Raising Volvo AQ questions

[johnnywhale]

I have seen it posted by murfman, that a Volvo 290 transom shield is essentially a free way of raising the x on an AQ 2 or 3 inches.
I'd like some advice.
Ralph Sav and I were speculating if my GT21 would benefit. Stock x height seems fairly deep. (How is it actually measured anyway???) 383 sbc ~ 400 real horsepower
64 / 65 mph usually, have seen 67 in perfect light chop / conditions
23 Solas @ 5k gets about 65 GPS.
Tons of height available, I could probably raise it a foot before anything hits the hatch.
Boat handles and planes fine as is, but you know....

Any speculation? Pros or con? Fire away!

[mattyboy]

the only difference I know on the 290 from the 280T is the trim lines were contained with in the cutout and transom seal on the 280 they were outside of the seal and cutout the 290 cutout is massive . raising the cutout would mean re glassing the transom and if you are going to do that why not go to a modern drive.

From the LGDCC library


http://www.lgdonziclassic.com/pdfs/280template.pdf

things I would be concerned with

1. the aq lower hates disturbed or aerated water
2. if you using the drive water pickup you may have water supply issues off plane
3. from what I have seen they idea was to get the anti cav plate close to even with the bottom line getting it above that might hurt handling and to get up on plane.

[johnnywhale]

Matty,
He had said both here and on the OSO Magnum board that the 290 cutout was larger - obviously - and using the bottom of the 280 cutout as the bottom of the 290, you could install it without issue and raise the x. I pm'ed him, but was also looking for any input on benefits to raising it. I spoke with an old Donzi head I met and he felt it would be pretty beneficial. I bought a 280T and a 290T transom shield / hydraulics on spec, If I use them great, if not, back on craigslist.

Any thoughts?
Thanks!

PS External pickup, I will look to see where the cav plate is in relation to the hull today.

[f_inscreenname]

I think the main issue is the pivot point from the shield to the drives fork. Besides that the shield can be 10 times bigger and still wouldn’t matter. Just because the shield is bigger you (maybe) can move it up and down in the old cutout and may be a way to raise the X but it won’t be much. I’m gonna have to pull out a 290 and a 270 shield and see how they match up later. I do know the 290 is the biggest shield I have ever dealt with. If the original hole was cut out right you can fill a OMC drives hole with it.

[smidgen too]

I have seen it posted by murfman, that a Volvo 290 transom shield is essentially a free way of raising the x on an AQ 2 or 3 inches.
I'd like some advice.
Ralph Sav and I were speculating if my GT21 would benefit. Stock x height seems fairly deep. (How is it actually measured anyway???) 383 sbc ~ 400 real horsepower
64 / 65 mph usually, have seen 67 in perfect light chop / conditions
23 Solas @ 5k gets about 65 GPS.
Tons of height available, I could probably raise it a foot before anything hits the hatch.
Boat handles and planes fine as is, but you know....

Any speculation? Pros or con? Fire away!

My twin engine Magnum has the Volvo 280 drive raised 3", love it making a 5mph improvement over stock . What really makes this application work are the Mercruiser Mirage 23p props. What does not work with the Volvo 17 spline 250, 270,280 & 290 drives raised are the Solas props as they have way to much slip do to there fat blades. Jeff Hall will test to this after he raised his drives on his Magnum using them, but they did worked well in the stock set up. My Volvo drives have the Merc prop shafts so I can use any Merc prop I want making selection easy, but these shafts are no longer available, wish they were . Since Volvo has a 17 spline shaft we use to be able to broach out Merc props to the Volvo shaft but newer Merc through the exhaust hub props do not have the meat to do that now. Jeff & I made adapters to convert the new Merc square hub props thinking this would be a good alternative but the labor & cost was to intensive. Jeff has since found some older props on ebay that were broached out & work very well for his Magnum. The alternative now my be finding Merc solid hub ocean wheels that can be broached out but finding a shop today to do this may be hard.
Jeff & I are not using any power trim on our Magnums as we like the set it & forget it set up with the drives raised up, but we could use my simple power trim made with Merc outboard parts that I have talked about here before. I think this would be much easier than going to a 290 set up if power trim is all you want like I have on my X-18 Donzi. The other down side to using a complete 290 drive & shield is hooking up the external power steering as the top of the drive is different than Volvo 250, 270 & 280 drives, it can be done but takes more work.

[johnnywhale]

I thought the Solas claim to fame was no slip? Or do you need a chopper type when raised?

[smidgen too]

I thought the Solas claim to fame was no slip? Or do you need a chopper type when raised?
Solas work fine when you have Volvo drive @ stock height, but when you surface them they slip. You cant beat the price & quality of all the used Merc props out there to try, that's why we made the Merc square hub adapters. Maybe if Solas had all the pitch & 3 & 4 blades available to try you may find one to work but it's a no brainier to use Mercuser they have been tested & used on all Trs & Bravo boats racing. If you want to get most out of a boat try B Blades props but you will pay $$$ & it will still have a Merc splined hub, no Volvo hubs.
When I was racing our Skater Cat we tested @ Mercury Marine old Lake X for a week trying many types of props, that was a real awakening on what props work & don't, hard to beat Mercruser.

[murfman]

Before:http://i184.photobucket.com/albums/x205/murfman_photo/Magnum/image_zps75bc9802.jpg (http://s184.photobucket.com/user/murfman_photo/media/Magnum/image_zps75bc9802.jpg.html)

After:http://i184.photobucket.com/albums/x205/murfman_photo/Magnum/image_zps9216cbdf.jpg (http://s184.photobucket.com/user/murfman_photo/media/Magnum/image_zps9216cbdf.jpg.html)

The black marker lines on the transom show the old Vs new centerline of the primary drive shaft

I was able to raise the drive 2' with the 290/SP transom shield.

I could have gone about an inch more and the transom shield would have still covered the cutout but the gasket (O Ring) would have been over the cutout, it would have been an easy patch, but the top of my transom flares back at the top, and I didn't want to get into notching it.

The issue with external hydraulic steering is with the SP drives, if you run a 290 the Typical top plate can be run as the top of the 290 drive is the same as the 270/280.

The reasons I went with the SP drives are as follows:
1. I prefer Volvo to Mercruiser
2. I am running Chrysler small blocks (No simple way to connect them to a Mercruiser drive)
3. I wanted to add Hydraulic trim (I considered using the Mercury outboard ram setup but found the 290/SP shields were cheaper than the parts required to add the Mercury stuff)
4. The 290/SP flange looks clean with the trim installed unlike the 270T or Mercury parts
5. Raising the drive 2" was just an added benefit I found when playing around with the template on the transom

[murfman]

I am holding out hope for a way to mount Mirage props on my drives, but I also feel I will be able tuck the drives with my now available hydraulic trim to get the boat up on plane with the Solas props, and then trim it out for top speed.

[murfman]

My twin engine Magnum has the Volvo 280 drive raised 3", love it making a 5mph improvement over stock . What really makes this application work are the Mercruiser Mirage 23p props. What does not work with the Volvo 17 spline 250, 270,280 & 290 drives raised are the Solas props as they have way to much slip do to there fat blades. Jeff Hall will test to this after he raised his drives on his Magnum using them, but they did worked well in the stock set up. My Volvo drives have the Merc prop shafts so I can use any Merc prop I want making selection easy, but these shafts are no longer available, wish they were . Since Volvo has a 17 spline shaft we use to be able to broach out Merc props to the Volvo shaft but newer Merc through the exhaust hub props do not have the meat to do that now. Jeff & I made adapters to convert the new Merc square hub props thinking this would be a good alternative but the labor & cost was to intensive. Jeff has since found some older props on ebay that were broached out & work very well for his Magnum. The alternative now my be finding Merc solid hub ocean wheels that can be broached out but finding a shop today to do this may be hard.
Jeff & I are not using any power trim on our Magnums as we like the set it & forget it set up with the drives raised up, but we could use my simple power trim made with Merc outboard parts that I have talked about here before. I think this would be much easier than going to a 290 set up if power trim is all you want like I have on my X-18 Donzi. The other down side to using a complete 290 drive & shield is hooking up the external power steering as the top of the drive is different than Volvo 250, 270 & 280 drives, it can be done but takes more work.

Are you giving up on the Prop adapters? In the pictures you posted, is the square rubber isolator modified? If not, I take it its just the aluminum adapter broached for 17 splines on the inside and stock Merc dimensions on the outside?

[smidgen too]

Are you giving up on the Prop adapters? In the pictures you posted, is the square rubber isolator modified? If not, I take it its just the aluminum adapter broached for 17 splines on the inside and stock Merc dimensions on the outside?

Robert getting on plane with the raised drives & Solas props is not the problem what is the faster you go the more they slip. Jeff has the numbers, maybe he will chime in ?? There is a lot of CNC work to make the aluminum adapters to fit the stock Merc plastic square hub, to bad Solas does not make a Volvo universal hub for Merc props. As of now Jeff has the props that work well with his raised drives & not using the adapters & my sport has the right Merc props. My Sedan Mag I'm now restoring will run the Volvo 270 drives @ the stock height with the 15x23p Nibrow props with the 400 cu small blocks as I don't plan to run it any harder than 55mph so they will be more than adequate. I may add my power trim as I can build it with the Merc parts for less than $350.00.. Mark

[johnnywhale]

Looking at the Magnum pictures, and considering where the drives on twins are relative to the hull, on a single like mine, the prop is considerably deeper. But water flow level would be even with the depth of the hull, so the effect of raising the dimension is the same on single or twin applications, yes?
Would weight of the boat play into this also?

[mattyboy]

What is the measurement of the cav plate to the center bottom line on the twin sharp keel raised x setup and what is it to the hull bottom it intersects. Yes the Solas is an in water prop if you go towards the surface you need a prop with a blade design that likes it I had a 25 chopper and a 26 cleaver both merc props with a Volvo hub justsayn20 bought them to try on his setup maybe a source to try one
where is the cav plate on the gt now
On my hornet it is a little low but the 280 drive is a tad longer that the original drive

[murfman]

Robert getting on plane with the raised drives & Solas props is not the problem what is the faster you go the more they slip. Jeff has the numbers, maybe he will chime in ?? There is a lot of CNC work to make the aluminum adapters to fit the stock Merc plastic square hub, to bad Solas does not make a Volvo universal hub for Merc props. As of now Jeff has the props that work well with his raised drives & not using the adapters & my sport has the right Merc props. My Sedan Mag I'm now restoring will run the Volvo 270 drives @ the stock height with the 15x23p Nibrow props with the 400 cu small blocks as I don't plan to run it any harder than 55mph so they will be more than adequate. I may add my power trim as I can build it with the Merc parts for less than $350.00.. Mark

I have contacts at multiple machine shops in the Chicago area and may be able to get these made. My other thought is making new shafts with the merc splines out of 300m. What is the interchangeability on Volvo shafts? I have a spare 290-SP lower unit I can disassemble for myself, but if I make 3 or 4 for myself (spares) I might as well make 20. If they fit the 270 and 280 it would be an easier sell to move them.

As as for using the Merc trim parts, it didn't make sense for me as I needed to replace my transom assemblies anyway and the SP shields cost the same as the 270-280 style.

[johnnywhale]

You could get Strange to do it, they're in your backyard. Other options could be Moser or Mark Williams. Might be interesting to drive over on your lunch hour and ask. It'd probably be worth the $ to a bunch of people.

[murfman]

You could get Strange to do it, they're in your backyard. Other options could be Moser or Mark Williams. Might be interesting to drive over on your lunch hour and ask. It'd probably be worth the $ to a bunch of people.

I have better sources than Strange. Strange is set up do do rear axles. I have a couple of shops I deal with that make headsets and shafts for transmissions and transaxles.

[johnnywhale]

It's good to be the king!

[murfman]

It's good to be the king!


i have done calibration work for Strange , and their facility is top notch. I'm sure they have the capability and equipment to make shafts for the Volvo but their shop is set up to run production on automotive rear axles and parts. They really don't have the man power to do one off type pieces. They are geared up (lol) to do quick turnarounds and production of one product.

[TXDONZI]

How would these work?

82865828668286782868

[smidgen too]

I was told that my Mecruiser to Volvo prop shafts were made by Ron Hills prop shop but not available anymore. Back in the 70's there were shops all around the Detroit area that made made one of Volvo drive parts, Kenny Blacks shop Muskie Tool was one of them. [ no longer in business ] Today it would be very hard to find a shop to do that most are set up for high volume production.

[f_inscreenname]

I have one of those prop shafts sitting on a shelf for years. Just last year I decided it was time to do something with it. Got a 270 drive ripped down and then noticed that the shaft is for a Volvo 250. Everything was just a little smaller. Now it's back on a shelf.

[Ralph Savarese]

Don't see the advantage of raising the cavitation plate above the bottom you will then airate the prop the bonus will be never enough to make it worth while.
I did that originally before I did my restoration and had nothing but cavattion issues being an inch above.