Slidin' in a cam. 165 HP inline 6 cyl.

[Dodgerrr]

Okay, just a reminder that I had to replace the engine in the boat and I took it out of our old combine. Now, after some research I have found that most 250 in line 6's had a different camshaft than the Mercruiser. The difference is originally the boat had 165 HP and this engine has 140-145 HP. All on account of the camshaft. Being a diesel mechanic, most of the older engines I have worked on never even had cam bearings, primarily Perkins diesels.
My Question is ... Can I just slide in the new (proper) cam and lifters with out changing the bearings? Has anyone done this? The engine still has very good oil pressure. The extra 20-25 HP would explain why it takes so long to get up on plane. Both engines have flat top pistons so I don't believe that higher valve lift will be an issue.

[THEFERMANATOR]

I've done cam swaps many times without doing bearings. The biggest differrence in the cams is taht marine cams are designed to minimize overlap so as to avoid any chance of sucking water back into the engine whereas cams used for cars and off road don't have to worry about that.

[macojoe]

when i had my 165 i swaped a truck motor in to it cause boat motor was junk. we did not replace the cam, instead we just proped it with a 15 x 15 1/4 and it was like nothing changed.

[Dodgerrr]

I cannot believe how hard is is to find the original cam specs and the original specs from the combine. (I assume the combine is an industrial or truck version). The original cam from Merc is NLA and the combine is definately on the missing in action list.

Off topic...I have an original 1974 owners manual , a Mercruiser 120-140-165 Marine engines installation manual and one more engine specific manual all totalling about 40 pages. I would like to share with the group but don't know where to post them on the site. Full of great information.

[macojoe]

scan them then email to me, i will add to the gallery with the wellcraft brochures

[spareparts]

these guys will have a cam for you
http://www.cliffordperformance.net/

I'll see if i can find a factory service manual for the 165, it will have the stock cam specs

[THEFERMANATOR]

I cannot believe how hard is is to find the original cam specs and the original specs from the combine. (I assume the combine is an industrial or truck version). The original cam from Merc is NLA and the combine is definately on the missing in action list.

Off topic...I have an original 1974 owners manual , a Mercruiser 120-140-165 Marine engines installation manual and one more engine specific manual all totalling about 40 pages. I would like to share with the group but don't know where to post them on the site. Full of great information.

The combine will most likely have a truck or industrial generator type camshaft in it. I'm 99% certain that MELLINGS stil makes marine camshafts for the 250 as MICHIGAN MOTORS still remanufacturs the 250 for marine useage. If not CLEVITE may still have them. CLIFFORD does alot for performance use, but I don't know if they did much for marine use. They do still have alot of performance parts for the straight 6 dinosaurs.

MELLINGS does still make them, part number 22118. And it is quite differrent in the duration and cam lobe design VS the truck cam, so I could only imagine how differrent it is from the combine cam. I found it at several places for $140.
http://www.omnitek.co/mellingweb/Partdetails.aspx?Part=22118&From=A

[Dodgerrr]

Macojoe,I sent you some emails containing the manuals. If you cannot view them let me know and I will send them to you again. I used your gmail address.
Dodgerrr

[spareparts]

basicpower has it http://bpi.ebasicpower.com/p/MEL22118

[Dodgerrr]

MELLINGS does still make them, part number 22118. And it is quite differrent in the duration and cam lobe design VS the truck cam, so I could only imagine how differrent it is from the combine cam. I found it at several places for $140.
http://www.omnitek.co/mellingweb/Partdetails.aspx?Part=22118&From=A

Well thanks to everyones help I think I have finally found the specs I need. There certainly is a difference in the 250 Marine cam.
Mellings 22118 seems to be the best one at $139.95. The link below shows a wide variation between the auto/truck/marine cams. I tried to post it as a pic but the PDF file is too large. (really it is only 2 pages)
Thanks again all!
Dodgerrr

http://www.inliners.org/tech/cams250.pdf