Aftermarket distributor cap rotor

"My 2001 5.7 MAG MPI goes thro

"My 2001 5.7 MAG MPI goes through caps and rotors each year and they are pricey ! Are the aftermarket ones just as good ? For axample, Mallory ? Or can you recommend one ?

Thx"

Unless you are putting a heck

Unless you are putting a heck of a lot of hours on the engine I can't understand the need for a cap and rotor every year. Caps and rotors will last for years in most cases. Are you doing the work or are you having it done?

"It's moisture that is kil

"It's moisture that is killing the electrical contacts inside the cap. The ignition wire contacts on the 'inside' of the cap, where the rotor rides, get almost a fuzz on them and corrode. Mercruiser mechanic says it's a normal problem and they rec changing cap and rotor every year.

There is no abundant moisture in my bilge actually it's usually dry. Surprisngly, the cap does not have any form of gasket, something I'm playing w/ retrofitting.

Re: aftermarket caps - do you have experience w/ them ?"

"some merc V8 caps come with g

"some merc V8 caps come with gaskets, stick on the cap side."

"" aftermarket caps - do y

"" aftermarket caps - do you have experience w/ them ?"

Yes, they'll work. Look for brass wire studs."

Can you recommend the best bra

Can you recommend the best brand aftermarket cap and rotor ?

Re: brass wire studs - mercruiser was making them for a year or two w/ aluminum studs - those were even more horrible.

Is it OK if I 'clean' (w/ emory ) an old cap and re-use ? It seems that the studs get worn w/ use ( they go from perfectly round to having a slight flat side ).

Thx all...

alan in my opinion yes you can

alan in my opinion yes you can clean them with emry cloth as long as there is no major damage to your prongs and the cap is not cracked. it puzzels me. why for 1. marine dist and no gasket and 2. why the moisture problem there . after all is clean you may want to direct one of your vent hoses to that paticular area and just experiment

"Thx.

It could be that my

"Thx.

It could be that my i/o cover closes right near where the dizzy is. I do have a raised lip where the hatch closes, but water, as we know, can get anywhere. I was thinking of either gasketing that area or making some sort of 'catch' to re-direct any rain or wash water away from the area.

However, I could undersatnd that water gets on top of the dizzy cap, but inside ?

I have never had a gasket on any mercruiser replacement cap - although I am playing w/ the idea of making one from silicone or gasket material - it's just that the cap and dizzy contact area is so tiny, 1/16" lip for either - not much room !

I do have (2) vent hoses that go to the bilge for gas fumes, but w/ an FI, it's not that much of an issue. The hose connects to a vented scoop on the side of the boat. I could re-direct?

But, my bilge is very dry - the engine, well - looks new... If it weren;t for the cap thing, I'd have few complaints - except for keeping corrosion at bay ( I have a Bravo 3 )

Note: my neighbor has the same motor as me ( same mercruiser mech too ) and the same thing happens to him and the mech tells him to change it every year too. And the mech has been nothing but good to this DIY'er..."

"I have the same cap and rotor

"I have the same cap and rotor on my boat, 350 ci mercruiser 260 hp 1987 cobalt. The cap and rotor I replaced in 1995 when I purchased the boat. Been on there ever since and NOT ONE ISSUE!! almost 14 years!!!

I believe you have found the common element here with you and your nieghbor..................SAME MECHANIC

I have been working on mercruisers since 1990 and never had to rplace a cap of only one year of age. Most have almost 1/4 inch of growth on the terminals inside the cap and still perform fine. Typically the sensor board craps out before a cap.


I am wondering if he is seating the rotor/sensor wheel correctly?? If not then it would reek havok inside the cap. The rotor/sensor wheel must be removed (pried upward) with 2 screwdrivers as it is a assembled with screws.

Something sounds ""DIZZY" here!!"

Alan im with GHOST something j

Alan im with GHOST something just isnt right! I know he's your mechanic and you trust him as we should be able to. But if i could tweak something to move a ton of caps every year then more than likely its happening not to point fingers but take your cap off and inspect your dist real close for any sings of alingment/warpage

"I'm open to every idea.

"I'm open to every idea. But, how could it be the mechanic ?

It's moisture that's getting in there. And, the moisture is what seems to be creating a problem.

The boat runs great ! Except, 1-2 times during the season, I have to clean the cap as a "crud-like fuzz" develops on the contacts. This crud either makes the boat run like it's misfiring, or as my neigbor says - cross-firing. Once cleaned - all is OK again.

I think that if the moisture issue is resolved ( if that's possible ), then all should be perfect.

Based on the above info, what would your course of action be ?

Thx guys !"

The dist. cap should have a ve

The dist. cap should have a vent on the lower side. Make a gasket from rolled gasket material. You could spread a thin layer of silicone "Form-A-Gasket" on the gasket material and let it dry before installation.

Get a can of "tuner cleaner" from an electronic shop and clean the inside of the cap before installation. It leaves a film of protectant on the inside.