Well, things are coming along, but I am stuck.

As I understand it, there are three or four methods for checking proper push-rod length. I have watched a ton of videos, talked to a bunch of people, and in the end I used Tim Meyer's method, which is quite simple.

Let me go big picture, then talk about Tim's method, and tell you where I am at.

Method 1: Make a solid lifter, use an adjustable length pushrod, mark a pattern on valve stem with a Sharpie, turn engine over, check pattern, adjust length of adjustable length pushrod until pattern is centered. Didn't use this method because it is too difficult to make a tie-bar hydraulic roller lifter solid (I am using Lunatis sourced from TMI with Scorpion roller rockers.

Method 2: Install soft checking springs, and do same as above. Checking springs compress before lifter compresses. I can do this, as I do own the springs, but I would have to pull the head (already torqued) and replace two of the springs, reinstall, torque, check, remove, reinstall OEM springs. I may do this if method 3 fails me.

Method 3: Make sure cam is on base circle of valve you are checking. Extend adjustable length pushrod until you have zero lash (no slop) being careful not to compress hyd lifter plungers.. Measure pushrod. Add .050" to that length for your pre-load.

So...I used method three. I get (Before adding .050" prefload...IE these are zero lash (no-slop) lengths using the Comp Cams adjustable pushrod I bought).

#1 Intake: 8.854
#1 Exhaust: 8.885
#2 Exhaust: 8.891
#3 Exhaust: 8.885
#6 Exhaust: 8.891
#7 Exhaust: 8.883

The pushrods Tim sent me are marked 9.150", and they actually measure on my digital caliper 9.130 to 9.143. Tim told me that that is the most common size used in my build, he does not think my measurements are correct. He thought maybe I was not on the base circle of the cam, but I verified that I was indeed, and as indicated above I checked multiple valves to be sure.

Regardless of whether my caliper is spot-on or not, I have a difference of .244 to .281 between the adjustable length pushrod zero-lash measurement length and the 9.150 labeled pushrods I have, IE there is a quarter-inch difference between them (or four times the pre-load extra length I thought I was supposed to have).

If I use an average length (zero lash) of 8.888, and add .050" to that, I come up with 8.938.

I see a size available in 8.950 from Manley.

I am quite concerned that the pushrod lengths I have calculated are not jiving with Tim's experience. I don't know if my block was milled too much, or my heads, but a quarter inch variance is huge! My pistons are not sticking out above the bores (they are flush) and Tim rebuilt my heads, so I am stumped. Perhaps Scorpion has changed their rocker CNC specs, or perhaps Lunati has changed the overall height of their lifters?

I may just take the whole engine to my local machine shop (he has been in business 30 years) and bring him everything I have and let him calculate length for me. He does it with checking springs.

What would you guys do? Does anyone have a log of a similar build? I will call Tim on Monday or Tuesday and discuss further.

Build:

302C Aussie quench heads
Ford 400
TMeyer "Pantera" grind hydraulic roller cam.
Scorpion roller rockers
Lunati tie-bar hydraulic roller lifters

 

I have a receipt for a set of 9.200" Trick Flow Pushrods dated 9/03/08. I'm not sure what motor that I used them on. That must have been the motor that I sold. That had a small base circle cam and 5.0 lifters with Crane Energizer rockers and 351C-4V heads.

 

Hello Shane,

I just read your thread for the first time and thoroughly enjoyed it.

With regard to your valve train geometry I would take the engine to the local machine shop as a 'hands on' opinion will be accurate, whereas telephone calls and/or emails are difficult to be accurate.
I assume Tim is not near to you.

In your first post you mentioned that you weren't sure why cylinder 7's lifters (and no doubt cam lobes) and push rods were knackered.
The only way to bend a push rod is for the piston head to hit the valve.

I fitted new heads and roller rockers etc last year (first time D.I.Y. for me) and confused the sh$t out of myself when it came to setting the valve lash.
Needless to say I set the lash so tight that I had no compression and I had the valves locked wide open !
Didn't take long for a lifter in cylinder 2 to protest to the extent that it lost 2mms and the corresponding lobe, well, enough said !
When I rebuilt my engine I found 7 bent valves !

So just maybe in your case the initial valve lash was too tight.

In January this year, after many, many hours of studying (inclusive of Tom Monroe's book), like you, I rebuilt/upgraded/blue printed my engine.

I managed to create a spreadsheet wherein I could work out my Static Compression Ratio (SCR), and with the cam's IVC, I then used Wallace Racing's on line Dynamic Compression Ratio (DCR) and Cranking Pressure (CP) calculator.

Many sites suggested using the 0.05'' timing for the IVC, but I found that the 0.006'' IVC gave a true calculation.

Personally, I took a fat chance with a predicted DCR of 8.86 and a CP of 181. (Don't laugh ! ).

After my engine had been run in, and I'd done about 1,000 miles, I did a compression test (engine warm, plugs out, cranking only) and got readings of 175 - 180.

I was very happy with that result, because it was as predicted, but not happy with the pinging, which initially was seldom, but became more often.
My cam had an IVC of 54 degrees (@.006''), so I got Edelbrock's cam, 2172, because it has an IVC of 68 ( @.006''), and the predicted DCR dropped to 8.1 and the CP to 162.

I finished fitting the new cam only 2 hours ago, and I haven't checked the cranking pressure yet, but I heard a bit of pinging !

Sorry for waffling on, but here's the point I was getting to.

I read your initial engine specs on page 1, and I got to a DCR of 7.82 and a CP of 154, which in theory shouldn't have given you pinging. (In theory!)

Your new cam has an IVC of 69 @ .006'' which is more or less the same as what you had, but, with the zero deck and 30cc pistons, I estimate a DCR of 7.35 and a CP of 142, which should also not give you pinging.

I'm hoping to clarify(learn) if a squish of +/-.04'' (estimate of yours) is more efficient and less prone to detonation than +/-.075'' (mine), and if hotter spark plugs for a higher compression unleaded engine reduce detonation.

I went one plug cooler (as commonly advised for a higher compression engine) and got non stop pinging ! I haven't tried a hotter plug yet.

I hope I'm not guilty of this :
Cheerz4now,
Nick

 

On my last build, someone else (a friend of mine and one of his employees) built the engine, and I have no idea how they determined push-rod length.

On this build, I am going with an already proven setup by going with what Tim Meyer recommends. The cam grind, pistons, lifters, and rockers were all purchased from Tim, and he has built many engines with this exact setup, so I am confident it should be OK once I get over this push-rod hiccup.

I had bad luck with that Edelbrock cam, and it pinged the whole time I had it, even with 93 octane - especially when it was hot outside. There simply was not enough quench to use that cam with Aussie heads and OEM type pistons.

Tim's pistons and the Pantera cam grind along with the Aussie heads should hopefully provide enough quench to keep things under control and prevent pinging. I'm hoping I might even be able to run 87 or 89 octane and still be OK.

I already calculated both Static CR (9.5:1) and dynamic CR (9.03:1)...cylinder pressure should come in around 186 PSI.

My plugs are stock temp; I may drop down one-step cooler if necessary.

 

Hi Shane,

I hope I didn't come across as doubting the build, far from it !

I was just surprised that you were getting pinging on a lowish Cranking pressure (CP) on the previous setup.

That said, I also calculated an SCR of 9.5 on your current engine, but the figures of 9.03 DCR and 186psi CP look too high. I think the DCR of 7.35 and CP of 142psi are closer to what the engine will produce.

The only pump gas I can get is 91 octane (95 octane equivalent here in South Africa) but I think it's closer to dishwater than good fuel.

I tried some 98 octane race gas (102 octane here) and , as expected, no pinging. I read about higher octane levels reducing detonation, but needed to see for myself.

I have Edelbrock ally heads with a 60cc closed combustion chamber (similar to the Assie spec heads) which should allow higher engine pressures !?

Would you mind asking Tim if he thinks you got pinging because your squish was too high, and not at say +/-.04'' with a zero deck.
Would you also mind asking him if a hotter plug should be used on an engine with an increased SCR, DCR etc running on unleaded.
I read that a colder plug was in order, until recently, where now I'm reading that a hotter plug goes with unleaded fuel !!??

I'm pretty sure you'll be able to run on 89 octane. No idea about the 87.

Laterz,
Nick

 

Epic progress was made today.

Tim Meyer sent me a bunch of shims and and assortment of push-rods of various lengths; additionally he provided me some excellent tech support via FaceTime (we both have i-Phones) and was able to look at my valve-train geometry and talk me through shimming everything.

The bottom line is all of my rollers were biased on the valve stems toward the intake side (wear patterns were toward the intake valley).

I ended up shimming the whole engine .080" on every pedestal. The push-rod lengths I calculated with a .050" addition for lifter pre-load were coming in around 9.060-9.070" or so...so I had a choice between going with a 9.050" push-rod or a 9.100" - I ended up going with 9.100" That will put some of my lifters in the middle of their travel range (as much as .090" pre-load on a couple of them) but that is actually what Tom Monroe recommends in his book. I wanted to have that vs. any of them coming up shy...Tim told me .030" to .060" is a good target and had I gone with the 9.050" rods some of them would have been on the fairly low pre-load side.

Anyway...the push-rods and Scorpion roller rockers are all in.

I got most of it buttoned up...but I have a distributor question for you gurus:

When I point the rotor in the distributor precisely at the terminal I have chosen for #1 plug, should I have the harmonic balancer at TDC on the compression stroke, or should I have it at 10 degrees BTDC on the compression stroke?... i.e. it is dropped in, and I can rotate the billet distributor base to match either, but I don't know which is most correct for a "static" timing before I fire it up and use the timing light.

I'll try to put some pics up of the progress tomorrow if I have time.

 

I usually use TDC when I install the distributor, but it will not cause a problem if you use 10 BTDC. It might start a little easier at 10 BTDC.

 

As promised...just need some valve cover bolts and some header bolts and it is ready for installation!

 

Beautiful!

 

Getting close...all that is left is the A/C system, wiring, radiator, and a few miscellaneous hook-ups.

 

.. Hello,

.... Your week long project seems to have run over a bit, but you'll be much more satisfied with the results. The cam Tim suggested looks closer to what I would have said and is vastly better than that big duration low lift monstrosity Comp came up with which wouldn't have pulled hard till 3500 RPMs and would have wanted RPMs higher than your engine is designed for and it would have sucked for MPG and street drivability/cruising. I would have suggested pushrods of two different lengths for that split lift/duration cam and/or shimming the pedestals to two different heights. Also like the lifter pistons only pushed in about .020" to prevent damage from lifter pumpup at highest RPMs. Also, gives instant recovery from pumpup. Allows use of barely adequate valve spring pressures to save the cam lobes of a flat tappet cam.

.... To answer other's questions above, yes, the crappy quench/squish effect was increasing the pinging. The KB/Silvolite 351C pistons Tim suggests have ~.040" higher compression height compared to most crappy replacement 400 pistons and equal reduction in quench/squish distance for much improved quench action and lower octane requirements and higher MPG. Although, an ounce or two (~1/8 - 1/4 coffee cup) of kerosene added to a full tank of gas (~16-20 gallons) will usually eliminate any pinging problems that occur in any engine thats not too horribly mismatched in parts. I can't see any reason to ever use the crappy stock replacement 400 pistons in a rebuild or performance build. They make a sucky stock engine even worse in so many ways. When going to a cooler sparkplug to eliminate pinging, you also have to look at the ground strap design, reach design, and body shell/thread length to make sure you aren't introducing new pinging sources.

 

My distributor has arrived, but now I have the flu. Maybe next week.

 

.. Sorry to hear that, hope it doesn't last long. I had assumed you had it running by now. At least you have warmer weather to work in than we do up here in N.W.Ohio. We had 50's over weekend, but highs in 40's or 30's coming up. I'm sure you'll be amazed at the difference from the old setup. What's your rear end ratio? Tire size?

 

I thought that you were using the HEI distributor?

 

It didn't fit with my A/C compressor; diameter was too big and it was so tall that the vacuum advance hit the compressor oil fill nipple.