What is EDP plated exhaust parts?

[cliffblue]

I'm ready to buy my replacement exhaust manifolds to replace my one piece units on my 4.3L I'm only considering OEM units and saw this description in one ad."(Industry's only internally and externally EDP PLATED direct replacement exhaust products.)" Can anybody tell me what this is and since I only do fresh water, do I need it? Thanks, Cliff

 

[NHGuy]

Re: What is EDP plated exhaust parts?

EDP = electro deposition plating. Sounds like a fancy term for powdercoating to me. They may be the internally coated anti-corrosion type. My understanding is they are intended to slow down the effects of salt water. I'd get the standard type for fresh water.

 

[achris]

Re: What is EDP plated exhaust parts?

If you are looking at OEM, then you have 2 choices, EDP or EDP... All Merc elbows and manifolds are now EDP... A few years back there was also a choice of SS, which I bought for my old engine (1994) and they are still good, and that's in salt.... Merc discontinued them on the basis that they were prone to cracking... But, I'm a total sceptic on that... I think they realised these things will last basically forever, and they were missing out on sales of replacements....

Anyway, the EDP one will be great for what you're looking for, salt water or fresh....

Chris........

 

[Fun Times]

Re: What is EDP plated exhaust parts?

EDP, Electrode Deposition Paint. Paint applied through immersion in paint with an electrostatic charge to create an outstanding bond to a metal's surface for barrier protection against corrosion.

Which reading that reminds me, before installing the hardware be sure to clean out any possible left over paint that could have gotten into the bolt hole threads by using a chaser to clean them out so you won't have to go through the same ordeal the guy quoted below went through.

Interesting thing happened that I felt would be important to share with other DIYers out there. I was helping my buddy replace the exhaust components on his '95 370DA with 7.4s. All new OEM Merc parts. Got the manifold installed and torqued no problem. In fiddling with the riser blocks and elbows, two of the manifolds cracked during torquing of the top nuts (before we even got to 30 ft-lbs) - one of the four threaded holes on two different manifolds cracked - so out of 16 bolt holes, 2 stripped and cracked the casting. I have to preface the discussion with a disclaimer - Jon has had these elbows and risers off probably 10x for gasket replacement and I had done mine probably 4x, so we are not new to this process. Additionally we used proper torque settings and tightened the bolts evenly and slowly.

SO, fast forward a week later. Back to the marina with two shiny new manifolds (the dealer gave him one gratis as a replacement from Merc, but not both). During the installation, guess what happens? The first one we put on cracks one bolt hole again! Now we're fit to be tied. Before we proceed we take a look at the second new manifold which was still in the box. After closer examination of the manifold and the new bolts that he purchased, we noticed that some of the black paint (e-coating?) ran down into the threads. Also, the bolts come through with the threads pre-coated with some sort of red sealant that is very stiff. So before we F up another manifold, we get the tap and die set out and clean all the threads (bolts and manifolds). After that, everything proceeded as normal with no further problems.

For those of you taking on this job, I'd say it's VERY important to chase ALL the threads, despite the fact that the parts are brand new. We all know that threads need to be chased and bolts need to be cleaned before re-install when replacing gaskets. But new stuff apparently has to be done in the same manner for two reasons...
1. paint and sealant create too much resistance
2. paint and sealant likely give a falsely high torque reading b/c of the gunk that accumulates.

 

[cliffblue]

Re: What is EDP plated exhaust parts?

Thanks Fun, good to know that going in.