exhaust manifolds switching from one piece, to 2 piece.

[t0mmy91]

hello, all, hope all is well. digging deeper into my project, here are the exhaust manifolds. i dont see any signs of water intrusion like rust or anything, but they are significantly rusted, probably causing over heating, and possibly why there is no thermostat in the t-stat housing. they dont make these one piece manifolds anymore, so i guess i have to switch to the 2 piece ones? i found these (newer pics) on marketplace. my question is has anyone switched over from 1 piece to 2 piece? and are these the corect ones? my one piece manifolds are oval at the ends, going into the rubber boot, but these 2 piece manifolds look circle at the boot. any thoughts or guidance?

 

[t0mmy91]

marineengines.com says you cant interchange them and i would have to replace the exhaust pipes, in addition to the one piece manifolds?

 

[scoflaw]

Forget Market place, look your parts up at Mercruiserparts.com. Enter your engine number

 

[t0mmy91]

Forget Market place, look your parts up at Mercruiserparts.com. Enter your engine number

hi, i did that, but the one piece manifolds are NLA, no longer available

 

[scoflaw]

Let me look. What's your engine number?

 

[t0mmy91]

Let me look. What's your engine number?

hi, thanks for checking...

it is OL353367

 

[scoflaw]

Ebay has a conversion for that. Type in 807293a2

 

[t0mmy91]

Ebay has a conversion for that. Type in 807293a2

is GLM any good? found this one also. http://www.mooreperformance.info/MercruiserV6conversionkit.html

 

[scoflaw]

Wouldn't be my first choice

 

[Scott215]

I think the one scoflaw picked out is a pretty damn good deal

 

[t0mmy91]

Ebay has a conversion for that. Type in 807293a2

just ordered the kit you sent from ebay. ordered it direct from the company for $1209.

still waiting on the gauge, shrader vale and plugs to do the pressure test.

 

[scoflaw]

Excellent, let us know if you have any concerns

 

[Scott215]

Yeah I know it sucks exhaust parts are expensive for boats

 

[Thornton69]

Just a FYI. Looked at several of the links along with the original market place photos you initially posted. Most of them show a restrictor gasket between the manifold and elbow. Depending on the plumbing you have, it is more likely than not that you need the gaskets with 4 slots. Here is Merc service bulletin on the subject.
Hope this doesn't add more confusion.

 

[t0mmy91]

Just a FYI. Looked at several of the links along with the original market place photos you initially posted. Most of them show a restrictor gasket between the manifold and elbow. Depending on the plumbing you have, it is more likely than not that you need the gaskets with 4 slots. Here is Merc service bulletin on the subject.
Hope this doesn't add more confusion.

Yeah looks like you're right, nice catch!

 

[Bill Curtis]

If engine is raw water cooled, the restriction gaskets (2 slots and 2 holes) are the ones that are recommended. Four open slots are for closed cooling (heat exchanger) engines.

 

[t0mmy91]

If engine is raw water cooled, the restriction gaskets (2 slots and 2 holes) are the ones that are recommended. Four open slots are for closed cooling (heat exchanger) engines.

hi, thanks for the info, what are you your thoughts on this bulletin? im not exactly sure which configuration i have, i believe 4A?

 

[t0mmy91]

here is my t-stat housing. 4 ports in total. 2 smaller ones go to exhaust manifolds, middle size comes from stern, and largest one comes from waterpump

 

[t0mmy91]

now im not sure which gaskets to order, any thoughts? im not sure which of these scenarios is my boat. i have a 4 port t-stat housing with one large port comng from engine waterpump, 2 smallest hoses going to the exhaust manifolds, and the middle size hose coming from the outdrive. any thoughts?

 

[t0mmy91]

here is a paste from mercruiser bulletin 2005-12. they have the 4 slot gasket in their conversion kit 864293A02.

Parts Required The 864293A02 kit contains nuts, bolts, rubber exhaust tubes, hardware and instructions to make the conversion from a one‑piece exhaust manifold to a two‑piece exhaust manifold. Due to shipping limitations, a complete kit is not available with exhaust manifolds. The following parts will need to be ordered as well as the kit:Qty. Description Part Number2 Exhaust manifold 99746A172 Exhaust elbow 807988A22Intermediate exhaust elbow (for use without risers) 14478T011Lower exhaust Y pipe (not required unless original Y pipe has failed) 807130A4