1999 Longhorn Nautique Restoration Thread

Yes you might be on the edge transmission wise, in comparison torque wise 3rd gear is usually the one that goes in a T-5 manual once you get over 400hp/torque.   being your typically in lower RPM you might be ok with a larger oil cooler for awhile but looks like 80 series might be next step up.

DHMcFadin wrote: Here's my concern with the trans, it's not the horsepower I am worried about, its the torque. This engine with the gt40 intake made 488 ft lbs. That seems like a lot of torque for a PCM 40 series trans.

Eh - I have broken about a half dozen drive shafts and bent a pylon pretty good but my 40 series transmission has over 800 hrs on it without so much as a fluid change.   Those transmissions were used behind pythons from the factory and they made pretty decent torque.

That's one of the better real world examples, because you provided the dyno numbers, to see how an engine has to breathe in, combust, and breath out to live up to it's potential. What an increase with some extra fresh air!

THAT is an impressive difference. Very cool

ultrarunner wrote: Check your PM's Dom..

Thanks for reminding me!

Much more in line with what I would have expected. He should have run it up to 6000, looks like power was still climbing.

I wouldn’t worry about the transmission. If Joe and all the 502ci pythons out there can’t kill it, you won’t either.

DHMcFadin wrote: Kinda what I am thinking as well. I already have a larger oil cooler ready to install. My only concern with my current 40a is I have no idea how many hours are on it.

Well since the boat has been in the family since new and has over 4000 hours on it (from the first post in this thread) somebody must know if the transmission has over 4000 hours too or if it's been rebuilt or replaced at some point.

Everything else on the boat will be new or refurbished..................you know what you'll end up doing, it's only money.

By the way, do you have a marine flame arrestor for that setup that will clear all the pulleys etc. and fit under the engine box without hitting the front of the box?

8122pbrainard wrote: TRBenj wrote: I wouldn’t worry about the transmission. If Joe and all the 502ci pythons our there can’t kill it, you won’t either. If Joe didn't bust his trans, then I agree there is no concern. . DHMcFadin wrote: rosconole wrote: you might be ok with a larger oil cooler for awhile but looks like 80 series might be next step up. I already have a larger oil cooler ready to install. . Ross, Why the larger cooler? Unlike a automotive where there's slippage (oil shear) in the converter, a marine clutch packs are locked up. The only time there's gear to gear face slippage is in reverse when the planetary is rotating. I question the need for more cooling with more HP.

I should have clarified. I went to a larger dual oil cooler because I wanted an engine oil cooler as well as the trans.

DHMcFadin wrote: KENO wrote: By the way, do you have a marine flame arrestor for that setup that will clear all the pulleys etc. and fit under the engine box without hitting the front of the box? I have a flame arrestor from a PCM ZR409 6.0. With the flame arrestor installed (the one in the video above) the intake sticks out further than the pulleys by about 3 inches. Not sure what I’m going to do there. May have build out the engine cover a little bit.

That's why I was asking

I didn’t think you needed a “marine” flame arrestor, isn’t it considered a dry manifold ?

The would be nice! The intake does have a breather hose coming from a pcv on the valve cover.

Gary S wrote: I didn’t think you needed a “marine” flame arrestor, isn’t it considered a dry manifold ?

So what’s the consensus on the flame arrestor. Would a throttle body screen be sufficient?

Here's a link to a PCM ZR6 engine and if you read down a long ways in the description You'll see words that say it's equipped with a USCG approved flame arrestor.

Just an example, plenty more examples to be found.

Look at what you have on the engine on the Dyno-mite video and look at your GT40 arrestor, I figure you'll see words saying they're USCG approved

link

It might also reference on the arrestor, Underwriters Lab UL1111 approval or SAE J-1928 approval which satisfies the USCG

rosconole wrote: More power its going to make more heat, heat is the #1 killer of any transmission.

Ross,
From what component(s) in a marine trans is the heat generated with the extra HP?