Ambler
I don’t think it was ever discussed, but in first post you mentioned the intake was from a 70’s vintage. Is the intake separate from the head, or all cast into one piece??

The intake and the head are one piece.

 

[My66Mustang]

And consider that the cfm on the Rochester is 280 and your stock carb may have been 185 cfm. But if your head is a 1970 it has a larger log than what was on the 1966 200 1240cc vs 1100cc. Changes like this will probably require tuning skills but old cars require that usually. Any corrections on this from anyone are appreciated.

Ok, currently doing more research on this, because this just opened up a rabbit hole that I need to go down.

So since the intake is larger, is it possible that the stock carb isn't powerful enough to pull enough air and fuel into it? I might have to upgrade to a better carb too.

 

[DON]

That the same head I have. I have been told it’s a good head for the 200’s. Mine has been modified for a 2 barrel. Allegedly it is a little bit of a rare head

 

[bmbm40]

Ok, currently doing more research on this, because this just opened up a rabbit hole that I need to go down.

So since the intake is larger, is it possible that the stock carb isn't powerful enough to pull enough air and fuel into it? I might have to upgrade to a better carb too.

The Rochester is a carb, a 2 barrel, not like your stock 1 barrel, and it flows more cfm which can increase performance when setup and tuned properly. This pdf is for fitting a 2 barrel Carter BBD to head like yours but the process for mounting will be similar for a small base Rochester 2 barrel. It is a rabbit hole haha.

 

[My66Mustang]

That the same head I have. I have been told it’s a good head for the 200’s. Mine has been modified for a 2 barrel. Allegedly it is a little bit of a rare head

The same one!! That's so cool. I'm trying to find more info on the head, looks like the codes say it came out of a falcon or a maverick if my research is right. Yours has a dash in between the 0 and the A, mine doesn't. Interesting

 

[My66Mustang]

The Rochester is a carb, a 2 barrel, not like your stock 1 barrel, and it flows more cfm which can increase performance when setup and tuned properly. This pdf is for fitting a 2 barrel Carter BBD to head like yours but the process for mounting will be similar for a small base Rochester 2 barrel. It is a rabbit hole haha.

Ok I'll read into this!

 

[DON]

If I remember right, the guy in California who did the modification said it was from a bronco. The dash /no dash is interesting, I would guess cast at a different place or a different guy making the tags that day

 

[Frank]

Ok I'll read into this!

Read into it, but don't do carburetor/intake modifications at this time: The Carter carb on the engine is good, plenty good, bigger than the original carb already. Get the distributor, get what you have tuned up. It's going to run strong, assuming good internal condition. . . It's easy to get caught up in the excitement of the conversation and bite off more than is practical up front.

 

[My66Mustang]

Read into it, but don't do carburetor/intake modifications at this time: The Carter carb on the engine is good, plenty good, bigger than the original carb already. Get the distributor, get what you have tuned up. It's going to run strong, assuming good internal condition. . . It's easy to get caught up in the excitement of the conversation and bite off more than is practical up front.

Good deal I was thinking that I possibly needed to invest in a different carb. I will get that distributor and go from there!

 

[awasson]

Ok, good work! Now that we know for sure that you need the distributor, it’s smooth sailing. I’d do the compression test to make sure your rings and valves are sealing correctly but putting together a well running 200 is a cakewalk now.

There are so many recipes to make these engines perform better and have fun but to promote the smoothest direction to the finish line, I’m going to also recommend that you call Bill about one of his custom curved Duraspark II distributors and he will probably also be able to discuss the best carburetor and initial timing etc. for your engine. Once you’ve got the engine working for the best of its abilities, there’s always room for headers and camshafts and other things to make it an awesome cruising vessel.

By the way, it’s also worthwhile pulling the damper off and the timing cover to see what shape the timing gears and chain are. They’re steel gears so it’s not likely that they’ll jump a tooth but if there is too much slack, you might as well get a new chain and gears for a smoother running and quieter engine.

 

[My66Mustang]

Ok, good work! Now that we know for sure that you need the distributor, it’s smooth sailing. I’d do the compression test to make sure your rings and valves are sealing correctly but putting together a well running 200 is a cakewalk now.

There are so many recipes to make these engines perform better and have fun but to promote the smoothest direction to the finish line, I’m going to also recommend that you call Bill about one of his custom curved Duraspark II distributors and he will probably also be able to discuss the best carburetor and initial timing etc. for your engine. Once you’ve got the engine working for the best of its abilities, there’s always room for headers and camshafts and other things to make it an awesome cruising vessel.

By the way, it’s also worthwhile pulling the damper off and the timing cover to see what shape the timing gears and chain are. They’re steel gears so it’s not likely that they’ll jump a tooth but if there is too much slack, you might as well get a new chain and gears for a smoother running and quieter engine.

That all sounds good, I could check out the timing chain for sure. I did look at Bill's distributors and I was looking at the wiring but I got worried because it didn't look compatible with the coil I have. Guys on here suggested I can rewire it to make it work with my coil, but rewiring stuff is way too intimidating for me right now. I was looking around online and eventually found what I'm looking for, I'm going to pull the trigger on it tomorrow.

It is compatible with my year engine, has good reviews and a very detailed description, and it has a wire for a tach which is something I would really like to have. Made in America too! This will be fun.

 

[Frank]

That all sounds good, I could check out the timing chain for sure. I did look at Bill's distributors and I was looking at the wiring but I got worried because it didn't look compatible with the coil I have. Guys on here suggested I can rewire it to make it work with my coil, but rewiring stuff is way too intimidating for me right now. I was looking around online and eventually found what I'm looking for, I'm going to pull the trigger on it tomorrow.

It is compatible with my year engine, has good reviews and a very detailed description, and it has a wire for a tach which is something I would really like to have. Made in America too! This will be fun.

Post a link to the site selling the product please. It will still require one rewire, it's not difficult, we'll help.

 

[66 Coupe driver]

It will be an incompatibility problem if you have the LOM distributor, as explained above. When possible, remove the distributor cap and get as good a picture of the inside of it as possible, this will answer the question. "How so" is, the LOM uses a unique method of advance, all timing advance is done with vacuum only. This requires a matching carb with the vacuum passages set up for this distributor. Normal carb/ distributor combos, centrifugal weights in the distributor handle most of the advance, and the carb adds a part-throttle vacuum to increase advance in that operating parameter. The two designs are not compatible.

Remember to open the choke and throttle to wide-open during the compression test. Easy to forget. And all spark plugs out.

Frank, how critical to the compression test is having the carb at wide open throttle?

 

[Frank]

Frank, how critical to the compression test is having the carb at wide open throttle?

It's important for accuracy. Reason: when the piston is dropping on the intake stroke, any restriction in the airway will reduce the volume of air inhaled, and the compression pressure will read lower. On a restrictive log intake it's more pronounced since there is a relatively small volume of air in the plenum for the intake cycle. If the throttle or choke are closed the readings will not be 100% accurate, and there may be more difference in the readings cylinder-to-cylinder.

 

[66 Coupe driver]

It's important for accuracy. Reason: when the piston is dropping on the intake stroke, any restriction in the airway will reduce the volume of air inhaled, and the compression pressure will read lower. On a restrictive log intake it's more pronounced since there is a relatively small volume of air in the plenum for the intake cycle. If the throttle or choke are closed the readings will not be 100% accurate, and there may be more difference in the readings cylinder-to-cylinder.

Thank you for explaining it. Makes sense. #4 was the lowest and #6 was the highest but all within the acceptable range. I'll run the test again and remember to step on the gas this time.
Thanks again!