Schubeck Lifter Update

[Aubrey N Bruneau]

I won't be using Schubecks again. I got pretty lucky this time. It happened in the middle of 3rd gear, when the engine suddenly laid down and missed. I thought I had just punctured one more rocker arm, but I DID IMMEDIATELY drop it in neutral, to idle, and shut the engine off. Coasted a 1/4 mile to where my truck / trailer was parked, and rolled right up on the trailer ! ( VERY easy loading trailer ). Pulled the cover right there, and that's when I discovered the issue with the "loose rocker".

My engine had about 2 1/2 hours on it.
Cam.. scored a bit from the edges of the lifter, but otherwise OK ( Of course it gets changed )
Cylinders... a bit of scoring opposite thrust side. It'll hone out
Pistons... skirt coating didn't hurt. I measured... should be able to prep and re-coat. ( VERY loose ! )
Oil pump... un-marked
Crank... un-marked
Bearings... I'll be changing them
Heads... untouched

I do my own work, so I never figure the HORRIBLE job it is to R&R the engine ! ( first driveshaft at transmission, then scattershield and headers, then work on engine removal !... and the engine has to be out in order to remove the pan )

So... Complete disassembly, BIG wash job... and fix it faster !
Doubt it'll be running this season though. From now on, this thing gets no money, unless it comes from something else that I sell !


Mark, this is just my take on it...
Performance advantage of the Schubecks ?
Probably 1 horsepower ( reduced friction )
Really what they do, is tolerate the ridiculous ramps on Stocker-type flat tappet cams... which are the heart of the horsepower.
Probably worth 50+ horses.

Because of course due to the Stock rules, piston-to-valve clearance is at a minimum.
Mine measured .070" on the intake, .045"+ exhauast ( cam is retarded 4 deg ).
Pistons are "clean" in the area where the exh valve gets close, but no evidence of contact.
My rocker arm "puncturing was actually more prone to the intake... the ramp on the intake lobe is a little more aggressive ).


I still have never wiped out ( or even hurt ) a cam lobe, in any engine. ( knocking on my head right now ! )


My plan is to change to the products from Performance Research. IE, tool steel lifters, steel billet cam...
that's why no-rebuild anytime soon !

[Rich Biebel]

Advance the cam and you'd have a little more exhaust clearance. Yes you'd lose intake clearance but since your exhaust side is so tight, I'd move it.... What lobe was the lifter that broke exhaust or intake? I'm not saying it hit since you say there is no mark but I'd be more comfortable with a tighter intake side and most engines like the cam advanced. Shubeck lifters appear to have a real high failure rate and if they have a specific running clearance to the lifter bores......why isn't that info given to the buyer of the lifters!......The Nascar stuff looked like the way to go.......

[Hans Olsson]

Originally Posted by NHRAstocker409

Because of course due to the Stock rules, piston-to-valve clearance is at a minimum.
Mine measured .070" on the intake, .045"+ exhauast ( cam is retarded 4 deg ).
Pistons are "clean" in the area where the exh valve gets close, but no evidence of contact.
My rocker arm "puncturing was actually more prone to the intake... the ramp on the intake lobe is a little more aggressive ).

Aubrey,what method did you use when measuring the piston to valve clearance?

[Aubrey N Bruneau]

Yes Rich, I agree, more clearance at the exhaust would be desireable.
However, the engine seems to have responded VERY well to the "late" cam. Above 6000 is a different animal all together. Also, it's of course a stick car, and never sees below 3500 at any time during a run... and still has a terrible traction problem.

Hans, I check piston-to-valve by the "light spring" method. My "close" spot,is about 10- degrees before TDC on the exhaust valve.

oh yeah... it was an intake lifter... hot clearance had been set to .014" ( .016" hot by the cam card from Comp )

[Hans Olsson]

Originally Posted by NHRAstocker409

Yes Rich, I agree, more clearance at the exhaust would be desireable.
However, the engine seems to have responded VERY well to the "late" cam. Above 6000 is a different animal all together. Also, it's of course a stick car, and never sees below 3500 at any time during a run... and still has a terrible traction problem.

Hans, I check piston-to-valve by the "light spring" method. My "close" spot,is about 10- degrees before TDC on the exhaust valve.

oh yeah... it was an intake lifter... hot clearance had been set to .014" ( .016" hot by the cam card from Comp )

Thank you Aubrey.
What spring pressure do you use?
The "light spring" method shows the least amount of clearance does it not?

[Aubrey N Bruneau]

oh yes, spring pressure...
250-255 seat... around 470 open.

The valve clearance ?
just geometry... !
pre-assemble everything, and check the "lash" ( measure with a dial indicator, the distance you can push the valve to the piston, when the crank / cam is positioned near overlap ).
really, very easy to do. be sure to check in various postions.

[Hans Olsson]

My question was, does the "light spring" method give less clearance then the "clay and actual valve springs" method. Sorry for the confusion.

[Aubrey N Bruneau]

I don't like the "clay" method.
"less clearnce" ?
I suppose the light-spring method COULD possibly end up indicating .0015" less !

The spring method lets you actually "feel" what the parts are experiencing.

[John Lang]

Can anyone tell me the correct lash on Shubecks Hyd, 70 Ply RR 440. 6 Pak Got 34 passes and alls well. The reason i'm asking is i set them at .004 which i was told on this board, and i'm just wondering if that is close to right . John

[Fishlips]

I have never run the Schubeck lifters although I do have two sets in the garage for an upcomming Stocker project. What type of pushrods are you running and what is the possibility that the stock rockers and pushrods are flexing enough to allow the lifters to smack back down on the cam instead of following the ramp? Another thing, you mentioned. You thought you had punched another hole in a rocker arm. Was this lifter on one of the lobes where you had a rocker arm failure?

I have found on my super stocker (the hard way I might add) that if for any reason the rocker arm comes loose and the lash gets big, breaking a rocker arm or anything, then you must replace the lifter on that cylinder. It is going to break!! It may not happen that day or even that race, but within a few runs it is going to destroy the lifter!!!!!!! I have had this happen enough to realize it is a must to replace the lifter after it has run uncontrolled on the cam lobe. I believe the cam smacks the lifter and damages it.

Maybe you had previously damaged the lifter and after a while it fails.
Just a thought!
Good luck!!