I'm about to purchase a cam for my 400SB. What are the differences, advantages, idle quality, driveability, etc??? I hear a lot of good reviews about the 280H cam and I'm really leaning in to buying this. The 274H, I just happen to run accross and wasn't sure if it would be any different..if not better than the 280.

I like the idle, sound, and performance of the 280 and some people tell me it's actually small for a 400SB. To be honest, I'm a novice when it comes to camshafts and camshaft selections. So far I have been basing my decision on the 280 by what I've seen and heard from other people and their cars.

The tech at Comp Cams just told me that the 274 is just a streetable "milder" version of the 280. Not sure if that is true, but if that's the case, then the 280 will be my choice.

Please shed some light about these two cams, or if anyone has any experience with these...please feel free to tell me about it.

So-cal Jack

The XE line is a more aggressive grind and will actually launch the tappet over the nose in a controlled valve float. That control off course is dependant upon how well you set up your valve train's geometry and the quality of the springs and the spring's installation on the head (shimmed for similar open pressure that live within the coil bind parameters).

I recommend the Magnum as a good grind for the street (I also like to look at the marine grinds with similar numbers because they are designed to live at WOT for hours to days at time without risking a failure).

I say all of this while I have an XE roller grind in my 406. I have been racing for decades, and I am familiar with the concept of preventive maintenance; that considers valve springs to be a consumable product. If you do not wish to follow my lead and trash valve springs and titanium retainers on a regular schedule then I would stick with the Magnum.


Big Dave

Dave,

Thank you for your advice and experience. You have confirmed what many others have been telling me. I'll take the advice and run with it. I do think the Magnum is the way to go.

I just wonder how it will sound. :D

So-Cal Jack

i have the comp cams 292 magnum in my car, and its a nasty little cam..sometimes i think its over kill..but when doing about 50 the car still pulls real hard..its real ratty sounding..no brakes though..lol

What is the setup that you have for your engine?

so-cal Jack

Brodix heads, victor jr intake, 358 with trw flatops. 3000 stall with 3:55 gears

I've been running the 280H CompCam for years and it has served well.

i like the 280 cam myself. used it several years ago in a 355 and it performed excellent!!

Does it have to be a Comp ??? The Lunati Voodoo series are pretty nice cams with agressive profiles like the Comp XE but a quieter lobe.

What is your compression ratio, what heads, gears, stall, etc? This all makes a difference when picking a cam.

I have had good experiance with installing a 280 Magnum in a street driven small block 400! :thumbsup:

Thanks guys for all of your posts. I feel more confident now with my decision. It is hard to judge a cam on paper, and I know people out there are running the 280 in their 400 setups.

Doug and Chris....how much horsepower and torque did you increase with the 280 and what are the current specs now? (if you happened to dyno the car yet)

Thanks again for the advice and information.

So-cal Jack

I never dyno'd the car but best time with a dead hook and 2.73's gave me a 13.5@101... now this was only using 1st and 2nd gears in a th350 auto,a torker intake,750DP Holley,and stock 400 heads home ported (1.94/1.6 valves). Once I put in the 3.73's and no changes it went 13.2@103 spinning running out of breath at about 5500 or so.

*Computer says 386hp at old combo
and with new heads claims 437hp

Rough Engine Horsepower Estimation Program (http://www.bgsoflex.com/roughhp.html)

and another one... http://www.fastcoolcars.com/hp_calculator.htm

449 @ flywheel
359 @ wheels

Doug, thank you for the info....again. :thumbsup:

I forgot to ask before.......how did you break in the 280H cam to make it last so long?

So-cal Jack

Just as normal. Install and get timing as close as possible before starting, be sure to use lube that comes with cam, fire it up and regulate between 2000 and 2500 for 20-30 minutes or so, and then let it cool. Never let it idle during break-in, and be sure to use good oil (seems Rotella is the sh*t right now).

BTW, motor has been apart a few times over its life for a check-up (bearings) and new gaskets. Looked machine shop fresh,no sludge,cross hatch looked great,no ridge,and bearings were fine. Use a good oil and change frequently.

Is it true that diesel engine oil is another motor oil to use during camshaft breakin, because of the additives that are not available in regular 10/30 or 10/40 oil? I was told it was ok to use for up to 3000 miles for the breakin only.

So-cal Jack

Diesel rated oil (those that start with an API "C" letter instead of the "S" for spark) is the best quality motor oil you can buy for any motor. That is why it is more expensive for diesel grade mineral oil. If you feel bad having to buy seven or eight quarts for an oil change just think of the semi driver when he pulls into the service bay with a 42 quart oil system, and an air and oil filter that costs as much as a cheap computer.

Shell Rotella is higher in zinc than any oil on the market right now, it's perfect for a flat tappet cam breakin, but 3000 miles,,,, NO WAY. Do your breakin, and change the oil and filter. Breakin by defination is two opposing components 'wearing' to common mating surface. You really don't want the debris circulating throught he bearings and everywhere. 5 qts of Rotella and a filter is going to cost $10 to $12,, CHEAP insurance IMO. It makes no sense to spend the bucks to build a performance motor, then not do everything possible to keep the oiling system clean and free of debris.


My SOP for any breakin is 20 minutes max and change the oil, Dyno room, first trip to the track, or 100 street miles,, and change the oil again. Then on to a regular maintenance schedule, with synthetic oil going in at the 3rd oil change.

Rotella is just fine for any motor. I have used Moble1 in just about every thing I own and found that the only thing good about it is you don't have to change the oil as often.

Use Marv's SOP's.

DO NOT BREAK-IN WITH SYNTHETIC OIL.

Thanks guys for the information. I have not too familiar with Rotella oil, but I'll keep my eye out for it the next time I'm a the store and maybe stock up on it.

So-Cal Jack

Personally I use Cat diesel oil because my brother is the executive VP at Cat so I get a discount (my nephew works in the oil lab and gives me a break down on my engine condition by reading tea leaves and my old oil filter. That said:

Mobil 1 Turbo Diesel Truck 5W-40 and Mobil Delvac 1 (truck oil) 5W-40 are the same product just branded differently for different markets and is just as good as Rottella (as far as zinc content , buffering agents emulsifiers and detergents). Good news you can find it at Wall Mart stores just about anywhere.

Specifications and Approvals:

5W-40 API CI-4 PLUS/CI-4/CH-4/CG-4/CF-4/CF/SL/SJ X
ACEA E7/E5/E4/E3 X

Mobil 1 Turbo Diesel Truck Meets or Exceeds the following industry and builder specifications:

Caterpillar ECF-1 X
Cummins CES 20072/20071 X
Detroit Diesel Power Guard Oil Specification X
Ford WSS-M2C171-D X
Global DHD-1 X
JASO DH-1 X

Jeff Paquette, Raymond, NH asked the question about the presence of zinc in engine oils. Does Mobil Delvac have zinc in the oil? A lot of racers are using Shell to break in their cams in HP engines due to the zinc in the oil. It works the best. I think most oils for non-gas cars have zinc in the oil to help something? -- Source Mobil Oils web site.

Response: All engine oils have an additive called ZDDP (Zinc DialkylDithioPhosphate) for wear protection. In general, heavy duty engine oils (truck oils like Mobil Delvac) have a higher level of ZDDP than automotive engine oils. Automotive engine oils generally have a lower level of ZDDP to protect the catalytic systems and the oxygen sensors.


Big Dave

Thanks Dave for the detailed info. Is it okay to run diesel oil regularly? I've heard conflicting stories saying "yes" and "no". I'm leaning more to using diesel oil for breakin, and then switching to synthetic for regular use.


so-cal Jack

Yes you can run a diesel designated motor oil in a gasoline car and it will not effect anything. Diesels quality oil is usually a better grade than gasoline use.

The American Petroleum Institute is a non-commercial technical forum allegedly unallied with any one company whose function it is to provide the government and industry with information about petroleum products. they rate the motor oils as to quality defined as Grade, Viscosity, ash content, freezing point, and flash point and the density of the product. API is responsible for testing the oils and assigning them the "SF, SI, SJ, SL" etc. labels which tell you what the quality of the oil is (S means spark or gasoline motor, and the letter after the S is the quality; with the higher the letter in the alphabet being the better quality).

From Mobil's web site (I am in no way affiliated with them, this is just the cheapest product that will meet your needs, because I'm of Scotch ancestry and an engineer that's the way I think).

SAE Grade 5W-40 (SAE stands for the Society of Automotive Engineers of which I was once a dues paying member)
Viscosity, ASTM D 445
cSt @ 40ºC 102
cSt @ 100ºC 14.8
Viscosity Index, ASTM D 2270 151
Sulfated Ash, wt%, ASTM D 874 1.35
Total Base #, mg KOH/g, ASTM D 2896 12
Pour Point, ºC, ASTM D 97 -45
Flash Point, ºC, ASTM D 92 226
Density @ 15ºC kg/l, ASTM D 4052 0.854

Features
Advantages and Potential Benefits Meets or exceeds demanding specifications of major OEMs One engine oil for mixed fleet operations Outstanding thermal and oxidation stability Reduced low temperature sludge build-up and high temperature deposits Enhanced film strength at high temperatures Reduced engine scuffing and bore polishing Inherent stay-in-grade shear stability Wear protection and reduced oil consumption; maintains viscosity in severe, high temperature service Advanced formulation and viscometrics Improved fuel economy Low volatility Reduced oil consumption Exceptional low temperature pumpability Easier engine start-up and reduced wear Enhanced TBN quality reserve Deposit control and extended drain capability Outstanding resistance to corrosion Extended life of critical wear surfaces Long drain capability Increased operating efficiency and lower overall cost Component compatibility Longer gasket and seal life, extended service intervals


Big Dave

I went to my local Kragen, and could only locate 15W-40. Is this weight ok to use?

so-cal Jack

thats what i put in my cummins is 15w40

I think the 5-40 would be good for first break in.

i think 20w50..

Since diesel oil will change shortly as they are now required to comply with Federal EPA smog equipment being installed to remove oxides and particulates we will all be running rollers or racing oil. Racing oil is not sold by your local "Quickie" oil change emporium because it can not be used on the street (because it contains ZDDP). It also contains all of the detergents you would need to run your car on the street (anti-oxidizers, buffers, etc), but the manufactures can not legally induce you to break the law using their products by telling you this. (It is also more expensive per quart than diesel grade which is why I do not use it).


Big "Blabber Mouth" Dave

Gm sells an oil addative called EOS. i heard a lot of guys use this in their break in process.

EOS is the best for break in but it will clog your oil filter if used continuously which causes the bypass valve to open which means your just like the original SBC 265 no optional oil filter. A "good" oil works just fine. Synthetics do not have ZZDP unless it says so on the can (look at me I said "Can" LOL, just showing my age. Shucks I have a one quart glass jar with an oil spout from when we got oil by the 55 gallon barrel and had to hand pump it out for customers) I meant to say written on the plastic liter sized container.


Big Dave

I go by a couple of rules when choosing an oil. Small blocks in general use 20w50 oil. There are exceptions of course. The higher the horsepower, the thicker the oil. Unless your breaking 600 hp to the ground there is no need to go heavier than 20w50. (True hp, not a guess becuase "it feels like it") Once you pick an oil, stick with it. Oils have additives in them that may not mix well between brands and cause sludge build up. Like Doug said, change it often. The harder you are on it, the more you need to change it, but don't be like the guy who thinks he needs to change the oil after every pass. You only do that for high horse alcohol applications.