Author Topic: Pushrod clearance to intake  (Read 2800 times)

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Dot Heton

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Pushrod clearance to intake
« on: March 27, 2017, 12:00:38 AM »
I'm putting my 390 together with Holly Street Dominator intake, ford adjustable rockers. The heads have had .002 skimmed off, the block decked but I don't have the deck height on hand. Custom ground cam similar to comp 270s on new blank so I'm assuming stock base circle. The pushrods are stock ford and might be a hair short but I have a couple threads of the adjuster still showing above the rocker. One pushrod is close to the intake, maybe within .030". I kept the oil shields in place. The oil shields are .024 thick, I really wanted to run without them but I'm not sure why. Stock shafts and stands. It's going in an old truck that I just cruise in so no high RPM's.

Is this no bueno? I was so meticulous with putting on the intake and it went on so perfectly that I'm reluctant to pull it. I could pull it and relieve the troubled spot if you twist my arm.

« Last Edit: March 27, 2017, 12:04:39 AM by Dot Heton »

Barry_R

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Re: Pushrod clearance to intake
« Reply #1 on: March 27, 2017, 05:07:22 AM »
.030 is a mile.  Some folks don't mind if they nearly touch - including Kaase, who told me not to worry so much about it at one time  A light linear touch is no different than all the engines that run guide plates....  I still prefer to have a little daylight.

Yellow Truck

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Re: Pushrod clearance to intake
« Reply #2 on: March 27, 2017, 10:07:39 AM »
Certainly not comparing my experience with Barry R or Jon Kaase, but with a Holley Street Dominator and T&D Edelbrock style rockers I had contact and had to grind some clearance. I had no daylight and ended with about 1/100th of an inch - hard to measure but 2 to 3 thicknesses of a sheet of paper.

Doesn't seem to be doing anything strange.
1969 F100 4WD (It ain't yellow anymore)
445 with BBM heads, Prison Break stroker kit, hydrualic roller cam, T&D rockers, Street Dominator Intake with QFT SS 830.

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My427stang

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Re: Pushrod clearance to intake
« Reply #3 on: March 27, 2017, 12:45:35 PM »
Same here, as long as it isn't touching hard or trying to turn a corner, it's OK, but I like to try to get a calibrated eyeball .005-ish, which means enough room that I can confidently see it
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Ross
Bullock's Power Service, LLC
- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

jayb

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Re: Pushrod clearance to intake
« Reply #4 on: March 27, 2017, 02:37:30 PM »
I assume that you checked the clearance while turning the engine over?  The pushrods move around in the holes with cam rotation, due to changes in the location of the pushrod end of the rocker.  If you didn't check while rotating the engine, you should do that, especially on that close one...
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

Dot Heton

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Re: Pushrod clearance to intake
« Reply #5 on: March 27, 2017, 03:56:58 PM »
I rotated the engine and checked it at multiple spots. I called the machine shop and they said the pushrods were very close to the correct length.  im not too worried about it now