I have been reading on a couple of RV sites and there are 3 different answers. I 'm installing new plugs & wires on a Vortec 8.1 engine. My book says they should be gaped as per engine specs. I can not find it any where in the book that came with the coach the correct gap. This is the second set of plugs, first set was installed by a shop when the Air Ducts were installed as The coach is a Winnebago Adventure 35A With a Vortec 8.1 . The new plugs I want to install are AC Delco R44LTSM That's what the book says.My question is do I gap them at 0.60 0.45 or 0.50There is over 30, 000 miles on this set of plugs. I noticed on my last trip I did not have the power I did have and it would spit & spudder every once in a while. I do know it needs new wires. so while I'm at it I' just going to replace plugs& wires.Any one know what's the correct gap??Thanks a bunch

Mandalay Parr wrote:Did you search Vortec 8.1?Yes, I sure did. and got 3 different answers.

Chassis year?And a quick search found others from 6-10 years ago with similar troubles, frequent cause was plug wires due to engine heat.

According to Delco, they come pre gap when made, It states not to try to re-gap.

This is always one of the best sites for Workhorse 8.1L info:OEMYS PerformanceHe says to go with .045 or .060. Don't forget to install the heat shields.

Correct Gap for Spark Plugs | Good Sam Community

Mandalay_Parr
Explorer
Sep 29, 2018
Did you search Vortec 8.1?
egh33
Explorer
Sep 29, 2018
Mandalay Parr wrote:
Did you search Vortec 8.1?

Yes, I sure did. and got 3 different answers.
wanderingaimles
Explorer
Sep 29, 2018
Chassis year?
And a quick search found others from 6-10 years ago with similar troubles, frequent cause was plug wires due to engine heat.
MountainAir05
Explorer II
Sep 29, 2018
According to Delco, they come pre gap when made, It states not to try to re-gap.
rgatijnet1
Explorer III
Sep 29, 2018
This is always one of the best sites for Workhorse 8.1L info:
OEMYS Performance
He says to go with .045 or .060. Don't forget to install the heat shields.
Chum_lee
Explorer
Sep 29, 2018
Try searching for the recommended gap according to the plug manufacturer. Know the part number, plug type and/or heat range. Most plug manufacturers (Bosch, NGK, Champion, Denso, etc.) will post their standard gap specifications somewhere in their literature. Be aware that sometimes the engine manufacturer will recommend a different gap, especially if the OEM plug is discontinued, superseded, or currently made of unobtainium.

Nowadays spark plugs are usually good for about 100,000 miles. As plugs wear, the gap generally increases. So, if you get several different answers, its usually safe to go with the middle one. Unless you are having drivability issues or getting a check engine light, chances are you'll be fine.

Chum lee
Chris_Bryant
Explorer II
Sep 29, 2018
Not an authoritative answer, but I cannot see a modern ignition system using a .045 gap, what my 87 460 with pretty basic ignition used. Bigger gap, fatter spark. These coil on plug systems can surely fire an .060 gap.

Or, maybe I'm all wet, lol.
MountainAir05
Explorer II
Sep 29, 2018
Chris Bryant wrote:
Not an authoritative answer, but I cannot see a modern ignition system using a .045 gap, what my 87 460 with pretty basic ignition used. Bigger gap, fatter spark. These coil on plug systems can surely fire an .060 gap.

Or, maybe I'm all wet, lol.

My 2012 has coil on plug and they are set at .040 and when they wear to a certain point you replace them. But that said they should last by the manual till 80 to 100000. Not there yet. When I do check them they will be replaced due to the tear down to get to them.
K_Charles
Explorer
Sep 29, 2018
For some reason Iridium plugs have a smaller gap then platinum plugs for the same application. The Iridium plugs should not be gapped, if the gap isn't right don't use it as they are pre gapped.
egh33
Explorer
Sep 29, 2018
wanderingaimlessly wrote:
Chassis year?
And a quick search found others from 6-10 years ago with similar troubles, frequent cause was plug wires due to engine heat.

Yea, Our MH is an 06 (Bought it new) and we had Plug wires trouble on the first trip. After a short time and 2 sets of plug wires Winnebago informed me I needed to have some air ducts installed. I had to pay for the scoops and duct work, but Winnebago installed it for free. Last time I had the new wires replaced I had new plugs also. That was over I think some 20,000 miles ago. Haven't had any problem till this last trip. It now has 55,000 miles or so on it.
They said that when the body was placed on the chassis they did not allow enough air to get to the last 2 plugs on each side .