just fitted new heads on a 2 litre 'CV' case engine. Push rods are now too short, they are 270 mm. I expect it was originally hydraulic lifters and converted to solid lifters at some stage.
Has anyone got a link to a guide on determining new push rod length, or is there another typical rod length apart from 270 mm?
thanks.
From memory, standard 2 ltr hydraulic lifter pushrod motors have a length of 260 mm, make your self an adjustable pushrod to work out what length you need, then pursue them. check out the net for setting up valve geometry & you should be okay, cheers Frank ps, to make an adjustable rod, just cut one in half, tap both inner ends, screw in a 25 mm long metal thread in between both ends, a pair of locking nuts wouldn't go astray. If you have a non injected engine, study the right hand carb adjustable linkage, same princible, cheers Frank
Adventure Before Dimentia
thanks.
anyone know of a good website to set up the correct pushrod length?
The length I will need will be longer than 270mm.... does this sound right?
Anyone in Australia selling type 4 pushrod kits that can be cut to length?
try richard or one of the others that specialise in type 4. maybe 66deluxe?
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I am just wondering why the need for longer pushrods, have you changed the rocker ratio or installed thick spacers between cylinder & heads. My original response was to help you determine the actual length required for your engine. Once the length is attained, its not a simple proceedure to just "cut & shorten" some extra long pushrods. you need a buddy with a lathe to cut the rods, then cut an inner recess so that the pushrod end cap fully bottoms out on the rod, then you dont just hit the cap on with a hammer, you need to fabricate a holding fixture for the pushrod that is placed very close to the receiving end of the rod, (this is to prevent bending the rod) you then place the assembly in a press, place the pushrod end cap onto the rod, use a piece of copper between end cap & press ( so as to not damage end cap) slowly press cap until fully bottomed out. When you do the second one, reposition the copper so that a fresh contact surface is used. If you say that the motor has now a solid cam, you might need to check to see if there is a difference in rocker ratios between solid & hydraulic camshafts and the job might be as simple as replacing your rockers with a suitable set and not stuffing around with modifying pushrods. hope I have been of some help, good luck cheers Frank
Adventure Before Dimentia
I am also wondering why the need for longer push rods. As I havent done anything other than replace the heads with new AMC heads.
Looks like I need to do a comparison with some calipers and verniers etc.
solved.
Found that the AMC heads are slightly different to stock. The valves sit lower in the head by about 3 mm. Which means the stock pushrod, rocker arm and adjuster are on the end of their adjustment to catch the top of the valve.
So thats a problem that is encountered by everyone who uses AMC type 4 heads.
Added to that, the previous rebuilder had machined the faces of the solid lifters to square them off, and had shortened them by 3mm.
Damn !
Anyway, we are back on track now. Just got a heap of top-end rebuild bits from European Motor Works and Jake Raby's Type 4 Shop and we can see what we should be doing with it all.
Got a 1.8 litre naturally aspirated with DTM, and a 2.0 litre (ex vanagon) with DTM, CSP Python, CB performance EFI stuff ready to fire up. This weekend could be interesting.
Correction. I realise now that its probably not possible to machine hardened steel once its been hardened. But the lifter is shorter from face to pushrod cup by several mm. Doesnt help the problem.
