Trivia and Tech

[Bill S.]

OK now a question that was asked at a car show and nobody could answer it. Just how does oil reach the rocker arm for lubrication in a solid lifter car? Normally the oil passes through the push rod in a hydralic lifter car. Seems to me the solid lifter cannot be truly "solid" -- does it have a passage to allow oil to travel up the push? Bill

[grr]

Re: Trivia and Tech

Two chevy solid lifters are offered,one looks like a hydraulic lifter and controls oil going out the top of the lifter with an internal flapper valve actuated by inertia. This is the most common mechanical GM lifter.Stockers.

The other type mechancial lifter controls oil moving out the top on the basis of clearance available between lifter and bore.This will reduce total oil circulation rate into the heads by as much as 10-20%(strickly for racing dry sumps).

If you have any SB or BB books such as the HP versions look up tappets and you can see the oil holes. Easy to see and understand than explain.The facts speak for themselves,solid lifters means quicker revs. and no floating valves. grr#33570

[Iron Duke NCRS #22045]

Mechanical lifter applications

The original "edge orifice" mechanical lifter (5231585) was used with the Duntov cam from '57 to '63. The introduction of the 30-30 cam in 1964 was accompanied by the new "piddle valve" lifter (5232695), and it effects an increase in overhead oiling. It was also used with the 30-30 cam in the '67 to '69 302 Z-28 engine. With the introduction of the LT-1 engine in the Corvette and Z-28 in 1970 Chevrolet reverted back the the "585" lifter with the new "LT-1" cam, which was a developement/modification of the 30-30. On rebuilds it is probably best to use the "585" with all SB mechanical cams and aftermarket grooved rocker balls. The "695" lifter was also used on all mechanical lifter BBs including HD (L-88), and this type of lifter should continue to be used on BB rebuilds.

Duke

[Jeph South]

Re: Mechanical lifter applications

Duke, Is there an easy way to identify the lifters? The intake is off of my 70 LT1, and the lifters look like hydraulics. Since there is no valve noise and the valves are adjusted to solid specs, I feel reasonably comfortable that they are solids, but would like to verify them if possible. Thanks in advance.

[Redondo Duke NCRS #22045]

Re: Mechanical lifter applications

There is a picture in my old Chevrolet Power Manuals. The "695" appears to be a two piece design with a visible snap ring, so it looks similar to a hydraulic. There is an oil entry hold on the unmachined area at the center of the lifter body.

The "585" edge orifice lifter is a once piece design with no snap ring and a metering hole on the upper machined circumference. According to the parts catalog a '70 LT-1 should use the "585". So either it is wrong or it sounds like someone changed the lifters at some point. For a street engine, either lifter is acceptable.

BTW, the parts catalog lists the "585" for use with the 30-30 cam in '64 to '65, but I think the OEM lifter with the 30-30 was the "695".

Duke

[Wayne M.]

Re: Mechanical lifter applications

Duke/Jeph --- In the '65 Shop Manual (section 6-4) there is an excellent x-sectional view of the "585" solid lifter. As Duke says, it doesn't have the round retaining (snap) spring for the push rod seat, but it DOES have a flat metal spring/ring which sits concave, to hold the seat in place, as viewed from the top. This is the ONLY solid lifter referenced in the '65 manual (pre-BB publication), so use of the "695" must have begun later. If the lifters are GM (and many aftermarket units are hard to differentiate), and if the hole is in the non-machined/recessed portion of the lifter body (ie a hydraulic or the "695") the hole in the hydraulic version is located just under the step down from the machined to the non-machined portion, whereas the hole in the solid (non-585 type) is about 3/5 down the non-machined surface from the step.

Duke, my 1971 copy of H to H BBC's says that the "695"s are the most common BBC (solid) lifter, also used in Z28 version of SBC; The "585" is found in SBs from '59 to '65, and also some of the lataer 302's. The "585" reduces top-side oil circulation by as much as 20%.

[motorman]

Re: Mechanical lifter applications

the edge orfice lifter was the only way to fly with 427s because the the piddle valve lifter let too much oil upstairs and would cause the oil pan to run dry. the oil drain back in the 427 was bad. drag racing would cause the oil pressure to drop as the sump was running low on oil by the end of the 1/4 mile. if you did not change the lifters you had to run a extra quart of oil. if you moly coat the rocker balls on a new start up there is no problem with scuffing. they are still available from speed pro if chevy does not have them. if you use roller rockers there is no sweat at all.