Rocker arms hold down kit and side play

Posted By: Coke

Rocker arms hold down kit and side play - 12/16/12 10:14 PM

I,m and mounting my Huges engines rocker arm kit using a Mopar Performance hold down kit.Engine is a 440 with Mopar alu heads.

Huges recommends 0.005-0.0015" side play between two rockers.The kit come with 0.015" and 0.030" washers but i,m noticing that the side play varies depending on how you tight the hold down, due there is clearance between this piece and it�s bolt.

So the way that i have found for getting the proper play is to insert a feeler gauge between the rockers spacer and remove it after tightening the bolt.

Then ,are these hold downs kits designed for correcting the side play and are the washers more for centering the roller tip over the valve stem?

Thanks

Posted By: AndyF

Re: Rocker arms hold down kit and side play - 12/17/12 12:46 AM

It usually takes some time and maybe a trip to the machine shop to get the rocker arms all dialed in. You want the rocker arms lined up over the valves and you want the correct side clearance. Sometimes you need to move the spacers arond to accomplish both goals.

Posted By: Stanton

Re: Rocker arms hold down kit and side play - 12/17/12 05:35 AM

Whatever you do, you want at least one shim between the rocker and the holddown to eliminate wear. You should also find that the spacing is equal for each pair of rockers and that once you find the combo, each set will have the same shim config. (the valves all have the same spacing as do the pedestal bolts). The holes in the holddowns are also usually large enough to allow some movement.

When I assemble mine I cut 2 .015 shims in half and used a half on each pair of rockers as I tightened the holddowns. When I reached the right torgue I took them out - VOILA, each set with very close to the same clearance.

Posted By: Coke

Re: Rocker arms hold down kit and side play - 12/21/12 01:35 PM

Quote:

Whatever you do, you want at least one shim between the rocker and the holddown to eliminate wear. You should also find that the spacing is equal for each pair of rockers and that once you find the combo, each set will have the same shim config. (the valves all have the same spacing as do the pedestal bolts). The holes in the holddowns are also usually large enough to allow some movement.

When I assemble mine I cut 2 .015 shims in half and used a half on each pair of rockers as I tightened the holddowns. When I reached the right torgue I took them out - VOILA, each set with very close to the same clearance.

Sounds like a very good idea so i cut two 0.015 shims and i,m doing the same.
The only thing is that i had to remove two of the 0.015 whole shims that i had between the rockers and the spacers to allow one half shims on every couple of rockers.Huges recommends 0.005 to 0.015 side play, but being aluminium rockers,don,t like too much less than 0.015".

About the wear between the rocker and the hold down ,this kit come with a wide washers (0.122" or so) wich must go between the rocker and the holddown .You can add a shim for centering the rocker but you can,t remove this washer from that place.

Posted By: Cab_Burge

Re: Rocker arms hold down kit and side play - 12/21/12 06:39 PM

With aluminum roller rocker looser (.030) is way better than a tiny bit(.014) to tight

Measurethe width of a rocker arm at room tempertures and then heat that rocker arm up to 100 C in a oven and measure how wide it is at 100C, adjust accordingly

Posted By: Stanton

Re: Rocker arms hold down kit and side play - 12/21/12 09:56 PM

Quote:

About the wear between the rocker and the hold down ,this kit come with a wide washers (0.122" or so) wich must go between the rocker and the holddown

Really !?!?! Can you tell me which kit you bought. All the holddowns I've seen are wide enough that a .120 spacer would never go between the holddown and rocker!

Posted By: Coke

Re: Rocker arms hold down kit and side play - 12/22/12 10:08 PM

Quote:

Quote:

About the wear between the rocker and the hold down ,this kit come with a wide washers (0.122" or so) wich must go between the rocker and the holddown

Really !?!?! Can you tell me which kit you bought. All the holddowns I've seen are wide enough that a .120 spacer would never go between the holddown and rocker!

That is rare,cause the holddowns are Mopar Performance(#P5249714)and the rockers arm kit is from Hughes Engines and everything seems to be made for fitting .

I have taken a few pics.

Posted By: MLR426

Re: Rocker arms hold down kit and side play - 12/23/12 03:22 AM

Quote:

Quote:

Quote:

About the wear between the rocker and the hold down ,this kit come with a wide washers (0.122" or so) wich must go between the rocker and the holddown

Really !?!?! Can you tell me which kit you bought. All the holddowns I've seen are wide enough that a .120 spacer would never go between the holddown and rocker!

That is rare,cause the holddowns are Mopar Performance(#P5249714)and the rockers arm kit is from Hughes Engines and everything seems to be made for fitting .

I have taken a few pics.

I've used that rocker system a few times and they are nice pieces. Be sure to check rocker to retainer clearance and clearance under rocker if needed.

MLR426

Posted By: fourgearsavoy

Re: Rocker arms hold down kit and side play - 12/23/12 04:25 AM

Quote:

It usually takes some time and maybe a trip to the machine shop to get the rocker arms all dialed in. You want the rocker arms lined up over the valves and you want the correct side clearance. Sometimes you need to move the spacers arond to accomplish both goals.

This is a before picture of my rockers before I had them machined to center them over the valve stem

After I got them back from the shop I was then able to the clearance I wanted with some shims I picked up from Harland Sharp,good guys over there

You can also get shims from Mancini racing.
Gus

Posted By: fourgearsavoy

Re: Rocker arms hold down kit and side play - 12/23/12 04:33 AM

Here they are after about 3 hours of work

Gus

Posted By: Coke

Re: Rocker arms hold down kit and side play - 12/23/12 01:16 PM

Wow! That before picture is very exagerated.I suppouse that kind of rockers are harder to center.

However ,what do you guys do for determining that it is correctly side centered? I mean on roller tip rockers.

Mine seems to be ok and i haven,t done anything.The valve stem is in the center of the roller tip,it can vary the 0.015 of side clearance,of course.

I use a magnifing glass to check it and seems to be ok.I don,t know any other method for this...
Besides, in the Hughes instructions sheet,they say that centering is not mandatory and sometimes some offset can be allowed.

Posted By: fourgearsavoy

Re: Rocker arms hold down kit and side play - 12/23/12 05:47 PM

Yours are probably pretty close out of the box and may only need a small amount of shims to get it right.You can eyeball it to get it as close as you can.I am concerned about one thing in your original post though

Did I read it right that the clearance changes when you tighten the hold downs? That is something you need to address before you go any further

If it's not too late I would exchange the MP units for the Hugh's hold down kit with studs

With aluminum heads rocker shaft studs are a better option.
Gus

Posted By: Stanton

Re: Rocker arms hold down kit and side play - 12/23/12 07:29 PM

Ok, now I understand why the .120 shims are there ... they ensure you don't run the rocker against the holddown which will wreck one or the other or both!

Hughes rockers ... no holes for valvespring oiling !!!

Quote:

If it's not too late I would exchange the MP units for the Hugh's hold down kit with studs With aluminum heads rocker shaft studs are a better option.

Those holddowns are junk for any decent head combo. They're pretty but they're also soft aluminum which will not hold up very well with a big cam and stiff springs. The Hughes steel holddowns are cheap insurance. Likewise, you want studs (the right ones for your heads - from ARP)

Quote:

Did I read it right that the clearance changes when you tighten the hold downs?

Probably due to the aluminum holddowns.

Posted By: BSB67

Re: Rocker arms hold down kit and side play - 12/23/12 08:00 PM

There is nothing wrong with the aluminum hold downs, unless there is some QA/QC issue specifically. The side load is so minimal with the BB valve train its a non issue, just put a shim between it and the rocker. The reason it changes with tightening is due to the clearance hole in the hold down, just like all manufacturese hold downs. It is not a function of the material.

Posted By: Coke

Re: Rocker arms hold down kit and side play - 12/23/12 10:06 PM

I think that i didn,t explain it very well
I did mean that it changes depending how you tight the hold down because it can be moved side by side BEFORE to thight them,so you can vary the side play a lot.

About the studs,i have been checking the Hughes page and they seem to be similar to the valve train parts that my old 906 heads had.

[image]

[/image]

Using the hughes rockers i would need something to keep the distance between these and the studs.

Posted By: ahy

Re: Rocker arms hold down kit and side play - 12/23/12 11:39 PM

I'll just add to all the good suggestions... it may be necessary to mill a little off the sides of the hold downs to get things lined up and clearance right. That's what I had to do with mine... then use shims to get everything dialed in.

Posted By: fourgearsavoy

Re: Rocker arms hold down kit and side play - 12/24/12 12:35 AM

Quote:

I think that i didn,t explain it very well
I did mean that it changes depending how you tight the hold down because it can be moved side by side BEFORE to thight them,so you can vary the side play a lot.

About the studs,i have been checking the Hughes page and they seem to be similar to the valve train parts that my old 906 heads had.

[image][/image]

Using the hughes rockers i would need something to keep the distance between these and the studs.

This is the set I used

Gus

http://www.hughesengines.com/Tools/Popup...itle=HUG%207442

Posted By: BSB67

Re: Rocker arms hold down kit and side play - 12/24/12 01:37 AM

I do like those old Isky rockers. Do you have the ones with the hardened pad insert at the valve? They are wider toward the pedestal than all of the other rockers that I have used, requiring more work to get them aligned with the valve tip. Usually have to grind the hold downs. Uusally you need to completely remove the tabs on the factory hold downs. Then a clean up the pedestal too.

Posted By: fourgearsavoy

Re: Rocker arms hold down kit and side play - 12/24/12 04:18 AM

Yeah I scored a set of early 70's hardened pad rockers in a trade for some tranny work I done

I sent them to RAS to correct them and have new bushings and hardware.I got them back and still had to have them machined even more.Good thing I got them for next to nothing because I have about 5 bills in them with the holddowns and shafts

If I was doing it over again I would go with the HS rockers from Mancini with the bushings instead of the rollers

Gus