Discussion in 'Mech Tech' started by Gnasha, Feb 25, 2019.
Scat just talk American. High rev = HD, in this instance.
I modify the rockers for swivel feet with a carbide countersink in a pedestal drill (rockers are hardened). But you’re entering into a world of rocker geometry, pedestal shims and custom length pushrods that I thought you wanted to avoid.
They are the same springs & retainers & followers I bought
I modified my rockers some time ago. I think it was Deefer66 who posted a good thread on modifying them on his type 4 build.
yes you're correct, i'd prefer to keep it simple, ive already allowed the scope to creep with 2056cc
Swivel foot adjusters are nice to have but they’re not essential; standard adjusters will work just fine with a C35 cam.
Would you say that swivel feet are kinder on the valve stem heads? And more forgiving if the geometry is not perfect.
They’re definitely kinder on the valve stems because the contact patch is much larger. More forgiving if the geometry is wrong – maybe.
My guess is most engines are running with less than perfect geometry, especially those ‘off the shelf’ refurbished engines, and they generally run for a reasonable length of time. But if the geometry is wrong wear will increase and efficiency will decrease.
Did your swivel feet come with shims included?
No they don’t. I cut the pedestal shims from 1mm thick steel.
After fitting the swivel feet you find you need pushrods of a different length, can you purchase these ready made or are they diy?
Are the swivel feet fitted directly over the valve stem? Or to one side to encourage rotation of the valve?
I’m sure you can buy pushrods already cut to length but I can’t remember from where, sorry. But it’s fairly easy to DIY; I’ve just cut and fitted these - https://www.csp-shop.com/en/engine/push-rods-alu-109-301-2950a-10984a.html
Fit the swivel foots off centre.
If your geometry is wrong the valve guides wear out faster.
They certainly will, and as I said up there my guess is there are a lot of engines running with less than perfect geometry. And of course the geometry is only perfect at one point in the lift.
So rebuild back in the bus. Built oil pressure nicely & fired up. Ran 2-3k for cam bedding in for 15mins no problem. Changed oil & filter & re checked valve clearance when cold.
Problem is i have is a very lumpy idle. It’s running on all cylinders but shaking as if its out of balance. Above about 1500 rpm it’s smooth.
I have taken wayoutwestie’s advice on carb set up as he is a guru with twin 34 ICT carbs.
I have fitted the better CB performance manifolds. Rejetted the carbs with his 2.0 recomended jet set up & fitted a balance pipe.
Although these changes have improved it slightly it’s still lumpy.
It sounds “chuggy” on idle.
I did balance the piston & rods to within 1-2g of each other and cc’d the cylinders so I don’t see why it should be unbalanced.
I have driven the van for a couple of 5 mile runs & she pulls ok with no flat spots.
Checked plugs after run & they were all a nice pale brown colour.
Thoughts please appreciated.
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