6.0 mulit port EFI in F36

Struts and Rudders · Post by **Struts and Rudders** » Wed Feb 23, 2011 5:03 pm

Hello all,

Here is my plan:

375hp 6.0 multi port EFI engines
ZF 2 1/2:1 gear ratio
Turning a ACME 18"X25" prop on an 1 1/2" shaft
This set up is currently being used on deep v inboards weighting 14-16K lbs with great success per a lengthy conversation with the owner of the company. He claimed that the motors had good torque at low speed and ran nicely on top end.

My Trojan F36 was delivered with 330hp big blocks with 1:1.88 Velvet drive transmissions turning a 20"x20" prop on an 1 3/8" shaft.

How do any of you gurus feel about my plan....

Constructive critics only need reply:
Hold off with the "you're going to have more in the boat than it is worth" as I am aware of my folly vs. the worth of my recreational time.

SRD
1980 F36 461

Stripermann2 · Post by **Stripermann2** » Wed Feb 23, 2011 5:57 pm

Just curious...what are you using for fuel control and timing. Does the package come with an onboard computer? Are they counter rotating to each other and marinized?
I believe your stock shafts are 1 3/8". You're going to a bigger prop shaft?

Interested in the details. Thanks.

prowlersfish · Post by **prowlersfish** » Wed Feb 23, 2011 6:13 pm

I ran the numbers and they are good. Good choice on trans ratio 3 blade props I assume by the numbers I ran .

I would think about going with 20"X22" wheels maybe with a slight cup. I believe the 20" wheel would be a better choice

On you engine choice , I would still go with big blocks only because of the rpm the 6.0 turns not saying its the wrong choice just not mine.

The 6.0 needs to be propped to turn 4800-5200 rpm And you gear/prop choices will put you there .
BUT remember to get a good cruse speed 20 knots + your will be cruising at 4000 rpm . The 6.0 is set up to do this and it will . I just don't like it myself . but it your ok with that , Go for it .

As far as the 1.5" shafts thats fine But you can stay with 1 3/8 shafts you have now with no problem as they are more then ample . going to 1.5 is over kill and $$ not needed to be spent.

prowlersfish · Post by **prowlersfish** » Wed Feb 23, 2011 6:19 pm

Jamie

The 6.0 will both be turning the same way . the shafts counter rotate due to the gear boxes one gear box will be in the "A" postion when the other is in the "B" postion ( B postion reverses the output) I asume he may be using a ZF63 or even a ZF220 or ZF280 gear ?

Struts and Rudders · Post by **Struts and Rudders** » Wed Feb 23, 2011 9:29 pm

The only big block engine that is currently being manufactured in the 8.1L as I want multi port injection. Haven't really even looked at those engine as I was told that much horsepower will lead to too much speed that leads to a falling off the keel, which is a scary feeling!

I will take a hard look at using the current shaft and props with some tweeks.

We really intend to use the boat as a trawler...just pushing along at a very slow speed, but will have the power to get somewhere if pushed into a corner by weather or timing. I hope this package will be a good compromise.

I will be using some type of electronic controls and the ZF63 I am thinking right now.

I want to reduce the wiring,cable connections and gauges on the instrument panels as well.

Thanks for your input and good questions,

SRD
1980 F36

prowlersfish · Post by **prowlersfish** » Thu Feb 24, 2011 7:01 am

I do believe you will be OK with the shafts you have . reworking your props from 20x20 to 20x22 may also work OK , just remember that a repiched prop never works as well as one that is made at the needed pitch , but by redoing yours you will find out if you need more or less before spending some big bucks on new ones only to find your off a little .

I will run the numbers on the shafts

RWS · Post by **RWS** » Thu Feb 24, 2011 7:21 am

looks like a sound plan, (o.k. here's the but part...)

however I would take a look at the comparison on torque. Don't make a decision on HP alone.

For your intended use, these sound fine but will these engines enhance the resalability, hurt it or have no effect?

Would you consider a pair of used 671's ?

They are available and at reasonable prices.

Cheap to rebuild (comparatively)

Another issue is how many hours do you intend to log annually as that factor is important as well.

All in all you are probably going to be fine overall with the 6.0 units.

Just wanted to throw some other considerations out there.

RWS

prowlersfish · Post by **prowlersfish** » Thu Feb 24, 2011 7:38 am

RWS , there is no way the 671 will fit , the Cummins B is about as big as you can go . The 671 is much bigger , taller longer over twice the weight .

My Cummins are 1280 Lbs ( no gear ) the 671 2850 no gear , and the gear for the 671 is at least 500 lbs more . the Cummins 41" long Vs 71" for the 671 ( incl the large tubo ) the Cummins is 30" tall and real close to the floor , the 671 is 9" taller .

The cummins B is pretty big but looks like a toy next to a 671.

Good thought though

rossjo · Post by **rossjo** » Thu Feb 24, 2011 8:56 am

The 6.0s don't have near the torque of your original 330hp big blocks. Heavy boats need torque. Just because you have 502's doesn't mean you have to run them hard. In fact, you will probably get better fuel economy running the 502s at 2/3 throttle than running the 6.0s at 90% throttle.

But I'm a Cummins B guy as well ... and always opt for bigger when it comes to boat power (454 in my 26, 200hp in my 18, 50hp on my 14' skiff)

Join BoatDiesel.com ($25/year) - they have the best power and prop calculators int he internet (not diesel specific at all - probably where King Paul is getting his numbers).

Sorry - been out of touch guys. Boats shows, new products, fishing/boating all in the way (plus I've been playing a bit of golf).

prowlersfish · Post by **prowlersfish** » Thu Feb 24, 2011 9:29 am

Thats exactly where I got my numbers . He has done done his home work as his numbers are right inline , Using the right reduction to keep the right size wheel . There is another F36 on here that is also ruining a smaller high output engine ( 350 350hp ? ) but use the wrong gears so they have to use to small of a prop ( and still over propped)

rossjo · Post by **rossjo** » Thu Feb 24, 2011 9:36 am

With stock strut, whats the biggest diameter you can run on an F36 (with 10-15% clearance)?

F32 is 17" ...

prowlersfish · Post by **prowlersfish** » Thu Feb 24, 2011 10:17 am

I am running a 22" but its behind the strut a extra 1" or so more and the clearance is barely 10% , with no problems . the boat was made to run 20" wheels

Allen Sr · Post by **Allen Sr** » Thu Feb 24, 2011 6:48 pm

Prowler did you repower your boat to what you have or did it come that way and you made changes?

Geoff R · Post by **Geoff R** » Thu Feb 24, 2011 7:16 pm

There,s no replacement for displacement