Carb spacer

[Marty C]

I noticed a slight decrease in engine performance when engine is hot 

Hos anyone added a spacer to their 1 bbl Stromberg carb on their 1952 Dodge Coronet flathead 6 ?

if so which one?

[desoto1939]

are you talking about a plastic spacer that would mount on the top of the intake manifold and the base of the carb that is bolted down.

 

If you do not have a governor  on the car then the current spacer would have four slots and one of the slots would line up with a tiny hole in the top of the intake manifold. The slot is there so that air can pass through the hole and into the carb.

 

When you mentioned slight decrease in performance when engine is hot please explain in more detail. It is hard to diagnose an issue with out a lot of information. Maybe you have a fast idle or the carb is out of adjustment, or the timing is to advanced.

 

Rich Hartung

desoto1939@aol.com

[Ivan_B]

I believe that he is referring to the (not so known?) practice of installing a heat insulating spacer (made out of special plastic, these days) to prevent the gas inside the carb bowl from overheating. Not sure whether or not this is expected to increase hot performance, but I believe it is generally known to reduce the evaporating fuel (and associated hot starting issues) on engines prone to this problem.

[Plymouthy Adams]

15 minutes ago, desoto1939 said:

are you talking about a plastic spacer that would mount on the top of the intake manifold and the base of the carb that is bolted down.

 

If you do not have a governor  on the car then the current spacer would have four slots and one of the slots would line up with a tiny hole in the top of the intake manifold. The slot is there so that air can pass through the hole and into the carb.

 

When you mentioned slight decrease in performance when engine is hot please explain in more detail. It is hard to diagnose an issue with out a lot of information. Maybe you have a fast idle or the carb is out of adjustment, or the timing is to advanced.

 

Rich Hartung

desoto1939@aol.com

not to pass air into the carb, this is the passage for the vacuum piston and thus provides vacuum FROM the manifold to react upon the piston to meet load conditions as needed.   

[desoto1939]

48 minutes ago, Plymouthy Adams said:

not to pass air into the carb, this is the passage for the vacuum piston and thus provides vacuum FROM the manifold to react upon the piston to meet load conditions as needed.   

Plymouthy: Thanks for explaining the purpose of the hole. All I know is that you have to have the slotted spacer if you do not use a governor on the car. I am not an experienced mechanic.

 

Rich Hartung

 

[Dan Hiebert]

I've had spacers that were touted to improve performance in a couple vehicles, although not L6s.  They didn't contribute anything noticeable.  If you're just trying to remedy the performance issue - assuming everything else is copacetic,  I'd check the accelerator pump lever link setting at the bottom of the bowl, there is a small lever there with three holes in it, one (closest to the throttle shaft) is a short stroke, one is a medium stroke, and one is a long stroke.  They are for high-altitude / hot weather driving, normal summer driving, and cold weather driving (same order).  There is a small linkage between the lever and the pump that you adjust along those holes.  They control the amount of fuel injected into the carb throat when you push the gas pedal.  If you have it on the long stroke/winter driving hole, the car's performance will be affected when it's hot out.  We've been in the same general climate as you the last 20 years, I've kept mine at the medium stroke with no issues.

Edited July 13, 2023 by Dan Hiebert

[Marty C]

6 hours ago, desoto1939 said:

are you talking about a plastic spacer that would mount on the top of the intake manifold and the base of the carb that is bolted down.

 

If you do not have a governor  on the car then the current spacer would have four slots and one of the slots would line up with a tiny hole in the top of the intake manifold. The slot is there so that air can pass through the hole and into the carb.

 

When you mentioned slight decrease in performance when engine is hot please explain in more detail. It is hard to diagnose an issue with out a lot of information. Maybe you have a fast idle or the carb is out of adjustment, or the timing is to advanced.

 

Rich Hartung

desoto1939@aol.com

 

[Marty C]

Yes I’m talking about a spacer between the carb and the manifold. My Carter AFB on my Pontiac 389 is used to help with hot starting and fuel vaporization with today’s fuel. 
it’s hard to explain the decrease in performance but the car just seems peppier when it’s cold. The car does run hot and I’ve replaced the water pump added an 8 blade fan and an aluminum radiator and sitting in traffic the temp creeps up to H until I start driving again.

I’ve also had 3 different freeze plugs Pop when I was driving and didn’t notice the gauge was pegged on H

the latest overheating issue just happened today. 
the timing is fully advanced (doesn’t ping) and the accelerator pump is in the middle hole and does shoot gas down the carb.

I was just thinking a spacer might boost some hot engine performance 

as far as the freeze plugs popping , it’s a newly rebuilt engine and my fiend who is friends with the builder thinks I will need to change all the freeze plugs 

I do have an extra set I bought from Andy Birnbaum mopar parts

[FarmerJon]

Well, that's concerning. 

A spacer might help with carb heat, but your engine getting hot is a MUCH bigger concern. Fix that first, then see if the carb is still a bother.

 

When engine was rebuilt,  did you put a new water distribution tube in, or pull, clean, and inspect the old one?

What temperature thermostat is in it? 

Have you checked the accuracy of your gauge?

What pressure is the cap on your new aluminum radiator?

how long are you sitting in traffic before it starts going towards HOT?

What weight oil are you running?

Was the head milled for compression? 

How much overbore on the cylinders?

These aren't Fords, overheating isn't the natural state of the Mopar 6. 

 

[vintage6t]

Loss of power and running hot. Sounds like your engine may be running lean. I'd read the plugs and also check around the carb and manifold for a vacuum leak.

 

Maybe try backing off the timing a bit to see if that makes a difference in power.

[Marty C]

3 hours ago, FarmerJon said:

Well, that's concerning. 

A spacer might help with carb heat, but your engine getting hot is a MUCH bigger concern. Fix that first, then see if the carb is still a bother.

 

When engine was rebuilt,  did you put a new water distribution tube in, or pull, clean, and inspect the old one?

What temperature thermostat is in it? 

Have you checked the accuracy of your gauge?

What pressure is the cap on your new aluminum radiator?

how long are you sitting in traffic before it starts going towards HOT?

What weight oil are you running?

Was the head milled for compression? 

How much overbore on the cylinders?

These aren't Fords, overheating isn't the natural state of the Mopar 6. 

 

Well I didn’t rebuild it myself but it was a reputable builder specializing in antique engines 

when I replaced the water pump I made sure it was there . 
I have a 160 thermostat 

I have Castrol 20-50 high zinc formula oil in it 

I replaced the 5 blade fan with an 8 blade fan

i replaced the stock radiator with an aluminum one 

the cap I have installed is a new Gates 4 lb

ive over heated with a 7 lb cap and now a 4 lb cap 

The engine has 3 times blew a freeze plug 

not sure if it’s overheating problem or a freeze plug problem

the engine with all the latest upgraded parts runs normal (gauge in the center) and when stuck in bumper to bumper traffic gauge showed high normal and cooled down quickly when I started moving 

I thought but was fixed until this last issue yesterday 

in all 3 cases the freeze plug just tilted out from the top each one being a different one

im very confused now

[Marty C]

1 hour ago, vintage6t said:

Loss of power and running hot. Sounds like your engine may be running lean. I'd read the plugs and also check around the carb and manifold for a vacuum leak.

 

Maybe try backing off the timing a bit to see if that makes a difference in power.

Sounds like it’s lean but actually I think it may be rich 

I only get 11 mpg 

im thinking it should be around 15 

I know a rich condition when an engine is hot has the same effect as a lean engine 

I thought a spacer might help but I posted this spacer question before my engine overheated for the 3rd time!!

with a new water pump thermostat fan and aluminum radiator!! I’m stumped as to why these freeze plugs are popping in the dead of summer?

[Sam Buchanan]

So what does the rebuilder have to say about all this, especially the freeze plugs?

Edited July 13, 2023 by Sam Buchanan

[Los_Control]

Just now, Marty C said:

in all 3 cases the freeze plug just tilted out from the top each one being a different one

When you say the welsh plug just tips out ..... reminds me of the mistake I made when I installed mine.

The plugs are concave with the bubble facing in the block when installed.

I installed my plugs the same way as the photo the side showing is the outside.

 

This is backwards, this plug you see is the inside of the plug with the bubble facing outside.

When you smack it with a hammer to install it, the bubble inverts to the inside expanding the diameter of the plug to make it a tight fit.

Some people will use a silicone sealer to help glue in the plug also. ..... Might help if you have pitting & wear around the holes.

 

Just saying that is how I installed my plugs (backwards) They do not leak or cause a problem yet ..... I'm still only yard driving & not on the road.

I know my plugs are going to fall out some day, I already have a replacement set here .... I will change them before putting it on the road.

 

 

Your radiator cooling kinda sounds normal if you have a small radiator?  I wonder if you have a 2 or 3 core radiator? ..... Maybe a 4 core?

 

Just my opinion, our old engines had big ol honkin radiators with lots of water capacity & good flow.

Newer modern vehicles with a better engineered cooling system use smaller radiators with less coolant capacity.  Old cars need more imho.

 

My truck has a used aluminum radiator, same H-W dimensions as the original except it is 3.5" thick .... I say it is a 3 core, it might be a 4 core I dunno.

It will idle in the driveway for 1 hour & just maintain a steady temperature.  I can watch the gauge move up from 160 to 168 or so then the T-stat opens and brings it back to 160 again .... actually below 160.  Then after several minutes it goes up & T-stat opens ...... I believe this is normal operation & the radiator has enough capacity to cool the engine long enough for the radiator to cool the hot coolant down before it is needed in the engine.

[desoto1939]

Can we asumme that when the engine was rebuilt they dipped the engine and cooked the engine block and also took out the old original welsh plugs?  If they did not cook the engine block then there still could be old crud in the block and scale.  This can also cause the engine temp to increase.

 

So when you replace each welsh plug do you ever try to see if there is any crud in the holes with a coat hanger? Do not use the welsh plugs that look like a cup you need the flat plugs like the other poster put a picture on his reply.

 

I would also recheck the timing. Get the factory timing back to see if that also solves the heating issue.  My 39 Desoto with the big 6 block is set at 2 degrees before TDC. Check your service manual.

 

Just some suggestions.

 

Rich Hartung

[Marty C]

8 hours ago, Los_Control said:

When you say the welsh plug just tips out ..... reminds me of the mistake I made when I installed mine.

The plugs are concave with the bubble facing in the block when installed.

I installed my plugs the same way as the photo the side showing is the outside.

 

This is backwards, this plug you see is the inside of the plug with the bubble facing outside.

When you smack it with a hammer to install it, the bubble inverts to the inside expanding the diameter of the plug to make it a tight fit.

Some people will use a silicone sealer to help glue in the plug also. ..... Might help if you have pitting & wear around the holes.

 

Just saying that is how I installed my plugs (backwards) They do not leak or cause a problem yet ..... I'm still only yard driving & not on the road.

I know my plugs are going to fall out some day, I already have a replacement set here .... I will change them before putting it on the road.

 

 

Your radiator cooling kinda sounds normal if you have a small radiator?  I wonder if you have a 2 or 3 core radiator? ..... Maybe a 4 core?

 

Just my opinion, our old engines had big ol honkin radiators with lots of water capacity & good flow.

Newer modern vehicles with a better engineered cooling system use smaller radiators with less coolant capacity.  Old cars need more imho.

 

My truck has a used aluminum radiator, same H-W dimensions as the original except it is 3.5" thick .... I say it is a 3 core, it might be a 4 core I dunno.

It will idle in the driveway for 1 hour & just maintain a steady temperature.  I can watch the gauge move up from 160 to 168 or so then the T-stat opens and brings it back to 160 again .... actually below 160.  Then after several minutes it goes up & T-stat opens ...... I believe this is normal operation & the radiator has enough capacity to cool the engine long enough for the radiator to cool the hot coolant down before it is needed in the engine.

Ok so you’re saying the the concave faces in towards engine? Yes that’s the way mine are the bubble side out. But you’re saying when you tap it in it’s supposed to flex In towards the engine???

i think you would have to really hit these hard to get these plugs to reverse the direction of the concave 

is this what you are saying is the correct way of installing them?

[Los_Control]

Just now, Marty C said:

i think you would have to really hit these hard to get these plugs to reverse the direction of the concave 

is this what you are saying is the correct way of installing them?

Is exactly what I'm saying.

 

I'm no expert, I will use a 1" diameter water pipe 3" long. Then use my 3 pound sledge hammer to give it one mighty  smack & invert the welsh plug.

They are often called expansion plugs ..... when you invert them they expand. ...... These were the very first examples & the newer models changed over the years.

 

Smack that Biotch with a hammer.

 

[Young Ed]

Isn't the idea to pound them towards flat not make them concave the other direction?

[Dave72dt]

8 minutes ago, Young Ed said:

Isn't the idea to pound them towards flat not make them concave the other direction?

Yes, and using a solid punch like a 1"dia  piece of shaft instead of a hollow pipe would be preferred.

Edited July 14, 2023 by Dave72dt

[Marty C]

On 7/13/2023 at 12:02 PM, desoto1939 said:

Can we asumme that when the engine was rebuilt they dipped the engine and cooked the engine block and also took out the old original welsh plugs?  If they did not cook the engine block then there still could be old crud in the block and scale.  This can also cause the engine temp to increase.

 

So when you replace each welsh plug do you ever try to see if there is any crud in the holes with a coat hanger? Do not use the welsh plugs that look like a cup you need the flat plugs like the other poster put a picture on his reply.

 

I would also recheck the timing. Get the factory timing back to see if that also solves the heating issue.  My 39 Desoto with the big 6 block is set at 2 degrees before TDC. Check your service manual.

 

Just some suggestions.

 

Rich Hartung

Yes I know the block was thoroughly cleaned , I saw it before it was assembled 

I’m sure they put all new plugs in tho I can’t be sure 

the engine runs quiet and smoothly and since the rebuild I’ve put on hundreds of miles without using any oil 

I personally think they didn’t use the proper sealer on the plugs 

just my opinion 

[Marty C]

17 hours ago, Dave72dt said:

Yes, and using a solid punch like a 1"dia  piece of shaft instead of a hollow pipe would be preferred.

This is going to be hard with the engine in the car!

Has anyone done all the freeze plug’s install with an engine in the car?

[Plymouthy Adams]

while usually forbidden and in the absence of the exact tool for the job.....a ball peen hammer with the ball against the disc and then carefully struck with another hammer will dimple these right nicely....remember, we not driving railroad spikes into an anvil here....

[Los_Control]

16 hours ago, Young Ed said:

Isn't the idea to pound them towards flat not make them concave the other direction?

I think you are more correct then I, they are probably closer to flat .... yet they have a optical illusion to me to look concave ..... like they go past the 1/2 way point to rest comfortably.

 

Just now, Marty C said:

This is going to be hard with the engine in the car!

Has anyone done all the freeze plug’s install with an engine in the car?

It will be a job. When I did my truck I pulled the front sheet metal off & just the motor sitting in the frame, easy access.

I still pulled the distributor & the oil fill tube out for access.

 

You can maybe .... I have never worked on a car like yours so just a guess. Remove the drivers front tire then the inner fender.

This will mean removing a whole bunch of stuff that is bolted to that inner fender. Tie everything up & suspend it in the air .... wire harness & whatever else is there. To pull the inner fender.

You will then have a easier access & room to swing a hammer .... while still having a bunch of crap in the way .... but doable is my guess.

 

It would probably take me a full day just to get it jacked up & inner fender removed. Another day to replace the plugs, then another day to put it all back together ..... It will be a job.

[Sniper]

1 hour ago, Marty C said:

Has anyone done all the freeze plug’s install with an engine in the car?

 

I've seen where someone has used an air hammer to do the trick,

 

That someone was not me.

 

 

 

Might try a set of DORMAN 568010

 

https://www.rockauto.com/en/moreinfo.php?pk=1261394&pt=5332&jsn=11

Edited July 14, 2023 by Sniper

[Plymouthy Adams]

This is the tool I was so used to using as most of the shop back in the day had this on hand.  In the case of the concave plug, was taught at very young age to use the ball only...

 

 

Edited July 14, 2023 by Plymouthy Adams