Re: Clearancing push rod holes
[Re: 440mopar]
#2669581
06/24/19 10:21 PM
06/24/19 10:21 PM
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Joined: Feb 2005
Posts: 20,185 PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,185
PA.
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A double cut is easier to control and takes smaller bites. I usually recommend either turning down the air pressure or better yet getting a router control at Harbor Freight for you electric grinder. Keep your burr clean buy dipping it in transmission fluid or wd40. Lots of ways to go about it but that will get you started. If you need burrs quickly Summit sells them.
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: Clearancing push rod holes
[Re: ZIPPY]
#2669706
06/25/19 09:26 AM
06/25/19 09:26 AM
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Joined: Oct 2005
Posts: 8,881 Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,881
Ontario, Canada
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Buy the burr for cutting aluminum, not steel This is the best advice !! Aluminum cutters are much coarser so they don't clog as easily. I have used the cutters that all those chinese tools vendors sell at the swap meets with no problems. You'll also need cutters with a long stem to reach where you need to cut so get ones with 6" stems.
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Re: Clearancing push rod holes
[Re: Stanton]
#2669725
06/25/19 10:15 AM
06/25/19 10:15 AM
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Joined: Sep 2003
Posts: 19,479 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,479
north of coder
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also, bar soap works for a lube. best stuff, [in my opinion, your mileage may vary] is machinist's wax. works super on aluminum using course cutters at a somewhat slow speed. most guys crank the speed to max, but slow and steady does the best job. make sure to use eye and face protection ! if not, "You'll take yer eye out, kid !" [to paraphrase a popular movie saying. ]
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Re: Clearancing push rod holes
[Re: 440mopar]
#2669728
06/25/19 10:24 AM
06/25/19 10:24 AM
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Joined: May 2011
Posts: 4,489 northern,Ohio,USA
Clanton
master
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Did you think about opening the oil drain holes?I used a 1/4 double cut bit 4" long on both
Last edited by Clanton; 06/25/19 10:28 AM.
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Re: Clearancing push rod holes
[Re: Clanton]
#2669875
06/25/19 06:28 PM
06/25/19 06:28 PM
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Joined: Oct 2005
Posts: 8,881 Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,881
Ontario, Canada
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make sure to use eye and face protection Another piece of VERY good advice !! Whenever I do ANY grinding with burrs I always wear long sleeves and welding gloves with the sleeves tucked in. Those little pieces of metal are sharp as hell and fly everywhere. Welding gloves are thick enough the shards won't penetrate.
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Re: Clearancing push rod holes
[Re: 440mopar]
#2669972
06/25/19 09:48 PM
06/25/19 09:48 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,209
New York
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Remember that (although it's frequently the easiest way) a larger round hole does not track the actual path of the pushrod tube as it cycles. The relief hole's actual shape has a length (on the crank axis) of the tube OD + safety margin, but the cross (left-right) axis is 2 holes this size joined by a relief that allows the full in-out swing of the rocker arm (not an ellipse, the sides are parallel). This will depend in part on your rocker ratio - high ratio rockers are commonly made by shortening the tappet (short) lever, which increases the sweep of the adjuster. If you're copying a known-to-be-safe similar engine, beware of cam & rocker differences.
Boffin Emeritus
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Re: Clearancing push rod holes
[Re: polyspheric]
#2670101
06/26/19 09:34 AM
06/26/19 09:34 AM
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Joined: May 2011
Posts: 4,489 northern,Ohio,USA
Clanton
master
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master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
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Remember that (although it's frequently the easiest way) a larger round hole does not track the actual path of the pushrod tube as it cycles. The relief hole's actual shape has a length (on the crank axis) of the tube OD + safety margin, but the cross (left-right) axis is 2 holes this size joined by a relief that allows the full in-out swing of the rocker arm (not an ellipse, the sides are parallel). This will depend in part on your rocker ratio - high ratio rockers are commonly made by shortening the tappet (short) lever, which increases the sweep of the adjuster. If you're copying a known-to-be-safe similar engine, beware of cam & rocker differences. Well said.I have center located push rods in the roller lifter 1.5 rockers.I opened the oil drain holes to help from the head gasket and after market block covering a lot of the holes open area but I think it would help in any case.
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Re: Clearancing push rod holes
[Re: 440mopar]
#2675836
07/09/19 03:57 AM
07/09/19 03:57 AM
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Joined: Jan 2005
Posts: 2,540 Milwaukee WI
TRENDZ
master
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master
Joined: Jan 2005
Posts: 2,540
Milwaukee WI
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Been away on vacation so I haven't worked on clearancing the pushrod holes yet but I plan on picking up a bit this week. I will get a bit for aluminum but have one more question. Should I get a 1/2" diameter bit (the size of the pushrod hole), insert it in the hole and just work it upward till I have the needed clearance (basically ovaling the hole vertically) or would it be better to do the same but use a smaller diameter bit like 3/8" (the size on sizediameter of my pushrods) and just notch the hole at the top where the pushrod is making contact? I hope my question makesze sense. You can’t be size on size with a burr bit. The bit always needs to be smaller than the radius, or you will get impossible to control chatter.
"use it 'till it breaks, replace as needed"
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Re: Clearancing push rod holes
[Re: 440mopar]
#2676094
07/09/19 08:51 PM
07/09/19 08:51 PM
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Joined: Dec 2011
Posts: 257 Way North Idaho
1KoolBee
enthusiast
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enthusiast
Joined: Dec 2011
Posts: 257
Way North Idaho
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I need to clearance the push rod holes on my Eddy heads and have to buy a bit for my hand grinder to do so. Would like to know what type of bit works best. Should I get a single cut cylinder bit or a double cut or perhaps something else? What rockers are you using? I found that when I went to Harland Sharps for Edelbrock Heads on my Stealths, the material removal needed to clearance the pushrods was dramatically reduced. Fixed the scrub pattern too.
'68 Bee 383/TF/Factory Air...high school sweetheart '67 GTX Clone project,500 six pack,Hemi4-speed,Dana 05 Dodge Viper, 505 V-10, 6-speed Tremec
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Re: Clearancing push rod holes
[Re: 1KoolBee]
#2676177
07/10/19 09:28 AM
07/10/19 09:28 AM
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Joined: Aug 2007
Posts: 732 USA
440mopar
OP
super stock
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OP
super stock
Joined: Aug 2007
Posts: 732
USA
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What rockers are you using? I found that when I went to Harland Sharps for Edelbrock Heads on my Stealths, the material removal needed to clearance the pushrods was dramatically reduced. Fixed the scrub pattern too. Comp Pro Magnums.
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Re: Clearancing push rod holes
[Re: 440mopar]
#2676184
07/10/19 10:07 AM
07/10/19 10:07 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I've learnt over the years to use tootsie rolls to do this.. on my B1 I could use the mill and a end mill but I had a lot to take out.. seldom do I ever use a alum cutter in a air grinder.. its to easy for it to wobble around the hole and it takes too much material off to quickly(I would rather use a steel cutting bit which is much easier to control
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