Spark arrestor replacement on 5.7L Vortec

[Hill Country LSV]

I have the 5.7L Vortec V8 with the pancake aluminum spark arrestor air filter. I want to replace it with one of the new ducted cone filters that I am seeing on some of the new engines. I can't find a replacement kit. Any help?

[Mikey]

Not available as far as i know and not likely any better air flow compared to the metal spark arrester,About as unrestrictive airflow as your going to get.

I looked into this briefly a couple years ago.

[04OUTBACK]

Check k&n. I thought someone mentioned there was a k&n option. Could be wrong

[Razzman]

Do a search for "K&N Flame Arrestor Conversions" or something similar. Spark Arrestors are for off-road vehicles which could be the reason your not finding anything.

I had looked into this somewhat myself a couple years ago and all i could find then was a K&N marine replacement that was roughly the same size and shape as the flame arrestor. Then I realized the aftermarket makes conversion kits for autos that use the cone shaped filter. These kits have a custom plastic plenum that relocates the filter element. As the throttle body is a standard size it would work, probably a GM product kit. Problem is finding one that clears everything and fits easily without having to "buy & try". In the long run I determined it's not worth the hassle as there's no benefit.

[Razzman]

This is what I'm referring to in order to gain the cone type filter, it's much easier just getting a K&N Flame Supressor. You would have to custom route something to similar to this, probably have to be custom made. There's no call for this stuff aftermarket for our type of boats. It's on the 340 CAT motor because the manifold design dictates it.

12821

[KSmith]

I guess I am missing the point, so I'll ask. What benefit do you expect there to be in replacing it?

[NCSUmoomba]

I am with KSmith on this one. I am not sure why anyone would want to do this. Also, TBI motors are supposed to have actual spark arrestors, not air filters. The serve a specific purpose. That is to keep the boat from catching fire.

[Razzman]

I am with KSmith on this one. I am not sure why anyone would want to do this. Also, TBI motors are supposed to have actual spark arrestors, not air filters. The serve a specific purpose. That is to keep the boat from catching fire.

Not true, the Indmar 340CAT, 6.0L & 8.1L motors all have K&N filters on them from the factory (See below) and K&N make Flames Arrestors (http://store.knfilters.com/marine/default.htm) that will work on the 325 Assault engine. With fuel injection there's a lot less chance of that happening versus a carbed motor.

12822

[Razzman]

I guess I am missing the point, so I'll ask. What benefit do you expect there to be in replacing it?

I can think of one major reason to replace the POS flame arrestor. How many have pulled it off? Did it come off easy of was it hard and did you have to rock it back and forth to do? Probably the latter. How many have looked into the throttle body after doing so? How many of you have seen the all the aluminum chips sitting there after the flame arrestor shaves aluminum from the body drops them in? Everytime it happens, and I have to use a Q-tip with WD-40 to get them out so the engine won't ingest them.

Any filtering of the intake is going to reduce the amount of contaminants that the engine ingests and that can only lead to longer life. K&N filters are not restrictive at all so you wouldn't loose any performance, in fact it's probably more open than the arrestor is!

[KSmith]

I've never had any issue getting the flame arrestor come off nor have I had any shavings in the throttle body to concern myself with. Although that sounds more like an attachment issue more so that a flame arrestor problem.

If it solves a problem for some then more power to ya, for me there is no problem to be solved so it would be wasted money.

[rdlangston13]

I am with KSmith on this one. I am not sure why anyone would want to do this. Also, TBI motors are supposed to have actual spark arrestors, not air filters. The serve a specific purpose. That is to keep the boat from catching fire.

my boat is not a TBI engine. it is definitely port fuel injection

[zabooda]

As long as it has the approval numbers on the spark arrestor then you are OK. I'm sure the arrestors used by Indmar are certified and marked accordingly. All states would have the same requirement since the CFRs is a Federal requirement.

46 C.F.R. PART 25—REQUIREMENTS
Subpart 25.35—Backfire Flame Control
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§ 25.35-1 Requirements.
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(a) Every gasoline engine installed in a motorboat or motor vessel after April 25, 1940, except outboard motors, shall be equipped with an acceptable means of backfire flame control.
(b) Installations made before November 19, 1952, need not meet the detailed requirements of this subpart and may be continued in use as long as they are serviceable and in good condition. Replacements shall meet the applicable conditions in this section.
(c) Installations consisting of backfire flame arresters bearing basic Approval Nos. 162.015 or 162.041 or engine air and fuel induction systems bearing basic Approval Nos. 162.015 or 162.042 may be continued in use as long as they are serviceable and in good condition. New installations or replacements must meet applicable requirements of subpart 58.10 of this chapter.
[CGFR 65–50, 30 FR 16653, Dec. 30, 1965, as amended by CGD 88–032, 56 FR 35820, July 29, 1991]

[brain_rinse]

I can't seem to find the specific thread, but Indmar has stated in the past that the aluminum flame arrestor is very non-restrictive and there would be no performance gains going to a cone filter. If you have another reason to swap that's cool, just thought you should be aware.

[bzubke1]

Do you ever need to replace the metal flame arrestor? I just clean it ever 50 or so hours with carb cleaner. We have 540 hours on the boat so if it does need to be replaced at a certain interval were probably past it.

[NCSUmoomba]

I have never had any trouble getting my spark arrestor off either, and I have never seen any aluminum shavings from it. Also, when I mentioned that all TBI engines have them, I know the 340 and the other MPI engines do not have them. TBI and MPI are not the same fuel injection system. The TBI system is very similar to a carburetor in that the fuel is sprayed in right at the opening. The MPI system is spraying the fuel in further down in the engine, protected from stray sparks.