Logo
FULL SITE MENU

454 Rebuild. Aprox HP with Comp Cam

H

hottoddie

Contributing Member
On the verge of moving forward with having my two 1986 Crusader 454/350's rebuilt and putting mild performance cams from CompCam. These would be the "entry" level Xrteme Marine Hydraulic Flt Tappet cam. Specs are Duration @.050" lift - 218* Intake / 224* Exhaust. Valve lift 505" Intake / .515" Exhaust. Lobe Separation 112*. For those of you that are schooled in these motors what would be your guess as to the increase in HP and Torque. Also would in be much of an advantage in replacing the stock cast iron intake with an Eldebrock Performer dual plane intake while I'm at it. My 39 ft. Sea Ray Express can really the increase and I am hoping for around a 15% increase in HP and torque. What do you guys think? Thanks
 
What makes 15% the magic number?

For that much boat, you want max torque as soon as possible to make you more efficient....HP is really a don't care. Any other things you can do to make the engine more efficient will help too...above all, keep your peanut port heads but don't hesitate to clean them up.

The rest of your rebuild choices will determine the end result in combination with the camshaft selection. I personally think you will be hard pressed to do much better than the factory choices.

If you have the $200+ for each of the intake manifolds, make sure you have the clearance before parting with the originals...I don't think you will see any change in performance by swapping the manifolds...Also, depending upon which 'performer' you select, you may have to switch to a squarebore carb too...
 
Because one motor is reverse rotation the camshaft core for that motor was hard to find. I have it on order and is supposed to arrive tomorrow. If it is correct I will bring it to the machine shop that will be doing the work and we will decide which camshaft to use for the standard rotation motor and send the unground core to be ground to the same specs. At the same time I will discuss the intake manifold situation with him. He is a very well respected performance engine shop and has many years experience in high performance race car and marine engines. The manifold clearance is not a problem as there is 4-5 inches above the top of the K&N Marine flame arresters.

One of the members at our yacht club did a similar rebuild to a Sea Ray 390 several years ago and he claims that the boat went from an 18 knot cruise to a 21 knot cruise getting the same mpg. If can accomplish the same I will be happy.
 
I would think a stroker kit that bumped the motors up to say 489 or 496 would reap more benefit than a cam change. I spoke with a performance/marine builder here in so Ca. about it and he said without any other changes on my engine it should make just over 400 h.p. and over 500 ft lbs torgue. With mild cam change closer to 430h.p.and 520 torgue. I used boat diesel to figure my prop pitch and with these numbers can go from turning a 19x21 wheel to a 19x24. The bad thing I was warned about is the reversion with a longer overlap cam. They like hydraulic roller cams Which can give the same or better performance without the long duration or overlap. Pricey though...especially when sourcing one for the reverse rotation motor. I'm guessing the Sea Ray owner changed prop pitch to accomplish the higher cruise? Best of luck with your endeavor.
 
You failed to mention what hp it is making now. If it is a stock Crusader type BB Chevy, then it has a fairly mild cam. That means a significant increase in hp is possible with such a radical (for marine use) cam.

That said, the top speed may not increase all that much for it takes a ton of extra hp to produce a bit more top speed.

Finally, you need to check the valve to piston clearance before running that motor to make sure the valves don't hit the pistons with that much extra lift. Also, I've had to re-machine the valve guides on motors when adding that much more lift.

Jeff
 
The engines are the stock 350 hp. The stock cam is as Jeff says is fairly mild. If we change the cams they will not be radical and valve to piston clearance should not be an issue. The engine shop is highly respected and has built and dyno tested hundreds of these motors so I trust his judgment on his. If we can't locate a reverse rotation cam then we may convert the reverse rotating motor to standard rotation and change the transmission to compensate, but we will know that soon.
 
Jeff is right about piston to valve clearance but the shop should check this for you if they are doing the assembly. Sounds like you are in good hands. Let us know how it turns out.
 
Make sure your builder knows EXACTLY what you are doing with the engines....you aren't trying to move a 2000# jet boat...but rather a fairly large hull weighing in at many tons...

If you spend most of your time cruising, you want to build the engine so its torque peaks as soon as possible and stays flat (ideally) until just past your cruise RPM...anything beyond that is something you will pay for but rarely use.

The other little things you can do will also pay dividends - specifically, optimize the condition of the rest of the drive line. Making sure it is all ture and properly installed is time well spent, especially if the engines are out...and getting the props worked using a propscan (digital) system once sized will help much.

The other item to consider is to open your exhaust up...Those engines were likely to have the 3" outlet elbows on the end of the log exhaust manifolds...A four inch elbow on top of a center riser manifold flows much more air and will help the engine run more efficiently.

Just my thoughts...
 
Mark I have had those conversations with the engine shop and they are being taken into consideration. The exhaust are Crusader log style with 4" elbows running into Aqua Lift mufflers with a 5" outlet so the exhaust should be ok with a mild upgrade like I want. Talked to Atlantic Gear in Topsfield, Ma today and they said that I can change out the Velvet Drive 10-18-006 (1.91-1) opposite rotation trans mission on the motor that we may convert from RH to LH rotation to a 10-18-008 (2.10-1) standard rotation unit and have the props tuned to compensate. Not sure I like the son of doing that.
 
Still no luck locating a reverse rotation cam core. Wondering if changing the rocker arms out from the oem stamped steel that are 1.7 to 1 for a set of roller rocker 1.8-1 may be an acceptable option. Valve lift would increase from 0.461 to 0.486 on the intakes and from 0.479 to 0.508 on the exhaust. These are not as much as the gain would be with a Comp Cam but very easy to do and along with upgrading the intake manifold to a Eldelbrock Perfomer and the ignition to the high energy Davis Unified Ignition distributor with .050 plug gap I can pick up maybe 30-40 hp fairly easily and not have to change out gearing, etc. Will be talking to my engine guy today but looking for more opinions. Thanks.
 
Roller rockers help operating efficiency by removing friction...whether you go stock or longer, you'll find you need to elevate or replace the rocker covers...the typical approach is to get a set of "tall" ones but they won't fit due to the exhaust manifolds. You'll need 'mid-sized' or custom made ones or a spacer under the stock ones...

The baffles will also have to be removed from the stock covers - that's a different story.

The reverse camshafts shouldn't be rare as rebuilt engines are still commodity items...speedpro (part of FMC) used to OEM the GM camshafts but not sure if they are still around...if i find part numbers, I'll post them
 
Can't find any current speedpro cam numbers...thank you FMC!

That said, Melling replacement cams for the standard production 7.4L are # 22217 and 22218. The magnum versions are 22219 and 22220. that you provide you with more than enough to get rolling.
 
Update: The CR engine came out last Sunday and was brought to the engine shop on Monday. Got a call from shop Thursday that an unground reverse rotation cam core was located and will be sent out to be ground to a spec yet to be determined. This along with Comp Cam Magnum Roller Rockers and the Eldelbrock Performer intake should yield around 420 HP. As my main concern is getting maximum mid range torque (3000-3200 rpm) anyone have any opinions on what cam specs would work well. I am also somewhat concerned about the cam causing water ingestion because of valve overlap and so on. Also Pat from Davis Unified Ignition is suggesting Autolite Platinum tip plugs @.055 gap. An comments on this as well.

Of course going this route will require the other motor to get the same treatment which I was kinda hoping to avoid but the end result should be awesome.
 
Intake:

I would start out with the factory intake after the build. It will give you the exact torque curve you need. You can experiment after the break in with the Performer manifolds.
 
If you have the stock "peanut" port heads, there isn't a lot to be gained switching intakes due to the huge mismatch at that interface...
 
Expecting to get motor back the next few days. Here is what has been done. Bored .010 over with new coated pistons. Crankshaft polished. Mild custom ground camshaft by Comp Cams. Comp cams lifters and roller tip rockers. Heads redone with correct valve springs per camshaft specs. Eldelbrock Performer intake. Davis Unified Ignition with AC Delco Rapid Fire 10 Platinum Spark Plugs. Stock Quadrajet Carb (rebuilt). Because this is a reverse rotation motor so we cannot dino test it. When the starboard (LH rotation) engine is done to the same specs in the fall it will be dino tested so we will then know the rated HP. We expect around 420 HP and props will then be changed from 19X18 to 2X19 or 20X20.
 
Keep us posted...kinda want to know what the options are when this time comes for me. Where did you purchase the cam blank?
 
Last edited:
Reid Auto machine shop found the cam and had Comp do the custom grind. He wouldn't tell where he got it. However I was also looking on my own and located them at Melling. Melling told me they only had 5 reverse rotation ores left so I suggest you get one know if think you will need it.
 
Just an update. I had only the port motor done this spring do to time and budget constraints. The motor now has 30 hours on it and it runs great however the props are still the Sea Ray 19X18 stock props on both sides. The starboard motor will come out in Qctober and be reworked to the exact specs and then dyno tested. The port motor is the counteraction motor and therefore could not be dyno tested. The starboard motor will be dyno tested and the boat will get the correct props installed based on the dyno test results.
 
Good to hear the report...I was wondering how it turned out. I spoke with CNC motorsports about a torque motor after seeing one of their motors on youtube dyno 530 ft Ibs at 3000 rpm. It had the 496 crank kit and some secret Crower grind on a roller tappet cam though. Will be interesting once you get the starboard side rebuilt. Do you get a little lumpier idle with the new cam grind?
 
The idle is very smooth and sounds the same as the stock motor. The main difference I notice is that the stock motor requires more throttle to keep the same RPM as the new motor. At 3100 RPM cruise the stock motor needs throttle push about 3/4" further forward. At 4000 RPM it needs more than 1" more throttle. I do notice slightly more rocker arm noise at idle but that should be expected with mild Comp Cam and rocker arms. Based on past experience Reid Auto expects 410-420 HP.
 
hottoddie said:
Also would in be much of an advantage in replacing the stock cast iron intake with an Eldebrock Performer dual plane intake while I'm at it.
Click to expand...
If fitted with Closed Cooling, you can use the automotive dual plane aluminum intake manifold.
However, if Raw Water cooled, you will eventually see some corrosion develope due to the cast iron/aluminum proximety in a non PH balanced environment.

hottoddie said:
1.... The main difference I notice is that the stock motor requires more throttle to keep the same RPM as the new motor. At 3100 RPM cruise the stock motor needs throttle push about 3/4" further forward. At 4000 RPM it needs more than 1" more throttle.

2.... I do notice slightly more rocker arm noise at idle but that should be expected with mild Comp Cam and rocker arms. Based on past experience Reid Auto expects 410-420 HP.
Click to expand...

1.... It's not uncommon to see twins of a different build and/or horse power/torque.
As long as you maintain the same RPM between Stbd and Port engines (in sync)......., you can may this work.

2.... With higher valve lift (valve stem travel), you will get more rocker arm "wiping friction" across the valve stem. This may shorten the valve guide/valve stem life.... but probably of little significance.
Roller tip rocker arms would reduce this "wiping" action friction.
 
RicardoMarine said:
If fitted with Closed Cooling, you can use the automotive dual plane aluminum intake manifold.
However, if Raw Water cooled, you will eventually see some corrosion develope due to the cast iron/aluminum proximety in a non PH balanced environment.

In my case thee are FWC. I would never own a RWC motor when running in salt water. Also in my case the only problem the extra height of the Eldelbrok manifold created was having the adjust the angle of the throttle cable for smooth operation.


1.... It's not uncommon to see twins of a different build and/or horse power/torque.
As long as you maintain the same RPM between Stbd and Port engines (in sync)......., you can may this work.

The boat has a sync so that eliminates that issue. The props are still the stock 19X18 so as long as the engines are in sync the boat goes straight.

2.... With higher valve lift (valve stem travel), you will get more rocker arm "wiping friction" across the valve stem. This may shorten the valve guide/valve stem life.... but probably of little significance.
Roller tip rocker arms would reduce this "wiping" action friction.
Click to expand...

The new rockers are Com Cams stamped rockers. Rollers rockers would require taller rocker covers which will not fit next to the Crusader exhaust manifolds.
 
Reid Auto preadjusted the valves when they assembled the motor. I told him I would adjust the valves once the motor was running and warmed up. Jim Reid looked at me and said don't waste your time we know what we are doing. So I left them as he adjusted them and 30 hours later they have been fine. BTW with the Melling high out oil pump the oil pressure runs at 60 psi at idle and 75 psi at 3100 rpm cruise with 20w-50 Valvoline Racing Oil with zinc additive for the flat tappets.
 
Those melling pumps are fantastic! I experienced the same thing! But, you said your rockers were making some noise? If they're clicking, they're too loose. Otherwise you're good to go.
 
glad you are rolling...

regarding the throttles' relative position....don't read too much into that unless you have mapped the "stick position" into throttle opening....even then, some difference is to be expected as the engines are different.

Regarding Mr Reid's static adjustment on the tappets - his approach is sound and sounds like he's willing to stake his reputation to it.

finally, regarding alternate rocker arms; there are a few options besides "tall" valve covers, all with pros and cons....we have full roller rockers under "stock" covers though there were a couple minor mods.
 
20w-50... Fresh bore job, should be a somewhat low clearance engine while new. What are the measured main bearing clearances? One rule I tend to follow is use the lightest weight oil that will still maintain pressure when at its hottest temperature. You want thin oil to make it into the clearances when cold. I might try a 5w-30 synthetic after breakin and study the oil pressure. Also, forcing the pump to 75psi takes away from crank power, loosing some of the roller cam power benefit. You have elements in this rebuild good for high rpm race engines, but what you need is a tractor engine to push a 39'ray.
 
..."forcing the pump to 75psi takes away from crank power"

It doesn't do the cam bearings a lot of good either. My race car engine used to wear out the cam gears when I was running 90 pounds oil pressure (like dope).

Jeff
 
Back
Top