just hoping some one can shed some light on rocker questions
to fill you in i have just done head rebuild on a stock 1500
new guides, valves and cut valve seats.
i also got some new CB swivel feet adjusting screws.
Q1: is it nomal to have to shim rocker gear up by 3.5mm
( more shim than supplied)
Q2: i am aslo worried that the adjusting screws will hit rocker cover. i put the rocker cover on with out a gasket and the screws touch, with a gasket they dont touch.
this is my first aircooled rebuild all the angles look ok but very close to rocker cover which can be solved with a good ball pein hammer.
update
just been in the garage thinking and looking and noticed that i could remove (grind or file ) 1 to 2 mm off the under side of the rocker where the adjusting screw hole is and remove some off the shim
any thoughts?
1970 bug /1500 stock as a rock.
1976 standard bug ready to be modified 😁😁😁😁😁
If you use the swivle feet and shim up the rocker posts the rocker arm geometry will be out , i have had to use longer pushrods to over come this problem, using a dial indicator to get half the valve lift, at this point the centre line of the adjusting screw should be inline with the centre line of the valve stem, this will allow the rocker to operate half it lift either side of the centre line, i never had a problem with the rocker's hitting the tappet cover but if you want to check how close the rocker are to the tappet cover you can use some modeling clay inside the tappet cover to see what clearance you have, a good reference book is " hot to hot rod volkswagen engine's " it is a old book but full of usefull imformation that is still relevent today.
Your onto it, you need to grind off upto 2mm from the bottom of the rocker to fit the adjusters correctly. Check also the depth of the oiling hole to line up with the oil passage in the arm. For the correct shim pack height, you need to set the rocker shaft height to get the adjusting screw in perfect alignment (in a straight line) with the valve 'at half lift'.
Use a dial indicator to easily measure half lift with a tempory adjustable pushrod installed.
This pic shows inlet valve at half lift with rocker gear shimmed.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
Sounds like I'm getting the hang of this air-cooled thing improve my angles and romover 0.75mm of shim just buy matching rocker and push rods combinations, there does seem to be a bit of variance between each rocker and also each push rod. Do expect to have little discrepancy
As the valve ends are not exactly the same hight. I will qgrind rockers tomorrow and check the half lift position I dqont think it will be to far out.
Thanks it always good to have a little guidance
1970 bug /1500 stock as a rock.
1976 standard bug ready to be modified 😁😁😁😁😁
The height of the valve stem tips should be all the same height, this way you avoid the problem of them having different rocker geometry for each valve,
When getting your valve stem tips to the same hight do you surface grind the long ones or cut the valve seats on the low ones.
1970 bug /1500 stock as a rock.
1976 standard bug ready to be modified 😁😁😁😁😁
Pushrod length is custom for your engine, as variations occur in every engine, depending on crankshaft stroke, cylinder deck height, head cc's and compression ratio.
To get stem heights equal, this is done after valve seats are cut, then the longer stems are trimmed untill all equal length.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE
Great read cheers
Been playing around with rockers today and this is what I have come up with please let my know if I have it all wrong.
I found that 2mm shim under rocker stands is the max I want to go to.it should get the centre of ajusting screw centre with the valve stem at between 1/2 to 3/4 opening. So I set up the rockers with out the adjusting screws and measured the gap between stem tip and rocker ad found for eg that it was 7.5mm and the head of the swivel adjusting screw measured 8mm so there for if I take 1mm of the rocker it should all work.
So then I figured that if I get an old adjusting screw, screwed it in and stop it 1mm from were it stick out and start grinding until I hit the screw I should be close to the mark.
1970 bug /1500 stock as a rock.
1976 standard bug ready to be modified 😁😁😁😁😁
Thinker wrote:just hoping some one can shed some light on rocker questions
to fill you in i have just done head rebuild on a stock 1500
new guides, valves and cut valve seats.
i also got some new CB swivel feet adjusting screws.
Q1: is it nomal to have to shim rocker gear up by 3.5mm
( more shim than supplied)
Q2: i am aslo worried that the adjusting screws will hit rocker cover. i put the rocker cover on with out a gasket and the screws touch, with a gasket they dont touch.
this is my first aircooled rebuild all the angles look ok but very close to rocker cover which can be solved with a good ball pein hammer.
update
just been in the garage thinking and looking and noticed that i could remove (grind or file ) 1 to 2 mm off the under side of the rocker where the adjusting screw hole is and remove some off the shim
any thoughts?
YIKES
You guys... I do know that
You can buy high clearance alloy rocker covers
I have those.... on My beetle
You need the alloy covers and new spring bales to fit...
Lee
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---
