TheSamba.com :: View topic - CB 1.25:1 rockers going in...push rod length?

Tue Feb 18, 2014 5:26 pm

Hey Sambites
Finally going to put my hi ratio lifters ( http://www.cbperformance.com/ProductDetails.asp?ProductCode=1685 ) in.
I know from the last try that the stock push rods are too long. Anyone know how much to shorten to use these?
I know about setting up with an adjustable but dont have one and dont want to pay shipping twice (once for the tool and again for the pushrods). Also, could order all my stuff now before I get the engine totally back together.
Going into stock 041 heads, 85.5 cyls, Engle 100 cam.
Current rods are 11.063 tip to tip.
If you need anymore info, I'm all ears.
Just hate to spend all the time and money if someone out there knows....if I have to I will but would be nice :)

Tue Feb 18, 2014 5:39 pm

Sorry, but you really should get an adjustable pushrod and set your geometry correctly. Many have successfully bolted 1.25s on with a spacer under the rocker block, but it's not always ideal, and there is argument as to how thick the spacer should be. Theoretically a spacer of half the increase in lift (new ratio - old ratio times cam lift, then divide by 2) should get you back where you were, but how sure can you be that it was perfect to start with?

Tue Feb 18, 2014 5:40 pm

VW style 1.25 rockers usually require rockers shimmed up .060-.080 and pushrods approx .040-.060 longer due to the swivel adjusters.

Tue Feb 18, 2014 6:39 pm

That's been my experience with them. .060 shims under the rocker assembly where they bolt to the heads. Also you may need to take your new ratio rockers to the grinder (grinding them opposite side from where the adjustment nut seats on the rocker) too to get the added adjustment you may need on one or two of the adjusters. I would just run the stock pushrods. Don't try to shorten them. But. You will need large ID push rod tubes too. Else the push rods hit the tubes and you will be moping up oil on your garage floor from under the car in about 6000 miles. The push rods will get worn like these in the picture where they will hit on the stock pushrod tubes.
Buy the CB-Performance 1565 Racing push rod tubes or the 1557 stainless steel version.
Installing New Large ID Racing PushRod Tubes. Looks like two sets of the .060" shims are included in the kit you show in your post. If you run these with the stock push rod tubes they tend to hit the top of the tubes near the head end.

Tue Feb 18, 2014 6:52 pm

My bet is you will come in around 10.56-65" with lash caps ..... but that is only a guess(based on the rocker adjuster being on the Pushrod side) No shims under rocker..

Tue Feb 18, 2014 8:10 pm

thanks all,
for the oversize push rod tubes, do they need the holes in the heads and case opened? how are they bigger than stock if not?
The rods that came out already had those marks so who knows what to expect with the ratio's in!
I have new vw tubes but in looking in thel I see the 'accordian' reducing the ID, that I take it is wear they hit...

Tue Feb 18, 2014 8:44 pm

The holes in the case and in the heads do not need to be enlarged. The tube is just bigger at the head end. No Bellows on the head end.
There is not that much to installing ratio rockers! You will want to get the side to side valve geometry as uniform as you can using a extra set of rocker shaft shims to fine tune them keeping the side play on the rockers down to 1 or 2 thousandths of an inch. Sounds like your building the engine so the 1565 or 1567 pushrod tubes would work but if you already have the engine together your stuck using the others recommended on the CB-Performance link in your original post above. Be sure you have new silicone push-rod seals and a good quality high temp silicone grease to lubricate and seal them with. Be sure to stretch the bellows a little, about 3/8" of compression is needed for a good tight fit. Make sure the tubes install straight as they can get out of align at the bellows.

Tue Feb 18, 2014 9:12 pm

Thanks for that! Yes, building the motor up totally.
Will probably go with the scats that aircooled.net has. Want to get the motor going together and the heads down so will load the tubes and the final rods last.
This things like a puzzle, loving it!!

Tue Feb 18, 2014 10:24 pm

I used them about a yearago on a build,I dont recall the exzact shim size but I think I ened up using .015 or .030 under the rockers. but valve stem hight & other things can alter this. be sure to use the correct pushrod tubes.

Wed Feb 19, 2014 8:23 am

Is there a requirement to have to have shims under the rocker shaft blocks?
The motor was built in Mexico and I found four different round washers :shock: tucked away under them when i took the stock ones off.
I'm guessing and havent researched yet that they are as required to set the geometry?

Wed Feb 19, 2014 2:39 pm

No you don't need them at all if the engine will go together without them. But if you need them. I would get the correct shims as opposed to using washers.
Don't use any more shim than is necessary. If you were close without shims but not close enough I would just grind down the rockers a little so I did not need them. I think the Ideas is to have the adjusters fit but be close to being backed all the way off perhaps within 1 turn when the valves are properly adjusted. That little rectangular piece here is them: http://www.cbperformance.com/ProductDetails.asp?ProductCode=1685

Wed Feb 19, 2014 3:25 pm

If your pushrods were rubbing with stock rockers and there were washers under the blocks my guess is that your geometry was never set up correctly to begin with. Do it the right way and set your geometry, using dodgy pushrod tubes and such is just putting off pay-day. With that cam and 1.25s you should at most need to flare the top edge of the pushrod tube, or something is out.

Wed Feb 19, 2014 3:53 pm

A lot of stuff on the Samba about push Rod geometry, You will find diagrams showing just how to set them on links like this push rod length ???, But the heads and the valve job may be beyond your control, and so is the up/down position (yeah you can add a pile of shims but that's no good) Side to side is about all you can actually set up. The swivel ball tappets or the elephant feet tappets will do more to mask valve mis-alignment than you will be able to do with block shims. Now the side to side rocker shaft shims, you can set them pretty much right where you want. I set mine just off to the left of center. They need to be a pretty tight fit on solid shaft assemblies. Not more than 1 or 2 thousandths play Side to Side installed. The rocker shaft studs are fixed. so your a little limited so it is nice if your have a few extra blocks and rockers to match things up nice. This is do-able with 1.1:1 Ratio Stock VW rockers. One reason I like them over the 1.25:1, No real reason to run the 1.25:1 Ratio rockers if your going to have the engine apart and can put any cam you want to run in it. Remember the extra .15 of ratio will multiply times the weight of the valve train as well as increase the pressure on the cam due to valve spring pressure and valve lift. Better to just run stock rockers if your doing the engine ground up.

Wed Feb 19, 2014 6:37 pm

you dont need any shims if it dosent need any,if it needs them use the ones it needs.the only way to know is to check to see what it needs or dosent need.then the pushrod length can be figured easyer.but they kinda both need to be figured at the same time.different rockers can set up diferent. and also be set up the same,many factors can change things ,as do ideas of just what is right. I dont use the half lift method,but it works,but so does my way...so... witch is better????my way of corse. and then comes the ratio's that cant all be set up the same way...sometimes.I like the rocker to be as low as possiable,but some ratios cant do that.the 1.1 rocker cant be as low as a 1.25 can be run.and there is also what are you willing or capable to do end of the spectrum of things.or pretty much a bolt on type of person.and thats just fine if you get them right or even close to right witch can be +- a lot or very little.

Wed Feb 19, 2014 8:46 pm

The higher the stem height and the more the lift the less shims will be needed.
VW heads don't have tightly controlled tolerances in this respect so a guess is only a guess, but if it's really far off from normal then maybe you need to re-examine the whole thing. The kit comes with shims because generally they are needed..........not just to be lazy and let you re-use your pushrods. :lol:

Sat Mar 01, 2014 11:43 am

Rockers are in.
Measured the full lift at .460.
Starting height - 1.638 / full compressed 1.178 = 0.460
That sets the half lift at 1.408 (1.178+(.460/2)) (measured from retainer to head in line with the valve stem)
Added .080 shims under the blocks. Haven't measured the pushrod yet (adjustable)
In the video the pause is at the half lift measurement
From my understanding the geometery should have the force vector directly down the stem at half lift.
Video attached, I think I'm pretty close but would love some experienced feedback if I'm on the right track!

Sat Mar 01, 2014 12:12 pm

Here is a quick visual way. Take a head stud or an all thread rod and couple it with the adjuster via a brass intake nut. At half lift you want that joker to be in line with the valve stem. A magnetic telescopic retrieve tool on the valve retainer will help visualize this even more. In this pic my adjusters are on the PR side, but you get the idea.

Sat Mar 01, 2014 12:17 pm

Thanks MURZI
Just checked it that way and it looks lined up, it made sense to me that way so I appreciate the validation!