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Re: Mid cabin 1988 repower

Posted: Thu May 13, 2021 8:37 pm
by prowlersfish
Lt1240z wrote: Thu May 13, 2021 6:24 pm RWS you are running zf63 I didn’t think they were strong enough to hold that much torque. I am in no rush but would like to get the gears in the next month.
I am at the boats now redoing skylight windows.
My main curiosity would be the pros and con 1 .5vs 2.0 gear.
Bob states I can only swing an 18 “ prop. Bob did you just change props or shafts too? Prowlerfish what’s the rating on your 6bta’s?
Also Bob what cpu are you running?
Thanks,
Frank
Pro on the 1.5 gear is you will probably will be ok with the shaft. With the 2.0 you likely will have to up grad the shaft.

My Cummins info , Starboard 300 6TBA 300HP@2800 rpm (proped to 2975), port 370B 355HP@3000 (Proped to 3150) ZF 220A gears .
Lt1240z wrote: Thu May 13, 2021 7:52 pm Also the motors I bought were originally stern drive, dampener plates are all the same correct?
No they are not. They must match the gear. Also, gear and bell hosing must match.






.

Re: Mid cabin 1988 repower

Posted: Thu May 13, 2021 10:02 pm
by Lt1240z
Prowlerfish,
So you are running mismatched motors. Interesting since the base is the same does one have bigger injectors/turbo etc?All mechanical?
As Cummins has a lot of upgrades easily obtained.
Have you tried to match them?
Yanmar seems to be much more restrictive. Seems tractor pulling may be path to wisdom.
Can you tell me the equivalent prop size to RWS 20x20 in an 18”?
RWS can you share some mount pictures etc 😀

Re: Mid cabin 1988 repower

Posted: Thu May 13, 2021 11:03 pm
by prowlersfish
Lt1240z wrote: Thu May 13, 2021 10:02 pm Prowlerfish,
So you are running mismatched motors. Interesting since the base is the same does one have bigger injectors/turbo etc?All mechanical?
As Cummins has a lot of upgrades easily obtained.
Have you tried to match them?
Yanmar seems to be much more restrictive. Seems tractor pulling may be path to wisdom.
Can you tell me the equivalent prop size to RWS 20x20 in an 18”?
RWS can you share some mount pictures etc 😀


300 has the older Denso injection pump the 370B has Bosch and of course different injectors. Same turbos ( 300 replacement upgrade s the 300/370 turbo ) as it was replaced. The 370B replace a 300 that blew. No, I have not tried to match them . See no need to spend 15-25k to get another 370B when they are pretty close match as they are. I did however upgrade the 300s cooling system to match the 370.

2.0 gear 3 blade 18x23.5 18x21.7 all cupped

1.5 gear 3 blade 18x14.7 cupped 4 blade 18x13 cupped ad .7 without cup on all

Re: Mid cabin 1988 repower

Posted: Sat May 15, 2021 9:38 am
by Lt1240z
So essentially 18x22 cupped is a good starting point with 2.0 gear.
Took out a electric pump yesterday on the 454 to get rid of a delivery problem. SOB would stall out starboard motor at the channel marker every time. Like it knew ! Missed it once by 3 ft second time it did it!
Going to take her out today or tomorrow
RWS did you utilize the existing aluminum mount that is about 4” wide and runs down the stringer or just add too it?
Prowlerfish why not just change pump and injectors?
Thanks,
Frank

Re: Mid cabin 1988 repower

Posted: Sat May 15, 2021 10:26 am
by prowlersfish
Lt1240z wrote: Sat May 15, 2021 9:38 am
Prowlerfish why not just change pump and injectors?
Thanks,
Frank


Because it's not that simple (is it ever?) To change from a Denso to a Bosch pump takes a new gear case, different lines and bracket And of course different injectors. Now the injector spray pattern is different so the Bowl in the position is different. so to do it right new pistons would be in order. A bad mismatch could cause piston failure ( maynot be the case here but .....)

A lot of time and money. And for what gain? A knot or so at wide open? Unless you really know Cummins and the pump you can't tell the difference between the engines. You sure can't tell by running the boat.

Re: Mid cabin 1988 repower

Posted: Mon May 17, 2021 7:11 pm
by Lt1240z
I see your point.
RWS do you know the size of the trans cooler hose?

Re: Mid cabin 1988 repower

Posted: Mon May 17, 2021 9:56 pm
by RWS
I do not know the size, sorry.

Also we bonded and bolted a pair (one per side) of flat aluminum plate to the stringers to better spread the torsional load from the diesels engine mounts.

RWS

Re: Mid cabin 1988 repower

Posted: Mon May 24, 2021 8:22 pm
by Lt1240z
Thanks RWS I used to power steering cooler for reference. It’s 1.5 . I have all the stock at my buddy's I need of aluminum.
Did you utilize the original at all? The Yanmar mount is definitely wider or par with existing plate.
Picking up the gears on Wednesday. ROAD TRIP :P My buddy’s on me to start the Yanmars this weekend . We’ll see.
So I ran Tiki harder than I had ever, opened up the 4 barrels and set her to open buffet. I did grin a bit missed the sound of opening 4 Barrels. Boat impresses me more every day.
I did break the widow on the Carver doing the window seals , a month ago.... I just did the template yesterday.
I feel a little bad, just a little.

Re: Mid cabin 1988 repower

Posted: Mon May 24, 2021 9:33 pm
by RWS
Didn't use the Trojan factory mounts or plates at all.

My front mounts included heavy wood blocks, as I recall.

Here's a 2006 photo of the mounting system used

RWS
Yanmar_Mounts.jpg
Yanmar_Mounts.jpg (129.2 KiB) Viewed 7820 times

Re: Mid cabin 1988 repower

Posted: Mon May 24, 2021 10:06 pm
by Lt1240z
RWS
Thank you
As they say a picture is worth a 1000 words. On the mid cabin the mounts ride inside the Stringers , mounted about 4-5 inches down on a single plate that runs al the way to transmission mount one piece.4 -5 inches wide max. Will either bulk it up or make a new one.
Image
I have a whole machine shop/dynojet sitting unused except by me and son-in-law. Sad a lot of power came out of there back in the day. He Tuned the green bomber from fast and furious. They made him stop at 1500hp@wheels leaving a lot on the table. RIP Sr.

Re: Mid cabin 1988 repower

Posted: Mon May 24, 2021 11:35 pm
by Lt1240z
One of my motors
Image
Image
Just figured out picture posting :mrgreen:

Re: Mid cabin 1988 repower

Posted: Tue May 25, 2021 5:17 am
by RWS
Suggest you run the valves, replace the timing belt and tensioner while the Yanmars are out.

simple, easy and NOT EXPENSIVE and the parts are available through Yanmar or Toyota dealers or on Amazon/Ebay.

RWS

Re: Mid cabin 1988 repower

Posted: Thu May 27, 2021 12:50 pm
by Lt1240z
Will Do RWS
Went to Harkers
Island NC yesterday,nice place!
Came back with gears
Image

Re: Mid cabin 1988 repower

Posted: Thu May 27, 2021 12:57 pm
by RWS
John Leed requested that I install a VACUUM BREAK when I did the repower.

He also provided the necessary exhaust items to make this work out with my existing system.

I took his advice.

BEST !

RWS

Re: Mid cabin 1988 repower

Posted: Tue Jan 03, 2023 5:42 pm
by prowlersfish
How is the repower coming?