Rocker pedestal

[Gadgetman]

Having nearly rebuilt the spare Vitesse 1600 engine and in the last throws of assembly, I have a problem. 

When I put the rocker assembly onto the head I can’t get it down without compressing a valve when the cam is at max lift, even with the rocker adjuster wound right out!

a bit of history. The head has been skimmed  30 thou so 30 thou shims  have been put under the rocker pedestal to keep the geometry correct. 

A 2ltr 308778 can has been fitted but that only give 12 thou more lift than the standard one

The small diameter tappets have been bored out and the larger ones from Jigsaw fitted. 

now I have a 63 thou gap under the rocker pedestal when the pushrod touches the rocker and the rocker contacts the valve !

all I can think is that the jigsaw tappets are thicker and are lifting the push rods up too much. 

Were the 2 Ltd push rods shorter?

any ideas????

https://www.chriswitor.com/cw_technical/camshaft_applications.pdf

 

[Colin Lindsay]

It's hard to tell without being there, and I may be completely wrong - just thinking out loud here - but isn't one or more of the valves going to be compressed / open to some extent anyway - I don't know if you have that much adjustment that you can fit the rocker assembly with all valves closed, but I never found it on the GT6 - one or more was always open when I replaced the rocker assembly, even though I had slackened them off as far as they would go. I've never completely reset an engine to all closed and then adjusted from there, but then I did it my way, as the song says, and it's not always the proper method.

In the past I've broken a rocker because of an incorrectly seated push rod, but if you tighten up as is, do they all open and close normally as the cam rotates, or is there any resistance?

Canley's list two different push rods, the 1600 is 129058 and the 2000 is 151073 but a for differences, I'm not sure if it just means they're thicker rather than any longer.

[daverclasper]

From memory?, when I replaced shaft on Vit Mk1 2 Litre, it was same scenario as for Colin.

Dave  

[Gadgetman]

Thanks

guys good point well put. Yes two will always be opening so I guess this is normal! Thanks 

[Pete Lewis]

Its also possible  the larger cam followers need a shorter push rod ,  can you compare /measure the depth of the pushrod location to the  cam face on the two types

There are a number of length options on pushrods. 

Pete

[Gadgetman]

41 minutes ago, Pete Lewis said:

Its also possible  the larger cam followers need a shorter push rod ,  can you compare /measure the depth of the pushrod location to the  cam face on the two types

There are a number of length options on pushrods. 

Pete

Pete

id need to pull the head off again to swap them out. I’ll check tomorrow to make sure I can get the cold clearances. If I can then I guess its ok. 

I wasn’t expecting to have to compress the valves putting the rocker shaft on with the adjusters wound right out. 

[Pete Lewis]

1600 and mk1 2ltr have the same pushrod   so were the followers std  or specials? 

Have you changed the pedestals ??

And  yes  ,There is aways some valves need opening when clamping the shaft down ,and  probably enough to eliminate adjustment

Pull it down and turn it over to get the 'offender' on the back of the  lobe and check the  0.010" is achievable

Pete

 

 

[Anglefire]

I skimmed my head (About 0.75mm) to raise the CR to 9.5 and haven't lifted the pedestals to compensate - I can't see it making much difference to the geometry. Doesn't seem to have done anyway.

But have standard rockers on.

[Pete Lewis]

i reckon we took 3mm off the  Vit6  1600 head with no problems 

Pete

[Gadgetman]

All sorted, I was just too cautious winding down the rocker pedestals. 

All cold gaps set  and nearly finished the build...

on a Vitesse can you drop in the engine fully dressed, ie carbs on, generator fitted, gearbox fitted with starter attached?? Thanks 

[Pete Lewis]

Dont see why not do you have a tilt bar to change the angle   dont need much tilt , other than sump over xmember and gearbox 

Above its mount plate

Pete

[Colin Lindsay]

33 minutes ago, Gadgetman said:

All sorted, I was just too cautious winding down the rocker pedestals. 

No problem in being too cautious - it's the lack of caution that usually causes bother. Be like me, think out loud a lot in the forum, and you'll get the solution to whatever it is that's puzzling even if it turns out to be something really simple.

[Pete Lewis]

And often drift to something wildly away from the original quest

Keep,asking we all have to learn 

Pete