165HP I6 VS 130HP I4

[THEFERMANATOR]

They say the 3.0L will push them to mid 30's top end, and I've found new 3.0L's for around $7K each(complete assemblys). Would love to get one and do a VOLVO D3 conversion though. 190HP diesels should put it in the 40 knot range top end with a hull that can take 3 footers @ 25 knots and keep on goin. Would be nice.

[rb437]

Originally Posted by spareparts

those 3.7 l engines have a bad reputation

Spare
I'm curious, since I own one but have not had trouble with it, why the bad rep on 3.7 l. What kind of problems do they have?

Rick

[spareparts]

there were a lot of issues with them, but most were fixable and easier for mechanics to blame the engine rather than figure it out.

Rough idle: its a big honking 4 cylinder, what do you expect? Actually it can be smoothed out with the right tuning and posible carb change( the mercrab only had one idle mixture screw for both barrels)

Charging system: yes its expensive, they gave problems because the regulator that mercruiser used created a lot of heat by running the excess voltage to ground, if you have to replace the regulator, use the rapair regulator, its a true on/off type regulator that doesn't create as much heat, but if you really have charging problems( and if you have the room) put the altenator conversion on it

Hard to start/flooding problems: most of this can be attributed to the Mercarb( made by Nikki in Japan), its a cheap copy of a Rochester 2BBL, the early mercarbs were calibrated use Japanese fuel blends(they offered a water cooled fuel linie to help with vapor locking), later versions were better but still were not as good as a Rochester, I converted a Rochester off of an old 888 Mercruiser to work on a friends 3.7, it cranked easier, idled smoother, never heat soaked(thought about putting the water cooled fuel line on it but didn't need it), the engine ran better all the way throught he range, never checked fuel consumption( i doubt it was much difference), the 4BBl Rochester was still the prefered set up(488/485/190)

Cooling system problems: early versions had a 3" heat exchanger, the later 4" was much better

Elbow/riser gaskets: when they changed to the aluminum manifold and cast iron riser, the gaskets would not seal, allowing antifreeze to leak into cyl #4, had a lot of these sent back to Mercruiser under warranty, they updated teh gasket to a better material, haven't had any problem after that, the risers do need to be replaced often if used in salt

Parts are hard to find, and expensive: no arguiing this one, a lot of stuff on this engine were Mercruiser only, I've replaced the pistons with 460 Ford with good luck( they do rattle a little because there is no pin offset as needed in an inline engine), never found a bearing cross over, gaskets are now available aftermarket

Camshaft seals leaking: ever had antifreeze leaking out the bottom front of the engine? its coming out of the weep hole, its not that bad of a job to replace the seals, but sometiimes the cam seal surface is worn, requiring a speedy sleave, seen lots of people plug up the weep hole and didn't worry about it till they got antifreeze in the oil

All this being said, i still liked these engines, my old roommate had a 3.7 in a 17 Stingray, we got that boat running 53 on radar, not bad for a 4cyl, we hurt a lot of peoples feelings with V6's and some V8's. I highly recomend replaceing the points with an electronic conversion, and setting the timing back to 5 degrees( (an early service bullitin).

Any one got an old 3.7 laying around they don't want? My old roommate( sold his original Stingray years ago) has found another Stingray to rebuild, its got a 3.0 in it, he's missing that power of the 3.7, would love to find a 180-190 hp version

[Blue_Runner]

Hey man, that link is great. I really am in love with that 26 and what the guy did to it. Check out the folding arch. Gotta build my boat shed to fit one of the Bertram 26's one day ;D That 24 degrees at the transom is a thing of beauty!

[rb437]

Spare, thanks for the good info. So is the difference between my 165hp and the 190hp the carb? Also what would max RPM on this motor be?

[spareparts]

the carb, oil cooler and lines, flame arrestor,fuel line, you may have to change the valve cover to allow the throttle cable to come from the correct direction( the valve cover has a small anchor point for the throttle cable) or you can modify one to work, i checked on every thing else (we were going to change out my old roomates 3.7 to a 4BBL and I cehcked all the part numbers). The Mercruiser replacement long block carried the same part number for each engine, even listed the same cam shaft. The only other thing I would recomend(especially if you're a hot rodder) is to upgrade the rocker arm system to a roller or at least roller tip type rockers, the stock ford rockers suck, anything for a 429/460(Lima series) will bolt up, you may have to use an adjustable stud set up to achieve proper lash, but knowing how inaccurate the stock rockers were, its worth investigating. Check with some local Ford car guys, someone may have half a set of rollers laying around

[rb437]

Hey Spare,

One more question. What RPM should I be looking for at WOT?

Rick

[spareparts]

i think factory is 4200 to 4600, the stock valve train doesn't like more than that. We were turning that 165 4800-5000 in that Stingray, every once in a while we stuck a pushrod thru the rocker. Years ago there was a guy around Atlanta that was running a 3.7 in a drag car( econo modified dragster), he was runnig an aluminum aftermarket head, came up with his own cam drive( went to gear drive from chain) and ground his own cams, heard he was turning it 9000 rpm!

[deshet]

I had the 3.7 190hp. Also know as the 470. The motor is decent but they did not have alternators and the cooling systems is expense and know to have problems. They had problems with the front seal leaking (mine did not)
I still have a new heat exchanger in the garage. close to $300.
Stay far away from these engines they are good when running right and pretty effeicent but repairs aren't cheap.

If you buy a bertram do it right and put in a diesel. They have conversion where you can drop a truck diesel into your boat.

[THEFERMANATOR]

If I can afford one I'll go this route with it. Light weight and plenty of gusto. 150 HP set up for an ALPHA 1(I would rather have BRAVOS with a diesel)

They sure look sweet in a 26 BERTRAM

Or this one. 190 HP VOLVO PENTA D3 duo-prop sterndrive.