Chris Craft 36 Commander Re-engine to 6BTA

[schpere]

I have a '84 36' Chris Craft 36 Commander. Currently, I have two Cummins 555s in it, and was thinking of putting in two Cummins 6BTA. The horsepower is approximately the same, but the 6BTA's will save about 2,000 of total weight from the boat.

Will this affect the stability and ride of the boat? I know it will go faster and get much better fuel consumption rates, but it might be hard to handle or have some other adverse handling characteristics.

[juiceclark]

That's a nice boat and not dissimilar to mine:


When I repowered my F-36 Trojan and replaced all the old fuel tanks with one aluminum tank, my boat lost about 2k pounds. It was no problem except a little more weight came off the transom than the bow. So, to prevent the boat from plowing and, most importantly, exhaust from backing into the risers I added about 500 pounds of lead to the transom. I just kept adding bars until the waterline matched the old waterline stripe. It rides better than ever.

Tony in Sw FL


by the way...if you go to www.trojanboats.net you'll find several discussions among those to switched from gas or old diesels to 6BTAs. They are clearly the engine of choice for boats like ours.

[schpere]

Yes, yours looks almost identical too mine. I have entirely gutted the interior and put about $60,000 on the inside, etc... and some on the outside also. Will post some more pics when I am done.

What is your tops speed with the 6BTAs?

[lazeyjack]

nice entry on the boat
Will go better and will get up quicker
what will you do with old engines? will you change the boxes?
Stu

[schpere]

Don't know what to do with the quite frankly. Any experience in something like I am thinking of doing?

[kapnD]

Schpere,
Dont think you will experience any negative stability/handling effects from this change, just positives in all the areas mentioned. It will cost you a lot though, and you will need to lower your bootstripe. You will probably have to change the boxes, shafts, props, mounts, struts, water inlets, exhaust. It would also be a good time to upgrade fuel filtration, controls, instruments etc. As for the old engines, well they are...old engines, low market value, old technology, and not in high demand.
What horsepower 6BTA's? You can go from 210-370 with very little weight penalty, depending on your needs. I am very impressed with the reliability and longevity of the low hp models.
Good luck with your project, Don