350/350 Spark Plugs
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,140
Likes: 4,248
From: US-PNW
I like NGK brand. They manufacture their own products and are considered a top-tier plug.
The XR5 is the equivalent to the AC-D R44S. NGK has a "reverse" heat scale where the lower the number the hotter the plug. The XR4 is hotter than the XR5 and would be roughly equivalent to the AC-D 45/46.
Is the R44S something you are pulling out of the engine or you saw listed on a specs sheet? The reason I ask is that the R45S would be more appropriate for today's gas. Have you examined the current plugs for deposits and coloration of the center porcelain?
The XR5 is the equivalent to the AC-D R44S. NGK has a "reverse" heat scale where the lower the number the hotter the plug. The XR4 is hotter than the XR5 and would be roughly equivalent to the AC-D 45/46.
Is the R44S something you are pulling out of the engine or you saw listed on a specs sheet? The reason I ask is that the R45S would be more appropriate for today's gas. Have you examined the current plugs for deposits and coloration of the center porcelain?
Thread Starter
Instructor
Joined: Jan 2007
Posts: 207
Likes: 2
From: Key Largo Florida
Thank you. Yes, the R44S in from what the original plugs were in 1969. Installed were the Champion plugs from last year that my local auto-parts dealer said are very similar the the R44S. I looked at the plugs I removed. Some were black but not oily. I have been having carburetor issues so I did not put a lot of confidence in reading the plugs. I will be installing the new carb in a few days. I was looking to put a hotter set of plugs in but wanted to establish a base line first.
Le Mans Master
Joined: Jan 2007
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From: Omaha NE
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1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,140
Likes: 4,248
From: US-PNW
Thank you. Yes, the R44S in from what the original plugs were in 1969. Installed were the Champion plugs from last year that my local auto-parts dealer said are very similar the the R44S. I looked at the plugs I removed. Some were black but not oily. I have been having carburetor issues so I did not put a lot of confidence in reading the plugs. I will be installing the new carb in a few days. I was looking to put a hotter set of plugs in but wanted to establish a base line first.
Thread Starter
Instructor
Joined: Jan 2007
Posts: 207
Likes: 2
From: Key Largo Florida
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Melting Slicks
Joined: Nov 2006
Posts: 3,416
Likes: 1,824
From: Apple Valley, MN
Thread Starter
Instructor
Joined: Jan 2007
Posts: 207
Likes: 2
From: Key Largo Florida
I guess I'm too much of a novice to truly understand that. My engine still has points (I like tinkering), the vacuum in my engine will be at least slightly different. The spring tension on my mechanical advance will not be the same, I have tuned headers and side pipes and an intake manifold for a LT1 engine. Am I making a big deal out of nothing?
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
I have ZERO doubt that a Lar's repaired carburetor would not start right up and be very close to perfect in the settings when he is finished with it. There are small differences that some of us can fix but if you are a novice then the suggestion to have somebody set up your carburetor makes sense.
Lar's is a well-known expert and I would trust him in a Nano-second to set up any carburetor or engine properly.
IF you want to learn and do this yourself then I might suggest that you invest in a Air/Fuel Gauge to show you the immediate air-fuel ratio that your engine is seeing.
I have one that I use when setting up a carburetor and it helps me a lot. I have it portable so I can switch it from car to car using the O2 sensor for the system. Having one of these will make setting up a carburetor much easier even for a novice. Being able to watch the air fuel ratio is very handy as the carburetor goes through the motions. Today the air fuel ratio gauges are less than $200 and are an extremely useful tool to have.
I had a custom Holley carburetor made about 20 years ago and it was pre-set for "my" engine. The fuel pump filled the bowls and the engine started right up and ran great. I didn't have to change anything other than idle screws.
Lar's is a well-known expert and I would trust him in a Nano-second to set up any carburetor or engine properly.
IF you want to learn and do this yourself then I might suggest that you invest in a Air/Fuel Gauge to show you the immediate air-fuel ratio that your engine is seeing.
I have one that I use when setting up a carburetor and it helps me a lot. I have it portable so I can switch it from car to car using the O2 sensor for the system. Having one of these will make setting up a carburetor much easier even for a novice. Being able to watch the air fuel ratio is very handy as the carburetor goes through the motions. Today the air fuel ratio gauges are less than $200 and are an extremely useful tool to have.
I had a custom Holley carburetor made about 20 years ago and it was pre-set for "my" engine. The fuel pump filled the bowls and the engine started right up and ran great. I didn't have to change anything other than idle screws.
Melting Slicks
Joined: Nov 2006
Posts: 3,416
Likes: 1,824
From: Apple Valley, MN