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cast roller cam problem


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running a cast core roller cam on the street with more than MINIMAL spring pressures IS JUST asking for valve train problems,heres a comp cams grind on a cast core failure,(BELOW) now ANY brand can fail....but IVE had few (NONE) problems with CRANE,CROWER,ISKY components, and that what I usually use

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I think youll find the CRANE/ISKY/CROWER parts significantly better made. you may also want to do what I do on most blocks...

cca-5003_w.jpg

 

http://store.summitracing.com/partdetail.asp?autofilter=1&part=CCA%2D5003&N=700+4294925139+400114+1005+115&autoview=sku

 

use this tool to significantly increase the oil flow on the cam lobes (look on page 334)

http://www.compcams.com/technical/Catalogs/106-07/330-343.pdf

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GRUMPY... What's your gut feeling about these (except for SBC and 1.6 ratio instead of 1.7)?? http://cgi.ebay.com/ebaymotors/ADJ-SHAFT-ROLLER-ROCKERS-FORD-302-351W-MUSTANG-1-7_W0QQitemZ230043719064QQihZ013QQcategoryZ33624QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

EDIT: Here are the CHEVY 1.6 RATIO rockers. I kept the above link because the close-up images on the this link don't work... http://cgi.ebay.com/ebaymotors/ADJ-SHAFT-ROLLER-ROCKERS-CHEVY-327-350-383-400-1-6_W0QQitemZ8076308844QQihZ019QQcategoryZ33624QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

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ive never seen those in person or known anyone useing them, but Id suspect its cheaply made. in china,.....that being said .....id probably invest the $300, on a set to find out PROVIDED I was very sure they would fit the heads I was useing after EXTENSIVE questioning of the seller

and ID pass on them if he would not answer the questions in detail, keep in mind most roller rockers are a high stress, disposable, item designed to be replaced or rebuilt on a regular basis, that require a mandatory and frequent check of the condition of the bearings, clearances, alignment, geometry, ETC.

theres a REASON that GOOD shaft mount roller rockers cost alot and that the fact they are designed to work under extreme stress, and use close tollerances and top quality materials, which ID SERIOUSLY doubt are in use on those rockers, but there are a few really good deals in the cheap imported parts, so it may be worth spending/wasting $300 to find out??

yet ID also keep in mind that ARP sells rocker studs that the chinese sell copys of, looking at them they apear similar, but in use the chinese copys fail far more frequently, your rarely if EVER going to get top quality parts,at bargin basement prices, simply because quality costs a good deal to produce while junk is far less expensive

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These should fit my heads... Performer RPM with stock Chevy valve placement. These seem to be the nicest of the cheap shaft-mount rockers... at least from I could find. The seller has been in business for over 30 years so that's SOME indication of reliability. Of course time in business often means little. He said they normally sell these for $399... I didn't ask him the MSRP... again this isn't saying much.

 

Regarding extreme stress... these will never see more than 6500 RPM and I have a fairly mild cam... works with a stock converter (barely). In these conditions, I think this rocker set will work okay. I just had to ask because I trust your opinion.

 

These arrived yesterday, BTW. Let me know if you want pics... please be specific.

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Okay Grumpy... I'm no expert by any means but I'll give you my opinion on these none-the-less. They seem to be of decent quality but could use improvement in a couple of areas that even I can see.

 

1) Not all the pins holding the roller tips are exactly centered... I'll drive mine to center if you think it's necessary.

 

2) The recessed area in the pedestals where the upper 8 head bolts should fit into are too shallow and there isn't enough material to machine them deeper. I'm havine to grind the hex heads on the 8 highest head bolts 6mm shorter so they'll fit.

 

BTW, I'm sorry these are thumbnails. I guess I should upload my pics to my web host. I think I can cut/paste them and they'll be full-sized. But it's late tonight...

 

The packaging and one pedestal...

http://forums.hybridz.org/attachment.php?attachmentid=1574&stc=1&d=1162094369

 

Close-up of rocker...

http://forums.hybridz.org/attachment.php?attachmentid=1576&stc=1&d=1162094390

 

Alignment F-B...

http://forums.hybridz.org/attachment.php?attachmentid=1577&stc=1&d=1162094401

 

Alignment R-L with no shims. This is just with the rockers resting on the valve stems. I haven't checked alignment with the pushrods installed and with full cam rotation yet...

http://forums.hybridz.org/attachment.php?attachmentid=1578&stc=1&d=1162094412

 

The area of misfit. The distance between A and B is 5mm or a bit less so I'm removing 6mm from the bolt heads...

http://forums.hybridz.org/attachment.php?attachmentid=1579&stc=1&d=1162094476

DSCN4100-c_thumb.jpg

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Mike, you need to do some research on valvetrain geometry before you put that in service. Just looking at the pic of the roller on the valve tip, it looks like the roller is going to be very close to the edge of the tip at full lift, which is undesirable. You may have to adjust the height of the shaft and then determine pushrod length. Try a search on "valvetrain geometry" or "rocker arm geometry". We have discussed it several times before, in much greater depth than I can go into.

 

Not trying to be an ass, I just suspect that's not a bolt on and go deal.

 

John

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JOHN... thanks for the deads-up. I didn't think they're centered properly either. Until I intall the pushrods and torque the bolts enough to bring everything into place, I won't know how these will align at full lift. That said, I don't see how they can be right if the rocker tips are already centered at zero lift. If there is an alignment issue the only resolutions are to either have the existing pedestals modified or new ones machined. If that's the case, I'll try to return these due to the extra costs involved. It makes no sense to keep these inexpensive rockers if they end up costing as much as Crane's or Crower's.

 

Of course you're not being an ass, John. I understand that your trying to help. And I appreciate it.

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Grumpy,

 

I hope you intended for me to post this info in this thread. If not, please tell me and I'll move everything.

 

Here are a few more pics. I decided to keep them as thumbnails because they take up less space on the page... creates less scrolling.

 

This is the absolute minimum that must be ground off the length of the bolt head...

http://forums.hybridz.org/attachment.php?attachmentid=1583&stc=1&d=1162161624

 

If the stud bolts were perpendicular to the rocker plane, I'd only need to remove 2 or 3mm...

http://forums.hybridz.org/attachment.php?attachmentid=1581&stc=1&d=1162161459

 

But of course they're NOT, so more material must be reomoved...

http://forums.hybridz.org/attachment.php?attachmentid=1582&stc=1&d=1162161616

DSCN4125-c_thumb.jpg

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DSCN4127-c_thumb.jpg

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MIKE thats what the forums FOR! to discuss ,what WILL or WON,T WORK and WHY, the potential advantages and problems and how the guys can avoid or over come the little problems and mis-matches that ALWAYS occure

frankly IM in AWE of your photograffic skills

 

and if it was my engine ID have looked into longer pushrods and spaced the rocker base higher vs cutting the bolts, or having the rocker base machined to clear, IF AFTER MEASURING that PROVED TO BE FEASABLE, and yeah, IM well aware that might require longer valves, differant springs, spring seats and lash caps, or machining or drilling the area abover the bolt head for clearance, to get the clearances necessary to clear the bolt heads, or perhaps swaping to studs with nuts on those 8 locations, stepping back, and thinking it thru is usually better than jumping into a quick fix,(ALL THOUGH , IVE CERTAINLY FIXED and OCCASIONALLY SCREWED UP MY SHARE OF PARTS over the years)

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Grumpy,

 

All this... in your post above... is way above my knowledge/skills:shock: In order to accomplish this task economically, I need to use the easiest methods possible that are mechanically sound:wink: Thanks for your kind words regarding my photos.

 

I've ground down and retorqued all the head bolts. The pedestals are test fitted and are now good to go. I've mounted one set of rockers and rephotographed the alignment of the tips. These look much better now that the pedestals are sitting flat:redface:

 

I'll post again once I've installed the push-rods and tested tip alignment at full lift.

 

Please notice the close proximity of the outer valve spring to the nearest inner part of the rocker. Do you think I should remove a tiny bit of material from the center of that area of the rockers?

 

EDIT: Oh... forgot to mention that these have some adjustment at the push-rods via locking set screws.

 

Here's a pic of the tip alignment now (MUCH better)...

http://forums.hybridz.org/attachment.php?attachmentid=1584&stc=1&d=1162169575

DSCN4129-c_thumb.jpg

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ROCKER TIPS NOT CENTERED... Some of the rockers are not perfectly centered side-to-side. They're not too far off though. Take a look at the pic. This is the one that's farthest off-center. Is this enough to be a serious issue? If so, can I just shave the proper amount of material off the offending part of the pedestal and shim the other side?

 

ROCKER ARM SIDE-TO-SIDE MOVEMENT... These don't use circle clips like some other brands do to keep the rockers centered on the the valve stems. Rather they rely on the pedestal walls for that. Also, there is very slight movement side-to-side. Do you think I should add more brass shims to eliminate this movement.

 

ADJUSTING THE ROCKER WIPE PATTERN... Can I buy a set of solid lifters (this is a hydraulic cam), mark the tops of valve stems, adjust the set screws to the existing push-rods, then just crank the engine with the starter a few turns? This seems like the easiest/fastest way to test for this.

 

BTW... stupid me... I already torqued down the intake. Now I need new gaskets.

 

http://forums.hybridz.org/attachment.php?attachmentid=1585&stc=1&d=1162184074

DSCN4140-c_thumb.jpg

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Side to side, I don't think any of those are off enough to make any difference. They're not perfect, but close enough.

 

A little side clearance is normal and necessary, say 0.020 or so.

 

The pushrod adjusters won't change the wipe pattern. The only way to change the wipe pattern on a shaft setup is to adjust the height of the shaft, or the height of the valve tip.

 

jt

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That's great news... no problems then. Shims were provided to raise the pedestal should it be necessary. The side-to-side rocker clearance is indeed approximately .010-.020... more good news. Yes, the push-rod adjusters only fine-tune push rod length. Now all I must do is get the wipe pattern right and torque eveything down. Woo hoo!!!

 

THANKS JT1 !!!

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