Crusader CH165 (GM 229), what differs from VP and Mercruiser?

[Paxman5]

Hello all!

In my boat I have a Crusader CH165 which is a GM 3.8 l/229 block with a 2 barrel carb. I have figured out that this is the same block as Volvo Penta AQ175 and Mercruiser 229. The engine is mid 80th in very good condition.

Thing is that I guess the Crusader is 165 hp (Ch165) and I have read that the VP an Mercruiser with this block have more horsepower (170 hp?) with the same 2 barrel carb. Does anybody know that differs my Crusader from the ones with 170 hp?

I have read that changing the 2 barrel carb on a VP and Mercruiser 3.8 l to a 4 barrel will give 185 hp. If this is the same for my engine I will get 20 hp more which would be rather nice! If there is other difference between the Crusader and the others maybe a carb change isn't worth it.

Any help is appreciated!

Cheers!
Fred
(From Sweden)

 

[Lyle29464]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

You will see different HP ratings from different Manufactures with the same engine. 5 HP in a boat is nothing. 20 is not much. I don't think you will be able to tell the difference. Often the "stock" set up is tuned better and performs just as well. Not as hard to find parts or people that know them. I am guessing a 100 HP increase will give you 10 more MPH in speed . So 20 HP "MIGHT" get you 2 more MPH. at WOT. figure 1 at cruise. That is a great motor. It does not like high RPM's

That money spent on find tuning and the correct prop will do you well.

Im too old to do the metric stuff.

 

[Paxman5]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

Thanks Lyle!

So my Crusader probably have the exact same parts as the other manufacturers engine with this block? No difference in camshafts or anything like that?

Good point about the speed increase (don't worry about metric, mph is pretty close to knots, isn't it?)...maybe I should go for breakerless ignition instead of changing carb...

Nice to know that it's a great motor...I have read here and there that they are rubbish but could never figure out why...

 

[Lyle29464]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

The engines are the same. Just the paint color is different. Yes the *breakerless ignition would be well spent money. That is a good tune up part. I would not spend anything on go fast stuff. As I said it is one of the best engines ever used in a boat. If you keep the RPM down they will run 1000's of hours. Be sure to keep up with your gearcase, seawater pump and exhaust riser.

* marine type

 

[Paxman5]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

Music to my ears!

So the rpm, should I go as per the manual or should I go lower at WOT?

The motor is in a 60th pleasure craft (Finmar SeaCabin 19 ft, probably never sold in the US) so I will not push it or do any racing. Speed was just shy of 30 knots WOT last summer but I think some pending, and completed, improvements will give me a few more. I might have to go for a step up propeller but that remains to be seen when the boat is put in the water.

Fyi, the motor is connected to a VP290 stern drive.

 

[Lyle29464]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

sounds like a good setup. If you can find a sweet spot not much over 3000 rpm I would run it there. If you must do 3500 to get a good angle ok. prop for 4200 -4400

Lyle

 

[Paxman5]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

That low?! According to the manual (VP AQ175 and Mercruiser MCM 185) max rpm is 4800 with cruising at 300-500 rpm below that.

Again, I will probably not run the boat very fast for long periods of time but I thought it was important to have a propeller that matches the recommended WOT rpm.

 

[Lyle29464]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

oops on the rpm go with the 4800 for proping. I would never run it that fast except for a short second test. Stay as close to 3000 max at cruise as make sence. Some hulls need more to plane correctly. Your best MPG will be in the 3k to 3500 range. I spend about 90% of my time at 1200 to 1400 rpm. in the 28 and 42

 

[Paxman5]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

Thank you so much for your help Lyle! I feel really good about my engine now!

I'm not sure what you meant with "in the 28 and 42" but I guess the smiley indicates that it wasn't that important.

Cheers
Fred

 

[Lyle29464]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

I cruse at hull speed in the 2 larger boats.

 

[Paxman5]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

Ah, I see! Maybe I should have gotten that you were referring to your big boats...nice boats by the way...I googled them.

Well I will do some fuel mileage tests to find the best rpm as soon as I have found the correct prop for WOT.

Thanks again!

/Fred

 

[Lyle29464]

Re: Crusader CH165 (GM 229), what differs from VP and Mercruiser?

The mileage test were run 40 years ago your 6 and and most every GM marine engine gets it best mileage around 3000 RPM

This can change a bit with a light hull ( 2700 or so. Heavy hull 3000 to 3500. When the bow starts down around 2800 or so keep increasing the gas untill it stops the fast rate of descent. Thats it. Trim for max rpm in the 3000- 3200 and your there unless you really need more gas to get the bow down.