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-   -   Ilmor 710's (https://www.offshoreonly.com/forums/ilmor-high-performance-marine/237302-ilmor-710s.html)

speedchangesyou 08-20-2010 07:18 PM

Ilmor 710's
 
I have a 1999 35 fountain lightning with blower motors and Bravo drives with HP gimbals. Will the 710 Ilmors work with the bravos or do you need tranny's and different drives with these. I would like to get out of the blower motor world. Thanks

Fanatic 08-22-2010 12:44 AM

Just build normally aspirated 700 hp big blocks...Might want to get XR's as well...

monstaaa 08-22-2010 09:26 AM

the ilmor engines are incredible. i service a set in an o.l . and whata pleasure. im sure yo can plug and play, with some changes obviously. but to give perspective, 40' o.l, ilmors, 6500 rpm, 115 mph. and idle like kittys.

Marginmn 08-22-2010 11:23 PM

There was a guy here on OSO who bought set of 625's V-10's for his 35 outlaw only to discover that they would not fit in the engine compartment. The V-10's are longer and they simply would not fit lenghtwise in his engine compartment.

Personally, I have a set of 625's in my 38 Fever and although the rigger did get them to fit it was only after an obscene rigging bill and literally months of delays by one of the premiere shops in the midwest. The Ilmors are a great product and I would recommend them in a heartbeat, but only in a boat that already had them installed. Switching to V-10's is not a plug and play exchange with GM blocks by any means. They had to reglass and re-cut my transom because the Ilmors sit higher in the boat. The motor mounts line up different. There is literally an 800 pound difference between a set of Merc 525's and a set of Ilmors - looks great in the ads but taking that much weight out of the back of your boat without offsetting it by removing weight from the front of the boat can totally throw off the center of gravity - not to mention that the weight difference totally throws off any X diminsion heights recommend from the factory. The back of my boat just sits higher in the water because there is less weight back there. I offset the change in CG by installing a set of Imco extension boxes to move to drives back to act as a pivot - not to mention the extra weight of the boxes themselves to help lesson the loss of weight.

The long and short of it, there is a heck of a lot more involved than just throwing a set of V-10's back there. Great engines and I love my set up now, but in hindsight it was not smart on my part to be the first person ever to have a set of Ilmors rigged in a 38 Fountain (or any Fountain for that matter). It cost way too much, took way too long, and it was all done on my dime. It would have been wise to let the factory figure all of this out on their dime and then buy one already set up. Live and learn. I've heard that the switch goes much smoother on cats but I have no experience with that.

Great engines but man was it ever a hassle on my boat. I have a rigging bill to prove it.

Marginmn 08-22-2010 11:55 PM


Originally Posted by speedchangesyou (Post 3187248)
I have a 1999 35 fountain lightning with blower motors and Bravo drives with HP gimbals. Will the 710 Ilmors work with the bravos or do you need tranny's and different drives with these. I would like to get out of the blower motor world. Thanks

From my experience the XR's handle the 625's well. I've blown one vertical shaft in five years, and that one in the first season probably because I used to come out of the hole a little quick. I've come up really slow since and not one drive issue in 4 years.

Others Ilmor owners have told me that the 710's are very hard on XR's and they often break. I would guess that the high rate of failure has much to do with Ilmor developing their own version of the 6 drive. . A 35 ex might be light enough that you could get away with XR's if you baby them. I don't think the Bravo's would work well at all. The 710's produce a lot of torque.

speedchangesyou 08-23-2010 06:05 PM

710's
 
Thanks for the imput everyone. I thought it wasn't going to be easy with the Ilmors and decided to stay with Mercury Racing.. 525's.. Speed

Uncle Dave 08-26-2010 05:17 PM


Originally Posted by Marginmn (Post 3188511)
From my experience the XR's handle the 625's well. I've blown one vertical shaft in five years, and that one in the first season probably because I used to come out of the hole a little quick. I've come up really slow since and not one drive issue in 4 years.

Others Ilmor owners have told me that the 710's are very hard on XR's and they often break. I would guess that the high rate of failure has much to do with Ilmor developing their own version of the 6 drive. . A 35 ex might be light enough that you could get away with XR's if you baby them. I don't think the Bravo's would work well at all. The 710's produce a lot of torque.


I have a single 710 in a 28 foot boat and it is an incredible mill.

Quite different from a BBC and indeed - hard on drives.
They make a lot of torque in the upper RPM range and spin very fast - and being so smooth its hard to "feel" the RPM.
It just keeps pulling.

54 hours before a total upper and lower rebuild on a Teague platinum.

BBC is a lot easier all the way around and when things like headers go- a lot cheaper.

That said Im delighted with the engine.

Uncle Dave

speedchangesyou 08-26-2010 06:13 PM

Yeah, nice engines seen them at Miami Boat show and there was a set listed on this site for 55K. Caught my interest.

Marginmn 08-26-2010 10:18 PM


Originally Posted by Uncle Dave (Post 3192411)
I have a single 710 in a 28 foot boat and it is an incredible mill.

Quite different from a BBC and indeed - hard on drives.
They make a lot of torque in the upper RPM range and spin very fast - and being so smooth its hard to "feel" the RPM.
It just keeps pulling.

54 hours before a total upper and lower rebuild on a Teague platinum.

BBC is a lot easier all the way around and when things like headers go- a lot cheaper.

That said Im delighted with the engine.

Uncle Dave

Yes they are great engines - my only complaint was the rigging headache to get them in there. I've thought about the 710's myself but after talking to other's I wonder if they would eat drives on my 38 Fever. The 625's have been about as turnkey as it gets.

Fanatic 08-26-2010 11:23 PM


Originally Posted by Marginmn (Post 3192689)
Yes they are great engines - my only complaint was the rigging headache to get them in there. I've thought about the 710's myself but after talking to other's I wonder if they would eat drives on my 38 Fever. The 625's have been about as turnkey as it gets.

You have any pics you can post?

Uncle Dave 08-26-2010 11:41 PM

2 Attachment(s)

Originally Posted by Marginmn (Post 3192689)
Yes they are great engines - my only complaint was the rigging headache to get them in there. I've thought about the 710's myself but after talking to other's I wonder if they would eat drives on my 38 Fever. The 625's have been about as turnkey as it gets.

It is an extremely tight fit at best for any boat built built for a BBC and is literally undoable in some boats.
Note the mold level clearance built into the engine compartment to clear the water return from the "mixer".

You are probably dead on about another 75hp a side eating drives- the 710 spin another 300 rpm as well although I rarely get to run up there on the Ocean my little 28's too small.

Uncle DaveAttachment 425658

Marginmn 08-27-2010 06:33 AM


Originally Posted by Uncle Dave (Post 3192752)
It is an extremely tight fit at best for any boat built built for a BBC and is literally undoable in some boats.
Note the mold level clearance built into the engine compartment to clear the water return from the "mixer".

You are probably dead on about another 75hp a side eating drives- the 710 spin another 300 rpm as well although I rarely get to run up there on the Ocean my little 28's too small.

Uncle DaveAttachment 425658

Tight but looks sweet :)

Marginmn 08-27-2010 06:39 AM


Originally Posted by Fanatic (Post 3192737)
You have any pics you can post?

http://www.offshoreonly.com/forums/f...r-my-38-a.html

Uncle Dave 08-27-2010 09:34 AM

What a great thread you linked to.

I definitely had it easier not doing a retrofit.

PM sent.

UD

C_Spray 09-16-2010 02:24 PM


Originally Posted by Uncle Dave (Post 3192971)
What a great thread you linked to...UD

AMEN to that. Interesting on how I wound up facing some of the same issues:
725/Indy retrofit project
Like Marginmn, the ILMOR factory came through when I needed them, though!


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