Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands?

[Darin Jordan]

I noticed that companies like HGE, GLM, and Barr, sell both Cast Iron and Alunimum versions of their Exhaust Manifold and Center Riser kits for my 1990 7.4L...

Osco only appears to make cast.

What are the general preferences out there of Cast vs. Aluminum?

Also, is there a preferred/better brand to get, whether cast or aluminum??

Or should one stick to the factory Merc pieces, assuming they still exist?

Would love to realize the weight savings of the aluminum, but not at the expense of reliability or durability...

Would be interested in your thoughts (you are the experts, after all... )

 

[HT32BSX115]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

you are the experts, after all...

Well.....I donno about that.......


Aluminum is pretty good, light and doesn't "rust".....although it will corrode....


I would love to have an aluminum (small) block, heads and manifolds/risers. It would remove a few hundred pound from the back of my boat!


They are expensive....... If you have closed cooling you eliminate most of the corrosion concerns....

If I'm not mistaken, GLM are imported and of questionable (casting) quality.

You probably get what you pay for here.....

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

OK, I've done a lot of research on this, and it appears that both GLM and HGE sell both Cast and Aluminum replacements. I've read discussions that some have had issues and others haven't, but none of these really specified whether or not there is an issue with going to the aluminum versions themselves...

If I'm reading things correctly, my options are these for both manifolds and risers:

CAST:

Barr
Osco
GLM
HGE
Sierra??

Aluminum:
GLM
HGE
Barr
???

From what I can tell, the GLMs have a more separated runner design which would help boost low end some.

Otherwise, it's tough to tell the difference.

If I had the $$$$, I'd opt for the total performance kit I found with the stainless tubular risers and separated runner manifolds... but that's $1600+ I don't have to spend...


Are there any other options out there I should consider.

I'm kind of a "Do it once, do it right" kind of guy, but I know these are a maintanence item and none of them seem to have more than a 3-year warrantee anyhow, so I'm leaning toward the aluminum, but I could use some experienced opinions to consider.

Any thoughts would be appreciated.

 

[Bondo]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Ayuh,... My current project is getting Kodiack manifolds,... Same this as the Eddie Marine aluminum manifolds...
They were the 1s who started the dedicated runners, rather than an open plenum design...

If you go with the cheap Chineese stuff,... Inspect them Very Closely...
I have a set of GLMs on my 4.3l that needed the riser gasket face decked to flatten it...
Search threads started by Me,.. I posted about them a year or two ago...

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Ayuh,... My current project is getting Kodiack manifolds,... Same this as the Eddie Marine aluminum manifolds...
They were the 1s who started the dedicated runners, rather than an open plenum design...

Wow... those are sweet, but way beyond my budget for this project... it's a family boat after all! The Hot-Rodder in me wants to go that route BIG TIME!

If you go with the cheap Chineese stuff,... Inspect them Very Closely...
I have a set of GLMs on my 4.3l that needed the riser gasket face decked to flatten it...
Search threads started by Me,.. I posted about them a year or two ago...

I'll go look some more... I think I did read about that. If it's a one time or every few years kind of deal, then I'm not as concerned. I'm more concerned about general reliability and just getting normal operation of of this boat. It's worked great up to this point, so I just want to keep up with more of the same, only I'll do better maintenance than my father did!

 

[wca_tim]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

you might find a second hand set of stinless marine, imco powerflows or the nice emis. most of these (depending on which specific set) are hard anodized and then powder coated. note that hard anodized aluminum cylinder heads are outlasting cast cylinder heads these days in salt water boats. the performance manifolds drop some weight and will probably make some difference in power if you rejet the carb to take advantage of it.

that's my experience at this point anyhow... I've bought cast heads for the current engine, but almost wish i had gone with aluminum... except that I run in brackish a good bit and the hard ano'd heads are awful spendy... I replaced a thermostat yesterday, and the waterjacket in my aluminum intake looks pretty good for a couple of years.

If I were just going with stock, I would probably go with factory oem merc manifolds and risers... of course, I never wind up replacing anything with stock it seems...

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Well... after researching, and even calling a couple of manufacturers and distributors/dealers, I have finally ordered a new set of manifolds and risers...

I decided to go with the HGE Aluminum setup. I talked to an engineer at that company today and also to the distrubutor, and they pretty much answered my questions and concerns, so I'm confortable with the decision.

My boat is used 95+% of the time in fresh water, and I will be dilligent with the mainentance, so I think they'll last just fine... AND, they will be almost 100lbs lighter to boot...

I'll update this thread once I get them and start the process of getting them installed...

 

[wca_tim]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

sounds like a good choice in your situation

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

sounds like a good choice in your situation

We'll see... Like I said, I talked to the company (HGE) as well as one of their distributors/shops, and I came away with a good idea of what I was getting into. I think this will be a good choice...

I definitely like it so far... just got the shipping invoice and the total shipping weight for everything is 63lbs!!

Now, if I could just find a nice EdelBrock or ??? 2-plane Oval Port BB-Chevy Aluminum intake...

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Received all the parts last night. On initial inspection, everything looks pretty good quality. I'll take a closer look this weekend and snap some pics to share.

One think I noticed right away was that the exhaust ports are a bit smaller than the gasket opening, and a tad smaller than on the stock manifolds... Looks like I may be doing some gasket matching before I install these to get optimum flow, but they are aluminum, so that shouldn't take too long...

The risers look good as well. I'll do a surface flatness check this weekend and report back.

Stuff is definitely lighter... 61lbs for the entire box of parts...

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Regarding the GLM casting quality- I have heard the same good and bad stories as you, but have never tried them myself.

I looked at those Eddie manifolds... way too rich for my blood... and really WAY overkill for the application... it's just a stock 1990 Maxum...

The distributor where I got the HGE stuff, when I asked him, told me he wished they didn't even sell the GLM stuff... the HGE, he said, was a much nicer piece...

We'll see!

 

[conway22]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Do you mind sharing the dealer you got your manifolds from. I'm in the middle of the same decision..

Respect,
Conway

 

[Don S]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Conway22
I would suggest you send him a PM (Private Message) He hasn't logged in since the end of November, and this post may be long gone by the time he comes back (IF he comes back)
At least with a pm, it will show up when he logs in again.

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Sorry Guys... Have been very busy with life and other projects... (Kid's football, boy-scouts, R/C Boat racing, etc... oh, and keeping the wife happy! )....

I have all the parts layed out on a work table in the garage, but haven't had time to install them yet. I did get my SeaWater pump rebuilt and installed.

The source I used to get the HGE manifolds was: http://bpi.ebasicpower.com/

Great Prices... cheap shipping, and I was able to talk with them on the phone a couple of times to get the info I was looking for. They were very candid about the quality of these manifolds and comparisons to other types/brands...

From what I can tell by inspection, these are very nicely cast units. They are true, solid, and nicely finished. I will update this thread once I get back to working on installing them. I'll make sure to take lots of installation pics for reference, as I know that helps some...

 

[conway22]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Looking forward to it! Thanks!!

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Hey Guys... FINALLY took the time to get the HGE manifolds installed my Maxum.

Overall, they worked out great. I'm a little leary of using bolts to hold the risers on, being threaded directly into the aluminum manifolds, as opposed to studs, but so far, so good.

Manifolds and risers installed just like stock, with the exception that the manifolds came with studs instead of bolts for the heads. VERY nice touch, in my opinion.

Everything seems to have sealed up great. I ran it for a 1/2 hour run on the trailer, and once it was cooled back down, retorqued everything, then ran it again. No water leaks that I can see.

May be taking it out for a run tomorrow, so I'll update this thread over time to give a report on the longevity of these units.

Happy to have it done, and also to have shed over 100lbs off the back of the boat at the same time.

 

[Mkos1980]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Good Luck! I'm going on 4 years with my GLM Aluminum ones with no issues to report.

 

[tenmile]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Thanks for this post. I followed your lead and ordered a set of HGE manifolds from manifoldwarehouse.com. They arrived the next day and we installed them yesterday.

I found this site after ordering and wish I had found it first. They take the HGE castings and apply a ceramic coating in/out and extend the warranty to 5 years.

http://www.perfprotech.com/store/articles/marine-exhaust.aspx

 

[Darin Jordan]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

Thanks for this post. I followed your lead and ordered a set of HGE manifolds from manifoldwarehouse.com. They arrived the next day and we installed them yesterday.

I found this site after ordering and wish I had found it first. They take the HGE castings and apply a ceramic coating in/out and extend the warranty to 5 years.

http://www.perfprotech.com/store/articles/marine-exhaust.aspx

Tenmile,

Any feedback for us on your installation??

I spent some time yesterday R&R-ing my thermostate housing. Seems it was warped slightly, so I machined the gasket surface and used some quality Fel-Pro gasket material (http://www.amazon.com/Fel-Pro-3195-..._2?s=automotive&ie=UTF8&qid=1280156546&sr=1-2) to make a new gasket. A little Hylomar blue and bolted her back together, and no more seepage!

Still no leaks anywhere else in the system and she's running great!

 

[tenmile]

Re: Cast Iron vs. Aluminum Exhaust Manifolds and Center Elbows/Risers and best brands

So far so good. No leaks. One thing I do notice is that the boat now sits about 3" higher out of the water at the stern due to the lower weight.

This was my first time changing risers and manifolds and as a complete noob, it only took us about 30 minutes. Found that if you hang tighten the two outside manifold bolts a couple of turns that you can hang the gasket on these bolts and the holes all line up easily. This is best done as a two man job for certain. Would not have been able to do this myself unless I grew a 3rd arm.

Question for you -- did you add pencil zincs to your manifolds? Looking at that other link I sent you and they absolutely require them for their 5 year warranty. They are super easy to add by removing the two drain plugs from the side of each manifold. Think I will put them on as my boat is in salt year round.