bertram31.com

There's a pair of 4bta-250 hp Cummins on EBay. They're represented as being recently rebuilt. Any thoughts? Not my first choice, but the price may be right.

John F.

Do it John. Doc has them and likes em just fine.

sounds like the right hp and size for a gas => diesel conversion.

watch the price, also check to see if you can get a set of reman 4bta's knowing everything's new & a 2yr warranty might be worth a few more$$.

The only problem I knew about were the injector tips falling into the pistons on early models. If rebuilt, I'm sure that flaw has been corrected, as Cummins acknowledged the problem and repaired/replaced complaints. Doc loves his and seems to get surprising performance from them. A bit rough at idle, but smooths out at 800+ rpms. Walter

Thanks for the replies-

I just checked with T&S--the 4bts are available reman'd only at 150 hp. The 6bts are 210, 315, 370, with the 315s at about $20K per side with gears, mounts, panels, etc. Its the quick arrival at $60K for a repower that makes looking at used 4bts something to think about.

John F.

"cavit his eruptor"

Unless you can confirm by a reputable Cummins dealer that these engines were rebuilt correctly, plan on adding rebuilding costs to those engines.

I can't tell you how many times people have tried to save money by buying "rebuilt" engines only to have to rebuild them again after taking delivery.

There are very few good deals out there.

Just remember, if it soounds to good to be true, it probably is.

Everyone,
John pm'd me on where these motors are from and I know the shop.

I won't post the name but run Forest, run from these engines.

This board is simply an incredible resource. Thanks for the input guys, and a big thanks to Bruce.

John F.

John, I've been tempted by the similar savings on rto's. In the end it probably just not worth it.


I know we've discussed this before, but here it is again for discussion.

With you doing most of the grunt work of cleaning and painting area and misc. stuff.

Should you choose a gas repower it will be about $15k per side with crusaders/merc/volvo for 8.1's (I don't think anything less would work in a flybride boat). So that's at least $30k per side plus about $5k for yard work in/out and some extras and $2k for a new tank (could be less). So for $37k you'll have new gas power and maybe have resale value of $60k and probably 10% less fuel.

Go with diesel and lets just say it's $20k per side for 300 cummins or new yanmar 240's. So that's $40k no add in the $5k yard work for in/out and extra's then add $4k for shafts and props. Now you're up to $49k and have a diesel boat which has a resale of $100k and probably burns 50% less fuel.

Now the kicker and what will probably drive me to do a conversion is that with diesel you’re less vulnerable to changes in fuel additives, ie ETHANOL. For me, the fuel consumption alone would probably mean I’d us my boat more often.

br,
JohnD

John,
Wait and do it right and it will last for years. Hope all is well.
Rob
Vitamin Sea

Thanks again guys. I'm definitely not going got those 4btas.

John F.

JohnD,

You got it right on the nose, but forgot ancillary costs. Bilge paint (gotta do it) engine beds (I can help fabricate, but someone has to. The wood ain't enough). Larger sized raw water intakes and all hoses, fuel return hoses and associated tank work, nice new Racors, maybe a tank cleaning, maybe batteries. Long story short, I did much work myself but was still at $55,000 and that was 3 years ago. Also it was for the Yanmar 240s. Any other engine and you need to upgrade shafts to 1.5" and that means different shaft logs, and strut work. Plus the spectre of larger exhaust may rear its head. But not with the Yanmars I put in.

It was done right (after two F&^%ed up gas attempts, yes, I learned my lesson), and god willing along with PM plan, it should be a long term set up. It runs like a dream.

The gas just was not comparable in cost. Particularly if you want to use the boat in any measurable way.

Dug

Don't forget the safety issue also with Diesel. They are simply safer period. Diesel will not burn untill it is heated. No blowers needed and all the other concerns with motors that spark in bilges. Go with Diesel. I'm sure glad I did. Good luck John. Dave K