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View Full Version : Stainless Steel instead of Cast Manifold and Risers?



Chimo
16-07-2012, 10:40 AM
Hi all

I have a friend who's boat is probably in trouble with failing manifolds and risers. :(

Anyone able to suggest someone to do the job. (Gold Coast suburbs on an air berth.)

Also has anyone any comments on the replacement of cast risers and manifolds with these?
Hi-Tek Marine Stainless Steel Manifolds of Queensland. http://www.hitekmarine.com.au/

Thanks in anticipation

Cheers
Chimo

The-easyrider
16-07-2012, 01:28 PM
8238582384Hi Chimo I replaced my Manifolds with the Hy-tec ones about 12 months ago, I did them myself and it was pretty straight forward onceI had the correct ones. The job was broken to two parts because the first setwas the wrong size on the outlet side, but I would say about 1 and 1/2 hoursper side depending on the access. Main reason for going SS was so I dont need to do them again in five years orNo great fuel savings or masses of extrapower as claimed but never expected to get them as they are only a set of so extractors in a water cooled jacket, although there is a noticeable increse inpower but that would be noticeable with even new cast manifolds as the old oneswere quite restricted with crap. There was a noticeable change in the exhaustnote but nothing over bearing and to be honest the Bevin in me likes the deepernote but a V6 can only sound so tuff. Probably picked up about a litre an hourin fuel saving but the most noticeable difference is the motor now respondsmore quickly across the rev range. Will try to dig out some pics I have an exel doc that shows the befor and after results but can't work out how to post it so can email it to you if you want.

Cheers AZZA

terryc
16-07-2012, 02:07 PM
I fitted Hi Tek stainless about 2 yrs 2mths ago to my 4.3L v6 mpi mercruiser, opted for the taller ones to help prevent against reversion (water flowing back into motor). Had to make up small bracket to extend out the oil filter which on mine sits on top of motor, also needed small bracket extension for cables (this supplied free by Hi Tek) I paid $2000.00 and am very happy with them, have removed one after 12 mths and still looked brand new. Found Hi Tek very good to deal with could not have been more helpful. By now with cast iron i would be half way to replacement again, expecting to get 10 yrs plus from stainless, i highly recommend. Also fitted them myself was fiddly and time consuming with allen key supplied but worth the effort.
regards terry

wirlybird
16-07-2012, 05:13 PM
Bloody expensive way to go i have got the alloy version and i can tell you you will save 3/4 in weight with the alloy ones.

its a no brainier

Chimo
16-07-2012, 06:41 PM
Hi whirlybird

Who does the alloy version and whats the price difference between them and the SS ones?

Whats the likely life of alloy vs stainless steel?

thanks

Chimo

The-easyrider
16-07-2012, 07:48 PM
Good point Whirlybird I think for memory the cast manifolds were 29 kg for the pair compared to the Ss at 6.6kg

wirlybird
17-07-2012, 06:03 AM
im not sure how long they last probably longer than sst as the sst ones crack.

with alloy you have a couple of options as my engine is close cooled i only use the alloy risers from memory around $200 for the pair

but it depends on the size and make of the engine

The-easyrider
17-07-2012, 12:29 PM
I did a far bit of research before going down the SS road and the only evidence of cracking in SS manifolds was with cast ones this was also reported as a problem with cast alloy. I could not find a bad report on the hi-tek ss ones. They are made in china these days but the workmanship is first rate and with a five year warranty I did not think I could go too wrong with units around ten years old and still going strong. Allan from HY-tek is down the gold coast way and is quite helpful and knowledgeable on all thing motor wise as he comes from a drag back ground.

wirlybird
17-07-2012, 01:00 PM
definatly not saying they are totaly crap but they do crack depending on the HP and temp you put through them and there are many other brands out there

http://teaguecustommarine.com/index.php/exhaust.html

the big thig is your replacing the whole manifold and you may not have to if its close cooled. The salt only hits the riser.

Either way you go at least you will be armed with all the information to make the right decision :)

terryc
17-07-2012, 02:28 PM
i did the same as easyrider, researched pros and cons and settled on SS, could not find a lot of support for alloy. My system is not close cooled so hence having to replace the manifolds & risers 4 to 5 yrs. The cost of mercruiser cast manifolds & risers were about the same cost of $2000. After market Cast would have been the cheaper alternative but i wanted to try and avoid the rapid corrosion factor. Longevity? for easy rider and myself only time will tell.

Chimo
17-07-2012, 03:44 PM
Well we cranked her up today while on the air dock with a fresh water hose , Mercruiser 350 MAG MPI and a solid, black, oily slick appeared from the exhaust. What else is going to be wrong?

Cheers
Chimo

The Woo
17-07-2012, 04:17 PM
Did it clear?

What you describe is usually just carbon deposits or unburned fuel upon start-up.

Chimo
17-07-2012, 04:21 PM
T W

Didn't seem to clear.

How long before you would expect it to clear?

C
C

The Woo
17-07-2012, 04:25 PM
10 seconds or so....

I assume you eman black shit running out the centre of prop with the water?

Chimo
17-07-2012, 04:37 PM
Woo

We ran it longer than that (couple of minutes) and I presume it came out the centre of the drive leg with the water. Didn't seem to clear

C
C

Chimo
25-07-2012, 04:50 PM
These are what is being fitted in the next days. Three inches higher with no exhaust restriction so it should breath a fair bit better and being SS rust should be a lot less of an issue. Just add $'s

Cheers
Chimo

http://www.hitekmarine.com.au/images/products/merc-chev/front-manifolds-lrg.jpg

The-easyrider
25-07-2012, 05:28 PM
Looks cool a trick I did with mine as there is no studs to hold the gasket in place was to tie the gasket to the manifold lightly untill you get two of the bolts in as they are a bit fiddly

Midnight
25-07-2012, 08:26 PM
Chimo, are they inlet and drain fittings on the water jacket? Nice looking bits of gear.

I'm gonna go all out here, the problems,(there are 2 majors), with all of the OEM cast exhausts, and all of the aftermarket exhausts I have seen is;
1. They all run wet exhaust designs right down to the manifold join. The raw water just pools in the exhaust after shutdown causing them to rust out. The stainless versions just delay this process.
2. When the inevitable corrosion, due to the above, breaks through the internal exhaust gas path manifold, the raw water just drains back into the exhaust port, and perhaps into the cylinder with an open exhaust valve.

To make it work properly, you need to go to dry extractors with heat shield blankets, and add the raw water after the spill over point, so that after shut down, all the salt water goes downhill and out the exhaust.

Thermal tape heat shield as used on many Harley's and drag boat etc will do the job for any stern drive installation.

A little research will reveal pics of what I am talking about, it is really simple to engineer.

Cheers,
Myles

BM
25-07-2012, 09:11 PM
Couple of Options here Chimo.

The best solution would possibly be to run freshwater cooling. This way the only sacrificial component is the exhaust elbows.

Alternately, you could run dry joint manifolds. These don't have the inheritent failure points in the union of elbow and manifold. It's 2 sealed (from water) surfaces mating. The water comes out a port in the manifold and goes in a port in the elbow. This keeps the elbow and manifold water cooled thus eliminating the need for heat bandages. Corrosion will get to these manifolds and elbows too but it will take longer as the fail point is usually the narrow gap between the exhaust chamber and the cooling galleries.

Fresh is the go. Need a seawater pump (pulley driven), hull pickup and hose, couple other hoses and some mounts.

I have a source (may have dried up by now) but they had a lot of Mercruiser stuff brought in from the US and they had a few heat exchangers and many other spare parts. I picked up a late model heat exchanger very cheaply. Still sitting on the shelf for a rainy day. :)

Cheers

Chimo
26-07-2012, 06:54 AM
Have passed on all your comments to the owner who is at present in the outback and as its his money it up to him which way he goes.

Can you do a dry exhaust with fresh water cooling, that sounds like a best of all worlds set ups, spoken by an outboard owner, by the way!

Cheers
Chimo

wirlybird
26-07-2012, 07:16 AM
Dry dosent come without its issues the heat still needs to be dealt with somewhere and the method of heat exchanging can vary
The offshoreonly forum has lots of pictures with lots of ideas to bes suit your needs and in most cases your talking to the creator of the manifold in question or the person who uses it to Race offshore so it should be ok for a recreational application..

BM
26-07-2012, 07:17 AM
Pete,

You'd want to double check with Mercury but I reckon yes you could use dry joint manifolds as a freshwater setup. The discharge point of the manifold would remain blanked off and the seawater exiting the heat exchanger would go straight to the exhaust elbows.

terryc
26-07-2012, 10:20 AM
Those screw in parts on the ss manifolds hold the sacrificial anode which gets replaced yearly. I've researched a lot on the Iboats forum about upgrading to closed water cooling and the general opinion was that if the motors were more than 12 mths old and run in salt water, it was best to leave them as raw water cooled as there would be scale inside which could break off and cause blockage problems.

snatchy
30-07-2012, 02:30 PM
Pete,

You'd want to double check with Mercury but I reckon yes you could use dry joint manifolds as a freshwater setup. The discharge point of the manifold would remain blanked off and the seawater exiting the heat exchanger would go straight to the exhaust elbows.

We have the 4.3 V6 with FWC as a factory option, which came with dry joint exhausts. 2005 model. Manifolds are part of the FWC. So it can be done using genuine mercruiser parts.

snatchy
30-07-2012, 02:35 PM
im not sure how long they last probably longer than sst as the sst ones crack.

with alloy you have a couple of options as my engine is close cooled i only use the alloy risers from memory around $200 for the pair

but it depends on the size and make of the engine

Whirlybird. Would you mind telling me what alloy risers you have, and any other usefull info on them?
I am looking at what risers to get for when ours need replacement.

wirlybird
30-07-2012, 03:02 PM
Hi snatchy
I have two types H&E and osco. The H&E ones are much lighter but the verdict is out as to what one will last longer but with proper anodes they should last for 10 years.

But if you have the money i would buy stainless and get a good brand name.

snatchy
30-07-2012, 04:51 PM
Thanks wirlybird

Chimo
30-07-2012, 06:19 PM
Its happening mid week. :P

Snatchy talk to Alan at http://www.hitekmarine.com.au/
Ask him why he reckons his don't crack.

Cheers
Chimo

cormorant
30-07-2012, 06:42 PM
Can stainless be ceramic coated both inside the exhaust and also the water galleries to give them a even geater life and at what cost?

Chimo
30-07-2012, 06:57 PM
They do it with HWS cylinders so you would think its possible but the cost may make it too dear.

Snatchy
"We have the 4.3 V6 with FWC as a factory option, which came with dry joint exhausts. 2005 model. Manifolds are part of the FWC. So it can be done using genuine mercruiser parts." How long has it / did it last? Would SS risers make it even"more better"?

Cheers
Chimo

snatchy
31-07-2012, 12:48 AM
Snatchy
"We have the 4.3 V6 with FWC as a factory option, which came with dry joint exhausts. 2005 model. Manifolds are part of the FWC. So it can be done using genuine mercruiser parts." How long has it / did it last? Would SS risers make it even"more better"?

Cheers
Chimo

Hi Chimo

Our setup is a bog standard from the factory FWC setup. As new and untouched. The engine/sterndrive package says built in 2005 but we first began the corrosion process in early 2007. Even better I am in the wet tropics to expedite the corrosion. I expect the risers to need changing in the next year or two, though they look fine and temperatures have not changed.

I need just the riser, and if i could get SS risers they would be a great option and indeed would be "more better" to complement the existing FWC manifolds that should last a decade plus. I have not seen SS risers available - Hi tek only seem to do the complete manifold/riser all-in-one thing. Has anyone seen SS risers for the newer dry joint system?

Cheers

snatchy
31-07-2012, 12:57 AM
Its happening mid week. :P

Snatchy talk to Alan at http://www.hitekmarine.com.au/
Ask him why he reckons his don't crack.


Cheers
Chimo

I'm right thanks ;D . I think it was wirlybird who mentioned cracking.

wirlybird
31-07-2012, 06:02 AM
there are some sst units that are known to crack probably made in china and there is more than 10 brands out there.

i have no experience with hitek but at 3-4 thousand they would want to be special.

you can get stainless risers only from the states but make sure they are pressure tested

Chimo
31-07-2012, 06:54 AM
The ones being used are quite a bit cheaper that the figure you mention WB. Anyhoo time will tell.

Cheers
Chimo

wirlybird
31-07-2012, 10:58 AM
Sorry chimo im quoting the big block prices

Chimo
09-08-2012, 02:13 PM
Done.

Sounds good and no doubt would be an even better V8 note if the the exhausts went straight out through holes cut in the transom above the water line instead of through the back-pressure inducing "Y" fittings and out through the leg.

Looks shiny too!

Cheers
Chimo

PS Still reckon an outboard is a better idea if its going to operate in salt water, or a diesel shaft with FWC.

MarkIC
01-11-2012, 11:27 PM
Hi Chimo

Our setup is a bog standard from the factory FWC setup. As new and untouched. The engine/sterndrive package says built in 2005 but we first began the corrosion process in early 2007. Even better I am in the wet tropics to expedite the corrosion. I expect the risers to need changing in the next year or two, though they look fine and temperatures have not changed.

I need just the riser, and if i could get SS risers they would be a great option and indeed would be "more better" to complement the existing FWC manifolds that should last a decade plus. I have not seen SS risers available - Hi tek only seem to do the complete manifold/riser all-in-one thing. Has anyone seen SS risers for the newer dry joint system?

Cheers
Hi Snatchy
have you pulled your risers lately?? I have a 660 whitley cruiser with the same set up you have and about the same age. I have only recently bought the boat and will be checking mine soon, just waiting on spares to arrive ex the USA. The original owner always flushed with MACS salt remover so it will be interesting to see how they look. I will pressure test as well.
I spoke to Hitech in Perth who do a lot of merc re-powers (different to the ss guy) and they are saying they are seeing some dry joint manifolds and riser lasting 10 years with proper flushing.
Will post pictures in the next few weeks when I get them off.
Cheers Mark