Chris Craft 283 C.I. engine!

[Dan-Q]

Hello all,
Anyone with any ideas about the Maximum Brake Horsepower and rated RPM of this common engine.
I've heard 180 HP (rated not MBHP) then 185. Then a Chevrolet site says the 4 barel carb (which I have) develops 220 HP at 4800 RPM. The 2 barrel set-up does 195 HP at 4800 RPM!!
The engine was originally in a 32 foot CC Cavalier 1964 or 1966.

Help!!

[Alan D. Hyde]

Go to the Chris-Craft Collection at

www.mariner.org (http://www.mariner.org)

I think you'll find that 180 or 185 is what Chris-Craft claimed in their sales materials.

Alan

[Peter Malcolm Jardine]

Alan is right about the horsepower, but the 283 is a very versatile engine. If you desire more horsepower, another camshaft, a modern aluminum intake manifold, and a different carb will probably bounce you up about 25 horse or so... balancing the rotating assemblies on small blocks will allow you to spin that motor up to about 4500 or so... (after that cavitation problems will be your biggest worry on older hulls )
I have two F series chris engines in my 63 constellation... one is getting rebuilt this year. winter putaway ... put some diesel in the combustion chambers,(stuck rings an issue) and carefully antifreeze them...

[Dan-Q]

Thanks Alan and Peter,

Alan, I was unable to find what I'm looking for in the link. I'll try more later.

Peter, what do you think my max RPM could be on a stock 283 engine?
Are your engines 283's? If so are they 4 barrels.

I'm now more convinced about the 185 HP because Riva put them in the Aquaramas in the mid '60s and claimed 185 HP in their brochures. But I do not know if they had 2 or 4 barrel carbs ... I'm guessing they were 4 'cause gas was cheap then.

[Peter Malcolm Jardine]

Hey Dan... Yep mine are both 283's called 283fl25 by Chris Craft in '63. four barrels, with the big high rise cast iron exhaust manifolds, that then go into a single pipe by way of a massive series of cast iron intersections. RPM's depend on how you pitch your prop I suspect, and so far I have only got up to about 3000 with 1:1 paragon transmissions running 18x18 props.. (stock configuration on this boat) I would think that 3000 is a little low, and that my engines are a wee bit tired, altho to see a 36 foot Chris wailing down the river at 3000 rpm is fairly impressive..I think about 25 mph or better..(gas consumption is EEEEnormous at that speed too)
IF you want revolutions, beef up your horsepower, and make sure the engine rotating assemblies are well balanced, (crank rods and piston assemblies)The typical 60's marine 283 was the chev truck version, with a cam designed for torque, and slightly lower redline (from what I can determine). 283's as a hot rod engine however had a amazing rep for hi rev's (6000 plus)
but ... thats kinda hard on a marine application so I think 4800 is a realistic figure... Hope this helps

[Dan-Q]

Hi Peter, thank you again for that.
Very interesting. I know what you mean about the prop governing the RPM but where is my limit. A friend mecanic told me I could put a small pitch prop on and go Wide Open Throttle until I hear the valves float. He says that that would put my max RPM 500 below that mark. I have yet tried it but perhaps I will.

It's just that if I had someone come straight out and say that a 283 1964 goes xxxx max RPM would be easier and safer.

I just received a new prop today. It's a 12"D x 14"P. I'm really anxious to see what it'll do for me. I'm told that at 4000 RPM I should be seeing 42 t0 45 knots ???

I'll let you know in a few days.

Thanks again
Danny

[brad9798]

I've got twin original (read that NEVER rebuilt) in my 1964 35' Chris Craft-

They ARE 185 hp with a 4-barrel and standard/stock equipment. Should say so right on your valve covers.

Anyway, on a good day, I can turn 3300+ rpms. When new, about 4,000 was 'top' speed.

Peter- Your valves are probably worn, rings, too. Your compression is not what it should be if you can only get 3,000 rpm.

---------------------------
IMPORTANT:

According to my original manual- 1964 from the factory-

185hp at 4,000rpm
261 ft/lbs torque at 3000 rpm

"Sustained speed in excess of 4000 rpm will VOID the factory warranty. A top cruising speed not in excess of 3600 rpm is recommended."
----------------------

That should answer your questions.

Brad

[Ed Harrow]

Jeez the small block in my plastic pig is good for 7000.

[Dan-Q]

Brad, that's great to hear ... I guess! It does give me a good idea of the numbers.
I'm wondering if mine beeing a much smaller boat and not a cruiser if the numbers remain the same. I'm guessing you would be a semi displacement hull where I would be a planing hull.

But remains that if CC say 4000 for your boat and considering that mine is freshly redone and that the cylinders were rebored and all, then perhaps I can look at 4200 as a max and no way 4800.

And then the max RPM is just a way to find a safe and "economical" cruising speed.

Ed; ... I'm sorry ... I just don't get your plastic pig thing!!

Salutations

[brad9798]

You should be set- Dan.

It it doesn't matter what type of boat it's in. Max rpm is max rpm. It is not specific to boat, according to my engine manual.

Good luck.

Brad

[Dan-Q]

Brad, I just thought maybe that if a motor is pushing a lighter boat it is less loaded and therefore could endure a higher RPM for a longer period of time, whereas the same engine pushing a heavier load would heat up more therefore wear out faster; hence a reduction in max RPM by the manufacture!?

Is there any sense in what I'm saying??

Also, just for the heck of it, what kind of speeds do you get at different RPMs and what size props do you have?

Later

[imported_Conrad]

Dan- the prop sets the load, not the boat. Safe max rpm is set by the cam and valve springs, hence the same block running safely at 4000 max or 7000 max. Your motor is set up for torque and max efficiency at lower rpms, but limited by this compromise to the 4200 rpm.

[brad9798]

Conrad- You are correct, the 283 marine block was not built for high end speed.

Dan- in a runabout, you can get substantial speed at 3600-4000 rpm on the 283 ... you have a lot less boat to push.

Mine (35' and 12,000+ pounds) will still plane and top out at about 23 mph wide open ... something I do about once per year just to clean out the engines.

Engine speed has nothing to do with the engine heating up ... mine run colder wide open than they do at idle.

My props- I'd have to check. They are stock, so they are probably 16 or 18"???

I run about 5-6 mph at 1,000rpm;, 10mph at 1,500; 12mph @ 1,800rpm; 16 at 2200rpm; 20 at 3,000rpm;
23-24 at 3,400 rpm.

What type of boat is this motor going in?

Brad

[brian.cunningham]

What Ed is talking about it peak RPM

We both have Corvettes :D
I don't mind buzzing the engine above 6000rpm, but it doesn't stay there long. On the highway I'm only running 1100rpm.

When SBC are delivered in a truck and boats they are substantial changes, the engines in these applications are meant for continous output at cruise.

That 283 is a sweet engine, enjoy it.
You could make power upgrades if you want.
But for the same $$$ you could go down to you local GM dealer and buy a 350ci crate motor, and hang on to the 283.

If you make any power changes, you'll have to change your prop to maximize the effectiveness.

on just run it as is.

[Dan-Q]

Brad, the motor is already installed in an 18' 1954 Hunter's Marine Runabout.
It is newly rebuilt and was originaly in 1964 32'CC Cavalier. Of course the prop that came with it was useless for me. 13"D x 9"P
I've been trying to match a prop to this boat and motor but was lacking info on the HP/RPM level.
With the help of you guys that replied to this topic and from what I was able to find on the net, 185HP sounds right.

As for the RPM thing, for a while I was told that 4800 should be about my red line but now, again from what you folks are saying , it's much less.

I know that the best thing is to try different props and compare speed vs RPM. So as we speak I now have a new 12"D x 14"P that I have yet tried (maybe tomorrow) and I believe it should work well for me. The shop that did the job on my prop says that should I lack speed at a given RPM, that he will add a bit of cup to the blades. But then again, how much speed should I expect?? We will see!!

Conrad; I hear you when you say that the prop governs the load. I had'nt seen it that way!

Thanks guys

[SailBoatDude]

There is no real comparison value in automotive to marine engines, even if the blocks are the same. The cam, sometimes heads, exhaust, sometimes intake, carb(s) and a host of other considerations make automotive applications of the same family engine meaningless as the parts that govern the performance are different.

Automotive engines operate at 20% load 90% of the time, whereas marine engines (even same family engines) run at 80-90% load 90-100% of the time. Big difference . . . The engineering needed to make an automotive engine successful in the marine environment is considerable and the reason we see less automotive conversions available to the equivalent dedicated marine engine.

In short, boats need more torque over a narrower band of RPM then a car so the marine engine is engineered to be less flexible then the auto engine. Boats run at idle, just below flat-out, and flat-out, cars need good response from a wide band of RPM use for stop and go traffic and getting on freeways and the like, the cam profile and intake/exhaust overlap and duration bear this out with the naked, let alone the numbers on a spec sheet.

The 283 is on of my favorite engines next to the 327 (it's newer sister in the early 60's) It is fast revving and can wind up to unheard of RPM in other 'under square' engines. The valve springs will start to float at RPM approaching 5000 (4800?) and I can't believe the specs I've heard here on the site concerning the first generation small block. The points will start bouncing at this speed and valve spring bind or breakage is a real problem without added equipment.

Yes, newer generations of the small block using roller cams & rockers, electronic controlled fuel and ignition and other such niceties can get a 350 powered Z06 Corvette over 400 HP and a ridiculous red line for Max RPM with 100,000 mile warranty to boot, but not in a boat spinning a prop and certainly not mechanical points, timing, hydraulic lifters and mechanical fuel metering.

[Dan-Q]

Hey Dude, thanks for the feedback.

What exactly are you saying in this quote;

"The valve springs will start to float at RPM
approaching 5000 (4800?) and I can't believe the specs I've heard here on the site concerning the first generation
small block. The points will start bouncing at this speed and valve spring bind or breakage is a real problem without
added equipment."

Which "bad" specs are you refering to?
Are you saying that 4800 RPM is impossible on a stock marine 283?
If so what would be your idea of a max RPM on such an engine?

Thanks

[capt jake]

I can't recall the specs off hand, but Sailboatdude is right on his discriptions. right down to the 'T'. smile.gif You can change the different springs to overcome the floating. But are you wanting to go that far??

[Peter Malcolm Jardine]

Just for information sake...
Zora and Bora Arkus Duntov (brothers )produced a set of performance heads (Ardun) for the 239 cu inch flat head ford v-8 that allowed for about 8500 rpm in cars, and over 5000 in boats in 1947-1952. Yes, with stock valve springs you will float the valves on a 283 at 5,000. You don't use stock springs... even in 1963. Performance parts are not a new thing for v-8's.

[Dan-Q]

Hey guys, I'm NOT looking for extra RPMs. I just want what the engine can deliver!!
I want to run her stock ... no mods!!
I'm SURE the valves will float at 5000 revs.
But will they at 4800 ... or will they at 4400?
I'm just looking for the safe max!!

... maybe it's 4200!!

[Peter Malcolm Jardine]

Sorry to add a bunch... but I haven't seen too many real greaseball motorheads on this site... and Sailboatdude, there is of course a great deal of similiarity between marine and automotive engines, they are built using calculated load and use depending on the application... frankly, most stock marine engines are brutally overpriced for their construction and performance, hence the performance boat market for the most part ignores stock marine period. Most serious marine engine builders throw out stock exhaust manifolds, (too heavy, bad flow etc)stock cranks, rods, pistons, and heads, blocks too..at least on gas which is what we're talking. Historically, most marine engines used the truck engine application, Chrysler crown, ford flatty, even 283 and 318. In the serious engine builders shop (which I have worked in) 283's with vintage performance parts could reach 400 hp PLUS.... and the ARDUN ford V-8 with Hillborne fuel injection was winning class at Bonneville in the early fiftys... 500 to 600 hp out of a three main 239 cu inch v-8. hydraulic lifter conversions, valve spring changes, intakes and cams all were available for marine and automotive applications starting in the late forties on. People like Ed iskaderian, and Mr Weber, and Edelbrock and Offenhauser were making limited amounts of marine performance parts long before the relatively mild performance of the new corvette v-8. In the marine performance world 500 hp small blocks are common NATURALLY aspirated. buuuuut... everyone is for most part right about stock performance, which is why I have referred to balancing,(add blueprinting, porting polishing and magnafluxing to that list) so even old timers can perform at the top of their game. but you might not want them to, and I respect that. butdon'tsayitcan'tbedone.

[Peter Malcolm Jardine]

Sorry to add a bunch... but I haven't seen too many real greaseball motorheads on this site... and Sailboatdude, there is of course a great deal of similiarity between marine and automotive engines, they are built using calculated load and use depending on the application... frankly, most stock marine engines are brutally overpriced for their construction and performance, hence the performance boat market for the most part ignores stock marine period. Most serious marine engine builders throw out stock exhaust manifolds, (too heavy, bad flow etc)stock cranks, rods, pistons, and heads, blocks too..at least on gas which is what we're talking. Historically, most marine engines used the truck engine application, Chrysler crown, ford flatty, even 283 and 318. In the serious engine builders shop (which I have worked in) 283's with vintage performance parts could reach 400 hp PLUS.... and the ARDUN ford V-8 with Hillborne fuel injection was winning class at Bonneville in the early fiftys... 500 to 600 hp out of a three main 239 cu inch v-8. hydraulic lifter conversions, valve spring changes, intakes and cams all were available for marine and automotive applications starting in the late forties on. People like Ed iskaderian, and Mr Weber, and Edelbrock and Offenhauser were making limited amounts of marine performance parts long before the relatively mild performance of the new corvette v-8. In the marine performance world 500 hp small blocks are common NATURALLY aspirated. buuuuut... everyone is for most part right about stock performance, which is why I have referred to balancing,(add blueprinting, porting polishing and magnafluxing to that list) so even old timers can perform at the top of their game. but you might not want them to, and I respect that. butdon'tsayitcan'tbedone.

[imported_Conrad]

Dan- relax, you'll be fine. The typical marine cam is very close to a current RV profile, optimized for torque and low rpm power. Max rpm is typically in the 4500-5000 range, depending on the specific cam used, with peak torque in the 2500-3000 range- which is where you want to cruise. Valve float is self limiting- the engine loses power when the valves float and stops accelerating. The only challenge I've had running these engines at the higher end of their rpm range (3500-4500) is that the points can burn- you might want to look into substituting a later style electronic distributor. It's one major improvement that all can agree on!

[John B]

Ed, are you sure that it's good for 7000. I mean, when was the last time it got WOT. I think you should check it out and get back to us.

Oh By the way. 18436572. It may come in handy sometime for either the 283 OR the LT1. ( misspent youth)

[brian.cunningham]

actually for smaller boat the power works out great

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[ 09-23-2002, 11:01 PM: Message edited by: brian.cunningham ]

[SailBoatDude]

The similarities mentioned end with the brain of the engine, the cam and other major engine components. The cam profile is similar to RV setups, but closer to a stationary engine (continuous duty generator, pumps, etc.) where they will be asked for a rather limited set of RPM ranges to operate in.

The durability issue (breaking parts at high engine speeds) can be addressed with double or triple valve springs, ratio rockers, roller setups, better head designs (valve angle less likely to bind the springs & flow better), electronic parts to replace the points, crank triggers and coil packs to replace the distributor and it's related gear, etc., etc., etc. Heavier spring rates are a poor way to solve this problem (valve float) as cams can and do break from the increased strain.

The power you're looking for is well within the scope of a near stock 283, though I'd work on beefing up the 283 design flaws for reliably. Balance the reciprocating mass. I mean every thing that spins or is attached to something that spins in the motor, it'll last a whole lot longer. Grind off all casting flash and seams smooth, replace the distributor with a second generation high energy setup (electronic) it bolts right in.

The first generation small block had some flaws that need addressing before you throw a 400 HP cam in her. The badest first generation small block was the early 60's fuelie 327 producing 375 HP in a Vette, somewhat less in a boat. GM was still fooling around with fuel injection back then and it was a setup that never worked to it's potential. The block itself needed webbing added to get reliable higher HP numbers, which is why the factory left the bench mark set at 375 HP, because they had to warranty the darn thing. We small block lover's had to wait (near 40 years to get over the 375HP bench mark) until the crank journals were reduced in size (frictional resistance) the front main web was reinforced, the valve train geometry rearranged, heads reworked, seals, wrist pin, crank, piston, intake, fuel distribution and metering and the whole block and made of lighter, stronger material. The new small block isn't anything like the old ones though some parts still do interchange.

I built a 350 having over 1,500 HP some years ago. It can be done, but the life span was measured in minutes not hours or miles. When it came apart (and we knew it would) it put 14 dents in the hood and fenders, and the guys at the track were a bit upset at the rather large slick of oil we left at half way down the inside lane not to mention the chips of track removed when the rods and crank pieces came through the oil pan. These were forged parts not cast, but . . . kaboom (it was more like "ca-kunk-win-clunk" then kaboom). In fact most boat motors come with forged insides rather then the stock cast stuff for this reason.

One horse power per cubic inch is safe, somewhat over this mark is okay. Select a cam with Max output around 3,000 RPM and don't ask a lot of tired metal. A new distributor, and short duration blasts past 4,000 RPM not too often, and she'll be fine.

Sure it can be done, but how close would you like to sitting to her when she comes apart? NASCAR produces small blocks that are very reliable with 600 to 850 HP costing $50,000 to $100,000 + a crack and run at 8,000+ RPM all afternoon then are rebuilt or tossed. The factories are conservative in their tuning and HP production because they're offering 100,000 mile bumper to bumper deals. It only makes good reason to insure the motors have a good chance of not biting them in the warranty butt.

A stock motor not giving what it should is friction, compression (lack of), fuel delivery or fire in the hole at the appropriate moment or a combination of. If the motor has good everything and is still not producing check the trans, shaft and prop.

[Dan-Q]

Thanks all for your very interesting input.
Once again I never had intensions to change the stock configuration of my engine, mind you the electronic firing sounds nice!!

Anyway, yesterday (tuesday) and today I had the chance to try my new prop. Today was the better day. This morning the lake was like an oil slick. 0 wind!! I took readings on my GPS and here is what I got with the 12"D x 14"P prop.

RPM MPH
1000 6.2
2000 14.3
3000 28.9
4000 36.0
4400 WOT 39.0

My conclusions; - I could have more pitch
- I will have cup added to the blades on this prop and have another prop I own done to 12"d x 15"P
- I did not sense valve floating but I think 4400 RPM is a little high to maintain
- I experienced cavitation on quick starts (something cup could fix)
- ...I had fun!!

Regards

[imported_Conrad]

Dan- sounds like success!- cupping the prop should kick your speed into the low forties while holding RPMs down to 42-4300. The interesting thing for me was how the wake changed, much narrower and more focused. Unfortunately, you'll still probably get some cavitation on hard starts- it's clearly all about compromises and priorities!

[Dan-Q]

Thanks Conrad, I'm anxious to see what "cup" will do.
Deep down I'm a sailor ... not a powerboater ... so I'm learning all kinds of new things here which is always pleasant.
I'll let you know the outcome.

[Allen Foote]

I believe this is the first Chris-Craft motorhead thread in a long, long time. Thanks guys! smile.gif