502 Rocker Arm Problem

[Barry Eller]

A pushrod went through the rocker arm on my 502. Has anyone ever see this happen?

[motorcity]

The rocker arm had to be defective. The pushrod would bend first before it would punch a hole thru the rocker arm normally. Roll the pushrod on a known flat surface to check it for a wobble.

[RickR]

Barry
I had some rocker arm problems with my new engine. Used long slot heavy duty rocker arms with my Hyd Roller cam and some ended up working their way sideways:shocking: which caused some galling on the valve end.
I switched to Crane's Aluminum http://www.competitionproducts.com/prodinfo.asp?number=13750EB

I agree you probably had a bad rocker BUT, I would check for spring bind and the valve and valve guide on your failed pushrod. How much piston/valve clearance do you have????

[Barry Eller]

Rick, I just pulled the valve cover off tonight. Last Tuesday I was running the boat when the "event" occurred. I have been loosing RPM's for the last 2 hours I had run. I thought it was water in the fuel. A couple of backfires, and down approx 400 RPM's. I changed spark plugs, did a visual on them. All OK. Some water in fuel filter. I changed filter, pulled carb and drained bowls, they were fine. No water in the carb. No water in my filter now. I'm thinking the rocker arm started giving way and that caused my RPM loss. When it finally gave in to the push rod, I knew I had a valve train problem.

My engine has 52 hours on it, the valve train is stock, this is the first time a valve cover has been removed.

I found the "piece" of the rocker arm laying on top of the cylinder head where it couldn't get in to a spring. The push rod is straight as an arrow.

I think is was just a bad rocker arm. I'll buy a new rocker arm, install it and see what happens.

When the engine is ready for a valve job, I think I'll go with rockers like yours.

I told my wife I was going to use JB Weld to fix it so we can run tomorrow....
or should I just "Super Glue" it?

[MOP]

Yes & Yes many at least a dozen or so times, never got a real handle on the cause. Checked push rods for oil flow, checked the rocker bleed hole never found anything.
Put a new rocker in adjust it and forget it ever happened, once fixed it never seems to happen again.

Phil

[Barry Eller]

Yes & Yes many at least a dozen or so times, never got a real handle on the cause. Checked push rods for oil flow, checked the rocker bleed hole never found anything.
Put a new rocker in adjust it and forget it ever happened, once fixed it never seems to happen again.

Phil

"Yes & Yes" to To the Super glue or the JB Weld?:wink:

[fasttrucker]

I had a push rod flatten out a few years ago.When putting my new crane cam and gold race-rockers in that I bought from teague marine.Teague blamed the engine shop.Engine shop blamed the part.

[BigGrizzly]

The problem can be a clogged or restricted push rod orifice. I usually use roller tip when nor using full rollers. The reason I do this is it slows down valve guide wear with higher lift cams. The horse power gain in this application is insignificant. We have found orifice restriction in new push rods before. This is not a new problem. I am a little surprised it took this long to show up, but then you probably take better care of your stuff than most car and boat jockeys. You are lucky. DO NOT use the old push rod again. I believe the yes and yes was what you tell your wife. In my case my wife has been around racing too long and I can't get away with it anymore.

[MOP]

Yeah Randy have to agree with the "Yes & Yes"! I should have said to replace the push rod also, the oil hole in the ball on some were thin enough to cut your finger on. Pushing through the tip is more common then some realize, 30 some odd years back I had the owner of Sendure come in with his new Four Winns. He was freaked out though the new engine was about to expire, had to pull the cover of a new about to be installed engine to steal the rocker & Rod but got him fixed up and got a fat tip and a big smile.

[Barry Eller]

Thanks for the information.

I work in sales at the Cadillac,Buick,Pontic,GMC,Saab dealer in Pensacola. I'll be heading to the Parts Dept in the morning for a rocker arm and push rod. They can get me anything I need from GM Performance.

What is the torque # for the rocker arm bolt? My OMC manual is for the Gen V. My 502 is Gen VI. Any difference in torque settings on head bolts, etc?

[MOP]

There is no torque you have hydraulic lifters they need to be set at 3/4 to 1 turn pre load, meaning after all the clearance is gone between the rocker and the valve tip then tighten to get the pre load. I like to do them dry for starters then after a warm up re set them with the engine running, I set them to 1 full turn on "new" and 3/4 on a broken in engine. Being as you work in the field see if one of your tech will do it, might just as well go over all of them as everything is seated by now.

Phil

[Barry Eller]

Thanks Phil,

My problem with getting one of the Techs at work to do something is, they get jealous of who gets to work on my Donzi. They know if they do work on it, they get to go for a ride...I can't take everyone that wants to go. I need a bigger boat!

[BUIZILLA]

is this an adjustable, or NON adjustable valvetrain??

[MOP]

is this an adjustable, or NON adjustable valvetrain??

Excellent question, non adjustable was on 91 through 98 454 & 502 I thought Barry's boat is newer?

[Barry Eller]

Excellent question, non adjustable was on 91 through 98 454 & 502 I thought Barry's boat is newer?

I don't know. I bought the new 502 crate motor in 2005. It's a Gen VI with rectangular port cast iron heads. Camshaft was upgraded from the supplier. www.1800runsnew.com

It is the 502/435 base marine engine. They upgraded the camshaft to their specs to 470HP using stock intake and exhaust. I did upgrade intake and exhaust.

See thread: http://www.donzi.net/forums/showthread.php?t=42706

Here is a photo of the head and rocker bolt/nut.

[BUIZILLA]

that's a NON-adjustable valvetrain....

sooooooooooooooooooooooooooooooooooooooooooo

you have THREE issues at hand

one, you have a coil bind issue

or

two, the rocker slots aren't long enough

or

three, it's eating a lobe

if it's a roller lifter, scratch #3

[Barry Eller]

that's a NON-adjustable valvetrain....
sooooooooooooooooooooooooooooooooooooooooooo
you have THREE issues at hand
one, you have a coil bind issue
or
two, the rocker slots aren't long enough
or
three, it's eating a lobe
if it's a roller lifter, scratch #3

It's supposed to be a roller lifter camshaft. The guys in the parts dept at work told me all Gen VI 502's came with roller lifters. The 502/8.2 liter is a GM truck engine. As the dealership I work at sells and services GMC's, I will get on of our techs to help me on this. I think I saw a GMC 3500 in the shop Friday with the 8.2 and the heads were off. I'll go do some snooping this Morning.

I'm thinking/hoping that the rocker arm was just defective. I'll get a new GM rocker arm and push rod at work and see what happens. If it happens again, I'll go another route.
The cam is a "Howards" cam, part number RG 202. My 502 is a Gen VI which uses "roller" cams.

intake valve lift .541 degrees of duration 306
exhaust valve lift .541 degrees of duration 306
lobe center 114

gross lift at cam;
intake .318 duration @ .050 229
exhaust .318 duration @ .050 229

this cam profile shouldn't cause any water reversion problems with a good exhaust system, and will idle well for good manners at the dock. But it still has a good "thump" to it.

Wish me Luck!

Barry

[BUIZILLA]

one, you have a coil bind issue pay attention here then, i'm not sure .541 lift at the valve is okay, I *think* the stock springs bind at .520-.530 lift..., or there is a retainer to guide issue....

[Barry Eller]

pay attention here then, i'm not sure .541 lift at the valve is okay, I *think* the stock springs bind at .520-.530 lift..., or there is a retainer to guide issue....

Thanks, I'll be careful with some apparent decisions I'm facing.

[Barry Eller]

Ok. Tech at work took one look at rocker. "Too much Cam for stock rockers".

Shopping now for new roller rockers. The GM Performance push rods that are in it now are "Hardened" as were the "rocker arms".

[Greg K]

Go with Comp's Pro Magnum Rockers (http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_747065_-1_10233)
About $300 for a full set at Jeg's
http://www.jegs.com/images/photos/200/249/249-1320-16.jpg

[gcarter]

Go with Comp's Pro Magnum Rockers (http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_747065_-1_10233)
About $300 for a full set at Jeg's
http://www.jegs.com/images/photos/200/249/249-1320-16.jpg
So do you have to install a set of studs in the head for these?

[Barry Eller]

What ratio on the rocker arm should I get? 1.5 , 1.6 , 1.7 ?

[BUIZILLA]

you have to change the studs to use those...

also, factory rocker ratio is 1.7...

and your stock valve covers won't work either...

nice pieces though, I swear by them on high rpm engines

[gcarter]

Just curious Jim, but how are the studs retained? Red thread locker?

[Greg K]

Yes,
stock is 3/8, ARP part number 135-7102 is needed. Has a 3/8 base with 7/16 head.

So do you have to install a set of studs in the head for these?

[MOP]

Another option!

http://www.cranecams.com/?show=browseParts&lvl=2&prt=24&showAll=yes

[Zinger]

Those are the stock non adjustable rockers , the problem you have is they changed the stock cam and should have changed the rockers check the preload on the lifters . If you need how to do check out comp cam's site or email me and I tell you how to do this.

[ClassicRazorback]

Is there a way a lifter might not pump down.
Have you looked at that lifter?

chris

[RickR]

Barry
I have milled my head and decked the block to increase compression. I also have a higher lift cam.
The Crane rockers I used fit under the stock valve covers BUT I had to mill the locking, adjusting nuts to prevent interference with the valve cover.

BTW +1 for checking on spring bind.

[Barry Eller]

Thanks for all the advice guys. I discovered tonight my problems are worse. I only looked at the obvious push rod sticking up through the rocker arm, looked again tonight...Oh Sh....

#3 cylinder intake valve push rod has been "swallowed".

I've pulled the exhaust and will pull the head tomorrow. What a way to spend my day off with "Spring Break" at Pensacola Beach! Well my Wife is happy I won't be pulling up to Hooters on the beach tomorrow! But she is not happy about the $$$$ I'm about to spend on the boat.

Please help me through this. All of your advice is very welcome.

Barry

P.S. I only got 1 skinned knuckle and 1 blood blister on my finger tonight. Doing Good!

[RickR]

BArry
How far down did the pushrod go???? If you can see it through the oil drain holes in the head you should be able to get it out with a magnet. Worst case, you would have to pull the intake, not the head?
If it went all the way to the oil pan (I don't see how it could get by the cam???? see pic) you will need to pull engine and oil pan :(

[Barry Eller]

I can see the push rod. If the rod is bent, will a magnet pull it out? Do you think the camshaft could have been damaged? What about the lifter, what has happened to it?

[Barry Eller]

I was able to remove part of the swallowed push rod, broken and bent. I'm going to pull the intake this morning and check the valley and remove that lifter to inspect it.

Oh Joy....

I need more coffee...

[Greg K]

Cam lobe could be wiped out..check the valves, might have kissed a piston, may be deeper than first thought.

[Ranman]

I don't know. I bought the new 502 crate motor in 2005. It's a Gen VI with rectangular port cast iron heads. Camshaft was upgraded from the supplier. www.1800runsnew.com

I take it you have no warranty? Seems like these guys f*cked up your "cam upgrade". I'd bee on the phone with them looking for answers on how they plan to address this.

[Barry Eller]

Cam lobe could be wiped out..check the valves, might have kissed a piston, may be deeper than first thought.

That means pulling the head...oh joy...:bonk:

Gotta do it to make sure. If the lifter looks OK, won't that be a good indicator that the cam lobe is alright, hopefully?

Gotta go to NAPA and get a new whip hose for my 3/8 ratchet and some tool oil. Time to break out the Air Compressor and get my serious tools out.

[BUIZILLA]

check for a broken valve spring or dampner.... usually the bottom coil...

[Barry Eller]

I take it you have no warranty? Seems like these guys f*cked up your "cam upgrade". I'd bee on the phone with them looking for answers on how they plan to address this.

Probably up the creek. Warranty was 1 year. I bought the motor in May 2005.
Warranty would have required me pulling the engine and shipping it back to them anyway.

When I have all my "Ducks" in a row, they will hear from me! They WILL KNOW NOT to put that much "Cam" with stock valve train again!

I will send copies of bills and photos of damage. Then ask for some help because of their mistake. You don't know usless you ask.

[Barry Eller]

Lunch and Beer break! Its 5 o'clock Somewhere! I got the intake off and found the other end of the push rod.
Pulled spark plugs, manually rotated engine. Camshaft is BAD. So off with the heads.

Is it possible to replace camshaft without pulling engine in a 22-C? That is if the pistons aren't damaged.

[Barry Eller]

More photos of the damage.

I think I'm going to get drunk this afternoon...

[zelatore]

Wow, this brings back memories. I'm having flashbacks to my drag racing days.

Been there. Done that. At least it's in a boat you can access. If this happend on my 32 Carver I'd just sit down and cry, then pull the entire deck off to get to the outside heads.

It is pretty BS that a professionally built motor had this problem. If I built it and screwed it up, I'd just chaulk it up as my own mistake and eat the cost. If I PAID somebody to build it - well, you pay people because they're supposed to be better than you, right?

%$&*!!!

Don

[Barry Eller]

Good News! I just finished pulling the head (damn iron heads are heavy), no damage to pistons or valves. After cleaning out all the water that spilled into the cylinders, I cleaned #3 piston and found no contact with valves.

My back aches now, I think I'll quit for the day, take some Advil, have a shower and a few cold ones now.

Will it be possible to R&R camshaft in a 22 without R&R the engine? :bonk:

Someone please say "YES"!:yes: :yes: :yes: :yes:

[Rootsy]

measure the length of the block itself.. then measure from the front of the block to the back seat... if that distance is greater than the length of the block you can probably get it out... otherwise... get out the sawzall or the chainfall...

[98shovel]

barry pop the outdrive off pull the motor ,to do a cam swap the pan needs to come off to do the job correctly it will take u less time to pull the motor than trying to do it in the boat plus i dont think u can get the cam out without a hole saw through the seat back
then u can reassemble the motor and put it back in complete with out a broken back from leening into the hole
also would not be a bad idea to check one of the rear rod and crank bearings since all that cam debri just went through

[yeller]

I doubt you'll have enough room to pull the cam, but I've never measured, so who knows.

I'd take Rootsy's advice (although not with a chainsaw:eek!: ). Pull the cam out until it hits the back of the seat, then mark that spot. With seat cushions removed, predrill a small hole through the seat back and then from the cockpit side, use a 3~4" holesaw.

:eek!: :eek!: :bonk: :bonk: is what many would say, but it's either that or pull the motor.


Doh!! I see 98shovel beat me to the punch with the holesaw.

[Greg K]

I'd pull it, with the lobes wiped out, who knows what bits and pieces are floating around in the motor, pan, oil lines, and oil cooler.

[RickR]

Sorry for the BAD news;

Some people say I am a little ANAL :bonk: but I would pull engine, dismantle and rebuild it. Check bearings, rings, oil pump and clean all oil passages. AND CHECK ALL CLEARANCES! Piston/valve, valve spring and rocker.
Your engine probably has a bypass valve so after your filter got full of debris the rest entered the engine :(

[RickR]

BTW; These guys have a lot of new "Take Out" parts for BBC.
http://www.competitionproducts.com/prodinfo.asp?number=652417

[BigGrizzly]

pull the motor it isn't that hard.

[98shovel]

barry
me and my extra right arm have got pulling the motor out of mine down to 45 min. not sure if this is a good thing or not

[Rootsy]

Sorry guys i neglected the "Sarcasm On" function at the beginning of my last post...

That motor MUST come out... It MUST be torn down, all of the way, all parts scrubbed, flushed and inspected, right down to the oil pump (replace it anyway it's relatively inexpensive) and EVERY bearing replaced. Anything less and you might as was well be playing russian roulette.

[Barry Eller]

Good evening all,

I am making plans to pull the engine and go through it. Dan (p729lws) came by on his way home to help me drown my sorrows. I got some free "Engineering" advice on building a chain hoist attachment to a overhead beam in my carport. I've paid $500.00 enough (4 times) to have my engine pulled. The roof isn't flat, and I have plenty of roof height to do it. I can do this work, I have the tools and have built engines before, my first when I was 15. I've been in a position in the automotive business for the last 33 years to tell people what needed to be done, how to do it, and what they did wrong.

So help me through this guys!


I do appreciate ALL of your advice and support.

This is a DAMN GOOD SUPPORT GROUP !


Barry

This is where I stopped tonight.

[b.guggenmos]

I pulled my 460 Ford that I had in a 88 Testarossa 22 that had sored a piston after a long hard run. It really is not that bad. Pulls forward a little off of the outdrive splines and right on up and out. Watch for any shims on the mounts. You will not regret going through the engine and doing it right. What are you going to use for a cam now? Just curious. Good luck, brian

[MOP]

Barry cut the oil filter open dump the contents into a clean pan, dilute it with a little gas. I am 90+% sure you will find flakes from the cams hardened surface, if I am right you will need to flush the blocks oil passages. It is also a good idea to replace not just clean the oil cooler, when a cam goes it puts out some extremely hard crap that can well us your imagination. Hate to be a Doom Sayer but a partial tear down would leave me spooky!

[yeller]

Sorry guys i neglected the "Sarcasm On" function at the beginning of my last post...I didn't take your choice of tools seriously. I suppose I should have used the same "Sarcasm On" function. If the only repair is the cam, going through the back seat is a viable option though.

[BigGrizzly]

Actually when I was changing cams every weekend in my Corsican, It had a hole in the back seat for cables, I did not put it there, but in the right spot. After doing it that once I found it was easier and faster to pull the engine anyway. Don't worry about the sarcasm button in this case the chain saw was a dead give away.l As for the filter don't bother unless your curious. I do this just to check after oil changes. When the motor is gone it is a waste of time, and messy. No offense Phil, but we are on a schedule, we need to get this ready for Cumberland. Master Bolts is counting on all of us to have a great time. Yeller, if you post questions all of us will help answer them. If our combined knowledge can't answer them NO ONE can!!!!-No sarcasm here!

[Barry Eller]

Just ordered a 2-ton chain hoist and a engine stand.

I'm going to completely rebuild everything...stronger!

More Power!

I may have to get bigger valve covers...

[MOP]

Ah another 22 will join the "Wolf Pack" will wait for your after break in results! Good luck with the project!

Phil

[The Hedgehog]

Just ordered a 2-ton chain hoist and a engine stand.
I'm going to completely rebuild everything...stronger!
More Power!
I may have to get bigger valve covers...

540..... or get some heads to go with those bigger valve covers! Or both! On the other hand, I am thinking that you are on the upper limits of your exhaust without having reversion issues.

[Barry Eller]

540..... or get some heads to go with those bigger valve covers! Or both! On the other hand, I am thinking that you are on the upper limits of your exhaust without having reversion issues.


Hummmmm.....

Dry headers might solve that problem....

[RickR]

I have an extra pair of Gil Offshore WET (risers only), cheap, if you are interested email me.
BTW I am using stock lifters w/.598 lift @ valve :hyper: .

[handfulz28]

First off, sorry to hear about the troubles. At least it's an opportunity to build it better..."we have the technology...we can rebuild..."
Pulling the motor is definitely the way to go.
I wouldn't recommend wasting your time with the engine seller. I've read numerous stories of them not honoring their "warranty" even on a brand new motor (less than 1hr!). Whoever they use for the actual assembly does a horrible job of cleaning before assembly.
Look forward to seeing/hearing the end result :shades:
Michael

[BUIZILLA]

I think fuzzy has some new 540 pieces he may part with...

[Barry Eller]

I think fuzzy has some new 540 pieces he may part with...

A 540 is a stroked 502, right? Different crank, rods.....Hummmmmm....

I need my chain hoist and engine stand to arrive....

[The Hedgehog]

Hummmmm.....
Dry headers might solve that problem....

Wow, you do sound serious. I am sure that the good people of this site could come up with a recipe for a serious 502 or 540 N/A monster motor.

I am a blower motor guy but think that there is nothing quite like the sound of 600+ hp N/A motor. Not that nice soft lope but an angry-harsh sound. Kind of like WWIII going on under the hatch.

[Barry Eller]

Wow, you do sound serious. I am sure that the good people of this site could come up with a recipe for a serious 502 or 540 N/A monster motor.
I am a blower motor guy but think that there is nothing quite like the sound of 600+ hp N/A motor. Not that nice soft lope but an angry-harsh sound. Kind of like WWIII going on under the hatch.

That would be cool, but not really what I have in mind.

I'm not going to build a "Monster". I going to pull the 502, disassemble and inspect everything. Replace bearings, oil pump and anything else that may be questionable.

I am going to build with a very strong valvetrain, and as much cam as my exhaust system will allow.

I'm not going to try to "Catch 22" or anyone else. I was happy with my mid to upper 70's performance. I just want to have a strong and durable engine.

My exhaust is Revolution Marine. I contacted them before I bought their product with questions concerning reversion. They stated they had used their exhaust with over .650 lift cams. Valve "overlap" is the main cause of reversion, thats where marine cam profiles differ from automotive applications. Also torque and power curves need to be different. Remember, boats are in first gear going uphill all the time.

I won't be putting that much cam in the 502. I had .541 lift, and I'm not sure what I'll end up with.

That is something I need to research and any imput is welcome.

Here is a link to Revolution Marines exhaust. It is a good system for the $$$

http://revolutionmarine.com/images/manifolds5.PDF

[The Hedgehog]

That would be cool, but not really what I have in mind.
I'm not going to build a "Monster". I going to pull the 502, disassemble and inspect everything. Replace bearings, oil pump and anything else that may be questionable.
I am going to build with a very strong valvetrain, and as much cam as my exhaust system will allow.
I'm not going to try to "Catch 22" or anyone else. I was happy with my mid to upper 70's performance. I just want to have a strong and durable engine.
My exhaust is Revolution Marine. I contacted them before I bought their product with questions concerning reversion. They stated they had used their exhaust with over .650 lift cams. Valve "overlap" is the main cause of reversion, thats where marine cam profiles differ from automotive applications. Also torque and power curves need to be different. Remember, boats are in first gear going uphill all the time.
I won't be putting that much cam in the 502. I had .541 lift, and I'm not sure what I'll end up with.
That is something I need to research and any imput is welcome.
Here is a link to Revolution Marines exhaust. It is a good system for the $$$
http://revolutionmarine.com/images/manifolds5.PDF


Makes sense. I just got a little excited when I saw the dry exhaust comment.

Mid to upper 70's is a good number.

Rock solid valve train, forged internals and the Revolution Marine exhaust would get along great with a Procharger... woops, starting to get excited again about helping someone spend some serious money.

I was curious if the RM manifolds had a better sound vs stock. I looked long and hard at them before I bought my Dana's. They looked like a good product. I still have some sort of dream of owning a monster motor.

[Barry Eller]

Makes sense. I just got a little excited when I saw the dry exhaust comment.
I was curious if the RM manifolds had a better sound vs stock. I looked long and hard at them before I bought my Dana's. They looked like a good product. I still have some sort of dream of owning a monster motor.

Click on the link at the bottom and turn up your volume. The 502 sounds great with R/M's

I'm looking at the HP500 cam now, that one is looking like it will be the way to go....stay tuned!

Hydraulic Roller - this is an upgrade to a HP 500 cam providing maximum torque and horsepower from a long riser wet perf. exhaust. This is a Hardin Marine/Comp Cam product.
I am looking at Comp Cam Roller rockers. Not the needle bearing type, the shovel type. Decided not to change valve covers and I'm not going to be turning 6000+ RPMs.

295-112008K 286 294 226 234 .591 .601 112°
Gen 6

The complete spec sheet wouldn't copy & paste. The .591 is the intake lift .601 is the exhaust lift

[BUIZILLA]

IMO, I wouldn't be so concerned with total lift cam numbers.... something around 540-560 would work with YOUR heads...the HP 500 stick is a good choice with port matching and some bowl work.

JH

[Barry Eller]

IMO, I wouldn't be so concerned with total lift cam numbers.... something around 540-560 would work with YOUR heads...the HP 500 stick is a good choice with port matching and some bowl work.
JH

Thanks, I realize that, just sorta documenting what I'm doing here for my own reference! :wink:

My engine does have rectangular ports, not oval. But they are "HEAVY" cast iron.

[RickR]

Barry
Beware, many HP500 engines had issues (reversion) with early style (short risers) Gil Offshore Wet Exhaust. I have an issue with Gil Choice so I am switching to Gil Offshore.
Most recommend a max lift of .550 @valve for stock dog bone type hyd lifters. It depends on how small your base circle is.

If you go with a higher lift I would recommend Comp Cams 929 spring.

Part Number: 169611 Grind Number: HR-284-2S-10 IG
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1996 Up CHEVROLET 8 HYD. ROLLER WITH CAST IRON DISTRIBUTOR DRIVE GEAR
Engine Size Configuration
454-502 C.I. V

Valve Setting: Intake .000 Exhaust .000 HOT

Lift: Intake @Cam 339 @Valve 576 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 352 @Valve 598
Rocker Arm Ratio 1.70

Cam Timing: TAPPET @.004
Lift: Opens Closes ADV Duration
Intake 33.0 BTDC 71.0 ABDC 284 °
Exhaust 77.0 BBDC 35.0 ATDC 292 °

Spring Requirements: Triple Dual Outer Inner
Part Number 99896
Loads Closed 150 LBS @ 1.900 or 1 29/32
Open 441 LBS @ 1.330
Recommended RPM range with matching components
Minimum RPM 2500
Maximum RPM 6000
Valve Float 6500

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 6.0 BTDC 36.0 ABDC 105 222 °
Exhaust 50.0 BBDC 0.0 BTDC 115 230 °

Remarks:
CRANE 16535-16 LONG TRAVEL HYDRAULIC ROLLER- LIFTERS MUST BE USED WITH GREATER THAN .570 LIFT CAMSHAFTS TO PREVENT ALIGNMENT BAR DISENGAGEMENT.