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View Full Version : Questions about idle reliefs and finger porting on Merc V6s...


Steve2ManyBoats
12-30-2008, 03:09 PM
I'm trying to narrow down my choices for a starting point for my first Merc V6 build-up. I've started a thread and read a bunch more. Folks here have been very kind and I've learned a lot. Since I'd like to try my hand at porting, I'd like to stick with a steel block. Since I'd like to make as much power as possible (on a budget), I'd like to start with a 2.5.

Here are my questions:

1. If 2.5 motors are behind the liner motors, do they need finger ports? If so, which 2.5 blocks have them?

2. Which 2.5 motors DON'T have idle reliefs? From my forum searches, seems that most do. Do all 2.5's have idle reliefs?

Budget constraints mean that I'm almost certainly going to have to start with a fishing motor block.

Thanks...Steve2ManyBoats
Capt.Insane-o
12-30-2008, 03:22 PM
Behind the liner blocks do not need finger ports. Your best bet for a non relief block is a 200.
Steve2ManyBoats
12-30-2008, 04:50 PM
There's a good running 98 150 available locally for a song and I was hoping that it wasn't an idle relief motor. Oh well, I'll keep looking.

Thanks...Steve2ManyBoats.
T-REX
12-30-2008, 07:22 PM
them Idle reliefs don't hurt az much az one would figger...I built a fren a 200 witout tha reliefs and it ran purdy good...when he blew it up(Stock cast piston broke) I hadda use a 150 block wit tha reliefs...HE COULDN'T TELL THA DIFFERNCE!!....jmo
Jay Smith
12-30-2008, 07:50 PM
The relief motor is not the "best" canidate for a hot rod motor IMO. I'd keep looking till I found a 200 without the relief slots...

my .02
Capt.Insane-o
12-30-2008, 08:23 PM
Uh oh.. not you two again! ;)
Da Bull
12-30-2008, 09:59 PM
I would perfer a 200 or 225ProMax. Both are realy good motors and neither have the relief slots.

DB
mach351
12-30-2008, 10:59 PM
ive only seen 150's and 175's with the reliefs - not any 200's, but i could be wrong:cheers:
Capt.Insane-o
12-31-2008, 04:32 AM
There's a good running 98 150 available locally for a song and I was hoping that it wasn't an idle relief motor. Oh well, I'll keep looking.

Thanks...Steve2ManyBoats.

Unless your racing for points and money, and this motor is in your budget buy it and use it. I've ported 2.0's and 2.4's with reliefs and they run very well. Like you said it's your first build and the motor can be had for a song, go for it.
T-REX
12-31-2008, 08:34 AM
Now I didn't say tha relief mota wuz better, naturlly tha non relief mota would be!!...BUT, az in yo own words, a 150 iz avalible for a song!!...Do tha 150 for a song, or go ahead and order ya a new block from mercury, and fergit ya on a budgit!!....it'z all about tha money...It don't meen az much to sum az it does ME!!!:D


Uh oh.. not you two again!

LOL....jay don't like them relief's...kuz they iz taller than he iz!!:D:D:p:p
Jay Smith
12-31-2008, 08:34 AM
:iagree::iagree:BUT a non relief motor block can be bought for almost "song" ..

my .02
Dave S
12-31-2008, 04:21 PM
The 1990 2.5 200 had them .... I think they droped them around 1995. The ones with the reliefs are trickyer to port as you have to get the port to be kind to the rings with this stupid slot in the way 1/3 ...2/3 in the port. How about some kind of Epoxi that would block some of the slot? They blow up ether way.:rolleyes: