? for big Block Builders, Need quick answer - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**1970 CST Short Wide** · 01-30-2005, 01:28 PM

Have any of you guys that build Big Block Chevy ever heard of drilling small holes in the oil gallery plugs in the front of the motor , behind the timing chain, so as not to form an air pocket and not oil the front lifters ????

I'm helping a guy do his motor and his machinist recommended this.

jhow66 · 01-30-2005, 01:35 PM

Very small holes to oil the timing chain better.

OLDROCK&ROLLER · 01-30-2005, 03:49 PM

I drilled one hole .080 in the center plug. To remove air and send more oil to the gear drive.

bagged91 · 01-30-2005, 11:24 PM

I would be interested in learning a little more about this too. I plan on running a gear drive on my 454 and a little more oil wouldn't hurt....

sniper2321 · 01-31-2005, 12:29 AM

what was previously said is true for the oilling part not so much for the air in the oil. its main jod was to let oil be sprayed on the thrust washer for thr camshaft. I like to use a .06 to .07 on the top middle oil plug.

**1970 CST Short Wide** · 01-31-2005, 10:53 AM

Talking to another machinist and he said it would not allow the lifters to pump up if you drill to big. This is our major concern. I did not do it on my recent BB build and I have no problems and neither of us are running gear drive.

Jeff M. · 02-01-2005, 12:00 AM

I've drilled several plugs on big blocks. On my old 402 as stock occasionally the lifters would tick a bit. Never have that on the one's we have drilled. That little mod has been around for a long time.

arkracing · 02-01-2005, 10:12 AM

just get a timing chain that has the roller bearing plate that rest against the block inbetween the cam gear and the block. I got mine from Manley as a complete kit with the, chain, rollerbearing, and thrust button. for $100.
PN# 73142 from Manley - SKU# 8 07298 01625 2
NO MACHINING REQUIRED WITH THIS SET UP

the main problem with big blocks is that the cam gear rides agains the block and wears the block out. - then you have to have it machined to accept a different type of roller bearing.

01-30-2005, 01:28 PM	#1
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,185	? for big Block Builders, Need quick answer Have any of you guys that build Big Block Chevy ever heard of drilling small holes in the oil gallery plugs in the front of the motor , behind the timing chain, so as not to form an air pocket and not oil the front lifters ???? I'm helping a guy do his motor and his machinist recommended this. __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

01-30-2005, 01:35 PM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Very small holes to oil the timing chain better. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

01-30-2005, 03:49 PM	#3
OLDROCK&ROLLER Registered User Join Date: Feb 2004 Location: WHITEVILLE N.C. Posts: 494	I drilled one hole .080 in the center plug. To remove air and send more oil to the gear drive. __________________ 72 CHEYENNE 10 SUPER 468/400/3.73

01-30-2005, 11:24 PM	#4
bagged91 Out draggin' Join Date: Jan 2004 Location: Pitman,NJ Posts: 1,574	I would be interested in learning a little more about this too. I plan on running a gear drive on my 454 and a little more oil wouldn't hurt.... __________________ 91 GMC Xcab LB-Bags/bd/caddy clip SOLD 72 C10 Cheyenne Super LWB SOLD 92 GMC K1500 Burb 72 C10 Burb (ex. Cheesewagon)SOLD 72 C20 Burb parts truck 71 C10 Burb "project"

01-31-2005, 10:53 AM	#6
1970 CST Short Wide Senior Moment Join Date: Mar 2002 Location: Pittsburg Ca Posts: 4,185	Talking to another machinist and he said it would not allow the lifters to pump up if you drill to big. This is our major concern. I did not do it on my recent BB build and I have no problems and neither of us are running gear drive. __________________ 1970 CST LS 1 6 speed Ford 9 inch Detroit Tru Track, Dakota Didgital, Vintage Air, QA1 Coil Overs Front & Rear Lots of FUN 2013 GMC PU, Oldest Son 71 GMC LWB. QA1 Suspension, Angry SB. Youngest Son 2019 GMC Diesil Dually. Youngest Son 2017 Toyota SUV Daughters car 2018 Traverse , Wife’s Ride Pittsburg Ca 94565

01-31-2005, 12:29 AM	#5
sniper2321 Registered User Join Date: May 2002 Location: S.E. Fla Posts: 185	what was previously said is true for the oilling part not so much for the air in the oil. its main jod was to let oil be sprayed on the thrust washer for thr camshaft. I like to use a .06 to .07 on the top middle oil plug.

02-01-2005, 12:00 AM	#7
Jeff M. Registered User Join Date: Feb 2000 Location: Pixley, Ca. Posts: 486	I've drilled several plugs on big blocks. On my old 402 as stock occasionally the lifters would tick a bit. Never have that on the one's we have drilled. That little mod has been around for a long time. __________________ 69 C-10 CST Short Fleet, Factory Air, BB427-400 Auto-2400 stall-tilt-cruise-Tach & Vac Gagues, 4/6 drop, power one piece side windows, Eaton posi.

02-01-2005, 10:12 AM	#8
arkracing Weekend Warrior Join Date: Oct 2004 Location: CT Posts: 1,787	just get a timing chain that has the roller bearing plate that rest against the block inbetween the cam gear and the block. I got mine from Manley as a complete kit with the, chain, rollerbearing, and thrust button. for $100. PN# 73142 from Manley - SKU# 8 07298 01625 2 NO MACHINING REQUIRED WITH THIS SET UP the main problem with big blocks is that the cam gear rides agains the block and wears the block out. - then you have to have it machined to accept a different type of roller bearing. __________________ -'07 GMC Sierra K2500HD -'66 C10 Suburban -'68/'71 K20 Service Bed Project -'69 Chevy C30 Mason Dump -'33Ford P/U 396ChevyPowered



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