Long pushrod source

T

tsm1mt

Member
I gave ihon a call yesterday in pursuit of some longer pushrods, and was directed to post here.. :)

I have a 196 I built. The boat rockers have plenty of oil (each "boat" was full), the lifters seem to pump up (I can't compress them by hand after the engine was running), but the engine sounds like I left out the oil gallery plug (btdt on a 345) - thankfully, I can confirm with a mirror that the oil gallery plug behind the distributor is in place, and I have pictures confirming the big plug in the bottom is in place.

Being a 196, it has a reground cam. I don't have the specs on how much the base circle was reduced.

Unlike every other engine I built, this one wasn't decked, so it's the first one that might need longer pushrods.

It has a set of boat rockers on it now. When I get back to the shop, I have a set of welded rockers cleaned up that I'll try and see which version May be more forgiving of the extra length.

Meanwhile, I'm not against ordering up some longer pushrods for either style.

-Tom
 
Thanks, Robert.

I'm going to have to keep them in mind - I should get some shorter pushrods for my race engine project, and maybe those tapered units would be a good way to go.

I decked the block between .050 and .060" (I need to check the final number - the whole thing was a bit out of square).

For this project, I found carquest carries pushrods, and they were able to get me some .040" longer units. Around $11 each (a few dollars more than ihon) and maybe I'll have them in a day or two to try.

The welded rockers and cup/ball pushrods didn't help my cause. It did feel better, since I'm used to that style and tightening down the 9-stand rockers they have some resistance with the welded rockers as you compress the lifters vs the overall sloppy install with the boat rockers, but it didn't make a difference.
 
Well, today's news is a mixed bag.

I got the longer pushrods from carquest. Unfortunately, the bag was marked "9.000" which I thought was short, but about right for a longer-than-stock 304 pushrod, but it was too late to change it, so I took it home... They never made it out of the bag and they're now in the car to take back.

On the flip side, of the three pushrod length checkers I ordered, two showed up today, including the one I needed for this job - the 9.7 to 11" unit.

I removed the welded rockers (and found that I likely missed the #4 (or 8th) lifter when I set those up - nice bent pushrod. This one is a little tricky, being up against the firewall, and the welded rockers have a good bit of preload when you tighten them down and it's always fun to hold the pushrods in place while tightening - and I fouled up on the one under the firewall.

Anyhow...

I reinstalled the boat rockers (and the 4 plugs since it's a 5-stand boat), and 7 of the 8 pushrods.

I removed the #1 lifter, set the balancer to tdc (remember, this is a 4cyl!), took a new lifter off the shelf, removed the spring, dropped two #6 nuts inside (after some trial and error) and made a solid lifter which was installed.

I then adjusted the adjustable pushrod close to stock, and torqued everything to 15 lbs-ft.

I proceeded to press on the rocker a bit and adjust the pushrod until I could feel no noticeable lash.

I then removed the adjustable pushrod.

2012-08-01_23-13-13_498.jpg


The adjuster is 28 threads-per-inch, for 0.036" per turn. I was three turns out from bottom, which is 9.700"

so 9.700 + .107 is 9.807" before adding any preload. Preload at around .050" puts me needing pushrods at 9.857" or 9.850 to 9.860 give or take.

Stock should be 9.780 giving me a need for an extra 0.080" of pushrod length or so.

I still don't have the reduced base circle numbers for the reground cam.

All of this sound reasonable? I'll be in search of the correct pushrods tomorrow..

(I also tried to stand the pushrods up on the milling table and use a dial indicator to check the height, but I wasn't able to get good results. All of my calipers stop at about 6" oal..)
 
I'm in the process of putting my ic 196 together. I had the block decked 0.030", iirc, and also had the cam reground to the 256 profile. I *understand* that it reduced the base circle about 0.050". If that is so, then I anticipate that my stock pushrods should be adequate. Hopefully I'll have an opportunity this weekend to put in a lifter and check preload. If it is at least 0.050" then I presume that's good.

But I've been following the threads about knocks, clatter, and all that. I've owned seven of these beasts over the years and only a few of the engines have really been quiet like a sbc.

Here's a question for Robert or michael. The other day I pulled out one of those books that was full of tips on rebuilding engines in chevys, fords, and chryslers. Apparently on one of the Chevy's (big blocks, I think it was) that a known problem was air building up behind the front plugs to the lifter oil galleries, which caused lifter noise. The sv has a similar configuration. The cure was to drill tiny bleed holes in the small pipe plugs, which would let the air out but not cause a drop in oil pressure. Has anyone considered this as a cause for noisy lifters in the I-4/svs? Just asking.
 
9.850" pushrods installed. Sourced from summitracing - tfs-21419850-8. $63.95 for a set of 8.

Cured most of the noise.

I did hear something still, but after removing the original valve cover for a butchered (windowed) one, I don't hear the noise - maybe I need to re-examine the underside of the valve cover.

With the engine running, the rockers throwing oil in my face, I only hear what I've generally thought of as "normal" noise now - you can hear the valves working. If I were in the cab with the hood closed, it would be hard to notice if you were looking for it.

(before it was pretty easy to note)

I even took video Of it running.

Now my only concern is that the 4th pushrod back from the front spins slowly, while the others spin rapidly.

On 7 of the pushrods, you can see the oil cork-screw around the pushrod, the pushrods spin that fast.

On the 4th one, it is turning, but slowly.

I'll pull that lifter and have a look see, and hope that the cam looks ok and maybe a second lifter will make it happier. I have to remove the 3/4 valve cover anyhow..

Mark - here's hoping you're in better shape.

I don't know the specifics on how much the base circle was reduced, but let's say mine was .050 like yours.

I did not deck the block.

I was .080 too short. If you cut the deck .030, that would put you .050 too short. I think that puts you very close to zero preload.

Close enough you might get lucky, though. :d

if it sounds like a sewing machine, and you're certain the oil gallery plugs are in place.. Check the pushrod length.
 
Tom,
assume a preload of 0.050" with oem parts and a deck at original height. The pushrod moves approximately in a straight line. Now, let's assume the lifter is sitting on the base circle and we have our 0.050" preload. Now if the base circle is reduced 0.050", the pushrod drops by the same amount and preload would be negated. But if the deck height is reduced by 0.030", then in theory the preload would be 0.020". Maybe not great or even enough, but not wiped out completely. Now, maybe my cam wasn't ground 0.050", but, say, 0.030" - I just don't know how much. But after I get a pushrod in there I'll be able to gauge preload and report back. Maybe enough, maybe not, then I'll have to get longer rods too. But we'll see.

But now you've got me to thinking. Years ago I rebuilt a non-ic196, and part of that was a reground cam. One morning I pulled the choke out and got a slug of gas in there and oversped the motor, floating the valves. Thereafter I dropped a few pushrods whenever I got up above 3k rpms (guesstimating here). I did crack a welded rocker in the initial event (a valve kissed the piston), but now I wonder what role, if any, insufficient preload May have played when I began dropping other pushrods. Maybe it wasn't springs getting progressively weaker (my thoughts on it once springs get floated) but due to insufficient preload. Hmmmm.....

Edit: just viewed your engine running. Isn't technology wonderful? Even tired the ic196 I have ran quieter than that!
 
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