TRS to Bravo conversion

[KerrLake]

Apparently my transmission didn't like my new engine too much. It is making a knocking sound while idling in nuetral and especially in gear. I am considering the swap to a modern drive without the transmission. Threre are so many different drive combinations I need help to decide which way to go. This is in an 86 z-25. This boat will never be the fastest on the lake, so I don't believe the hottest drive out will be necessary. I am looking for good all around performance and available parts for quite a while to come. I also would like to install hydraulic steering while the conversion is being done, I don't know how that effects the drive choice if at all. Thanks for any suggestions.

[BERTRAM BOY]

What is the condition of the TRS drive? If the drive is in good shape, it may be more cost effective and reliable to have your transmission rebuilt.

Which transmission, MercTrans or Borg-Warner?

[harbormaster]

Are you moving your engine backwards? We have some stellings standoff boxes that allow you to run a drive shaft back to the box and bolt a bravo transom assembly to the back of the box. You can also raise your X dimension by bolting it to your existing TRS transom assembly holes in your transom. All you need to do is add a rear engine mount to your engine. the box, bearing and shaft are 2k 1800 if you buy the drive & transom assembly from us. the transom assembly 2500 and the bravo 2950. That is an approximation of one way to do it simply.

I also have used parts such as bellhousings and etc.

Call me at 713-910-2000 if you have questions. We have doe quite a few conversions

[MOP]

Does it run Ok in gear and at idle does the knock go away as you raise the RPM's? Reason I ask I think they use sun gears similar the Borgwarners drives, a Borg drive will make a knocking sound if you have a miss or in some cases due a hotter cam.

[BUIZILLA]

It is making a knocking sound while idling in nuetral and especially in gear. what makes you think it is the tranny specifically, and not something else downline...

[BigGrizzly]

Just so you know. I have a TRS with the merctrans with 690+HP and it finally gave up because the lower unit broke. It has been together since 1201 and has over 800 hours on it. When the trans brakes it just slipps when knocking occurs it usually the lower unit or universals. The truth is the TRS is stronger than the bravo, but the merc trans is not. the TRS and velvet drive is much stronger than the bravo combo. Now if you are changing there are three options. 1) glass in the transom move the engine back approximate 11.5 inches and put the bravo or Volvo transom plate and lower unit. 2) use a merc or Volvo plat to cover the hole then same as above. 3) you can do Harbor master's idea with the plate ans shaft with the option of moving the engine or not depending on shaft length.

[Mr X]

It has been together since 1201 and has over 800 hours on it.
Dang Griz, your older than I thought! :rlol:

[BigGrizzly]

Thanks Ted I meant 2001. However some times I feel that old. I hope your project is working out well. You must have been busy lately. Hope the family is well too. looking forward to seeing you at Eufaula.

[KerrLake]

I have the Borg Warner trans. The knocking sound does go away as you idle up to about 1500 rpms. It is quite a bit louder if it is in gear. I am assuming it is the trans because it knocks when it is not in gear and idling. Could the knocking be in the drive even if it is not in gear? Last season I lost about 1/2 quart of trans fluid which I just found in the bellows when I pulled the drive off. That is another reason I thought it would be the trans. Are the orings on the drive shaft all that keeps the trans fluid from coming into the bellows, or is there another seal? Also, there is very little play in the u joint. This knocking is a new sound. I ran the boat with the new engine some last year and do not remember hearing it at all. I wasn't the happiest guy over the 4th to spend my lake days on our sailboat and not the Donzi.

[BigGrizzly]

There could be a slight sound but not much in neutral unless the prop was turning. Normally when in neutral there is no power to the drive at all. In your case I would repair it instead of changing drives.

[mjw930]

Call Galen @ Speedmasters, he's one of the most knowledgeable on the world regarding the TRS drives. He should be able to diagnose the problem over the phone and suggest your best alternatives.

http://www.speedmasters-inc.com/

[MOP]

It can very well be any of the things mentioned above! But it still may not be anything that is not fairly normal, the Borg boxes will make one heck of a racket from like I said earlier a miss or a hot cam. You did say the noise goes away with an increase in RPM, that is usually what a Borg will do. Do you have a buddy with a boat with a Borg in it, if so pull one spark plug wire and see if the sound is the same. Also does your boat run Ok out on the water?

[KerrLake]

I have a Borg in my Mastercraft that is the same year, although it is smaller, and I know what you mean about the noise it can make. This is not normal. If you put the boat in gear and go out to the drive you can also hear noise, not just in the boat. Does anyone know of a good shop in NC area. No one wants to work on the TRS locally from what I have found.

[KerrLake]

It does run fine on the water, no slipping. I am afraid to take it out again with the noise it is making though.