ever lost a cam lobe?

[grumpyvette]

you might want to read thru this

 

http://www.cranecams.com/?show=article&id=2

 

FROM MORTEC

If you are building a big block Chevy with a flat tappet cam, (solid or hydraulic lifters) be careful during the initial engine break in. It is very easy to lose a cam lobe and lifter during initial break in. This is especially true with a higher than stock lift cam and higher pressure valve springs. The increased pushrod angles found on the BBC and poor preparation can make cam lobe failure after initial fireup a distinct possibility. You can help prevent this cam lobe failure by making sure the engine is prelubed prior to intial fireup. Use a good high pressure lube on the cam lobes and lifter bottoms during assembly. If possible use a lighter pressure stock valve spring (or if using a valve spring with multiple springs, take out some of the inner springs) to intially run the engine. Then switch to the heavier pressure springs after break in. When the engine is first fired up, keep the engine rpms at 2,500 or above, don't let the engine idle for 20 minutes or longer. This keeps lots of oil splashing up on the cam lobes. Make sure the engine can be run for this time period by having enough fuel available, ignition timing set correctly, coolant available for the motor, valve lash set correctly, etc. The idea is not to crank the motor over excessively before it starts up for the first time. If your BBC flat tappet cam survives this initial break in period, it will be good to go for many miles. After the initial engine breakin, drain the oil and change the oil filter. Roller cams generally do not suffer these types of cam lobe failures during initial engine fireup.

if youve adjusted the valves correctly the lifter spins at all rpm levels,but that does NOT mean it wears EVENLY at all rpm levels due to several factors if you [color:"red"] look closely AT FLAT TAPPET CAMS [/color]youll see that the center of the cam lobe is NOT centered under the lifter and that the lifter surface is slightly angled , BOTH these factors force the lifter to spin in its bore as the lobe passes under the lifter slightly off center.

SOME of the reasons the higher rpm durring the break in phase is important is that

 

(1) the faster RPMs the better chances the lobe passes under the lifter floated on an oil film and the less time the oil film has to squeeze out between them

 

(2) the higher the RPM the greater the oil voluum and pressure the engine pumps and the more oil flow is available at the lobes

 

(3)the higher the rpm level the more oil is thrown from the rods onto the cam lobes

 

(4)the higher the rpm the greater the lifters weight and inertia tends to compensate for the springs pressure and lower the net pressure as the lifter passes over the cam lobes nose

 

(5) at higher rpm speed the better chance a small wedge of oil is trapped between the lifter base and lobe from the oil thrown from the lobes surface by centrifical force

 

(6) two differant metal surfaces scraping past each other at low speeds may tend to wear and GALL as the oil is sqeezed out but two differant hardness steel surfaces that impact each other at higher speeds covered with oil tend to work harden as they mate and will tend to be seperated by that oil

 

(7)as the lifter spins in its bore the contact point between the lobe and lifter base constantly changes and rotates with the lobe contact point not resisting its passage and the higher the rpms the faster the lifter rotates and the less time the lobe spends at any one point

 

BTW ADD E.O.S. to the oil and MOLY break-in lube to the cam

before starting the engine and prefill the filter and pre-prime the oil system before starting the engine.

I normally pour it in just before starting the engines cam break in,procedure. because I want to make sure that nothing in the oil/E.O.S. mix can settle out from sitting over a long period of time. now if your running a flat tappet cam you should have also used a moly cam lube on the lobes and be useing a mineral base oil for the break-in procedure, and youll need to do an oil and filter change after about the first 3-4 hours running time to remove that moly cam lube from the engine after its served its purpose of protecting the cams lobes and lifters at start up, aND AS THE LOBES/LIFTERS LAPPED IN. MOSTLY to prevent that moly grease and E.O.S from potentially partially clogging the filter after that mix cools down,but also because both those lubes might leave deposites in the combustion chamber ,over time that might aggravate detonation.

even G.M. suggests that E.O.S. is not a great long term oil suppliment, and that its main function is to add extra oil film strength durring new engine break in.

 

1052367

ENGOILSUP

EOS - Engine Assembly Prelube

Specifically formulated as an engine assembly lubricant. E.O.S. provides outstanding protection against run-in wear and piston scuffing as well as run-in camshaft lobe and lifter scuffing resulting from insufficient lubrication

don,t forget a few magnets in the oil pan goes a long way towards trapping unwanted metalic dust formed from the cam and rings lapping in durring break-in that might otherwise get imbedded in your bearings or cause other problems

heres the magnets I use in every engine

 

http://www.wondermagnets.com/cgi-bin/edatcat/WMSstore.pl?user_action=detail&catalogno=0035

 

http://www.cranecams.com/?show=reasonsForFailure

[cameron]

lol i've done it~~~ went from a v8 to a v6 real fast~

[Guest bucnasty]

i did it on a mustang once, but it was the lifters plungers were faulty in the set

knocked 6 lobes off and killed 6 sets of rings was running a v2 home lol

[boodlefoof]

I'm lucky enough not to have had this happen and I swear by EOS!

 

Grumpy,

 

Do you have any opinion on cam manufacturer and the cam's tendency to lose lobes? I've heard lots of people say that Comp Cams are more prone to lose lobes than others... then again it seems as though Comp is one of the most often used cams so the numbers may just seem inflated. Also, I have been told that Comp, Crane, Luntai, etc all get their cam cores from a single manufacturer so there shouldn't be any difference in cam material.

[grumpyvette]

well personally Id won,t use a CC cam... now thats mostly because thier TECH SUPPORT is a bunch of $%^&&**(()))__*&^%$%&%$^&^ and I was FLAT LIED TOO SEVERAL TIMES!!!

 

 

do yourself a favor and CALL and talk to several cam companys BEFORE buying the cam for your engine, write down all the info about your car, tell each cam manufacturer the same EXACT INFO,and DO NOT discuss info other cam companys give you, take detailed/ careful notes as to the part# lift ,duration and LCA each company suggested

 

CRANE 1-386-258-6174 Tech Line

 

crower 1- 619-422-1191

 

ERSON 1-772-882-1622

 

Isky 1-323-770-0930

 

LUNATI 1-(270) 781-9741

all give good tech support and have good products...of cousrse you do need to know rthe correct questions to as and ending the conversation with (what other advise can you give me??) helps

 

then BUY the cam that comes closest to the average suggested specs this method basically prevents you from getting one adviser who has little experiance from giving you bad info!

[Pyro]

Yes, I have kill many BBC flat tappet cams during break-in. The BBC is the best cam eater ever made! However, it seems some specific engines do it more often than others. BBC are also known to have lift bore alignment issues which can make the problem even worst.

 

I have a 454 that ate 3 cams during break-in so I ended up installing a roller cam to fix that. But, I think the problem was rooted in large main and rod clearances. It seems the two machince shops I had used to rebuild the engine both wanted to set the BBC clearances up like a SBC. And after doing a little research, I found that the BBC needs to be set up much tighter than a SBC.

 

For a BBC, 0.0015-0.0025 on the rods and mains with the rear main set at 0.003-0.0035. This will keep the oil pressure up and slinging correctly on the cam.

[grumpyvette]

I build more bbc engines than any other and most with solid lifter cams (flat tappet and roller,,using a few precausions on bbc engines tends to prevent that lobe loss

 

both crower and comp cams lifters(I use both in addition to the grouves)look, under lifters pg 107-108 have lifters with oil holes to spray presurized oil directly onto the contact point between the lifter and lobes (coolface lifters)

 

http://www.crower.com/misc/m_cat.shtml

 

http://www.compcams.com/Technical/CurrentCatalog/HTML/281-289.asp

(part #800-16)

 

using a tool to mod the lifter bores/ increase oil flow to the lobes helps a great deal also,yes it increases the oil flow onto the cam lobes and lifter base contact area. yes it cuts a grouve in the lower lifter bore from the oil feed hole to the bottom of the lifter bore (it cuts about a .040 wide and .007-10 thousands deep grouve)you must do this on a block before cleaning it the final time and before installing the cam bearings for best results because it scrapes small metal fileings from the lifter bores you don,t want in your engine. you insert the handle from the top of the lifter bore, hook onto the cutter that you insert from inside the block from the cam tunnel and pull the cutter up and slide it down in the same spot several times, the cutter scrapes the grouve, you must be carefull to cut the grouve on the side of the lifter bore that sprays oil onto the cam lobe as it starts to spin under the lifter not after it passes the lifter, look at diagram closely and figure out how your cam turns

 

http://www.compcams.com/catalog/335.html

 

this has little effect on oil pressure because the oil volume is low compared to the total amount moveing through the engine but its one reason I always use a high volume oil pump. btw IT COSTS ABOUT $140 IF I REMEMBER CORRECTLY well worth the price because of thev lower cam failure rates the extra oil flow promotes. yes both solid and hydrolic cams benefit, yes it slightly increases the oil falling on the spinning rotateing assembly but thats what a milodon style windage screen is designed to handle by quickly returning that oil to the sump.

[grumpyvette]

BTW

unless the clearances in your engine are on the really loose end of the spectrum I think youll do far better with a thinner oil viscosity than 20w 50 25 years ago thicker oil viscositys were comon in racing engines simply because heat tends to thin the oil and thicker viscositys were necessary , but todays oils are so superior that even endurance racing engines use thinner oils that carry heat from the bearings faster. to answer your question, Id run a good quality oil (mineral base oil)like texico,shell, valvoline ETC. (for the first THREE HUNDRED MILE MAX)then change to a good synthetic and a new filter after the cam and rings seat which should only take about 15-30 minutes not even the 3 hundred miles mentioned

 

oil (especially synthetic)has improved dramatically over the last 15-20 years and thinner oil tends to BOTH absorb and carry away heat from the bearing surfaces quicker due to the faster movement thru those clearances, and those more modern formulas of thinner oils do protect your engine far better than the older oils did. keep in mind PRESSURE is a measure of the OILS RESISTANCE to being forced under pressure thru your engines clearances, and thinner oil reduces the resistance to both flow thru those clearances and pumping losses the moving parts have sliding over the oil films surface, remember the oil molicules are very small, and theres hundreds of layers stacked in that thousandth or so of bearing clearance.

a quick way to get an idea on your clearances is to look at your oil pressure AFTER the engine reaches the proper operating temps which should be about(between 215F and 240F...... OIL TEMP NOT COOLANT TEMP)

and use the thinnest QUALITY oil that maintains about a 20 psi at idle (700-900 rpm)

! keep in mind you want the OIL temp to reach a MINIMUM of 215F to burn off moisture, and that OIL FLOW does MUCH of the critical cooling in the ENGINE, so if your running hot, a larger baffled oil pan, with its far greater surface area and oil voluum can also aid in the total cooling process, just swapping from a stock 5 qt to a aftermarket 8 qt pan is usually worth about a 10-15 degree drop in engine temps

the oil temp is more critical than the coolant temp(with-in limits of course) but don,t allow the oil temp to fail to reach and stay in the 215F-240F range once the engines up to operating temp. or it can,t do its clean/lub job correctly

coolant temps in the 180f-210f range are about ideal according to G.M. test for HP and LONG ENGINE LIFE

 

 

http://www.vtr.org/maintain/oil-overview.html

 

Oil weight, or viscosity, refers to how thick or thin the oil is. The temperature requirements set for oil by the Society of Automotive Engineers (SAE) is 0 degrees F (low) and 210 degrees F (high).

 

Oils meeting the SAE's low temperature requirements have a "W" after the viscosity rating (example: 10W), and oils that meet the high ratings have no letter (example SAE 30). An oil is rated for viscosity by heating it to a specified temperature, and then allowing it to flow out of a specifically sized hole. Its viscosity rating is determined by the length of time it takes to flow out of the hole. If it flows quickly, it gets a low rating. If it flows slowly, it gets a high rating.

 

Engines need oil that is thin enough for cold starts, and thick enough when the engine is hot. Since oil gets thinner when heated, and thicker when cooled, most of us use what are called multi-grade, or multi-viscosity oils. These oils meet SAE specifications for the low temperature requirements of a light oil and the high temperature requirements of a heavy oil. You will hear them referred to as multi-viscosity, all-season and all-weather oils. An example is a 10W-30 which is commonly found in stores. When choosing oil, always follow the manufacturer's recommendation.

 

WHAT VISCOSITY GRADE SHOULD I USE ? WILL A HIGH VISCOSITY GRADE (20W-50) PROVIDE BETTER PROTECTION ?

 

A. Mobil recommends that you follow your engine manufacturer's recommendations as indicated in the owner's manual. For maximum wear protection and maximum fuel economy, use the lightest oil viscosity that is recommended by the engine manufacturer for the temperature range expected. Heavier oils can lower fuel economy and rob horsepower. For normal driving conditions, 5W-30 and 10W-30 are the primary current recommendations of automotive manufacturers.

 

BTW

http://minimopar.knizefamily.net/oilfilterstudy.html

 

http://www.diabolicalperformance.com/clearances.html

 

(and while IM pointing out option, adding magnets to your oil pan collects the metallic dust before it can get embedded in bearings or damage rings, cam lobes etc.)

"Any source for the magnets Grumpy? "

 

http://www.wondermagnets.com/cgi-bin/edatcat/WMSstore.pl?user_action=detail&catalogno=0001

 

these are NOT REFRIGERATOR magnetS "#0001" can pick up a SBC cylinderhead, and you wont beleive the amount of crud they remove from your oil and prevent from reaching the bearings

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Ive been installing 4 of these lately in the corners of the oil pan sump,nothing magnetic (metallic dust from engine wear, assorted trash,etc.)can get past them, I also sometimes install one near the rear oil drain in each head to collect broken valve train shrapnel in case of a failure to limit damage on race engines. btw if you dont want to install them inside the sump you can J&B weld them to the outside of the oil pan permently or just place them there if you want them removable,TRUST ME THEY WON,T FALL OFF ON THIER OWN attached to the steel oil pan sump

[Michael]

My big-block Chevy had this exact same problem; Comp Cams Xtreme-Energy 262 cam, with their “K-kit†(springs etc.). I used plenty of assembly lube, and pre-soaked the lifters. The engine fired right up upon turning the ignition key. I held it for 20 minutes at 2000 rpm – no problems. Then shut the engine off, got in the car, took it for a spin around the block – and suddenly, problems! It sounded like a spun rod bearing, but was actually the cam lobes getting wiped. 20 miles later I lost half a dozen lobes – some were worn so badly, that the lobes were indistinguishable from the base circle! Broke one pushrod, bent several, and wore two lifters down to where the their internal cavity were visible from the lifter face!

 

That was almost exactly 5 years ago.

 

This time I’m going with a mechanical roller cam, 3/8†pushrods, a high-volume oil pump and a perfect, spotless animal sacrificed to the proper Deity.

 

However, the rod and main clearances are toward the loose side (0.0025â€-0.0030â€), I did not do Grumpy’s lifter bore modification, and I didn’t check the lifter bore alignment. The short-block is already assembled. Am I heading for a world of hurt???