what do you guys think of this as a replacement engine? 602 crate.

indy440

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I'm shopping for a 350 mercruiser and a friend who races dirt cars told me to look into a "602 crate" engine from GM. They're factory sealed for a specific racing class.

They can be purchased used for reasonable prices.

Here are the specs:

http://www.speedwaymotors.com/GM-19258602-CT350-IMCA-Sealed-602-Chevy-Crate-Engine,67820.html

What do you think about using this in a marine application (with appropriate head gaskets and casting plugs and ignition). They have aluminum intakes but we dont go anywhere near salt water. I would be using all the accessories and starter and ignition and oil pan off the mercruiser 350 i already have (and ran out of oil).

I would be using through the prop exhaust. The cam specs are:
  • Cam Lift: .435? Intake / .460? exhaust
  • Cam Duration @ .050?: 212 deg. Intake / 222 deg. Exhaust
  • Lobe Separation: 112.5 Degrees
I think I can get one used for around $1500.
 

Bondo

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but with more lift and duration to clear the engine exhaust quickly and move in more air – providing excellent mid- and high-range power, where you need it on the track.

Ayuh,.... It's the cam that's a Deal Killer,.... 218? exhaust is extreme in a boat motor, much less 222?,......

Ya need Power, from Idle to 5 grand,... mid-range is to high to start buildin' power,....
 

Fishermark

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From what I have read on the subject in the past, any cam with a lobe separation angle (LSA) of less than 113 degrees will be subject to some amount of water inversion - the sucking of water into your exhaust. Most stock marine engines have a LSA of between 113 - 116 degrees. This results in a smooth idle.

From what I have read is that Mercruiser recommends on their high performance engines after an extended period of idleing that they be revved up a few times before shutting off to clear any water from the combustion chamber and exhaust manifold. Dennis Moore has a great book on the subject - Small Block Chevy Marine Performance..

Just as a side note - I run basically that exact dual pattern cam in my 56 Chevy. It has a nice lumpy idle - sounds good and runs great. If it were me however, I would stick to something closer to stock for my boat.
 

Bondo

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Most stock marine engines have a LSA of between 113 - 116 degrees. This results in a smooth idle.

Ayuh,.... I ain't had Dennis' book out, 'n read up on it in awhile, but I believe those numbers are 109? to 112?,.....
 

Fishermark

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Ayuh,.... I ain't had Dennis' book out, 'n read up on it in awhile, but I believe those numbers are 109? to 112?,.....


Since my old brain loses more info these days than it gains, I actually had to look it up before I posted. On page 129 (I've had his book for years now - it's getting hard to find otherwise!) he writes ...


Racing engines used in race cars and race boats will have lobe separation angle of between 104 and 108 degrees. A lobe separation angle this tight will creat a very rough idle, necessitating high idle speeds. Tight lobe separation angles (because the intake and exhaust valve will be open at the same time longer) will also allow water to be sucked back up through the exhaust system in the combustion chamber on most marine engines.

Standard car and boat engines have lobe separation angles of between 113 and 116 degrees. A lobe separation angle this wide will create a very smooth idle and is less prone to suck water back up into the combustion chambers.
 

Fishermark

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He continues...

If the lobe separation angle is kept to between 109 to 112 degrees, an acceptable idle, but one with a slight lope, will be maintained and only a slight, if any, amount of water will be sucked back into the combustion chamber at idle.

This is also where he mentions about Mercruiser recommending revving the engine in this case after extended idling.
 

indy440

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ok, sounds like maybe it would be ok with a different cam choice. For the price of the motor, plus a cam and lifters, I could just go with a reman engine from rapido... Short block from them is 1400 plus 150 shipping. My heads only have 50 hours on them so i could reuse.
 

BigChris

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In another thread, I am removing a MEFI 4 system from my 383 and replacing with a carb. Albeit large displacement engines tend to "calm down" cams.
I'm using a Comp Cams 08-466-8 cam. Its .570 lift intake and .565 lift exhaust. 218? @ .050 intake and 224? @ .050 exhaust. Cam is installed at 109? ILC. with a LSA of 113?. "Slightly Lopy" idle.


I spoke with the folks at comp cams and Morgantini Racing regarding the possibility of reversion prior to purchasing it -no issue. I idle at 650 rpm, have put about 165 hrs on the engine, had it apart twice (see other thread) no evidence of water, non at all.

I build successful small 4 cycle race engines. This is me www.rperacing.com

That's my $.02
 
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indy440

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Just checked out your website, my 8 year old just started racing karts last summer. We love it.
 

BigChris

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Yep, it's really fun and challenging at the same time, sometimes kart setup tortures my soul. When I nail setup-that's a good feeling. As for the engines, I build a good one. I sponsor 5 different drivers in 3 different states, they all won their features last weekend.

I bet I've spent 300 hours on my dyno perfecting the current configurations. Then earlier this season due to that early season accident in Ga with Andy Ward, there was threat of an exhaust change on the clones. Which meant back to the dyno.

Are you guys running clones, flatheads, or animals? Flat kart, cage or champ?
 
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indy440

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Flat karts with flatheads

I just had a new motor done over the winter by a local builder. I havent even started it yet. We wont make a race for a couple weeks. I'm flat out busy and the kart is in pieces still... and I should buy another set of tires...

We just got started last year and paid someone to build a kart for us. Unfortunately I rushed into it and didnt research the guy enough. More or less, he stole from us and we were left with a hacked up kart with junk engine... We picked up the pieces and made the best of it and still ran 6 races in the fall.
 

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BigChris

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Good luck to you and your boy this season. Tons of quality time spent with my son doing this. I suspected you might have some familiarity since I recognized the crate engine you mentioned.

As for the cam, depends on what you want. Do you want a nice daily driver that Ward Cleaver would have? Or do you want something a little more exciting? I love when my wife fires ours up and drives her off the trailer with that nice lopy idle and brings it to the dock at the launch. Even with underwater exhaust you can hear it. It exudes this presence of where sophisticated meets rowdy.

As for in what rpm range it'll make power, I'm sure you know that can be adjusted by where you set ILC when you install your timing set (as you know they make adjustable ones).

Check out the spec for these two grinds from Comp, I'm listing them for comparison purposes.
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=186&sb=2
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=187&sb=2

Notice the suggested RPM range for both. The first falls short in terms of duration than what comes in the 602 but it comes close. The second is a little more than the 602. Note the suggested ILC install of 106? for both. That's what I'd be targeting if I was gonna go that route.

And lastly, a good used dirt track race engine should have the appropriate clearances required for a marine engine.
 
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