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Re: anyone rebuilt a Mercruiser 140?

Posted: Sat Nov 22, 2014 9:51 pm
by lovetowrenchit
Schurkey wrote:
lovetowrenchit wrote:this is good info, the 140s and 3.0 have 350 sbc block from what I understand
NO. The 153/151/3L all have an entirely different block design compared to the 350. The bellhousing bolt pattern on the 153 and 3L, and maybe the bore spacing is similar to the small-block.

As I said earlier, the 153 was a four-cylinder version of the 230 six-popper. This engine family was revised more times than I can count; but the 3L block seems to have more in common with the 153 and the six-popper than with the later versions of the 151.
thanks for clarifying that for me, and I need to go find some info on the 230 six-popper, sounds interesting

Re: anyone rebuilt a Mercruiser 140?

Posted: Sat Nov 22, 2014 9:58 pm
by lovetowrenchit
I'm actually looking at pics, and reading about the 230 6 popper, good stuff

Re: anyone rebuilt a Mercruiser 140?

Posted: Sun Nov 23, 2014 9:16 am
by lovetowrenchit
lovetowrenchit wrote:I'm actually looking at pics, and reading about the 230 6 popper, and the 153, good stuff

Re: anyone rebuilt a Mercruiser 140?

Posted: Wed Apr 08, 2015 8:49 pm
by lovetowrenchit
Well, I thought I would update this thread

I did finally rebuild the Mercruiser 140 over the past few months and I'm pleased with the results, here are a few videos

sorry not quite sure on how to post a youtube video

1st startup after fresh rebuild

here it is after about an hour of running, found out my Fel-pro 2 piece rear main seal stared to leak

here it is after re-installing a new GM 2 piece rear main seal and setting the electronic base timing

Re: anyone rebuilt a Mercruiser 140?

Posted: Mon Aug 07, 2017 2:02 pm
by rmyauck

Does anyone know if the 1987 head from my 3.0L (has dished D shaped pistons) will work on a similar year 3.0L rebuilt .060 short block (it also has a 2 piece rear seal and my flywheel will bolt up) I found that has flattop pistons (the owner claimed it had those) or will the compression ratio be too high? I could use premium fuel (91 pump) no problem.

I see a site showing 2 part # s for their replacement quicksilver heads, with one for 1963-94 and the other for 1990 and up having a different part #



Re: anyone rebuilt a Mercruiser 140?

Posted: Mon Apr 16, 2018 12:09 am
by pdq67
I know, it's a 140" 4-banger!

If still interested, try to find a copy of Leo Santucci's great 6-banger book.

Clifford 6=8 may help as might Langdons Stovebolt Engine Parts.

We have access here to the more modern design 153, 4-banger, 194", 230", 250" and the tall 292" truck 6-banger engines. It's just that the larger boat 4-bangers are kinda off the beaten path.

Sorry that I am not up on the older 261" GMC and 235" Chevy 6-bangers?? I think there is even a 300+" 6-banger in here too?

I do know 1st hand from way back that a hopped up 261" will RUN!! A solid Isky cam, split exhaust manifolds and (2), maybe (3), 1-barrels, (maybe small 2-barrels?), on her. Add a '55 Chevy Post with a strong 4-speed manual transmission andsay 5.38's in back along with real slicks and go big engine hunting in the 1/8th mile! Up the compression and add good gas and go..

I'm hoping that the 6-banger info I am providing might help you with a 4-banger is all...


Re: anyone rebuilt a Mercruiser 140?

Posted: Tue Apr 17, 2018 1:59 am
by ProPower engines
The 140 Merc came in 2 versions just for those that don't know about all the 140's.
1 version was really a 2.3Lt ford pinto/ranger PU engine the other was a version of the 153 4cyl. but with a 4" bore.
They used there own piston which fits not automotive application but they did use a std. 4" bore ring. They had a funny comp. height but the rod bearings used in those engines were a H series type or Chamfered bearing ( cb663hn is current # ) but they have the notchs cut in the shells to oil the thrust side of the bores cause they were prone to scuffing pistons when not used
And a regular main set although cheaper to use a set for a 250 L6 engine they are less then half the cost.
They had a different chamber size so the earlier head from the 153 while it fits has too much compression causing damage if used every time. Now they have updated the port sizes so there is a new head that must be used with all manifolds.
They do have a 2.02/1.6 valve combo with hard seats installed but they are still a thin casting and prone to casting.

They were discontinued in favor of the 470 and lated 485 3.7 Lt engines that were like 1/2 of a 460 ford engine.
Another very cool engine package with internal water pump and alternator so no belts making a great street rod engine as it has a sm blk bellhousing bolt pattern. But thats for another thread :lol: