Excess oiling in the rocker shaft/rocker arms 1500 BLMC

On 948 "A" series, original OEM rockers were positioned with springs and washers, which almost, kinda, somewhat positioned the rockers over the valve stems. Most roller rocker set-ups come with metallic spacers between rocker/rocker or rocker/pedestal. These spacers almost always have to be resized to center the rocker over the valve stem. Distance is made up with hardened machine bushing-like shim washers, a Torrington product.

I always assembled the shaft assembly with a shim washer on each side of each rocker with .001"-.002"" end play of each rocker. These shim washers act as a retainer for the oil pressure. Without some form of containment, oil can just run out.

A PIA as the spacers usually different head-to-head.

RJS
 
Ron Bartell":m3sy1xxh said:
Bob - I believe that you are providing some interesting entertainment for anyone who has actually raced these engines for years. A couple of points though: 1) Tough to do any math when you don't provide the top speeds for those portions of the track. 2) 8,400 to 8,800 is different from 10,000. 3) I noticed that you were running a 1275 at the Sebring race, not the 948. Do you actually run the 948's or just talk about them? (just kidding)
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Ron... Would be running the 948s (since '90) when you were at Sebring in Jan if we hadn't had a close encounter with the aforementioned wall under the bridge. The car at Sebring was our GP Solo car with a 3:90 rear and a radio in it. Also, if you get much more than 8,800 out a 948 with a 1:1 gear you have really eclipsed reality. With a 1.8 first gear you can get anything into the stratosphere... same with a 1.3 or 1.4 second. If I could run 9,500 in forth gear (1.1) I'd get the hell out of production and run in GT2. As for providing entertainment... don't have time for it.

Bob

PS from Jon Stamps: Depending on the wind and staying off the banking at Daytona rpm range in above mentioned car and setup was 9,200 to 9,500 in 1.1 forth gear with 4.55 rear.
 
Bob Hess":20revtu7 said:
Ron... Would be running the 948s (since '90) when you were at Sebring in Jan if we hadn't had a close encounter with the aforementioned wall under the bridge. The car at Sebring was our GP Solo car with a 3:90 rear and a radio in it. Also, if you get much more than 8,800 out a 948 with a 1:1 gear you have really eclipsed reality. With a 1.8 first gear you can get anything into the stratosphere... same with a 1.3 or 1.4 second. If I could run 9,500 in forth gear (1.1) I'd get the hell out of production and run in GT2. As for providing entertainment... don't have time for it.

Bob

PS from Jon Stamps: Depending on the wind and staying off the banking at Daytona rpm range in above mentioned car and setup was 9,200 to 9,500 in 1.1 forth gear with 4.55 rear.
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Running a 4.55 rear at Daytona kinda says it all as far as telling me who I am dealing with. Look, the motor doesn't make any power up there, why anyone would rev it out to that rpm, or purposely gear it that way is beyond me. Let me know when you break the motor and I promise I won't tell you I told you so. I'm just trying to give you the benefit of some experience, but some people can't be helped.
 
I forgot to mention: if memory serves me correct, rocker shaft is not under full pressure all the time, instead, pulsed every revolution of the cam via the notch in the front cam bearing connecting the journal center groove to the oil passage to the head. This makes it more of a drip oil system instead of a full pressure system. Not ideal for needle bearings. Mores the necessity to contain the oil in the rocker arms.

RJS
 
Bob Hess,

+1 on Bartell's comment. All you need to do to prove his advice to you is to write a simple Excel macro that calculates rear wheel thrust vs. mph and upshift whenever the rear thrust is higher. On my 948 (which was by the way probably the #2 948 EVER built, 102 corrected HP, Comptune small port head ( rooted through 50 castings to find the best short turn radiuses) , carillo rods, moldex crank, HL9B cam, offset cylinder head dowels (that one's a secret), crank trigger, valve spring oilers, dry sump with big sump vacuum, the right ringset and bore preparation, coatings, 16:1 CR (no BS)......the best of everything..........I NEVER ran it above around 8000 since that's where it began to fall flat on its face with lousy torque.

That being said.......my 948 would easily "pull" to 9500.......just didn't make any performancesense sense to do so.

Ron is right........running a 948 at super high rpms just shows you haven't done the homework. Sorry to be so direct but you'd be better off to gear it so that fastest track rpm is closer to 8000, not 9500.

But.........what the hell do I know?? I'm just a dumb mechanical engineer who raced a 948 for 30 years.
 
Ron and Jay... First off, I didn't build these engines. Jon Stamps Racing, Comptune (Dave Taber), and Harland Sharp designed and built these engines... and quite a few before that. The two I have with Jon's car were built in '99. I bought the car with both engines needing rebuild (rings, bearings, guides etc.) and have been running them a minimum of 5 to 6 times a year since Feb, 2004. I've rebuilt each 3 times and all of the original parts are still in them. Had to do valve seats on one head and sleeves on one of the blocks. Nothing else except the usual magnaflux etc. Now you guys come up and say some of the great innovators in SCCA racing history couldn't find their ass with both hands with a GPS. Jon got a podium finish at the runoffs with one of these and a huge amount of 1st place finishes wherever he raced. I've had great luck with the car and still run right behind the Hondas at every event. Any of you doing any better with a 948 against the Hondas etc.? As for me being misdirected, misinformed or whatever you'd like to label me and my skills, I've been building engines since I was 13 and 948s since early '90 when I rebuilt one of Huffaker Senior's engine that was in my first H Bugeye. Learned a lot about the engines then and even more after getting Jon's stuff in '03. Don't have the equipment to build Stamps level engines but my 15.1, 8,500 rpm max engines have proven to be stout and fast. That said, if you don't agree with 9,500 rpm engines and want to get vocal about it, drag your 948 Spridget down here and let's see how they match up. One thing, though... don't blow it up 'cause I won't let you forget that one! Other than that, I thought all this stuff was supposed to be for fun...

Bob
 
Bottom line,

If you get your own data, understand why something works or doesn't, don't rely AT ALL on what other people tell you or claim no matter who they are...........you'll be miles ahead of your competition.

Steve Sargis is probably the club racer's ultimate example of this philosophy in practice.
 
Ron Bartell":3m2tzb3f said:
Bob Hess":3m2tzb3f said:
Ron... Would be running the 948s (since '90) when you were at Sebring in Jan if we hadn't had a close encounter with the aforementioned wall under the bridge. The car at Sebring was our GP Solo car with a 3:90 rear and a radio in it. Also, if you get much more than 8,800 out a 948 with a 1:1 gear you have really eclipsed reality. With a 1.8 first gear you can get anything into the stratosphere... same with a 1.3 or 1.4 second. If I could run 9,500 in forth gear (1.1) I'd get the hell out of production and run in GT2. As for providing entertainment... don't have time for it.

Bob

PS from Jon Stamps: Depending on the wind and staying off the banking at Daytona rpm range in above mentioned car and setup was 9,200 to 9,500 in 1.1 forth gear with 4.55 rear.
Click to expand...
Running a 4.55 rear at Daytona kinda says it all as far as telling me who I am dealing with. Look, the motor doesn't make any power up there, why anyone would rev it out to that rpm, or purposely gear it that way is beyond me. Let me know when you break the motor and I promise I won't tell you I told you so. I'm just trying to give you the benefit of some experience, but some people can't be helped.
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Ron... Who you are dealing with is a 948 driver with engines that dyno tested 98 HP at 9,500 RPM. No power up there...?
Can always be helped... when I need it.

Bob
 
WOW !!!! a simple question turns into a pissing match between posters on this board, have not been here in a while and it seems like nothing has changed..... got the trickest of the of the 948's built in the country by one Steve Ellis and we are putting out 98.25 hp/70 lbs. of torque @ 7500 rpms ( dyno sheets as proof ), and there is some left on the table, probably one of a kind custom built exhaust and ground cam to the exhaust, pulls like a tractor out of the corners, don't know what it will above 8 K, no reason to go there and THIS is a top shelf 948 but alas, no longer competetive in H, why do you think none of us down here in Texas race LBC's anymore ?
 
What's a 948???? I heard people mention them, but they are kinda like bigfoot right, reported sightings, but no actual proof of their existence :mrgreen:

However if one spots one, I do have a customer looking for a billet crank, and Carrillo rod set for one of these elusive creatures.
 
Jay Lutz":3mwyjja1 said:
I'll bet Don Feller still has some 948 stuff left over.
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Got a contact number I can give my customer, you can PM, or email if you like, Thanks Jay. I got customer who has real neat project going, he is building two FIA prepared vintage race Bugeyes, one is going to have a S/C, not the Jenson, or Moss unit, but a German S/C deal starts with a S. He's building them to FIA rules, but wants a little extra insurance as for rods, and crank. His plan is to vintage race them here for awhile, then import them back to the UK, where this sort of stuff brings bigger money.
 
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