shimming rocker shafts

[turbo buicks]

if i shave .010 amount off the head and use a half of the stock thickness head gasket should i add those 2 numbers up and shim the rocker shaft with that much thickness of shims? where can i get rocker shaft shims? what im thinking is for example, if i get my heads milled .010 and use a steel shim head gasket thats say .030 thinner than stock should i get .040 shims to raise the rocker shaft up so i dont have to get adjustable pushrods? anyone follow what im saying? i think i heard steve wood talking about this before.

 

[blackbuick87]

Yeah, you may need a shim, but the proper way to do it is to measure the preload on the lifters, not by adding up the amounts of clearance you have removed.

Unfortunately I cant remember how much preload is required, hopefully someone will bail me out

 

[turbo buicks]

hmmm, how do you set preload? i know Reds been tellin me he has stock pushrods so i know you can use them but im not sure if he milled his heads or not. id like to set it all up correctly if possible.

 

[blackbuick87]

What HG did you use? Red has a single steel. I used double steels so I wouldnt have to worry about it.

You have to remember that Red takes his motor apart a little more often than you want to, so he is not as concerned with longevity either (I am talking 1000's of miles)

 

[turbo buicks]

i am planning on using one steel HG. last i talked to him he just blew the HG the other week but only after seeing repeated 6XX O2 mv blasts. how often does he take it apart? you asked him?

 

[blackbuick87]

http://www.turbobuick.com/forums/showthread.php?s=&threadid=69304&highlight=lifter+preload

All I am saying is Red has a mid-low 10sec ride. Anyone with a car like that will have the valve covers off a lot more often than a mid 11sec ride. Also I doubt he puts 10000 miles a year on it, though I could be mistaken. Steve Wood uses a single steel also, I believe because he likes the bump in compression, and the simplicity of a single vs. double. The bad thing is, as you have discovered, is setting the rockers is now a PIA and you may or may not have to have the intake milled to match up the bolt holes.

 

[turbo buicks]

ya i read on the other board that Steve Wood has had his heads milled 3 times and uses a single steel shim HG and has had no problems and it has better throttle response and spool up and max boost level isnt affected. Red told me his car has the off idle response of a V8 and he said a DS run he did showed that when he puched it from a 24 MPH roll it hit redline in one second, with a 70 series turbo thats awesome. thanks for the help blackbuick87, anyone else have any luck with shimming rocker shafts? ill talk to Red later and see what he says. luckily i am not in the middle of this now but im planning on porting the heads and doing a cam very soon and would like to take advantage of the most stuff i can.

 

[Steve Wood]

It is a standard Lawrence Conley trick...nothing I invented.

Ford used to sell rocker arm shims. I don't recall what the part number is.

As stated, you should measure the preload and use an average shim that keeps you in the desired range.

Seems like gnttype.org had an article on measuring preload?

 

[turbo buicks]

yes they do

http://www.gnttype.org/techarea/engine/pushrod.html

what size shims would you recommend when using 204-214 speedpro cam and a single steel shim HG and heads only milled to flatness?

 

[turbo buicks]

steve do you run your rocker shaft shimmed all the time?

 

[Steve Wood]

I would measure the preload and go with a shim that matches the average.

I think a single shim is around .019 which is about half the standard gasket compressed.

 

[Steve Wood]

I meant a single shim head gasket.....

 

[turbo buicks]

so Steve, do you run shimmed rocker shafts on your car or not? i read the lifter preload article and it recommended against this but didnt say why. i know sometimes rumors go around that you shouldnt do something b/c one guy had problems and then all of a sudden it becomes the norm to think this way i.e. split duration cams then when someone then actually tries it (Red and the 204-214 cam) it works great.

 

[Steve Wood]

yes, I run shimmed rocker shafts to restore the geometry. It's either that or determine the correct pushrod length and order custom or adjustable push rods.

As I said, it is an LC technique.. . and the way he normally does it.

 

[turbo buicks]

thanks

 

[JDEstill]

My PAW catalog has this kit which I believe is what you want:

CRA-99170-1 $7.95
Crane Cams Rocker Arm Pedestal Shim Kit for Ford V8
This shim kit is for Ford engines utilizing non-adjusting pedestal mounted rocker arms. Kit contains two thicknesses of shims to be placed between pedestal and cylinder head. Shim reduces preload by approximately 0.030, 0.060, 0.090.
Fits Ford 255thru 302, 351W, 351C, 351M-400, 429-460.

I called Conleys once looking for shims, and they said they got theirs from a local Ford place.

John

 

[Chris McDade]

I have Ford shims on my T&D rollers and it works good.

I hate to admit that I have a Ford product on my car, but if it works

 

[turbo buicks]

thanks chris and John

 

[texasturbo]

If whomever is using stock heads and stock valve train components. .030 to .035 lifter preload should be ideal. Typically anything less will likely make noise after the engine and oil are hot. Melling offers .030 and .060 longer pushrods to compensate for deck height and head cut variances. I believe the part number for the .030 longer push rod was MPR-187 but double check. I cannot remember what the .060 longer number was. hope this helps...

 

[turbo buicks]

Crane and Ford Racing both make rocker shaft shims and are available from Summit for $8.95 and $9.95, respectively.