|09-19-2007 12:43 PM|
I like to follow up on my problem when I come to a solution in case anyone else runs into this.
I ordered a set of Crane Gold Race Rockers that were "clearanced for valve spring diameters up to 1.630" "
Guess what? They didn't fit. I got about .030" clearance between the rocker and spring. .040" is usually required. Plus the rocker nut hit the slot of the rocker arm when I rotated the engine. Not good.
So I did some research and ended up going to a stainless shaft rocker system from Crower. It cost $1200. It seemed like a lot of money but after adding up the cost of new rockers, studs, guideplates, taller valve covers and a stud girdle it really isn't that much more. Plus a shaft system will increase the life of the valve train from more control. I was also able to use the same size pushrods I had and that saved me even more money.
Be advised that I still had to use -.050" valve locks to bring the spring down a bit.
So the moral of the story is, when going to a longer valve, don't get anything longer than necessary otherwise you will have a headache to deal with.
Thanks for all of your help and input.
|08-18-2007 11:04 AM|
have you tried installing a push rod like 1bad80 suggested ?
|08-17-2007 08:41 PM|
|dirtydave||You're right Mudbogger. 2" is high but required for my high lift, roller cam setup. My cam grinder recommended 240# on the seat from a spring. In order to get that force and to be out of coil bind range with my lift setup, I had to go to a taller install height. (which is helping cause this problem because the taller the valve gets the closer it is to the rocker arm stud since they aren't at the same angle)|
|08-17-2007 01:34 PM|
|BBCMudbogger||Isnt 2" installed height kinda high? I am thinking about 1.8"?|
|08-17-2007 11:03 AM|
Thank you all for your input so far! You definitely got my gears turning in the old noggin. To answer some of your questions:
I don't have any pushrods yet for this engine since I needed to install the rockers in order to see what length rod will be required for proper geometry. (i use a set of the adjustable pushrods to determine this)
When I installed the rockers, some would not even slide down the stud at all because of the interference (as hotrodf1 pointed out and as you can see in my first picture) I understand that the position of this rocker is all messed up but it's as far as it goes on. The rockers that could "squeeze" past the valve springs can't touch the roller to the valve tip, no matter what height pushrod is. The closest they could come is shown on my second picture.
Now as far as grinding the rockers goes, I understand that many people have done it before, but as much money that's in this engine, I would hate to risk a broken rocker and who knows what other parts if that metal winds up where it shouldn't be. Plus my spring force is pretty stiff in order to control my solid roller cam with .680 lift seen at the valve (minus lash of course) which I would think is another factor towards a premature rocker failure.
So I looked around for other rockers that would clear my springs without having to go to a shaft mounted rocker. Harland Sharp has a heavy duty aluminum set that say they clear springs up to 1.630" as well as Crane's Gold Race Rockers. I would like to go to a stainless steel rocker but the only one I found (by Crower, thanks CNC BLOCKS N/E) were around $500 for the set! I'm sure they are worth it though.
If you guys have any info of which of these I should stay away from, let me know. I'll keep you all posted which ones I get and if they clear. For future reference, the Comp Pro Magnums won't clear the bigger springs (1.560").
|08-17-2007 09:32 AM|
|CNC BLOCKS NE||We use a lot of Crower rockers which have more clearance and some times using a lash caps may even help with a retainer to rocker issues.|
|08-17-2007 06:43 AM|
How doe's the gap look with push-rods installed.
The rockers do not go down that far.
A longer push-rod does help most that hit.
Show some pictures with the rods installed, I dought there will be a problem.
|08-17-2007 12:38 AM|
|techinspector1||OK, I'll add my take on it. I figure that even Comp Pro Magnums don't have superfluous material in them that can be ground away. In the super-competitive environment of speed parts, it is doubtful that the engineers would have designed them with any more material than was absolutely necessary to do the job. Call Comp and find out if there is some other rocker that you don't know about that can be used in this application. If not, ask about using the beehives like the Deputy mentioned.|
|08-16-2007 11:12 PM|
Yep, you are correct. I missed that part. Ok, maybe I need to go edit my post? LOL
|08-16-2007 10:16 PM|
I think he said he couldn't even get some of the rockers onto the stud because the interference prevented it. He either has to clearance the rockers or get different rockers I believe.
|08-16-2007 06:49 PM|
Good call! If you raise the rockers up to about their "normal" position, the interference may end up a non-issue. A stock pushrod under it will get you close to finding out if you need to clearance the rockers or not.
|08-16-2007 04:33 PM|
I wouldn't grind them, but you have an option that should come out cheaper than a new set of rockers. Try the new beehive springs from comp cams (I think thats who makes them) they have a narrow top and widen at the bottom to the standard width. They have gotten a lot of good reviews as well. Just my .02
|08-16-2007 04:28 PM|
to grind or not
hi dirty dave, nice pics, only problem is your rockers will never be in the position you have them in in the pics. it looks like once you set the rockers in the proper position minimal clearancing will be needed. it is o.k. to grind for clearance. sam-missle
|08-16-2007 04:16 PM|
|RPM||I have run into that many times. I put the rockers in a mill and used an end mill to cut into that area. Never had a failure. Just don't cut anymore that you have to.|
|08-16-2007 04:09 PM|
I had this problem to a much lesser degree with my "no-name" rockers that I had before, but I wouldn't have thought the Comp rockers would be a problem.
So, even if you leave the pushrod end of the rocker up higher it still hits the retainer? It looks like you have more interference, and would end up grinding away a good chunk of material. I don't know what the effect would be, but I would be scared to do it too.
Not that this is good news, but I think the PVS (Miller Engineering) rockers that I just bought are clearanced for 1.55 springs. If you look on the website you can see how the underside is clearanced.
FYI: Competition Products has them priced really nice at $159 a set for small block and only $139 for big block. And they are nice, seem to be nice quality! Lifetime warranty on them as well!
Can see them here: http://www.mid-lift.com/PVS-PA.htm
If you click home at the top, then click on the STUD-BRIDGE will see the "STUD - BRIDGE" which is a wicked stud girdle. Talk about cinching everything up tight. It's a different design.
I like that site, really pretty interesting concepts.
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