Wiped cam lobe on big block

[MikeB]

I work part time for a guy who has an old car repair shop. He works on just about anything, but specializes in Fords so sometimes farms out the Chevy small block stuff to me. Today I looked at a rough running 72 big block Chevelle that has a lot of valve train noise. Turns out the #2 exhaust rocker arm is loose. And with it removed, the pushrod barely moves up and down when the engine is turned over. Sure looks like a wiped lobe to me. Since this is the first big block I've worked on other than external parts, I have several questions:

What kind of engine do I have here? Block VIN is TO302ALH. Head casting # is 10114156
The rocker arms are non-adjustable, kind of like an LS engine. Is this typical of a big block?
Must the oil pan be dropped to remove the timing chain cover, like on a small block?
Can I do that with the engine in the Chevelle? The pan looks to be pretty close to the crossmember.

And probably the most important subject: I've never encountered a wiped lobe. Should I assume that metal particles are everywhere, and tear down the engine, instead of just changing the cam and lifters?

Thanks.

 

[MikeB]

Forgot to say that the pushrod guide plates have "Mark V" stamped on them. After reading another post by Grumpy, it sounds like I'd need to convert to adjustable rockers if I use anything but a factory cam, right? Are factory cams still available? You never know if someone might have added an aftermarket cam and just tightened down the rocker arm bolts! Also, guess I should have grabbed a flashlight and mirror to see the block casting number.

 

[Grumpy]

the markV and VI had the non-adjustable rockers

10114156 454 91+ Oval Open 118 Gen. V and VI

Engine assembly plant: T= Tonawanda, New York.
Engine was assembled in March, day 02.

IF you install any cam in a stock mark V engine with over about .480 lift the valve train geometry clearances and piston to valve clearances must be checked carefully, the non-adjustable rocker engines from 1991 and up are much less tolerant than the earlier engines to cam changes, and any cam and lifter damage DID result in metallic trash in the engines oil system

http://garage.grumpysperformance.com/index.php?threads/casting-numbers-vin.93/

http://garage.grumpysperformance.co...ck-chevy-gen-v-vi-to-adjustable-rockers.4564/

http://garage.grumpysperformance.com/index.php?threads/magnets.120/#post-49772

READ, ALL THESE LINKS AND SUB LINKS, ALL THE WAY THROUGH CAREFULLY
IT helps to know exactly what year and casting number your engine block is as early production big block engines used a different rear cam bearing and cam, a potential rear cam bearing oil flow issue is found on the 1965- too a few very early 1967 engines ,if you install the older design BBC cam with a grooved rear main in EITHER config with EITHER rear bearing your covered, and since thats just not expensive and any decent machine shop can modify any cam like that cheaply is the smart route to take if your in doubt. obviously having the machine shop groove the rear cam journal under the cam bearing in the block like the later BBC engines would be ideal.
you need to read the fine print
many magnets lose their magnetic pull if heated to 200F
these below won,t

proper magnets trap metallic debris
SmCo Samarium Cobalt Disc Magnets
http://www.magnet4less.com/

http://www.magnet4less.com/product_...ucts_id=254&osCsid=ckl4nevgdrmireotnegg7jcf36

http://www.magnet4sale.com/smco-magnets-dia-1x3-8-samarium-cobalt-magnets-608-f-temperature/

Samarium Cobalt MAGNETS HELP
http://www.magnet4sale.com/smco-disk-magnet-dia-1x1-4-samarium-cobalt-magnets-608-f-temperature/
magnets are ceramic and glass hard, don,t try to drill or grind them, as they can shatter
KEEP IN MIND, MANY PEOPLE THAT HAVE BROKEN ROCKER STUDS HAVE FAILED TO VERIFY THE PISTON TO VALVE, CLEARANCES, ROCKER STUD TO ROCKER SLOT CLEARANCES,AND SPRING BIND CLEARANCES, etc.
it takes hundreds of pounds of force to bust rocker studs and or bend push rods, if you have those issues STOP AND LOCATE the geometry or CLEARANCE ISSUES CAUSING THE PROBLEM
theres several manufacturers and models available , heres a basic 1.5:1 ratio SBC version.

http://www.summitracing.com/parts/lun-85025
SELF ALIGNING ROCKERS (BELOW)
USED WITH PRESS IN ROCKER STUDS

used with press in rocker studs

yes they DO MAKE ROLLER ROCKERS IN BOTH STANDARD AND SELF ALIGNING VERSIONS

the grooved rocker pivot ball design was an effort by G.M. engineering to economically solve the issue of marginal oil flow causing rocker ball galling, and resulting noisy, or broken valve trains

check all valve train geometry and clearance on any engine you assemble or modify the valve train on.

if your heads have push rod guide plates you are not supposed to use self aligning rockers as yes they will frequently bind the push rods up and keep them from spinning, if you have guide plates you want the NON-self aligning rockers
as I've pointed out dozens of times a day spent reading links will save you a week of work and a wheelbarrow full of wasted cash.

keep in mind all that metallic trash, cycles through the oil pump BEFORE it reaches the oil filter


http://garage.grumpysperformance.com/index.php?threads/cam-bearing-install-tools-install-info.1479/


http://garage.grumpysperformance.co...k-after-a-cam-lobe-rod-or-bearings-fail.2919/

http://garage.grumpysperformance.com/index.php?threads/cam-wear-articles-you-need-to-read.282/

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.com/index.php?threads/valve-train-clearances-and-problems.528/

http://garage.grumpysperformance.co...t-compressed-when-installed.11356/#post-51869

http://garage.grumpysperformance.co...-pushrods-and-check-info-you-might-need.5931/

http://garage.grumpysperformance.co...ectly-and-get-it-to-last-cam-install-info.90/



while the links and sub links will take a few days to read through youll get a good education thats well worth the effort, theres books and a few videos , plenty of reference material and several dyno tests


http://garage.grumpysperformance.com/index.php?threads/another-496bbc.5123/

http://garage.grumpysperformance.com/index.php?threads/454-bbc-on-the-cheap-well-to-start.11739/

http://garage.grumpysperformance.co...-building-a-peanut-port-big-block-combo.2900/

http://garage.grumpysperformance.com/index.php?threads/468-build.11794/

http://garage.grumpysperformance.co...g-block-head-comparison.319/page-2#post-49217

http://garage.grumpysperformance.com/index.php?threads/big-block-chevy-info.710/#post-49737

http://garage.grumpysperformance.com/index.php?threads/newby-from-ontario-canada.12003/#post-57367

 

[MikeB]

Engine assembly plant: T= Tonawanda, New York.
Engine was assembled in March, day 02.

Block stamping: TO302ALH (maybe T0302ALH)
Looks like the ALH denotes a 1986 truck engine. ??? I need to get the block casting number next time I'm at the shop. Maybe someone put Gen V heads on a Mark IV block? Would they even fit?

 

[Grumpy]

yes they bolt on, they just require a special head gasket to function as the coolant passages are not an exact match between the heads and block of the two generations


RELATED INFO
http://www.ebay.com/gds/Big-Block-Chevy-Generations-A-primer-/10000000001563647/g.html

http://www.454ss.com/Articles_new/GEN5.asp

http://garage.grumpysperformance.com/index.php?threads/chevy-big-block-vi.9857/#post-37553

http://hotrodenginetech.com/top-10-reasons-to-build-gen-vi-based-big-blocks/

http://www.northernautoparts.com/ProductDetail.cfm?ProductId=3361

http://garage.grumpysperformance.com/index.php?threads/big-block-chevy-info.710/#post-49739]

BTW, , on BIG BLOCKS the oil pumps and oil filter adapters are different due to the block oil filter recess and rear seals being different

mark iv blocks

mark v blocks

(keep in mind that ALL '91 and later Gen.V and Gen.VI big blocks come with 4-bolt main caps. The two-bolt big blocks are no longer in production
MANY BUT NOT ALL aftermarket head designs have been modified to work on both the early MARK IV 1965-90 and later MARK V & VI blocks 1991-later.)
BTW, , on BIG BLOCKS the oil pumps and oil filter adapters are different due to the block oil filter recess and rear seals being different
GEN 4 or MARK IV

GEN V and VI

 

[MikeB]

Thanks for all the info. What are the holes that the arrows point to?

MARK VI BLOCK OIL CONNECTIONS

 

[MikeB]

Please recommend GM or aftermarket cam with close to OE specs that I can use with Gen V non-adjustable valve train. Customer doesn't care about high performance and is on a budget. Or even with a stock cam, is there an advantage to buying the stud kit that retains Gen V rockers?

Also, how can I edit my signature here? I don't see how to do it.

 

[87vette81big]

I have noticed that trend also.
Many want Bone stock Vintage V8 engines.
Don't want LS Power.
And don't want to Race.
A chance to make earn $$$$ building stock engines.

 

[Grumpy]

http://garage.grumpysperformance.co...chevy-cams-and-a-few-similar-aftermarket.133/

verify your dealing with a flat tappet or roller cam as chevy big blocks came in both types
now chances are excellent its flat tappet hydraulic
if your going to use flat tappet hydraulic lifters

http://www.jegs.com/webapp/wcs/stores/servlet/KeywordSearchCmd?storeId=10001&catalogId=10002&langId=-1&Ntk=all&Jnar=0&itemPerPage=60&Ne=1+2+3+13+1147708&searchTerm=01915+

http://www.cranecams.com/product/cart.php?m=product_detail&p=23897

 

[MikeB]

Thanks again, Grump. Those cams will work with stock springs, too, right?

Yeah, I know there's always a market for 600hp big blocks, but I think a 454 or 502 making >500 lb/ft torque would be a heck of a lot of fun even if it makes "only" 425 hp. Certainly would be fun in my 82 pickup, but I'm not sure my TH350 and 8.5" 10-bolt would be happy. They might live longer behind a 396 or 402, if one could be found in decent shape.

 

[Grumpy]

yes stock springs with either cam will be fine
http://garage.grumpysperformance.co...ck-chevy-gen-v-vi-to-adjustable-rockers.4564/
Thanks for all the info. What are the holes that the arrows point to?

ports that can be, and usually ARE, used for oil cooler hook-up lines

 

[Indycars]

Also, how can I edit my signature here? I don't see how to do it.

Just run your mouse over your screen name in the top right corner. In the new
window you will find your signature, 2nd down on the left.

 

[Grumpy]

thanks INDYCARS

 

[Indycars]

No problem, just doing what I do best!

 

[MikeB]

Grumpy, If I use this kit to convert to studs, I can use the stock pivot balls and rocker arms, right?
Also, please see my post on CT about the cam my boss chose. Thanks.

 

[MikeB]

Just run your mouse over your screen name in the top right corner. In the new
window you will find your signature, 2nd down on the left.

View attachment 6836

Rick, I don't have "Signature" as an option.

[/IMG]

 

[Indycars]

OK, Mike try it again and let me know what you find.

 

[87vette81big]

You Have To Have A Signature Here on Grumpys Site.
A Must Do.
Mine Is THE HELLCATS ARE HERE.
LOL.

 

[MikeB]

OK, Mike try it again and let me know what you find.

It works! Thanks.

 

[Indycars]

Working part time in 50-70s car shop sound like an excellent way
to stay active and earn a little money.