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View Full Version : My name says it all.-drive swap decisions!



Moody Blu'
07-26-2001, 06:52 PM
First I would like to say hello to all the members!!!!
if your in new jersey and want to see a couple donzi classics, go to the waters edge in forked river on august 12th 2001 11,am!!!
and now here is my rant!....

I recently woke my donzi up from the grave with a brand spanking new ford 351w 1975 block. check out the registry hull#: 1dbm18886
any how, I met a guy with a 1988 donzi with a jasper H.O. 350 chevy and alpha drive.
My boat has a 351w and a vovlo 250 drive with NO TRIM AT ALL :(
We raced each other and he was barely pulling away from me. He told me he had his drive COMPLETELY trimmed out. so this tells me if I had drive trim I would beat him.
now the question is,which drive should I throw on the back of this boat?with out reglassing the transom
I was thinking about throwing a volvo duoprop on the back, but arent they extra heavy? I dont want to buy something to slow the boat down, I know with the right drive trim and ratio my little 18' will reach the 70 mph zone(off course this is with some slight engine mods(roller lifter conversion carb spacer, shave a peice of my intake to make it like the edelbrock(AIRGAP INTAKE).( I have 20mph to go)- and those mods should definately do the trick.
HECK, if I had trim I know I would hit low 60's.

You guys will understand that I rant on, but Ilove my donzi!
so any how, do you guys think a duo prop on the back would be good? or too heavy?
can I throw a alpha on the back? HELP!!!
what about a bravo?
Is there any way I can switch my drive with a new one and not drill and glass holes?
someone help!
sorry for the ranting!
I have a need for speed!
I want to be the guy with the 18' blowing buy the 22's!!!!
thanks in advance for all the help!!!

TD
07-26-2001, 07:11 PM
Broque,
I am also the proud owner of a sky blue 18'.
Before I bought this 18', I owned jointly an X-18 with a mild 350(240 horse) and a Spinelli prop on it. Had a simalar situation: No tilt or trim. I owned it with a friend and one day we were out and the drive let go. We lost the upper housing. We found a late model Volvo duoprop(DP-D1) with very low hours and it bolted up to our bell housing. We had to cut out the transom a little and re-drill 2 holes but it was a pretty simple switch. The results were great hole shots, quick planing, but the same top end.(58 GPS) We had the most pitch props that Volvo offered(stainless) and thet did not give out pitch stats, but I do know that they the max they offered. I hopr this helps.
Terrell :D

Moody Blu'
07-26-2001, 07:26 PM
great! I realy dont want to cut the back at all. this boat with the duo prop on it, it had a chevy in it?
was it a stock marine chevy or was there some work done to it?
It sounds like I may be hitting the 65 range with a swap now, my 351w definately has tons of high rpms left, I just need to trim it out!!!!!!
hey td, did you guys think the drive was heavy in comparison to the stock one prop volvo?
if i have to cut my transom, I may just go with the lightest STERN Drive, sorry no jets for me.
another thing what is with this x- dimension people are talking about?
can some enlighten me to the engine angles or whatever you guys are talking about?
I installed my engine but I have no clue what the x dimension is or any other lingo you guys use someone enlighten me? :rolleyes: thanks ;)
anyone else with some stern drive swaps?
anyone know how good that gpi drive volvo make? supose to be some high performance drive?

BigGrizzly
07-26-2001, 07:29 PM
I have a 18 Corsican. I changes the 250/270 for a Volvo 290 it has trim and tilt. I cut about 1/2 inch in two places drilled 4 holes bolted it on. it uses the same props and all. I also have a 351 Ford, but it is a Clevland, and have run in the high 60's. If I had it to do over and a Alpha was available, I would still do the Volvo 290 again, its way stronger than the alpha.

Randy

Moody Blu'
07-26-2001, 07:34 PM
isnt the bell housing different for a cleveland? I have a holman and moody bell housing, (the housing that bolts to the engine). is the housing different? or is it the same housing?
cant you put a duo prop lower unit on a 290?
oh TD i meant to ask you before why dont they tel the pitch of the duoprops? sounds dumb.
hey big grizzly your the first person in a while to make me proud to have a vovo drive, since everyone bashes them.
my 250 drive is running good and all i did was give it some fresh oil, after sitting for 9 years!

MR MAGOO
07-26-2001, 07:50 PM
I have owned many Donzi classics over the years and although the Volvo drive is tough, the Merc Alpha is faster, less drag and a much better prop selection. There is a company that sells a cast plate to fill in the transom cut out and will accept an Alpha transom assy. If you like I`ll try to find and post the info. Good luck, Kurt in Maine.

boldts
07-26-2001, 08:05 PM
Broque,
I have a Volvo 250 on my 69 18' Classic. For now, I like you do not want to cut and glass my transom. My dad is a Civil Engineer and rather than replacing the drive, we found a way to get some more trim out of the 250. We filled and added material to the area of the drive where the highest trim hole is located. We then redrilled this hole 3/16" further out from the transom. We came up with this figure by using regular hardware washers of different sizes on the trim rod. I am running a right hand 14 1/4" x 22" stainless volvo prop at 4900 RPMs. Had to drill and tap the output shaft to accomidate the different prop cone that is required with this prop. My boat has no trim tabs and doesn't require them. I wish I could give you a speed increase, but I don't have a GPS unit yet. My wife says the boat is faster and I can feel a pushing back in the seat that wasn't there before. The bow rides higher and really offers a much better ride than before. It's not a new drive, but it is an option if you want to keep things original. Buy some different size washers and see how the boat runs in a higher trim position. Beware, you will lose your reverse lock due to the washers, so don't come flying into the dock and expect to be able to stop on a dime.

TD
07-26-2001, 09:06 PM
When I removed my old 270 drive I found rot and moisture in the transom any how so I cut to fit carved out rot and filled with kitty hair. So I guess evenually the drive might have broken away.There was no noticable difference between the old 270 and the new DP. The chevy 350 was not even a true marine 350, and had no HP modifications. The engine was not moved at all.
I've heard the Alphas will break when more than 300 HP is put to them. From an old Volvo reliability point of view that might be hard to stomach. On the other hand a New duo prop is big $$$$$.
Just my point of view. Like Big Grizzly, if I were to pull the switch, I'd stick with Volvo 290. :eek:

Looped
07-26-2001, 09:25 PM
1971_skyblue_donzi_classic,
Welcome! First of all that login name must be a pain to type every time you post.

Going to a Merc setup in your case will need transom work done to it, the Alpha & Bravo have the same whole but I believe that the Bravo will need two more additional boltholes added. The Bravo is much stronger than the Alpha and plus the Alpha really only will handle up to 300hp without any problems down the line.

I have wondered about the Penta douprop drives myself, you will get a better hole shot with one but you will also nip of some top speed because of running two props unfortunately. If you are looking for stability the douprop will give you some without the listing. The singe prop drives give a torque effect to the boat just like if you look at a car engine in park with the hood up and you give it gas it will twist in a certain direction. Running 2 props in different directions (ccw & cw) will for the most part eliminate this torque effect on a boat.

“X” dimension is again “I believe” the dead center of where the shaft runs threw the transom. By raising this dimension (2.5” is close to max on most 18’s without modifications) it will give you less drag on the outdrive in the water but the engine needs to be brought up this same dimension so you will need to do stringer work also in this case.

All right guys you can shot me down now.

Craig

Moody Blu'
07-26-2001, 09:55 PM
hey boldt, I still have one more pin left on my drive, but being that your father is a civil engineer I dont understand why you didnt try to just buy a hydraulic and put it in the place of the old tilt system the vovlvo 250 uses, that would definately work for trim, but I want to go above and beyond the stock 250 drive, I want all out speed I need a good drive for that, and my boat does not have trim tabs either, and I dont think I need them either, they will weigh the boat down.
I think my engine is definately in the 300+ range , but isnt the bravo ALOT heftier than the alpha?
I guess im gonna go duo prop or 290 arrggh decision decisions
well keep flooding in with different tales, maybe ill find exactly what im looking for!

boldts
07-26-2001, 10:12 PM
Broque,
We looked at a few hydraulic trim set-ups that had been added to the older Volvo drive. It was doable, but I really didn't like the look of things being added to the drive. What I saw kinda had that jury rigged look. My Classic is a Holman Moody Edition and I'm really having a tuff time with the original or update thing. I do however like the 290 drive option that Big Grizzly mentioned. I hadn't looked into that option due to thinking many modifications would need to be done if I changed the drive to anything other than what I already had. I have a 4 yr old daughter who up until this summer wouldn't let me run the boat over an idle speed when she was in the boat. Now by what I consider to be a miricle from above, she uses the words "Faster Daddy" and loves a 1' chop and WOT as much as I do. :D It's been a wonderful summer on the lake so far.

Forrest
07-27-2001, 11:10 AM
There is a company that sells a cast plate to fill in the transom cut out and will accept an Alpha transom assy.

Actually, Volvo-Penta makes a casting that adapts the Volvo Aquamatic cutout to the standard I/O cutout. It retails for about $750. When they made it, they had in mind that you would use it to upgrade to a Volvo-Penta SX, but the cutout is ths same for the Merc as well as the SX. The SX is actually a very good drive and is much stronger than an Alpha, and the SX has cone clutches not those stinkin' Alpha shift-dogs and cut-out switches. http://www.goldenplasma.f2s.com/forum/smilies/mad54.gif

Moody Blu'
07-27-2001, 05:10 PM
hmmm, forest, sx drive ehh? maybe I will get that? ill have to look into it.
My classic is a holman and moody edition too! well if you are in NJ on august 12th swing by the waters edge for a donzi classic meeting, you probably will never see this many donzi classics together in your entire life, unless we all meet up some time!

Shanghied Again
07-27-2001, 08:48 PM
1971_skyblue_donzi_classic Welcome!

I love Donzi classics and I had a 16 myself. But I have to set the record straight before I loose my other Donzi fellows at the Waters Edge in Bayville. The Donzi meet is for all Donzis not just classics There will be about 12 Donzi classics now, But there will be 2, 22ZXs One is my own. a 26ZX and a 28ZX. All Donzis are welcome Classics Zs Zxs and cruisers if they want to be there. I am now looking for a 16 for my son to restore. But there is a Hornet in Brick I wouldn't mind rebuilding. The N/E Donzi club welcomes all Donzis, We are all brothers at heart :D

Moody Blu'
07-27-2001, 09:00 PM
I am going to try to bring a couple donzi's along with me.one classic and maybe a sick ass zx something!

Any who, I just put my 750 cfm carbureator back on the classic. I ve been running a 600 for the break in but now its broken in!!
I will let everyone know how much of a mph gain I get,\. oh yeah I'll also let you know if i beat that other donzi.
I am thinking maybe I will be in the 60mph range with the 150cfm larger carb,
THERE IS A HUGE DIFFERENCE IN WOT POWER WITH THE 750.-the sound is awesome too!!
So im thinking 5 mph for the extra 150 cfm, and another 2-5 mph with the pin up all the way(1 up from where it use to be).
Ill let you all know with the gps.
any guesses?
it did 50mph with a 600cfm carb and the pin one up from the top.
Hmmm, I wonder If I should switch my coil to the jacobs coil I have sitting in my shed?
I saw a spark come out of a spark plug with that jacobs coil that was SOLID BLUE.
think the coil will give more power?

well there is another one of my rants!
I can type really quick, it didnt take a long time!
hehehehe
oh one more thing,
IF ANY OF YOU THINK ALUMINUM DOES NOT CORRODE IN SALT WATER YOU WILL BE SADLY MISTAKEN 2 YEARS DOWN THE ROAD OF A NEW INTAKE!!
( I read somewhere in the mess board some one saying that it doesnt corode)
ok now I am finnally done!!!

Shanghied Again
07-27-2001, 09:36 PM
1971_skyblue_donzi_classic

When you come up I will take you out for a spin in My sick a@# 22ZX!
See you there
Frank

Tomahawk
07-28-2001, 06:01 AM
Better fasten your chin strap Moody! :eek:

Moody Blu'
07-28-2001, 06:31 PM
awwwwwww shiiiiittttt I am siked for a ride in a zx, is it twin engine or single?
does it have a step hull?
the guy in my creek (mill creek) has a zx with twins and a step hull!!
those zxs are sweeeeeet!!!
BAH ILL smoke them in my classic! :eek: lol

oldLenny
07-29-2001, 10:57 PM
...these guys claim to have something...
http://www.bravodrives.com/plates.html

Moody Blu'
07-30-2001, 12:39 PM
thanks len that helps alot.

anywho, the boat is running great with the 750 cfm carb on it, and with the pin up one .
but I did something kinda stupid and kind of smart.
here is the dumb side of it.
I put the 750 cfm carb on the boat for more top end, and put the pin up for that too, when I changed the oil though, I went from 10w-40 to 20w-50 :rolleyes: so..... I am running about a mph faster than with the 600cfm carb and the pin down one notch.

On the smart side I can probably run the engine harder for a longer period of time with the thicker oil.

What do you guys think?
It only cost me 5.00 bucks for the oil, so I could change it again.
should I?
will 10w-40 or even 10w-30 suffice?
let me know what you guys think.

Forrest
07-30-2001, 01:42 PM
Don't use dino-based 10w40 in ANYTHING!!! 10w30 is OK (for cars), and 20w50 is OK, and for that matter, so is SAE 30. You pick. Just don't use 10w40.

If you don't believe me, ask BigGriz. :eek:

Moody Blu'
07-30-2001, 05:01 PM
what do you mean dino based?
whats wrong with 10w-40?
isnt the viscosity of 10w-40 higher than 10w-30?
could someone fill me in?
sae30? I take it that is 30w? but not multi viscocity?
HELP!
I think I am going to yank the boat out and change the oil right at the dock, unless someone thinks other wise. I am gonna put either 10w-30 or 10w-40 unless I get some strange reason not to use the 10w-40 then it wil be 10w-30,well see...

Formula Jr
07-30-2001, 05:20 PM
The gist is you never use an oil with a 30 weight span. Dino based means - from dead reptiles - as opposed to synthetic. I just use straight 30, or 40 if both the water and air temps are high. And don't use RACING oil unless you are racing.

Moody Blu'
07-30-2001, 05:43 PM
what if the water temps are low?
why is the gist not to use 30 weight oil?
or do you mean dont use dino based 30w oil?
why should I use a stright weight oil instead of a multi viscocity oil?
questions questions questions.... :D

Formula Jr
07-30-2001, 05:57 PM
A 30 weight SPAN, as in 5W-40 or 10W-50 or any oil that ranges over 30 points of weight. I saw a 0W-50 the other day and wondered if it was a misprint! 30W is fine for most uses since water tends to get real hard below 32 degrees. Your thermostate regulates the internal engine coolant temp in colder climes, but it can only open so far if its hot.

Moody Blu'
07-31-2001, 10:37 AM
Ok, I think I might have made a decision for the outdrive but I need some questions answered.
In the topic with the update of all the donzis out there there was a boat called an x-18 black hawk,
thats the drive I want!(mercruiser drive)
how would that drive be in rough water and will it mount up to a alpha one cut out?( I will be using a conversion plate from a volvo to alpha drive) so hopefully that drive will work in the alpha cut out?
anyone know how much it would cost for that drive and if it would work?
please let me know!
as for the oil I aM STILL CONFUSED
I guess I will switch to 10w-30 since everyone says not to use 10w-40.

Formula Jr
07-31-2001, 12:49 PM
X-18s never came with the blackhawk, the one on the List was a conversion. The blackhawk bolts to a Bravo Gimbal - or so I've heard.

BigGrizzly
07-31-2001, 05:24 PM
Yes the Cleavland has the same bolt pattern as the 302 and the 351w. there is one 351M that has a 460 bolt pattern.
Now for the carb question my boat is faster with the 600 CFM than the 750. It will pull 5600 rpms fine, and has better fuel economy. It is true I spent alot of time with jetting and timing to get it there. thw 750 is better at high RPM (6500 up with a cam change) but as less bottom end. I have worked on it for a long time and turned over every stone. On a motor that size a 750 is a waste. Look at Forest little green giant. A 302 450 cfm and close to 70mph (or over by this time) from a 16 fotter. Take your own shot at carburetors. BTW my 502 Procharged has dynoed 698.5 HP with a 825 CFM and will pull 5600 rpms.
Now for oil I have done the oil tests for a major engine, Auto Marine and Power equipment maker and can tell you 10w40 is the worst oil that anyone makes in their lineup. In 1984 GM released a service bulletin that states that they will void the warranty of anyone using 10w40. this is just 10/30 with Vips additives which are just polymers.
Racing oils that contain Nitro dispersants are the only ones to avoid. The rest are fine. The main thing to remember is too cold an engine oil is a problem- water condensates on the valve covers of a marine engine and the oil doesn't clean the engine internals. If you disagree than do the test yourself. It took us 6 months of running engines for 24/7 to reach the answers.

Randy

BigGrizzly
07-31-2001, 05:26 PM

AGUESS
07-31-2001, 06:43 PM
Hi, I also have just purchased a new 2000 ford 351W for my Classic 18.

The drive I went with was a Volvo SX. I was told the the DP drive was over kill.

I got a 1998 drive with bell housing, transom shield, manifolds, etc. for $3K.

Stromer, another member of this group also has this drive, and can't say enough about it.

A place called the marine connection in Ft. Pearce (spelling) flordia ( marine wholesaler) has the drives for about 2k and the transom shield for 1.5K. Ask for Ronnie.

Do a web search for volvo sx drives and you might find one cheap.

Good Luck.

Alex.

Moody Blu'
07-31-2001, 07:34 PM
thanks big grizzly you cleared up the oil question.
as for the carb question, all I have is a 750 cfm, I was running my friends 600cfm,
but I forgot to write down the gps mph, with the 600cfm, so im not sure if it is faster or slower, it is definately louder with the 750cfm.
I guess I have to switch back to the 600 cfm one more time to make sure.
the guy with the 16 footer doing 70mph, must have trim on his drive and ALOT of work done to that 302. id be interested to know his setup,(I.e. drive,prop, cam,intake, carb).
as for the drive setup, I know mercruiser use some stupid cone clutch thingy and volvo uses something else?(care to enlighten me?) but that black hawk drive looks like it could make a classic HAUL ASS.
could ssome drive expert give me some advice? or just anyones two cents ;)
oh I could get a transom plate for 750, not 1.5-that is a little harsh for a peice of aluminum. :rolleyes:

Shanghied Again
07-31-2001, 08:48 PM
1971_skyblue_donzi_classic

Sorry I didn't get back to you. I was busy trying to get the NE board together. My Donzi 22Zx is a single step with a little kick. I am supercharged 454/510hp a little 22 with an attitude problem. About 80mph and it gets hairy! So welcome aboard. Oh I use Vavoline racing oil 40.

BigGrizzly
07-31-2001, 10:19 PM
Forrest Your on. Hehas all the specs, and has posted them several times before. The more noise you hear is just that-- noise. the engine will take the fuel/air but won't use it to the advantage. The term is volumetric effiency. There have been many articles on over jetting and carburetoion in hot rod mags. Just swapping carbs without jetting is a wast of time. People do it and think they ar faster because of the sudden surge they get when the engine catches up with the fuel. Remember just swapping main jets isn't the ball of wax. all my boats run different primary and secondary jets. Anseer to your next question is, this is true of both manual and vaccume secondaries.

Hope this helps

Randy

Moody Blu'
07-31-2001, 10:40 PM
Randy, I aam running a edelbrock 750 cfm carb,(so i dont have to worry about blowing out the diaphragm if it back fires-holleys do it)
randy, do you think I should lean the 750 cfm out all the way?
when I am at no wake speeds the engine loads up, almost stalls then runs again and it is repeated.
I have a calibration kit that came with the carb, I was thinking of leaning the carb out as much as I could and then start from there. it seems to be running rich the way it is now and it IS leaned out 2 from stock now(I bought it this way)
I have a lunati 00110 1000-5000 rpm cam in it with an edelbrock performer rpm intake I think I may be able to get the use out of the 750 cfm carb but I have to fiddle with the jets, and I hate to do it, but I guess I have to.
what doo you think randy? should I lean it out as much as possible and then work from there?
the reason I am saying "lean it out as far as the calibration kit goes" is because I figure the leanest 750 cfm would be richer than any 600 cfm carb.
what do you think?
I just happened to lose my carb book too, so this is gona be tricky. I will go look for it again!
let me know what you think!

Formula Jr
08-01-2001, 12:18 AM
Well of Coarse you use racing oil Frank!
YOU RACE! :)

'71, listen closely to what Big Griz has to say, cause while at AOTH he quite casually took apart a 4160, IN HIS HEAD, and explained to me what every single part did.

Forrest
08-01-2001, 08:31 AM
Leaner air/fuel ratio = hotter combustion = possible meltdown.

Start with you stock jetting and determine which way you need to go by reading your (new) spark plugs after a WOT run.

Also, a larger carb (oversized in your case) doesn't automatically mean a richer condition, just less air velocity through the venturis, thus less atomization of the fuel.

Moody Blu'
08-01-2001, 10:36 AM
big grizzly, aka randy, or is it th eother way around? lol!
do you think it is at all possible for me to tune my engine with the 750 cfm carb on it?

you said, and I quote"thw 750 is better at high RPM (6500 up with a cam change) but as less bottom end"
if you could help me out I would greatly appreciate it, I have a lunati cam# 00110
check out the specs here: http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECC/Ford3.html its the first cam on the page. ( the kicker is the engine company swapped the stock cam out and kept the 2yr waranty on it!)
my engine seems to have more power all around with the 750 cfm on it.

I will be putting a edelbrock 600cfm back on it to make absolutely sure that it is faster with the 750.
I will check my plugs right after a wide open run and see what they look like.
I do have a little hesitation at idle speeds but once it gets more than idle speed it runs flawless.
randy, if you think I should switch I guess I will, but not until after I do this carb swap again, with my gps on board.

damn it, I am ranting on and on, HELP!