165 IL6 Manifold Replacement (UPDATE)

[FreeBeeTony]

I am in the process of odering a new manifold for my Mercruiser 165 IL6 from OSCO. There is a note on their web page that says not to use with a closed cooling system. I asked why and they said because it would get too hot and could crack. They also mentioned about air pockets in the system. <br /><br />Anybody have any experience with this? I installed the FWC system last year and it seemed to work OK, it did run hotter: ~190-210 but I thought that was reasonable.....the old manifold didn't crack........I am replacing it thinking it may be partially clogged and might get better cooloing with a new one.

 

[Laddies]

Re: 165 IL6 Manifold Replacement (UPDATE)

Get a Sierra here at iboats

 

[Bt Doctur]

Re: 165 IL6 Manifold Replacement (UPDATE)

What deg. therm .are you using?also the heat exchanger should be a 4 inch dia. system.what condition is the impeller in?

 

[FreeBeeTony]

Re: 165 IL6 Manifold Replacement (UPDATE)

180* thermo......H/E is from a V8.

 

[ziggy]

Re: 165 IL6 Manifold Replacement (UPDATE)

hey tony, i got no idea about your closed loop cooling or the ramifications of useing that osco manifold, however, osco website says, do not use on closed cooling applications. i'd just not do it. they must have some reason for saying that. Wondering what the price was for it though?. i'm interested myself. bet i will be replaceing my manifold also. mine for old age and has been repaired. Heres one. http://www.perfprotech.com/portal2/store/ProductDetails.aspx?productID=1440 ceramic coated? must be good huh? $399. best price i've seen for a manifold so far, ceramic coated or not. this manifold above says not for A11 use. i don't know what the A11 is. (my guess is two different carbs. 4 bolt or 6 bolt pattern, best i can tell)i got the 6 bolt. I wonder if there's a good reason to use or not to use a ceramic coated manifold? there's always oem i guess. i would think that would work on your fwc. mighty pricey though. ladyservice. i must be blind. i looked here for a manifold. i don't see sierra manifolds here at iboats for a 165. am i really blind?. for me i'd really rather go oem. oem parts always seem to work proper for me. for my situation though, old boat that is, i would think that aftermarket would be at least better than what i got.

 

[FreeBeeTony]

Re: 165 IL6 Manifold Replacement (UPDATE)

Think I am going to cancel my order with OSCO...........

 

[yoced]

Re: 165 IL6 Manifold Replacement (UPDATE)

Tony, I am familiar with your system, and seen the photos of how you did it. I can guarrantee the Osco will not back up you manifold once (if) it stress-cracks.<br /><br />The original design of the internals of the merc manifold was weak from the get-go, and everyone else copied the merc design. Mercruiser even stopped making them because of the warranty problems involved. Several years ago they even bought a whole bunch from Osco to try to solve their warranty issues. Osco has tried several times to fix the internals of that manifold, and their latest design (about 4 years old now I think) does do better, but will still crack under the conditions that your system imposes.<br /><br />The most bullet-proof I6 manifold (which is still sold actively by the major aftermarket folks) seems to be the Osco MO618 manifold - I have NEVER seen one crack internally for any reason. But they take some getting used to when it comes to implementation - and you would have to rig yours (again) to make it work properly.

 

[yoced]

Re: 165 IL6 Manifold Replacement (UPDATE)

Ziggy, that manifold sold by ppt is a direct copy of original design. The ceramic will change nothing when it comes to cooling problem.

 

[FreeBeeTony]

Re: 165 IL6 Manifold Replacement (UPDATE)

I ordered the one from PPT..........

 

[ziggy]

Re: 165 IL6 Manifold Replacement (UPDATE)

tony, the ppt looks like the way to go to me too. let us (me) know how ya like it after ya get to feel it for a little bit. i hope that fixes yer problem for ya. i'm a little concerened for you that the thermostat is doing just what it's supposed to do. reason i'm saying this is because of this statement. from the power squadron engine maint. book 102. thermostat. "Generally they begin to open at the rated temperature and are fully open at appprximately 20 degrees higher." that would put you right in the ballpark of your 180 t-stat. yoced. the osco web page for the MO618 said the same thing about not useing it period for a fwc sys. why flirt with disaster if ya don't have too. + it looks like some unnessasary work, starting with the 4 bolt carb. i'm assumming tony has the 6 bolt carb. i have the 6 bolt carb. fun enough to work on boats, but no point in makeing it hard. a direct replacement seems the way to go to me. i wonder why the osco manifold was not recommened for the fwc sys. i see no referance to a different manifold for a open vs closed sys. in the clymers manual(working on getting the oem maunal). if the osco manifold has been beefed up from oem, made better and stroger, because of a know defect(weak in the internals) in the oem design. why can't ya use it in a closed sys. what's up with that. the ppt manifold says its a copy, + their ceramic coating for corrosion protection. no mention that it couldn't be used for fwc. tony, are ya gonna do a riser too? on general principles since your thinking your manifold is clogged from corrosion. one last note. called the merc dealer here today, quoted $800 for oem manifold, .

 

[ziggy]

Re: 165 IL6 Manifold Replacement (UPDATE)

tony, let us know if ya think that cerarmic anti corrosion coating on that ppt manifold looks like its a good thing to you. guess it sounds good to me, if it stays adheared to the cast. darrendarnell just posted a website that has the 165 manifold for $363.5 i think, + gaskets and the likes. didn't read to see if the ppt came with gaskets or not.

 

[yoced]

Re: 165 IL6 Manifold Replacement (UPDATE)

Ziggy, the OEM never had FWC on their engine. In order to have FWC you have to take water OUT of the manifold. That manifold is not designed to do that. Tony got around that by drilling and tapping a new fitting on the rear of his manifold.<br /><br />The rochester carb that fits the Osco MO618 was also the original carb for the OEMs in most cases at the time.<br /><br />The same rigging that he did to his current manifold would have to be done on the MO618, and will have to be done on his new manifold. The main difference is that the MO618 has a top plate between the manifold and riser that could be modified (instead of using the rear plate as he did.) It is actually harder to accomplish, but the main benefit is that his water outlet is then the highest point - therefor it is self bleeding. Tony's current setup takes water out too low (opinion) and leaves him some steam at the top edges of his manifold instead of water.

 

[FreeBeeTony]

Re: 165 IL6 Manifold Replacement (UPDATE)

I didn't "drill and tap" anything.<br /><br />I simply replaced the rear end plate with one like the front end plate (with a hose fitting).<br /><br />I'm hoping I get enough of a flow as to keep the temp to a reasonable level.

 

[yoced]

Re: 165 IL6 Manifold Replacement (UPDATE)

corrected, I stand.

 

[Bondo]

Re: 165 IL6 Manifold Replacement (UPDATE)

Hi Tony,<br /> Last night I had a pretty good post going.... When I went searching for some info, I screwed up,+ Lost it all in cyberspace.......I'll try again now.......... <br /><br />I know I can Boil water in a Papercup with my Ox/Ac torches,.... So I Still don't understand the issue with the manifolds........<br /><br />yoced brings up a couple of interesting points,......<br /><br />The 1st one, I Disagree with......<br />Coolant is Pushed Into the manifold from the engine Block, thru the T-stat.......<br />The Only place water is Pulled, is from the H/E.........<br /><br />I Can See where an Air Pocket could happen...... The nipple that you're using Is below the Top of the waterjacket of the manifold........<br /><br />Even though I don't have that endcap anymore, I was out looking at the manifold.....<br />It appears to be about the Same as the 1 shown in the link above, only 2 cylinders shorter....<br /><br />They both have a 1/8th or 1/4" pipe plug, just to the Aft of the carb mounting flange..... I'm Thinking this port goes to the Waterjacket.... I couldn't remove the 1 in my 30 year old manifold,... Yet...... , But I Will before long.......<br /><br />My thinking is, If this plug goes into the waterjacket, You could install a Petcock in it,+ Purge the Air out of Your system when filling it.......<br /><br /><br />I don't know if this is even an issue with Your system, But, An Air Purge valve will tell you For Sure.........<br /><br />I'm going to either remove that plug, or Destroy the manifold trying...... Either Way, I Hope to have an Answer for you soon..........<br /><br />This post is considerably Shorter than last nites, But, I Think I covered most of the same points I meant too.........

 

[Don S]

Re: 165 IL6 Manifold Replacement (UPDATE)

It sounds like you are trying to run anti freeze through the manifold, if that's the case, then it will get too hot. Besides that, that's not how it's supposed to be set up. Look at the picture below that shows how the cooling system works with the closed cooling system. Besides that, 200° is way too hot for an engine in an enclosed engine compartment. You shouldn't be running over 180°.<br /><br />

<br /><br />

 

[FreeBeeTony]

Re: 165 IL6 Manifold Replacement (UPDATE)

Hey guys.......<br /><br />Bondo, the plug you are refering to is on the intake of the manifold.....I connected a vacum gauge to it when I set the idle on the carb..<br /><br />DonS, yes, I am running anit-freeze through the manifold. I took it one step further than the above picture and FWC'd the manifold....<br /><br />I'm hoping that the 200* temp is not too hot...I really don't want to re-plumb this thing!

 

[Bondo]

Re: 165 IL6 Manifold Replacement (UPDATE)

Bondo, the plug you are refering to is on the intake of the manifold.....I connected a vacum gauge to it when I set the idle on the carb..

In that case,<br />There's an area just below the riser flange, portside of the manifold, where you could drill,+ tap in a fitting to do the same thing........<br />Purging the air out.......<br /><br />Either way, I'll be watching for your posts in this endeavor............

 

[Don S]

Re: 165 IL6 Manifold Replacement (UPDATE)

200° is way too hot, you are just overloading that heat exchanger and raw water pump. They just can't keep up with that much heat.

 

[tommays]

Re: 165 IL6 Manifold Replacement (UPDATE)

tony<br />just wondering does the motor run at this temp all the time or does it climb as the boat speed and load is increased<br /><br />this would give a good idea if the heat exchanger is to small or you need more water flow to get to a better temp level<br /><br />tommays