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View Full Version : WHAT CAUSED THIS ROCKER ARM TO BE BEAT UP



ShadowBolt
12-20-2008, 07:07 PM
This was on the intake valve of number eight. The hole I was having oil trouble with. The top of the valve spring cap (or whatever it's called) looks perfect (as I assumed it would since it's made from steel and the rocker is made from aluminum). All the rest of the rockers were perfect.


http://www.precisionautoaccessories.com/CMC/christmas%2008%20016.jpg

Here is a pic of the hole with the deep scratches.

http://www.precisionautoaccessories.com/CMC/christmas%2008%20017.jpg

JJ

AI#97
12-20-2008, 08:59 PM
Thankfully your Driving talent exceeds your photography skills!! ;) :D

Rocker looks like the top of the valve either "compressed" and left, the retainer bent or the valve is walking side to side in the guide and the rocker was moving around as the valve floated...

If the valve stem is moving horizontally due to a bad guide, you would have serious oil problems in that cylinder as the valve stem seal would be incapable of dealing with that much horizontal movement....

I would suggest new valve guides, a valve job that is legal and all new valve springs and retainers. Sounds like you are getting into an engine that has needed a lot of TLC for quite some time! :cry:


edit: figured out the pictures were a LOT larger than my phone could see!

ShadowBolt
12-20-2008, 09:56 PM
Thankfully your Driving talent exceeds your photography skills!! ;) :D

Rocker looks like the top of the valve either "compressed" and left, the retainer bent or the valve is walking side to side in the guide and the rocker was moving around as the valve floated...

If the valve stem is moving horizontally due to a bad guide, you would have serious oil problems in that cylinder as the valve stem seal would be incapable of dealing with that much horizontal movement....

I would suggest new valve guides, a valve job that is legal and all new valve springs and retainers. Sounds like you are getting into an engine that has needed a lot of TLC for quite some time! :cry:


edit: figured out the pictures were a LOT larger than my phone could see!

I don't know why the pics posted up so large. The valve guides look and feel fine. I guess this rocker arm could have been screwed up from another install but this was the hole that was getting oil in it. The rocker arm is fine everywhere except where it's chewed up on the sides. The roller is still free and feels good. I agree we were lucky to finish every race last season. What do you mean a legal valve job? Is there any other kind?


JJ

AI#97
12-21-2008, 09:47 AM
What do you mean a legal valve job? Is there any other kind?


JJ

There are several types of Performance valve jobs...just make sure the machine shop doesn't do a 5 angle valve job if it isn't legal in CMC/2. Not like anyone could tell visually unless they tore you down.

marshall_mosty
12-21-2008, 06:00 PM
How's this?

http://www.mustangmods.com/ims/u/1280/3889/267815.jpg

http://www.mustangmods.com/ims/u/1280/3889/267816.jpg

mitchntx
12-21-2008, 06:58 PM
There are several types of Performance valve jobs...just make sure the machine shop doesn't do a 5 angle valve job if it isn't legal in CMC/2. Not like anyone could tell visually unless they tore you down.

Good luck finding a decent and reputable machine shop that DOESN'T do multi-angle valve jobs.

AI#97
12-21-2008, 08:38 PM
Well, after reading the 2009 CMC rules, I don't recall seeing anything that prevented 5 angle jobs...?

As for the piston wall jerry, looks like any other high mileage 5.0. Unless it was way down on compression, I might just put the sucker back together and run it! :P

ShadowBolt
12-21-2008, 09:01 PM
Well, after reading the 2009 CMC rules, I don't recall seeing anything that prevented 5 angle jobs...?

As for the piston wall jerry, looks like any other high mileage 5.0. Unless it was way down on compression, I might just put the sucker back together and run it! :P

Matt,

You can't see the scratches in that hole but they are there. This is the only one down on compression and the one with oil in it. Rebuilding the whole thing as soon as the parts get here. I was trying to figure what caused the rocker arm damage.


Mitch,
Do the factory heads not have a three angle valve job?

JJ

JJ

GlennCMC70
12-21-2008, 09:40 PM
Matt - thats the point, the rules dont say you can, thus its prevented.

Jerry - 3 angle valve jobs are the norm, that will be fine.

AI#97
12-22-2008, 08:58 AM
Matt - thats the point, the rules dont say you can, thus its prevented.

Jerry - 3 angle valve jobs are the norm, that will be fine.

I realize that Glenn, but after the rules were restructured VERY similar to AI rules...it leaves a lot to be read in between the lines....especially with NO detailed way of determining compliance on practically anything other than track width....and as I recall, it doesn't tell you HOW track width would be measured... AI rules atleast say with toe plates 3" above the pavement and averaged. While I like the fact they reorganized the rules, there are HUGE holes in them from what I read this weekend. It might be the fact they are formatted SO much like the AI rules, I might just have started reading them like the AI rules which could be very confusing for newbs... Just a thought.

GlennCMC70
12-22-2008, 09:37 AM
well they are not AI rules, so dont read them that way. there also isnt any lines between the lines. only do what the rules say you can. dont read into them. understand the intent. dont cheat and you will likely not be worried that the other guy is. CMC is about the driver and not about re-inventing the wheel.
you pointing out what you see as short comings of the rules is typical of the "new guy" POV. the rules work, they have worked before you came along and they will work after you go away. build the car, dont bitch about how your at a disadvantage, cinch up your big girl panties and come race.

AI#97
12-22-2008, 10:37 AM
I am not racing with CMC Glenn and your "like it or leave" type answer doesn't make me want to do so either... :roll:

GlennCMC70
12-22-2008, 10:58 AM
of all people, i thought you would prefer that type of delivery. i can sugar coat it for you if you need me to.

mitchntx
12-22-2008, 11:27 AM
Finally ... Glenn is fighting with some one else.

Thanks for taking the heat off, Matt.

8)

michaelmosty
12-22-2008, 11:45 AM
Mitch, grab some popcorn and enjoy the show. :D

David Love AI27
12-22-2008, 11:59 AM
Bulldog vs Candy Ass.... ROFLMAO!!!!!!!!! "Lets get ready to RUUUUUUMBLE".... wait sounds like rumball... I like rumballs better (hic) .... you guys have fun... I love AIX!!!!! :twisted:

AI#97
12-22-2008, 03:39 PM
Finally ... Glenn is fighting with some one else.

Thanks for taking the heat off, Matt.

8)

You don't have to worry about me stealing your boyfriend Mitch...I don't swing that way.

mitchntx
12-22-2008, 04:31 PM
Finally ... Glenn is fighting with some one else.

Thanks for taking the heat off, Matt.

8)

You don't have to worry about me stealing your boyfriend Mitch...I don't swing that way.

Guess I misunderstood your constant references to Team Schwing.

donovan
12-24-2008, 11:27 AM
Cobra Style 1.7 roller rockers are known to prematurely wear the valve guides and create the problem you have photographed.

I would not run 1.7's of any type on a Ford head, ask any decent head guy and he will tell you the same thing.

My GT-40 cast irons heads looked just like that and my GT-40X aluminum heads looked like that till I switched to 1.6 Comp Cam rollers.

DD

mitchntx
12-24-2008, 12:23 PM
Cobra Style 1.7 roller rockers are known to prematurely wear the valve guides and create the problem you have photographed.

I would not run 1.7's of any type on a Ford head, ask any decent head guy and he will tell you the same thing.

My GT-40 cast irons heads looked just like that and my GT-40X aluminum heads looked like that till I switched to 1.6 Comp Cam rollers.

DD

Ah ... so to put it terms that Marshall can understand, when rocking in a Ford, one needs to be more like Celine Dion instead of Stevie Ray Vaughn. Close?

marshall_mosty
12-24-2008, 12:47 PM
My engine can sing like the upper octives of CD... I use only genuine FRPP 1.6 rocker arms (blessed by CD, of course) 8)

ShadowBolt
12-24-2008, 04:37 PM
Cobra Style 1.7 roller rockers are known to prematurely wear the valve guides and create the problem you have photographed.

I would not run 1.7's of any type on a Ford head, ask any decent head guy and he will tell you the same thing.

My GT-40 cast irons heads looked just like that and my GT-40X aluminum heads looked like that till I switched to 1.6 Comp Cam rollers.

DD

Thanks DD! I had no idea. This was the only one that had any damage. More money to spend!

JJ

donovan
12-24-2008, 09:19 PM
don't take my comments and change anything!

Just pull the valve covers and inspect them regularly, and plan on changing the valve guides at the end if each season if you run every event.

I found that is what I needed to do.

I will send you some more info later, I spent three years messing around with the problem.

ShadowBolt
12-24-2008, 10:34 PM
don't take my comments and change anything!

Just pull the valve covers and inspect them regularly, and plan on changing the valve guides at the end if each season if you run every event.

I found that is what I needed to do.

I will send you some more info later, I spent three years messing around with the problem.

David,

If I change to the 1.6's will that fix the problem?

JJ

donovan
12-25-2008, 06:16 AM
Yes that would remove the issue.

Side loading the valves is causing the guides to wear faster than normal. Once they are worn bad enough it will allow the roller tips to walk out eventually the aluminum makes contact with the tips.

I have had this happen twice and both times the guides were worn very bad... the valves were still sealing fine but the top half of the valve guides were badly worn out.

This happened with a Stock Cobra setup and again with aluminum heads with FRPP 1.7s... Once I went to studmount 1.6's I have not see the problem.

DD

Adam Ginsberg
12-26-2008, 01:28 AM
If I change to the 1.6's will that fix the problem?

Unfortunately, 1.6 RR's are not CMC legal. Or so I've been told - 1.6 ratio RR's were never offered on a stock 5.0L engine. The stamped steel rockers are 1.6, but they aren't rollers.

Going to screw in studs and guide plates is really the only way to do RR's, but that's not permitted either.

ShadowBolt
12-26-2008, 12:54 PM
If I change to the 1.6's will that fix the problem?

Unfortunately, 1.6 RR's are not CMC legal. Or so I've been told - 1.6 ratio RR's were never offered on a stock 5.0L engine. The stamped steel rockers are 1.6, but they aren't rollers.

Going to screw in studs and guide plates is really the only way to do RR's, but that's not permitted either.

So in CMC the only thing to do is run the 1.7's and tear up the heads?


JJ

donovan
12-26-2008, 01:36 PM
or, you can run the stock non-roller 1.6 rockers.

You shouldn't need the rollers to make the numbers.

Adam Ginsberg
12-26-2008, 05:15 PM
You shouldn't need the rollers to make the numbers.

According to several FFR's drivers, this is true. They dyno'd before and after installing a set of RR's, and only found ~3-6 HP....not worth the $$ and hassle, IMO.

donovan
12-26-2008, 06:59 PM
yup, when I went from 1.7 to 1.6... I saw only a slight change, not even 1 percent..

They are only opening the valve slightly more, you are not going to see significant changes till you open them longer or change the LSA.

DD

David Love AI27
12-26-2008, 07:50 PM
yup, when I went from 1.7 to 1.6... I saw only a slight change, not even 1 percent..

They are only opening the valve slightly more, you are not going to see significant changes till you open them longer or change the LSA.

DD

ok... it is no secret that I'm ignorant when it come to motors so I'll go ahead and ask... what is LSA???

jeffburch
12-26-2008, 08:23 PM
http://www.lsadc.org/

I love google

jb

mitchntx
12-26-2008, 08:38 PM
JB ... you are over the top, sometimes.

Lobe Separation Angle

Aggressive LSA is what gives that tell-tale sound at idle

AI#97
12-26-2008, 09:15 PM
JB ... you are over the top, sometimes.

Lobe Separation Angle

Aggressive (smaller number...) LSA is what gives that tell-tale sound at idle

Playing with the LSA and general lobe timing, especially with the closing of the intake valve can help make SICK power from an N/A high compression motor. split lifts, split durations and tight LSA's can help make a motor that pulls like a truck down low and breathes like a high strung motor on the top end...

there are so many things you can do with camshafts now days compared to the e-cam which was developed in the 1930's.... :roll: CMC's got to be the suck for that kind of stuff...? :oops:

jeffburch
12-26-2008, 10:07 PM
JB ... you are over the top, sometimes.

Sarry.
Wus the pante fums tokin.
jb

ShadowBolt
12-26-2008, 10:48 PM
9.5 to 1.

Removed .050" from the heads. Eric had removed .010" at the last rebuild.

I got the heads back today. Start assy. tomorrow. I will have to shim the rockers and get different pushrods. This is getting expensive. Shortblock, oil pump, timing gear and chain, head work, headers, gasket set, water pump, oil pan, and cam, plus all the little stuff like plugs, oil and filter (two times) and other misc. crap. I hope the added compression will get me to the numbers. The old motor was sick!

JJ

Adam Ginsberg
12-26-2008, 10:52 PM
Jerry - using the stock steel rockers is SO simple and cheap, it's ridiculous. You can find excellent used rockers w/fulcrums for ~$20-$30. Bolt them into place, torque the bolts correctly, and go race. Hell, I think I have 3 sets laying around.

FWIW, I've gone back and forth about RR's, and decided awhile ago not to use them. Since we aren't permitted to do them properly (screw in studs, guide plates and hardened pushrods), I won't install a set at all, and stick with the stock steel units. Check them once a year for wear, retorque, go out and race. Does it get any easier?

Remember - KISS. ;)

David Love AI27
12-26-2008, 10:55 PM
JB ... you are over the top, sometimes.

Sarry.
Wus the pante fums tokin.
jb

All I got outta that was "tokin" :shock: did i really say that??? :oops:

ShadowBolt
12-26-2008, 11:04 PM
Jerry - using the stock steel rockers is SO simple and cheap, it's ridiculous. You can find excellent used rockers w/fulcrums for ~$20-$30. Bolt them into place, torque the bolts correctly, and go race. Hell, I think I have 3 sets laying around.

FWIW, I've gone back and forth about RR's, and decided awhile ago not to use them. Since we aren't permitted to do them properly (screw in studs, guide plates and hardened pushrods), I won't install a set at all, and stick with the stock steel units. Check them once a year for wear, retorque, go out and race. Does it get any easier?

Remember - KISS. ;)

Adam,

I would still have to shim the rockers and buy shorter pushrods.....right?


JJ

David Love AI27
12-26-2008, 11:05 PM
JB ... you are over the top, sometimes.

Lobe Separation Angle

Aggressive LSA is what gives that tell-tale sound at idle

you mean when the motor has a "lope"??... I remember back in high school when guys thought they were cool and said "sounds like its got a cam in it"... no shit sherlock :P

David Love AI27
12-26-2008, 11:11 PM
Jerry - using the stock steel rockers is SO simple and cheap, it's ridiculous. You can find excellent used rockers w/fulcrums for ~$20-$30. Bolt them into place, torque the bolts correctly, and go race. Hell, I think I have 3 sets laying around.

FWIW, I've gone back and forth about RR's, and decided awhile ago not to use them. Since we aren't permitted to do them properly (screw in studs, guide plates and hardened pushrods), I won't install a set at all, and stick with the stock steel units. Check them once a year for wear, retorque, go out and race. Does it get any easier?

Remember - KISS. ;)

Adam,

I would still have to shim the rockers and buy shorter pushrods.....right?


JJ

Why would you have to do both??? I would think you only need to do one or the other... if you shim the rocker the same amount as the shave, then they are back to the same distance from the cam and you should be able to use the stock rods, or am I missing something???? hell, what do I know.... need to get back in the shop and finish my end of the year cleaning... too many projects...

Adam Ginsberg
12-27-2008, 01:52 AM
Removed .050" from the heads. Eric had removed .010" at the last rebuild.

Sorry - I missed this. You have a total of .060 off those heads?????

Holy shit, Jerry. For starters, good luck getting the lower to bolt into place without modifying it, too.

For a number of reasons, I'm not going to go any further with this thread, as it'll only bring out previous history.

AI#97
12-27-2008, 10:43 AM
Removed .050" from the heads. Eric had removed .010" at the last rebuild.

Sorry - I missed this. You have a total of .060 off those heads?????

Holy shit, Jerry. For starters, good luck getting the lower to bolt into place without modifying it, too.

For a number of reasons, I'm not going to go any further with this thread, as it'll only bring out previous history.

I am going to guess that was supposed to be .005"...don't think there is a machinist out there that would remove .050" without a disclaimer of some sort and it certainly wouldn't be 9.5:1 any more! ;)

GlennCMC70
12-27-2008, 12:29 PM
my bet is Matt is right. .005" is a nice clean up cut. Mitch was having to pitch heads for a .023" cut.

ShadowBolt
12-27-2008, 02:07 PM
combustion chambers are now 60.5 cc's.

JJ

Adam Ginsberg
12-27-2008, 03:56 PM
combustion chambers are now 60.5 cc's.

Interesting....down from the factory's 64cc's.

ShadowBolt
12-27-2008, 04:33 PM
combustion chambers are now 60.5 cc's.

Interesting....down from the factory's 64cc's.


Yes, unless I totally did not understand what Tony said, iron heads can go to 10:1 and alum head engines 11:1. The GT40 heads make you lose compression from the E7's.


JJ

ShadowBolt
12-27-2008, 08:45 PM
combustion chambers are now 60.5 cc's.

Interesting....down from the factory's 64cc's.


Adam,
Cobra GT40's are 60 cc's, regular gt40 (non Cobra's) are 64 cc's.

JJ

Adam Ginsberg
12-27-2008, 10:34 PM
Yep - sorry, my mistake. The Lightning GT40 heads are 64cc.

So...if the heads have been milled .015 total, how is the CC 60.5cc's when the factory measurement is 60cc?

ShadowBolt
12-27-2008, 10:55 PM
Yep - sorry, my mistake. The Lightning GT40 heads are 64cc.

So...if the heads have been milled .015 total, how is the CC 60.5cc's when the factory measurement is 60cc?


The heads on CMC17 had 64 cc chambers. I have no idea where they came from but my machine shop milled the heads to 60.5 cc's. According to the shortblock mfg. this makes about 9:5 to 1. All I know is what I can find to read. I never hot rodded anything but a small block chebby (and that was 30 yeqrs ago).

On another note I was asked if there is such thing as a Cobra lower intake because the one I have could not flow squat! The holes at the top of the lower intake are way smaller than the ports are....way smaller.


JJ

AI#97
12-28-2008, 09:50 AM
On another note I was asked if there is such thing as a Cobra lower intake because the one I have could not flow squat! The holes at the top of the lower intake are way smaller than the ports are....way smaller.


JJ

Yes...they come as a pair usually (upper and lower)...and are usually good to 400hp...?

ShadowBolt
12-28-2008, 10:04 AM
On another note I was asked if there is such thing as a Cobra lower intake because the one I have could not flow squat! The holes at the top of the lower intake are way smaller than the ports are....way smaller.


JJ

Yes...they come as a pair usually (upper and lower)...and are usually good to 400hp...?

They come as a pair......damn Matt, I did not know that. Thanks.
JJ

AI#97
12-28-2008, 10:11 AM
They come as a pair......damn Matt, I did not know that. Thanks.
JJ

They can be sold as upper and lower, but typically are bought at the same time to work together. Reason being is there are two lowers...one for a 302 and another for a 351.

Download the FRPP catalog as a PDF and it should have a lot of the info you are looking for. Summit racing link...


http://store.summitracing.com/partdetail.asp?autofilter=1&part=FMS%2DM%2D9424%2DZ51&N=700+4294924761+4294908331+4294908282+4294925239+ 4294822100+115&autoview=sku