Javascript Disabled Detected

You currently have javascript disabled. Several functions may not work. Please re-enable javascript to access full functionality.

Do I need guide plates?

Started by _bon_scott_ , Aug 12 2009 10:07 PM

Please log in to reply

16 replies to this topic

#1 _bon_scott_

Guests

Posted 12 August 2009 - 10:07 PM

I got my cylinder head back from Westend today, and I was just checking to make sure all the bits fit and I was wondering if I'll need guide plates to run these roller rockers? All I know is they are crane something or others, but they do suit the Holden 6. The studs are 3/8, and there's one in the pic if that helps.

Posted Image

Cheers
Chris

Back to top

#2 _Brad1979UC_

Guests

Posted 12 August 2009 - 10:36 PM

someone here may want to clarify, wouldnt mind making sure myself...

I thought that guide plates were more of an ass cover kind of thing, so if you were to have a very agressive cam they help to keep the rod from possibly straying and damaging anything else if something was to go wrong like it bending, im running them, but you'd have to have the stud holes milled if you wanted to fit guide plates. So it probably would depend on how hot your 6 is but probably not nesessary.

Back to top

#3 dattoman

Do I feel lucky? Well, do ya, punk?

Administrators
16,472 posts

Name:Neil
Location:Perth Western Australia
Car:LX SS , 76 Cadillac , 3 x dattos
Joined: 04-February 07

Posted 12 August 2009 - 10:42 PM

Don't guide plates just stop the pushrods banging on things if they let go ?

I've always run guide plates on all my V8's and 6's with rollers

Back to top

#4 _bon_scott_

Guests

Posted 12 August 2009 - 11:32 PM

The cam isn't that ridiculous (I wouldn't have thought) and it is hydraulic rather than solid so maybe it'll be ok?

Back to top

#5 _Brad1979UC_

Guests

Posted 13 August 2009 - 12:39 AM

sounds like it'd be fine.....if you've got them, you may as well run them, but if not i probably wouldnt worry unless you want the bit of insurance they provide

Back to top

#6 _oldjohnno_

Guests

Posted 13 August 2009 - 07:21 AM

^^^Not quite true..

Be careful, guideplates aren't always an optional thing, sometimes they're essential.
It depends on what head you use; the older style heads that originally used ball-pivot rockers had narrow slotted pushrod holes that guided the rods. There is no need to run guideplates with these heads but if you do you must make sure the guideplate slot and the head slot are perfectly aligned so that there is no binding.
The later heads that originally came with aluminium bridge rocker pivots had a round pushrod hole with lots of clearance. The rocker pivot took care of alignment with these heads. If you use roller rockers or old style ball-pivot rockers with these heads you must use guideplates. Check the alignment when you mock the motor up as sometimes they have to be cut-n-shut to get everything perfectly straight. Also make sure you still have clearance around the rod where it passes thru the head though you should have plenty.
You must use hardened pushrods with guideplates, and also be aware that there is a difference in pushrod length between the ball-mount rockers vs the later ones.

Back to top

#7 Heath

I like cars.

Administrators
18,315 posts

Name:Heath
Location:Eastern Suburbs, Melbourne
Car:Heavily Modified UC Sunbird Hatchback
Joined: 07-November 05

View Garage

Posted 13 August 2009 - 08:25 AM

oldjohnno, please write a book. I'd love to read it.

Back to top

#8 _bon_scott_

Guests

Posted 13 August 2009 - 12:15 PM

^^^Not quite true..

Be careful, guideplates aren't always an optional thing, sometimes they're essential.
It depends on what head you use; the older style heads that originally used ball-pivot rockers had narrow slotted pushrod holes that guided the rods. There is no need to run guideplates with these heads but if you do you must make sure the guideplate slot and the head slot are perfectly aligned so that there is no binding.
The later heads that originally came with aluminium bridge rocker pivots had a round pushrod hole with lots of clearance. The rocker pivot took care of alignment with these heads. If you use roller rockers or old style ball-pivot rockers with these heads you must use guideplates. Check the alignment when you mock the motor up as sometimes they have to be cut-n-shut to get everything perfectly straight. Also make sure you still have clearance around the rod where it passes thru the head though you should have plenty.
You must use hardened pushrods with guideplates, and also be aware that there is a difference in pushrod length between the ball-mount rockers vs the later ones.

F**K
That's why I asked though as it seemed like the things would fall off if they were moving around a lot. Seeing as I just got the thing machined for studs, will it need more machining for guide plates?

Back to top

#9 _oldjohnno_

Guests

Posted 13 August 2009 - 01:38 PM

will it need more machining for guide plates?

Not necessarily. Obviously the rocker studs will sit a bit higher, but if you still have enough lash adjustment left and the tops of the bosses are reasonably flat and level you should be ok. You could even dress them up with a file if you were careful. If there's any doubt tho machining them should cost bugger-all and is really the way to go.
I forgot to mention that it's only the stud mounted roller rockers that need guideplates; the shaft mounted ones align themselves.

Back to top

#10 _bon_scott_

Guests

Posted 13 August 2009 - 02:07 PM

I think I'll see if I can get a set of guide plates and I'll dummy them up and see how it goes. Will it worry the studs losing a few threads of grip into the head? And yeah the reason I asked is the ones I bought are stud mounts and I thought when I put one on to have a look that it would probably rotate and jump off the valve if there wasn't something holding it in place.

Back to top

#11 _mello92_

Guests

Posted 13 August 2009 - 03:38 PM

oldjohnno and Dr Terry, please write a book. I'd love to read it.

There, all better. :spoton:

Back to top

#12 _oldjohnno_

Guests

Posted 13 August 2009 - 08:42 PM

Will it worry the studs losing a few threads of grip into the head?

No

Back to top

#13 Heath

I like cars.

Administrators
18,315 posts

Name:Heath
Location:Eastern Suburbs, Melbourne
Car:Heavily Modified UC Sunbird Hatchback
Joined: 07-November 05

View Garage

Posted 13 August 2009 - 10:54 PM

I think he already has!

Back to top

#14 _bon_scott_

Guests

Posted 14 August 2009 - 12:35 AM

Ok last question, would it be possible to make guide plates myself out of some plate steel? If so, approx how thick, how much clearance do the pushrods need etc, or do they need to be made out of a particular material?

Back to top

#15 _oldjohnno_

Guests

Posted 14 August 2009 - 07:26 AM

Ok last question, would it be possible to make guide plates myself out of some plate steel? If so, approx how thick, how much clearance do the pushrods need etc, or do they need to be made out of a particular material?

You could, but they need to be quite hard so it wouldn't be that simple. The cheapys are only 40 odd bucks so it wouldn't make much sense to make your own.

Back to top

#16 _bon_scott_

Guests

Posted 14 August 2009 - 02:52 PM

Yeah all the ones I found had 'hardened' written somewhere in the advertisement. I ended up ordering a set from the local auto parts place for $90 which is a little more than American Autos or ebay but I can deal with not having to wait for postage.