Push rod hitting cylinder head
#3071897
08/27/22 07:44 PM
08/27/22 07:44 PM
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Joined: Aug 2009
Posts: 2,037 Mooresburg, Tn
'72CudaRacer
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OEM RB block, Comp roller cam & lifters, new Indy EZ-1 cylinder heads, Hughes 1.5 rockers, 3/8 push rods. Because of the arc that the top of the push rod travels, from about half of the lift through max lift and back down to about half lift, all eight intake push rods rub the cylinder head behind intake mounting flange. Some more so than others, but all to some degree. In the valve closed position, the push rods are almost centered in the push rod holes. Other than removing the heads and material removal, is there any other solutions, such as going to Harland Sharp rockers? Is this a common problem with Indy heads? I can move the rockers side to side with shims to some extent, but what about in and out movement? Any way to decrease the travel arc?
Thanks, Brian
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Re: Push rod hitting cylinder head
[Re: '72CudaRacer]
#3071916
08/27/22 08:10 PM
08/27/22 08:10 PM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
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OEM RB block, Comp roller cam & lifters, new Indy EZ-1 cylinder heads, Hughes 1.5 rockers, 3/8 push rods. Because of the arc that the top of the push rod travels, from about half of the lift through max lift and back down to about half lift, all eight intake push rods rub the cylinder head behind intake mounting flange. Some more so than others, but all to some degree. In the valve closed position, the push rods are almost centered in the push rod holes. Other than removing the heads and material removal, is there any other solutions, such as going to Harland Sharp rockers? Is this a common problem with Indy heads? I can move the rockers side to side with shims to some extent, but what about in and out movement? Any way to decrease the travel arc?
Thanks, Brian Without seeing exactly what you have, that sounds like a large amount of adjuster movement. How many threads are showing one the adjusters? And what does your geometry look like?
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: Push rod hitting cylinder head
[Re: '72CudaRacer]
#3071934
08/27/22 09:02 PM
08/27/22 09:02 PM
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Joined: Aug 2003
Posts: 43,095 Bend,OR USA
Cab_Burge
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Time to get out the high-speed rotary aluminum cutter bits and make some clearances: wrench : I've had to do that more than once with big lift cams and Indy BB Mopar aluminum heads Same thing on 426 Hemi heads and aluminum blocks I had one of the cam grinders tell me that isn't really a problem if the contact isn't hard and bending the pushrods trying to shove them out of the lifter cups or off of the rocker adjusters He brought up SB Chevy and other motors with guide plates
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Push rod hitting cylinder head
[Re: '72CudaRacer]
#3071939
08/27/22 09:18 PM
08/27/22 09:18 PM
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Joined: Jun 2014
Posts: 3,148 Md.
carnut68
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OEM RB block, Comp roller cam & lifters, new Indy EZ-1 cylinder heads, Hughes 1.5 rockers, 3/8 push rods. Because of the arc that the top of the push rod travels, from about half of the lift through max lift and back down to about half lift, all eight intake push rods rub the cylinder head behind intake mounting flange. Some more so than others, but all to some degree. In the valve closed position, the push rods are almost centered in the push rod holes. Other than removing the heads and material removal, is there any other solutions, such as going to Harland Sharp rockers? Is this a common problem with Indy heads? I can move the rockers side to side with shims to some extent, but what about in and out movement? Any way to decrease the travel arc?
Thanks, Brian I'm running Indy EZs, I think the pushrod holes were clearanced. Harland sharp rockers also. Maybe Fast68Plymouth will chime inn. That's who I got my heads from. B3 racing shaft adjustment set up might help. Maybe he will read this.
Last edited by carnut68; 08/27/22 09:22 PM.
America First!
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Re: Push rod hitting cylinder head
[Re: Dragula]
#3072024
08/28/22 10:34 AM
08/28/22 10:34 AM
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Joined: Jan 2003
Posts: 14,491 So. Burlington, Vt.
fast68plymouth
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It’s very common to have this be an issue with EZ heads.
I usually do a bit of relieving on the EZ’s I sell.
1.5’s often rub on the side of the slot towards the manifold at higher lifts. 1.6’s often rub on the side of the slot towards the rocker shaft when the valve is closed.
Why this hasn’t been taken care of during manufacture is just another mystery of the car hobby.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Push rod hitting cylinder head
[Re: Clanton]
#3072320
08/29/22 10:53 AM
08/29/22 10:53 AM
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Joined: Jan 2003
Posts: 1,602 westerly, ri. usa
440lebaron
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most aftermarket heads you have to "clearance" pushrods, most say it in there instructions, last time I used a rat tail file with grease on it to catch chips
all parts are sold as is, all parts are considered used no warranties or returns paypal/check/money order, shipping is from zip 02891, buyer pays paypal fees 24% IRS 1099A plus 3% of part price, check/money order preferred site is not monitored 24/7 there might be a delay in response
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Re: Push rod hitting cylinder head
[Re: '72CudaRacer]
#3072950
08/31/22 03:56 PM
08/31/22 03:56 PM
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Joined: May 2014
Posts: 179 California, U.S.A.
Torquemonster440
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[quote='72CudaRacer]OEM RB block, Comp roller cam & lifters, new Indy EZ-1 cylinder heads, Hughes 1.5 rockers, 3/8 push rods. Because of the arc that the top of the push rod travels, from about half of the lift through max lift and back down to about half lift, all eight intake push rods rub the cylinder head behind intake mounting flange. Some more so than others, but all to some degree. In the valve closed position, the push rods are almost centered in the push rod holes. Other than removing the heads and material removal, is there any other solutions, such as going to Harland Sharp rockers? Is this a common problem with Indy heads? I can move the rockers side to side with shims to some extent, but what about in and out movement? Any way to decrease the travel arc?
Thanks, Brian [/quote
The comp pro magnum rockers helped big time in this department for me as far as pushrod clearance with my Promaxx heads and 3/8" pushrods. They utilize a cup style adjuster that improves the rocker geometry.
1966 Satellie.. 12.55 @107.75. 906 heads. 3780 lbs.
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Re: Push rod hitting cylinder head
[Re: Torquemonster440]
#3072952
08/31/22 04:13 PM
08/31/22 04:13 PM
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Joined: Feb 2005
Posts: 20,144 PA.
pittsburghracer
"Little"John
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All part of engine building. Test the fit before final assembly. When heads are made to fit different deck heights issues occur. Throw in X amount of rocker arm manufacturers and poop happens.
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: Push rod hitting cylinder head
[Re: pittsburghracer]
#3073204
09/01/22 10:41 AM
09/01/22 10:41 AM
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Joined: Jan 2003
Posts: 14,491 So. Burlington, Vt.
fast68plymouth
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There is a 505 going together locally with EZ heads that will be getting a HR cam and HS 1.6 rockers.
I did some clearancing on the heads........ but instructed the builder to test fit it all before bolting the heads down for the final time.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Push rod hitting cylinder head
[Re: fast68plymouth]
#3073547
09/02/22 12:33 PM
09/02/22 12:33 PM
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Joined: Jan 2003
Posts: 14,491 So. Burlington, Vt.
fast68plymouth
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Well, it would seem that this latest set of EZ’s has the pushrod slots moved towards the shafts compared to ones I’ve done in the past. With the HS 1.6 rockers, the pushrods were still rubbing the head on the side of the slot toward the intake manifold. The side of the slot towards the shaft, which is where the contact usually is with 1.6’s, had tons of room.
With 1.5 rockers there would have been hard contact with the manifold side of the slot.
In the past the interference was only up near the top of the slots....... but this set is extremely close for the full length of the slot.
Frankly, there just isn’t any reason this should be an issue at all. The heads should be made with the slots adequately sized and positioned to clear the popular brand/ratio rockers.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Push rod hitting cylinder head
[Re: fast68plymouth]
#3073645
09/02/22 06:02 PM
09/02/22 06:02 PM
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Joined: Aug 2009
Posts: 2,037 Mooresburg, Tn
'72CudaRacer
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Well, it would seem that this latest set of EZ’s has the pushrod slots moved towards the shafts compared to ones I’ve done in the past. With the HS 1.6 rockers, the pushrods were still rubbing the head on the side of the slot toward the intake manifold. The side of the slot towards the shaft, which is where the contact usually is with 1.6’s, had tons of room.
With 1.5 rockers there would have been hard contact with the manifold side of the slot.
In the past the interference was only up near the top of the slots....... but this set is extremely close for the full length of the slot.
Frankly, there just isn’t any reason this should be an issue at all. The heads should be made with the slots adequately sized and positioned to clear the popular brand/ratio rockers. To me, it looks like the angle of the cutter is off a few degrees when the holes were machined. There is absolutely no reason whatsoever, for that material to be left there. Maybe the program got tweeked when they moved the shop? Mine are also new, just shipped about two weeks ago.(ordered in March) On a side note, I got a brand new set of Harland Sharp 1.5 rockers yesterday, thinking that they might clear, but they won't even fit between the rocker stands on a couple of cylinders. So, off with heads and out with the grinder this weekend. Certainly not what I expected from Indy in this day and age. Not bashing, just disappointed. Brian
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Re: Push rod hitting cylinder head
[Re: '72CudaRacer]
#3073649
09/02/22 06:44 PM
09/02/22 06:44 PM
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Joined: Jan 2003
Posts: 14,491 So. Burlington, Vt.
fast68plymouth
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Would you say the HS 1.5’s will require more or less clearancing on the heads than for the Hughes rockers?
The placement of the slots is def not where it has been for years. I had done enough of them where I pretty much knew what needed to be done for pushrods to clear.
I’m not sure any of the popular rockers would have put the pushrods where they worked on this set of heads as they came ootb.
Possibly a T&D 1.6 or PRW steel 1.6. I don’t think any 1.5’s would have.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Push rod hitting cylinder head
[Re: fast68plymouth]
#3073708
09/02/22 10:17 PM
09/02/22 10:17 PM
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Joined: Aug 2009
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'72CudaRacer
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Would you say the HS 1.5’s will require more or less clearancing on the heads than for the Hughes rockers? Possibly a T&D 1.6 or PRW steel 1.6. I don’t think any 1.5’s would have. I will be able to answer this after sat. Right now, I can't install the HS because they won't fit between the stands. I'll pull the heads and mock them up on another block. (Too much work to try and do over the fenders!) I'm not sure a 1.6 rocker would have cleared one of the push holes without grinding. I have a set of 1.6 rocker that Indy sells for their -1 heads (maybe Dove?) that I will try before I start grinding. I will report back after I'm done. Brian
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Re: Push rod hitting cylinder head
[Re: '72CudaRacer]
#3073802
09/03/22 11:23 AM
09/03/22 11:23 AM
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Joined: Jan 2003
Posts: 14,491 So. Burlington, Vt.
fast68plymouth
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The HS rockers didn’t fit between the stands on this set of EZ’s either.
I didn’t mention the Indy 1.6’s as being a possible solution for fitting without modding the heads because they are no longer available...... but I wouldn’t be shocked if they fit. I’m pretty sure both the Indy 1.5’s or 1.6’s would work on heads where the PR slots were in the original location.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Push rod hitting cylinder head
[Re: fast68plymouth]
#3074354
09/05/22 12:33 AM
09/05/22 12:33 AM
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Joined: Aug 2009
Posts: 2,037 Mooresburg, Tn
'72CudaRacer
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The HS rockers didn’t fit between the stands on this set of EZ’s either.
I didn’t mention the Indy 1.6’s as being a possible solution for fitting without modding the heads because they are no longer available...... but I wouldn’t be shocked if they fit. I’m pretty sure both the Indy 1.5’s or 1.6’s would work on heads where the PR slots were in the original location. Good to hear that it's not just me, but Indy could have fixed this from the get go. Before I started grinding (after removing heads), I checked for clearance w/ Indy 1.6 rockers and they fit. (Barely!) They would also need a longer (about .200" longer) push rod. I checked both the Harland Sharps & Hughes rocker (both 1.5). Push rods hit the heads with both of these rocker arms in the same place, about the same amount. Had to adjust the rocker shaft shims on HS's just to get them on the heads. Somewhat surprising, the Hughes rockers had a tighter contact sweep and was more centered on the valve stem than the HS's. It looks to me like the HS's will need lash caps to get the geometry to be as good as the Hughes, although they will work like they are. Another problem I haven't mentioned, is the rocker arm tip (rollers) have to be moved (laterally) to the very edge of the valve stem, away from the intake port, to help the push rod clear the port. Don't want to chance cutting through the intake port. Offset intake rockers would help solve this part of the push rod issue (approx .150" over stock offset would be about perfect), but we will use what's available and make it work. Brian
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