Spark Plugs

[randyc2958]

I have a 1985 trojan 10 meter with 350 hp 454 cid<br />Crusader engines. I currently have A/C R43TS spark plugs installed by the prevouis owner. The owners manually calls for MR44T. I have researched the A/C R43TS and found they are for Corvette 454 engines and if I understand correctly they have a longer reach than the MR44T. I would think this would give me a better burn and since I am still using a point type ignition . One other thing since I am pushing around approx 13,000 pounds I would think a lower heat range would be even better. Does anybody have any feel for which plug would give me the best fuel economy. I think we will see close to $2.00 a gallon fuel on the lake this summer in midwest and want to get the best performing plug I can buy. Thanks In advance!!

 

[Trent]

Re: Spark Plugs

Book calls for your engine.. NGK= BPR6FS<br /><br />AC= R41-CTS

 

[dhammann]

Re: Spark Plugs

If your motor is running at the specified WOT rpm and not missing....new plugs won't offer better fuel effeciency. What determines a good plug is its longevity without spark loss (missing) Go with platinum plugs and your worries will be over for a very long time. Don't be fooled by hogus bogus adds for super plugs. buy a name brand any, (I prefer Autolite)) that meets your OEM specs and life will be good.

 

[randyc2958]

Re: Spark Plugs

That's another problem I am having I have not been able to hit the WOT RPM. The book says 4200 to 4400 WOT RPM I am only able to obtain 3750 and missing my top end speed. The boat MFG states the top speed to be 31 MPH. At 3750 I am reaching 24.7 MPH by GPS. When I purchased the boat the props were reconditioned and bottom was clean. I have had the distibutors checked for the RPM curb everything checks out. I am having boat pulled this spring for new bottom paint and going to pull props and have them checked for proper pitch. It wouldn't be the wrong plugs would it???

 

[Blue Thunder]

Re: Spark Plugs

No, plus or minus one heat range in plug temp will not change your engine performance. For what it is worth, I too have 454s and run the R43TS. That is what I have always run with no problems. <br /><br />It sounds to me like you are missing about 600rpm from optimal. This could be bottom growth or could mean props need to be re-pitched/changed. That of course is assuming the engines are making the stated 350hp. If the only change needed is props, I would think about 3"s less than what you are currently running would be perfect and will help your fuel mileage too.<br /><br />BT

 

[randyc2958]

Re: Spark Plugs

Hey Blue thanks for the update. One question I have. I am currently running 18X22 props are you saying try a 18X19 or 15X22 prop. The Bottom was clean when I ran my tests. Thanks for you reply!!

 

[Blue Thunder]

Re: Spark Plugs

Trojan.. the second number is usually pitch. That means you are running 22" wheels now and need to go to 19" to attain 4350rpm. Perfect in my book. If everything else is ok, this prop change should really help the drivablity of your cruiser. Let us know how you make out.<br /><br />Good Luck!<br /><br />BT