drill .040 hole in big block Chevy oil gallery plugs

[sirstude]

I was told to drill the oil gallery plugs under the timing cover for my Big Block Chevy to .040 on each to help oil the timing chain.  Has anyone else ever done this?  I am taking off the gear drive that I put on that motor for a good timing chain.  I don't feel like listing to the whine on that car.  Now would be the time to replace the drilled out gallery plugs that I have now.  Just kind of wondering.

This is the 454 in my Olds, not the 502.

Doug

[wayne petty]

i seem to recall... that was done..

most of the time. i would think that should have been done for a gear drive.. to get extra lube on the gears...

the oil squirts out around the front main bearing and around the front of the cam if you don't have some kind of retainer plate..   should be enough for most timing chains...

you might want to set up your cam degree wheel before taking the gear drive out.. verify where it came out at .. and where the timing chain is  going in at..  as you are more than likely going to end up with a 3 keyway crank sprocket.. or a 9 keyway crank sprocket...

there may also be offset bushings on the cam dowel pin that might fall into the pan..

just a few thoughts..
6
please.. be careful.. when doing this.. as i don't know what your cam lift or piston configuration is...    you might really want to take the time.. and pull all the pushrods... or at least the pushrods that at #1 TDC  are holding valves open..

lastly.. i know that you know this.. but on chevy.. when the cam gear dot is at the bottom.. the cam is set to fire #6 cylinder not number 1...


when the cam sprocket dot is at the top.. the cam is set to fire the number one cylinder...  this is the reason its so easy to get the distributer in  backward in a chevy...

if one really wanted to squirt the timing chain properly.. one might really think about how to either drill the galley plug holes at a slight angle. so it actually sprays the chain...   one would have to take into account the speed of the air moving around under the timing cover...


might have to clock the galley plugs like one does spark plugs...


or figure a way to make a fan spray out of the hole..  but that might make too much mist in the engine and cause oil consumption issues through the PCV system...

[sirstude]

Wayne,

Thanks for the info, I was told to do this when I first put the motor together, but the guy that told me has had more than a few motor failures since he said that.  He even got out to the motor business since.  I built this one, so know what is in there.  I have not fired it yet, so the valves have been backed off since.  This is the 3rd cam in it and still never fired.  Comp 260 with 8.2:1 compression.  The first cam ended up in my 395 (first engine in the Impala), then a Clay Smith blower cam, then this one when I decided to not hang a blower on this one.  I think I am going to put the original plugs (no hole) back in and then put back together.
It is a 3 keyway gear with the timing set.

Doug

[wayne petty]

i want to know more about what failed on his motors.... before you install yours...  sorry for the massive post...

it could have been as simple as somebody Dropped a micrometer and thru the calibration off....  

it could have been torque wrenches that were out of calibration...

it could have been dial bore gauge setting master with worn standards.. the 2", 3", 4", pins to make up for the difference between the dial board gauge and the setting micrometer spindle... there was one in a former shop that had deep divots in the ends of each one from the carbide balls rubbing from thousands of insertions...  the sunnen man said he had never seen one so worn..  the needle on the dial bore gauge would move 3 or 4 thou when you inserted it..   thats more than enough to create FAILURES...

just think of the things that get measured with the same dial bore gauge...    cylinder bores... main bearing bores.. main bearing ID when the caps and bearings are installed.. cam bearing bores...  sometimes rod big ends..

the torque wrenches in that shop.. were also way off in the assembly area...    10, 15 and 20 pounds light when i measured at 65 foot pounds...  yep.. turn it up to 65 foot pounds.. it only tightened to 45 foot pounds..

i would come in at 6 o clock monday morning and find them set to 110 foot pounds over the weekend..

things have wiped out motors as simple as not creating an area for the Radius on the underside of the rod bolt heads.. the radius split the rod when it was torqued tight..

did you open up the oil passage in the rear main cap... use a long reach carbide ball to smooth the inner passage where it turns...

i don't know if the big block uses the same style of block off plug as the small block..  about an inch in from the rear main cap.. to divert flow from the oil pump passage in the main cap out to the oil filter then back into the same passage going upward...

did the block just get pressure washed... not brushed out.. with oil galley brushes and hot water..   i almost wanted  to modify one of the oil galley brushes with a section of copper tubing slipped over the CUT off loop... with a compression by compression by pipe tee.. over the twist.. and a quick connect to the hot water hose... so i could have hot water spraying on the bristles of the oil galley brush as i am cleaning...  

i actually did find that i could pull the cover off the lower part of the jet wash tanks...  lowered my blocks into that after a  washing... ran the oil galley brushes into the partially submerged blocks...  then threw them back in the jet wash tank for another rinse..   i still ran hot water and the brush again through them when i got them home... i put a TEE in the water heater outlet pipe.. and i used a BOILER DRAIN VALVE... instead of a conventional garden valve... garden valves have a 9/16 opening... hose bibs have a 3/8 opening.. boiler valves have around a 1/2" opening. but have better quality sealing materials to handle fairly hot water...

i also tossed a big speaker magnet into the bottom of the jet tank i used at work..  got strange looks from the tear down guy when he was digging the slime out a few weeks later.. where the heck did this come from... man was that magnet furry with metal from the block machining and honing..  i just smiled... always thought about tossing one in the bottom of the CK 10 power hone... by the way.. did you know a vega timing belt fits the CK10.. even though its one tooth longer.. its thicker do to the micro V on the back to drive the water pump... so it fits perfect... that was a first generation CK10... don't know about the New ones..


read up on a few failures analysis articles..

http://www.circletrack.com/sch/02/failure/articles/

there are a few more interesting articles once you spread out to the performance group

http://www.circletrack.com/sch/02/failure/articles/?searchSource=Group

[sirstude]

Wayne,  The machinest that recommended the drilled plugs, had nothing else to do with my 454.  The engine came out of my buddies running Deuce, and I ringed and bearinged it.  It didn't have a lot of miles, just wanted to be sure at the time.  I just remembered that the first cam never even went into the block.  I bought it for that setup, but then put it in the 396, so I guess I have only had 2 cams in here.

Doug