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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I'm replacing plugs with the type that came with the HO, which are AC Delco MR43LTS with a .040 gap (a marine plug if you can believe it). The wires were 8 mm Chevrolet Bowtie Logo wires, but I think I'll try a universal set of some sort that I can cut to size. I'm considering the following:
The ACDelco Marine version of the R44LTS, would be Part Number: MR44LTS.
I have not seen the MR44LTS Spark-Plugs in stock anywhere for some time...
However, I do often see the MR43LTS Spark-Plugs available (One Temperature-Range Cooler).
CR43LTS (Commercial/ extended-life/ intended not to foul from excessive Engine Idling Time) were Stock for many of the 350 Vortec Engines that were built for Vans.
Not too COLD of a plug for a 9.25:1 Compression Vortec 350.
The plug part # is corrected above (thanks, my bad). I've had the MR43LTS for several years. I note that the newer 350 HO Deluxe manuals indicate the use of R44LTS.
I've used the Summit 860825r with good success. Notwithstanding the above comment, I've heard that the ceramic boots don't stay on well. I should add I previously used the Taylor Thunder Volt 8.2 wires and couldn't tell the difference. Maybe just me...
Brian
Last edited by brian p; Sep 17, 2021 at 03:44 PM.
Reason: more info
The plug part # is corrected above (thanks, my bad). I've had the MR43LTS for several years. I note that the newer 350 HO Deluxe manuals indicate the use of R44LTS.
JamesC
Well, I just HAVE TO ask....what is it about these plugs that makes them marine plugs (I was thinking in terms of a corrosion reducing coating on the metal parts), and what make them a "Non-Automotive Spark Plug"?
Well, I just HAVE TO ask....what is it about these plugs that makes them marine plugs (I was thinking in terms of a corrosion reducing coating on the metal parts), and what make them a "Non-Automotive Spark Plug"?
From another website:
Here's the official response from ACDelco. The only difference is marine and non-marine. ACDelco marine plugs feature
a nickel-plated, rust resistant shell on all applications, and a clipped
side electrode on some applications. These plugs are designed for higher
RPM engines. They also have a larger heat sink, and the porcelain is not
only pressed into the heat sink, it is glued.
Spark plugs must operate within certain limits if they are to provide the
performance and service life expected. Engine manufacturers select a type
of spark plug for the normal or expected service for which the engine was
designed.
The heat range, which is designated by the second numeric digit (second 4)
is the same in both spark plugs.
Actually, since those plugs have't been out in some time, a bit of penetrating fluid might be in order. Hopefully, the plugs were put in with some anti-seize.
Never hurts to give them a blast. It's the tooling that can be real pain. I've an assortment of sockets and wrenches to allow for good access. The 5/8" offset box end wrench gets to all the plugs but I only need it for a few. The rest are plug socket and ratchet accessible.
It's the tooling that can be real pain. I've an assortment of sockets and wrenches to allow for good access. The 5/8" offset box end wrench gets to all the plugs but I only need it for a few. The rest are plug socket and ratchet accessible.
Yep. Along with the off-set, I have a pass through socket set from Harbor that should do the deal. I'll get the car up on some Race Ramps in case, but it "appears" that I should may be able to access everything from the top.
