Cam upgrade

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Cam upgrade

Post by wokrdan AKA BU Balls on Tue Sep 27, 2011 2:37 pm

So I'm getting ready to put my engine back together when my neighbor mentions to me that I should get an upgraded cam shaft. I am engine illiterate and have been using a book/DVD to tear it down and reassemble. How hard is it to upgrade? Are there adjustments/ alterations that need to be made, or is it straight up pulling out the old camshaft and putting the new one in? The engine is a stock 350 with a 4 barrel Edelbrock carb that was put on to replace the 2bbl. Any info on how involved this process is or what exactly I'll be getting more of out my engine would be greatly appreciated.
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Re: Cam upgrade

Post by abajc3 on Tue Sep 27, 2011 4:05 pm

i assume this is a hydraulic flat tappet cam? you`re gonna have to replace lifters as well, and maybe install different lenght pushrods (some people don`t do that, but it will increase reliability) if the new cam is much different. you will have to do a cam break-in procedure, which looks like this: as soon as you start the engine for the first time, bring it up to 2000rpm immediately! than make it fluctate between 1800 and 2200rpm. what this does is it splashes oil on the new cam. you should keep doing that for at least 20 minutes. if there is a problem with the engine, shut it off immediately, dont let it idle or you can ruin a cam. but i`m sure this procedure is mentioned in your book.

i haven`t gotten to the stage of assembling my engine yet,thats the knowledge i`ve gathered from many books, so i might have missed something or got something wrong.

the other important thing is cam selection. which is the hardest part. you see, you can never have a cam with high low-rpm torque and awesome hp figures at the same time. you have to make a compromise. in your case, given that the engine is almost stock, i would go for a conservative cam which will make a lot of torque at low rpm.

you should also take the rear end ratio and transmission type into account. vehicle weight also plays important role here, but im assuming we`re talking about a malibu so its a pretty heavy vehicle, which "likes" a lot of torque at low rpm.

http://www.camquest.com/
try this programme, or you may want to give a call to some camshaft company and ask them for their expert oppinion.


and finally, YES you should definitely replace a camshaft.

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Re: Cam upgrade

Post by 77mali on Wed Sep 28, 2011 5:41 am

Was there something wrong w/ the cam? You should maybe speak w/ a reputable engine builder in your area, most of those companies are happy to answer questions and help enthusiasts. If your engine is all apart you may want to consider an upgrade but for my $0.02 you'd be better off replacing the cylinder heads and intake manifold to a Vortec design for much improved airflow and horsepower. This upgrade also eliminates the need to run the EGR. Most engines today are "roller's" versus "flat tappet" style (prior to 1987 or so) and this conversion would involve a new roller style cam and lifters, roller rockers, new push rods as well as an upgrade to the timing chain and prob some other stuff I'm forgetting. You can also build a "Stroker" style set up too but I'm not familiar w/ what the differences are there, sorry. It's not impossible to do but from what I've read & seen (personally speaking) I would leave that to someone who does it for a living (and is good at it Very Happy ). Good luck.
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Re: Cam upgrade

Post by abajc3 on Wed Sep 28, 2011 7:11 am

the main difference between the cam upgrade and modifications mentioned above is $$$. in case of flat tappet cam the cost is somewhere in 100-200$ range. and it will wake the engine up noticably. set of new vortecs is around 500$ and new intake manifold (required with vortecs) is around 200$. and you still have to replace the cam in order to get the best out of these new modifications. with all that you`re in the 1000$ range in no time.

converting to roller cam imho is not a reasonable decision with near stock motor. the main reason for that is that retrofit roller lifters are very expensive. and the roller cam alone is 300$. there is some gain to be made from that conversion, but it`s too expensive imo. another story is a factory roller block like i have, only extra cost here is the cost of a camshaft.

stroking the engine is a good way to add displacement, but you`re gonna need new crank, rods and pistons, plus some modifications on the block. stroker kits go from 2000$ up if im not mistaken. and to get the most out of it, you`re gonna have to customize the rest of your engine as well.

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Re: Cam upgrade

Post by bigredlaguna on Wed Sep 28, 2011 9:36 am

Since this is your first build, I suggest staying conservative. A 252 to 258 degree advertised duration cam and lifter set should do the trick. There shouldn't be any adjustments outside of the normal procedures for a stock rebuild.

You do need to be aware of the oil that is produced today is generally not designed for flat tappet camshafts, and can cause damage to the cam/lifter. There are additives that compensate for this, specifically a compound called ZDDP.

Comp Cams has a nitrating process that helps their flat tappet cams survive today's oils. If you do a Google search about oil and cam break in, this topic has been discussed many times.

The oil quality is one reason some choose a roller cam over a flat tappet so they don't have to remember to add ZDDP to their oil.

The golden rule about installing a new flat tappet camshaft is that a new cam requires new lifters.
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Re: Cam upgrade

Post by 77mali on Wed Sep 28, 2011 10:16 am

bigredlaguna wrote:You do need to be aware of the oil that is produced today is generally not designed for flat tappet camshafts, and can cause damage to the cam/lifter. There are additives that compensate for this, specifically a compound called ZDDP.

The engine shop I bought my new heads from told me this also and I just bought some from "quadrajetparts.com" for about $9.00 per 4 oz bottle. (cheapest I've found for small quantities.) I believe they say to add 1 4oz bottle to every 4-5 quarts of oil. They recommended that I consider using Joe Gibbs (or similar) hi-zinc oil also as it contains this product and other additives to protect the cam & cylinder heads. That's about $10.00/quart. Don't know which is a better option but either is better than just using the oil that is out there now.
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Re: Cam upgrade

Post by The Dude on Wed Sep 28, 2011 10:24 am

BigRed couldn't have said it much better. Stay small & you won't have to worry so much about getting the wrong cam. A stock engine rebuild with what I'm guessing will be 76cc heads & dished pistons should stay just one or two steps up from stock. Going on BR's Adv. duration numbers, you can also look for these numbers as well:

Between 200-215 deg. duration @ .050
Somewhere around .420-.450 lift.
Keep the lobe separation tight. Try to find something with around 108-110*. This will help your dynamic compression out. Should also give you a little bit of a lope.

Here's some cams to mull over & give you some ideas:
http://www.summitracing.com/parts/SUM-K00042/
http://www.summitracing.com/parts/LUN-60101LK/
http://www.summitracing.com/parts/CCA-CL12-234-2/

This one's on the larger side of the scale, but with 106* LSA, it should keep up enough of your DCR to function & the RPM range is only 1800-5,200. I want to point out that the Summit Street & Strip cams are just relabeled Crane Energizers for about $50 - $75 cheaper. video search Crane 274 Energizer if you want to hear this one run.
http://www.summitracing.com/parts/SUM-K00172/

Also notice that while it's ADV duration is much larger than the others it's @.050 isn't & yet its operating range is similar. This cam obviously has lazier ramps than the others. Possibly due to the Comp & Lunati cams being newer, aggressive designs. Lot of factors to look at when selecting a camshaft.
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Re: Cam upgrade

Post by pila on Wed Sep 28, 2011 10:59 pm

Good advice here...I've used a bunch of Comp Cams. If I do a stock type rebuild, I use the HE252 cam, which has a bit more power, and even wakes up a little 305. And for another notch up, I use the HE260, which is as high in duration as I would use with the stock compression of 8.5.

Like abajc3 stated, cam break-in is extremely important. like NEVER LET IT IDLE !! Very Happy Saw lots of guys wipe out a new cam because of not doing the break-in right....

And that's not the worst part...if the cam gets lunched, the metal from the trashed cam & lifters will get all over the inside of the engine, requiring a complete tear-down for cleaning all the particles out of the block etc....

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Re: Cam upgrade

Post by ant7377 on Thu Sep 29, 2011 12:11 am

Make sure you pre lube it too (get the oil moving through the motor before you even start it) .Heed the warnings about the oil VERY IMPORTANT !
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Re: Cam upgrade

Post by wokrdan AKA BU Balls on Sun Jan 01, 2012 6:09 pm

Ok, so I think I might have found one for an upgrade. Can someone let me know if this will work? I am just looking to pull the old cam and drop in the new one. I have a 1974 Malibu Classic with a stock 350 and stock transmission. The only upgrade (that I know of) is an Edelbrock 4-barrel carb and Edelbrock intake manifold. Here is what I found:
http://www.ebay.com/itm/Comp-Cams-12-364-4-XFI-252-Hydraulic-Flat-Tappet-Cam-/200607651411?hash=item2eb525d653&item=200607651411&pt=Other_Vehicle_Parts&vxp=mtr#ht_2342wt_907
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Re: Cam upgrade

Post by Limey SE on Sun Jan 01, 2012 8:57 pm

I like the Procomp Air Gap intake and Holley 4 barrel carb set up and both are half the price as Edelbrock.....

Cam I went with a Lunati VooDoo series cam with about the same specs as the Comp I dont like comp cams ..........

And that is because for awhile they were using inferior cores to make there cams and had serious issues with them , as it would wipe the lobes on start up for the cores were to soft of a metal to start with........

Whether or not that issue has been addressed I am not willing to Find out

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Re: Cam upgrade

Post by ant7377 on Sun Jan 01, 2012 9:44 pm

Dont use the stock cam that motor came with its a dog, call any of the cam mfg's and they will guide you the right way as to which one you should get. Lunati is a good choice so is Isky .Edlebrock even has some simple choices that are better than the stock one.
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Re: Cam upgrade

Post by wokrdan AKA BU Balls on Mon Jan 02, 2012 3:55 pm

Ok, I'm looking at getting a roller cam and getting new lifters in a kit. Do I need a hydraulic or mechanical roller cam? Also, is it as easy as dropping in the new cam and lifters (along with breaking it in when I'm finished) or is there additional hardware/ adjustments that have to be made? I have never messed with an engine before and don't want it to whoa nelly itself the first time I turn it over.
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Re: Cam upgrade

Post by ant7377 on Mon Jan 02, 2012 6:00 pm

Way easier to break in a roller cam,you are really just seating the rings in that case no try to get the lifters to wear correctly.You want a hydraulic roller cam. Check out Howards cams for that they are supposed to be good and made here and are affordable.
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Re: Cam upgrade

Post by 77mali on Mon Jan 02, 2012 6:00 pm

Roller Cam requires Roller Rockers & usually you'd put in new Pushrods & Balls (folcrums) as well as new hydraulic lifters. You may also want to get guide plates for the Heads as well. Speaking of heads, do you know the spec or casting number on the cylinder heads...are they in good shape? be sure they will be able to withstand all the new stuff, a roller system is generally less stressful on the springs & therefore valves but if your cam is too "hot" you'll wan to be sure (IMO).

Mechanical cam is a whole different system more for hardcore racing than street use.
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Re: Cam upgrade

Post by mychev123 on Thu Aug 30, 2012 10:09 am

What would y'all suggest for a stock 305 in a 77 malibu classic coupe?
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Re: Cam upgrade

Post by Limey SE on Thu Aug 30, 2012 4:49 pm

Pulling the 305 in place put a 350 lol if its in yur budget
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Re: Cam upgrade

Post by mychev123 on Thu Aug 30, 2012 6:13 pm

How much does a total swap usually run?
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Re: Cam upgrade

Post by 77mali on Thu Aug 30, 2012 6:16 pm

"Pulling the 305 in place put a 350 lol if its in yur budget"

x2....LOL

If budget is a concern you can get a complete GM 290 HP "Goodwrench" 350 for pretty cheap & It comes complete from oil pan to air cleaner lid and you could always swap the valve covers if you don't like the look of the big Goodwrench logo's.
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Re: Cam upgrade

Post by pila on Thu Aug 30, 2012 9:12 pm

Like I mentioned here earlier, the least expensive way to give a 305 a bit of a boost is the Comp HE252, which will work well with a stock compression ratio. I've even put a few of those in boats also, that have a 305. Mercruiser outdrive types. It made the difference in getting skiers up on plane.
Swapping to a 350 is a great way to go alright, but not cheap of course. And it's less expensive to buy a crate engine from places like Jegs etc, than building one yourself.

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Re: Cam upgrade

Post by mychev123 on Thu Aug 30, 2012 9:53 pm

Thanks for the info Pila, Im new at this and only 19 so all the help is huge! I found the cam with lifters kit for only 185 on Jegs.
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Re: Cam upgrade

Post by 77mali on Fri Aug 31, 2012 7:15 am

Read up on and be careful when "breaking in" the cam. Make sure you use a quality assembly lube and break-in oil when your finally ready to fire it up after install. Don't forget to examine your bearings too. Cam bearings and their quality are also very important, if your bearings need replacing get top quality. I chose Comp Cams products on my rebuild.

Also, consider using the "ZDDP" zinc additive in your oil for the future, cheap insurance against the low zinc oil grades of today or "Joe Gibbs" racing oil is another option that has a high zinc content but it's more expensive.
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Re: Cam upgrade

Post by Joe73 on Fri Aug 31, 2012 9:22 am

I'm with 77mali. ZDDP is REAL important for our type of cams. Make sure you have that in there on every oil change or you'll wipe out that cam. I've heard that diesel oil, like Shell Rotella "T" had ZDDP in it. Some guys have been using that in their older cars.
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Re: Cam upgrade

Post by 1973 454 MONTE on Fri Aug 31, 2012 4:01 pm

Joe73 wrote:I'm with 77mali. ZDDP is REAL important for our type of cams. Make sure you have that in there on every oil change or you'll wipe out that cam. I've heard that diesel oil, like Shell Rotella "T" had ZDDP in it. Some guys have been using that in their older cars.

i was told 15 years ago to use rotella 15/40 in my old monte. never used anything else. Very Happy
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Re: Cam upgrade

Post by pila on Fri Aug 31, 2012 8:21 pm

All brands of oil have went to lower ZDDP in recent years, due to auto mfgrs having to meet emission standards. Not sure if the EPA has a standard to meet. From what I've found, the old standard of additives like ZDDP are not in modern oils, except for "off-road" use, like racing oil, with an example being like Valvoline VR-1.. unless it's labeled as racing oil, it doesn't have the old level of additives in it.
Once the flat tappet cams are run for a while, the lessor ZDDP doesn't seem to affect the wear, but to play it safe, use an additive like the stuff from Comp Cams, Trick-flow etc at oil changes. It isn't cheap, like 10 bucks a bottle, but neither is cam replacement.......

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