Inliners International Forums General Discussion Engines mercruser

Has anyone just bolted a 250-165hp Mercruser in a car?? I got one and at a glance looks like you can remove all the marine stuff and it will bolt up.Is there a rotation issue with them and if so I guess the only way to tell is hook up the starter and give it a spin. I searched the foram and only came up with a couple of posts and nothing about a swap. Just thinking out of the BOX...........SCRAP.... :rolleyes: :rolleyes:

It's the same basic engine but you're right in watching out for a reverse rotation job. Not all boat builders use a left and right rotation engine for twin screws. Some change the prop shafts rotation through the marine gear
( transmission ) and both engines are conventional rotation units. Some engines will even have a tag or decal on the valve cover to indicate it is reversed rotation.

Mike

How about the cam in these motors..is it the same as the car 250?? Where can I find some specs. on this motor..SCRAP

Scrap, I've got a 181 Mercruiser/4-sp in my Model A 2-door. The bellhousing flange is the same as for the '62-up sixes and SBC V8s. I've had two of these before and they can really be made to run, while still get pretty good mileage.

Here's what I've done to the one I have now:

1. Pocket-ported the head and installed hard exhust valve seats, w/1.94" intakes and 1.50 exhaust stainless, swirl-polished valves. New double-wound springs were used, too.

2. Cam: (I recommend NOT using the marine cam, as they seem to have very weak low-end performance) I had a stock Chevy II 153 cam reground and hardened by a can grinder in Georgia. The specs are: Duration is 252 degrees (intake) 264 degrees (ex) or, 205 degrees (in) 214 degrees (ex) @ .050". The lift is .502" for the intake and .525" on the exhaust. The engine really pulls hard at low RPM, but will rev quickly and has a lot of mid-range power.

3. Carburetion: I bought two progressive two-barrel carbs from Tom Langdon and built my own intake (water-heated). They work great!

4. Headers: homemade, too.

5. The engine was bored and flat top 9:1 pistons used. New, stock configuration oil pump installed. I also had the rotating mass ballanced, but that was probably wasted money for a 4-banger.

6. Ignition: Bought a rebuilt HEI distributor from Tom Langdon. I could actually feel the difference in power and starting over old point-type distributor.

Hope this gives you some ideas. E-mail me and I'll send you some pictures of it. drh@digital-link.net

Thats a suprise,I was thinking the cam would be a bear on the low end as boats have to pull up skiers.....live and learn..Sound like you have a real sweet 4banger.Thanks for the feedback.SCRAP

Dennis,do you have any 153 rods?? I have a project in mind with a 250 block/292 crank and looks like 153 rods may be just what I am looking for...SCRAP

Sorry, I have a complete .040 overbored 153 engine, so wouldn't want to split it up. I believe 230 6 cylinder rods are the same, though.

FYI..Pulled the Mercruiser down to find the crank has been balanced at Chevrolet or who ever put these motors together for Mercruiser.The rods look to be stronger and have been balanced.The pistons were cast but I looked in the piston book and it showed that some came with forged pistons.The cam has somewhat higher lift and the GM# is 3891580...Wish I had some way of finding the specs ??? When I put it back together I will put a degree wheel on it and let you know. Going back with 307 flat tops .020 over and larger valves in a 184 head....should run plenty good for my 50 Chevy..SCRAP

Scrap,

I seem to recall that somewhere on a web site there are specs for that marine cam. If I remember right it is more duration and lift than the stock car cam but not as good as any of the currently offered 260 degree hydraulic grinds available. About 4 years ago when I was planning my 250 I researched everyplace I could think of and came upon that cam. I'm sorry I don't recall exactly where I found it but I know for sure that after running the numbers I decided against it for my particular engine.

Mike

I got a 250 160hp inline Mercruser from a guy
that had it in his garage for a few years,
had hardly any hours on it. Bought it for
$30.00, I didn't know if it would work in my
truck so I asked someone at Langdon's Stovebolt.
they told me everything about that engine and
that it would work so I droped it in and bolted
on a set of headers, Offy intake and a Edelbrock
carb. It runs great!

Martin

I am just about to bolt the head on and I have been thinking about valve/piston clearance ?? The 307 flat top pistons are about .015 taller than 250 stock pistons and I have .040 milled off of the head and 194 intake valves. I am using the Mercrusier cam that I do not know what the lift is....The head gasket is .020 thick..Should I put some clay on top of the piston and turn it through and see for sure...or...maybe some one out there knows how much room I have to play with.SCRAP

hello..good question...from what i learned from old timers is that you only need to be concerned when lift is .560 ish lift or more....but again , every engine has its own particularities...i would say you are ok... anybody else?

it is always cheaper to check the clearance. then to put the motor together and then find out you have to take it apart and fix a problem. every motor that leaves my shop has been checked.

hello...excellent point.... I just wanted to share info from an Old timer who use to build MANY chevy inline 6 round track race engines....he said he learned from buidling MANY Chevy 250 engines with an engine that had flat top pistons, a zero deck block, a head milled up to .090, and a cam up too .560 lift that he learned he didnt need to take time to check...just thought many here would be interested in that info.....again it is good to do as you state....seems most here use a cam under .560 lift , so maybe this info can help some.....

Take the time to check it with clay. A general figure to allow is .080" for intake valves and .100" for exhaust. If you put the head on without a gasket for checking purposes then just add the compressed figure of the head gasket you are going to use to whatever clearance the clay squeezes to. A head bolt on either side of the cylinder just tightened up snug is enough to do the job here. If you are worried about the clay sticking all over everything coat the valve faces and the top of the piston with either a light coat of motor oil or non stick frying pan spray like Pam. A clay ball about the size of a marble is big enough. From the info you have provided about the pistons, cam and head milling it sounds like you have lots of room but it's still good to know exactly what is going on.

Mike

Use the clay for safety. only time is lost indouble checking everything. Here is a little more food for thought as I learned this one the hard way and rather then taking it all apart it took over a month to find PLugs Iknow your running a flat top. My issue was with a poppup. Everything was checked to Specks.Everything But the PLugs. BIG Ops.They Hit the pistons. If this would have been Checked as well I would not have spent so much time looking. BUT I also learned something about Plugs. and that there is a min. of a.010 difference when the plugs are made. (no matter who makes them) So just because one set clears Don't mean the next set will. I could never gap my plugs more then .045 with champions and no more the .055 with autolites Because the pistons would hit the electrode(tip) and close the gap. So when I found that issue I started calling to different plug companys And thats what i found out about plugs. SO never second Guess just double check. It's by far safer & Cheaper.
hope this helps }[oooooo]

Learned piston/plug deal back in 1957 when I built my first 302 chevy SB. Back then I was big into "more is better". Those 11 to 1 Jans pistons at 0 deck and a FI heads made a mess out of my plugs. I removed the pistons and a friend of mine that at that time was a FORD guy that run at the Salt Flats fly cut the pistons and cut a flame path in the top.I ended up with a trick setup by just DUMB LUCK..He also cut the top off a GM fuel injection and welded a plate on top for a four barrel and I had the first tunnel ram and didn't know it...DUUH..."those were the days" SCRAP

Sweet deal them good ole days huh Flame cut kinda fuuny you brought that Up That is what I did in this new Motor Build up yeah gota luv them old tricks which should work very well on a 3staged piston now Now that too reminds me I need to get a few more pictures of that Before Get this thing all put back together. Thanks for that reminder LOL.}[oooooo]

hello...great comments!!!!!!!!!...I just want to let it be known I have learned more about these Chevy Inline 6's from Old timers than I have here On this Forum....dont take this wrong....I just know I have found old timers know what they are talking about with these engines-because they have built LOTS to these engines-especially back when the parts were CHEAP!!!!!....they raced them before most of us knew what they were and I am 47 years old....

so its safe to do what is suggested, but is is not necessary.... take this for what it is-not trying to start anything, just sharing time tested facts and from emails and calls i get some appreciate my comments-thats all....

Larry, try this site for Spark plug info...
http://www.edelbrock.com/automotive/sparkplugs.html

...here is a good way to to learn about Champion plugs(and basically most)...pay attention to the Regular Gap vs the Projected Gap.....PES has shared with me the 250's run best with the Regular gap and others Have recommended the Projected Gap for 292 drag racing...you may know this, but thought you and others may be interested-especially The concept of heat ranges and the projected tip-may be interested in this....I was educated on this and when I found this site, it only confirmed what the old timers learned YEARS ago and have shared with me..........

Thanks for the link...Thats some good stuff..SCRAP

Thanks Lee But i have been dealing with autolite for some time now and I run the Race plug from them. So far most my engines Like The autolites the best. I got hooked up with them many years ago
and have tried many plugs. Even running different heat ranges from 1,6 -2,5- 3,4 The different ranges Made a difference when I had the Offey intake.I'm sure the clifford single would have been pretty much the same as the offey.But not a lot of difference when I ran the clifford dual and with mine I went to one range across the board

One other Old trick was to cut the tips and side gap the plugs. that was one trick My BB 396/427 Loved was to side gap the plugs.
which was like the surface gap plugs or the angle gap. }[oooooo]

hello...Scrap,thanks for comment...it is good info, isnt it?

Larry, thanks for sharing about your Autolite experience...I thought sharing this site on Spark plugs would be helpful to many-not trying to pick 1 plug over another, just sharing this info....
hope others can find it helpful also....