Reed Jensen

Under ideal conditions it really doesn't matter where the oil hole is if there is enough pressure to create a film the cam runs on... I'll post a picture of a BBC cam bearing that didn't have enough oil flow... oh... by the way.... when I showed the damaged cam bearing to the builder... he said " that's normal"..

Reed Jensen

Here is another view of the cam bearing where the bearing material melted into the oil hole... nice.....

Strip Poker 388

Thats a hole lot of spring.

I like the Crower vasco's run them in the race cars,I just had to make sure ya had some temp in them Broke some inners in the begining.

Strip Poker 388

You must be talking about your buddy Teague

44MTI

What kind of life are you getting out of your springs and lifters and have you had any problems with either.
Just curios since I ran a .774 last yr, but very few hrs.
Thanks Michae.

jdnca1

I ran a comp 948 spring (~340 seat, ~1000 open) on old motor with .772" lift...soft lobe cam...first set of lifters lived 45hrs, springs were ready for change then also. Next cam was ~.785" lift, but with aggressive ramps...broke a lifter @6hrs...so the ramp speeds really affect things. My personal advise is to keep lift around .730" or less and use soft ramps...but there are lots of variables.

Reed Jensen

I'm not about to mention names... but I'll post his picture....

Dave_N

Maybe I'm missing something, but why not just use an igniton system that uses a crank sensor to achive precise ignition timing? Or it is cam timing that the builder is concerned about?

Dave

Reed Jensen

The part you are missing is "bragging rights".... My motor's got a gear drive for the cam.!... Gears are expensive to manufacture, noisy, and not as efficient. There is a HP loss through the gears. The force on the cam is linear through the chain. The only problem is there isn't a tensioner and the cam timing fluctuates through the slack in the chain. High dollar roller chains are better, but if you have line honed the block excessively the chain is loose. Then you need a special gear set to take up the slack. The fluctuation in the cam timing is the result of stored energy in the valve springs being returned to the camshaft on the back side of the cam lobes. Gear drives eliminate the fluctuation in cam timing but the engines weren't designed for gear drives so an "idler" gear set is place between the cam and crank to maintain correct cam rotation. These are generally "straight cut" gears and are noisy. Most people don't know that when straight cut gears engage and disengage, the driven gear slightly accelerates and decellerates. This causes problems if it hits a particular harmonic resonance. That is why people avoid using them in engines that run for long times at one RPM, such as boat with the throttle set in one position while cruising, or a car on a flat highway. That is the reason most engine builders don't bother with gear drives for their camshafts. They are either a gilmer cogged tooth belt or a chain, overhead cams or otherwise. Years ago when automakers used gears for cams on engines they were helical cut. That takes out the vibration problems. The last engine I knew of that had gears for cams was in the early 50's with Ford's flathead engines. There were several Italian motorcycle builders that steered away from chains or belts in the 70's. One was MV Agusta. Their engines had a stack of gears running up through the case between the #2 and #3 cylinders to drive the cams. The other was Ducati. Ducati had shafts with helical cut bevel gears for the cams. Both were inefficient and have since been scrapped by both companies in favor of belts.

nocigarette

This is not the reason at all........if i was going with a junk pete jackson maybe................