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Diameter is the same, ends are the same, length is 9.378" which is a perfect 0.122 from the factory spec of 9.500".... Niiiiiice
I have options!
EDIT: Still waiting to hear back from my friend about the push rod checker and the weak valve springs. Hopefully will hear back tonight. If not, I might just order some for myself... one of those "nice to haves"
.122 short is a bad bad idea. It'll be way too much slop which will allow things to break. Only time to go that route is if you went .100 longer on valves and had pedestal shims or adjustable valvetrain. That much difference opens a whole new can of worms
.122 short is a bad bad idea. It'll be way too much slop which will allow things to break. Only time to go that route is if you went .100 longer on valves and had pedestal shims or adjustable valvetrain. That much difference opens a whole new can of worms
youre right - I think I'm forgetting that the rocker arm has a ratio associated with it which multiples the amount of lift by the pushrod... So the same ratio works in reverse too if I shorten the pushrod.
youre right - I think I'm forgetting that the rocker arm has a ratio associated with it which multiples the amount of lift by the pushrod... So the same ratio works in reverse too if I shorten the pushrod.
If I were you, close up the Tom Monroe book. This guy is just getting you confused with some bad imfo. Just find your length by putting crank on tdc. Put light checking springs on. If your head is bolted on you don't have to do anything with head gasket thickness, if not find out crushed thickness and use feeler gages across the deck to mimic your crushed thickness. Put adjustable push rod in and mark to valve tip with some sort of marking compound you have around there. Put rocker on and adjust the push rod to zero lash. Turn the crank over while watching the lifter plunger doesn't compress. Run it through a cycle then remove the rocker, look at how the pattern is centered. If it isn't centered or close to center of the valves tip then now is where shims come into play. Select a shim thickness based on how far the pattern needs to be moved. Put the shim under the fulcrum and go back and set it all up again. Find zero lash again and repeat the procedure. I doubt you would run into a situation where you would need to grind the fulcrum but you never know till you get into it. Once you get the pattern reasonably centered ( your probably not going to get it perfect with the shims you get in a kit ) remove the push rod and measure it with a set of 12" dial calipers. Now add the preload figure to that measurement ( I always add .030 ) and this is your new push rod length. This is the reason all your valve tips must be the exact same heights. Finding push rod length is nothing more than centering the tips sweep on the valves stem while maintaining zero valve lash, then going .030 beyond that figure for the preload. Geometry is a whole different story that is a game of compromise for all out race engines running full rollers.
Trying to do this any other way is just going to get you in trouble. Much more than .060 preload is going to cause problems right down to it not even wanting to start or making it run like crap, low vacuum, even back fire. Keep in mind that preload does have an effect on the speed of revs. An old racers trick at the strip is they would back off to zero lash in the pits if they had adjustable rockers. An engine will rev noticeably quicker than one with .060.
So I did some fiddling with the rocker shims and I have some info to post... but before I do...
Originally Posted by mark a.
If I were you, close up the Tom Monroe book. This guy is just getting you confused with some bad imfo. Just find your length by putting crank on tdc. Put light checking springs on. If your head is bolted on you don't have to do anything with head gasket thickness, if not find out crushed thickness and use feeler gages across the deck to mimic your crushed thickness. Put adjustable push rod in and mark to valve tip with some sort of marking compound you have around there. Put rocker on and adjust the push rod to zero lash. Turn the crank over while watching the lifter plunger doesn't compress. Run it through a cycle then remove the rocker, look at how the pattern is centered. If it isn't centered or close to center of the valves tip then now is where shims come into play. Select a shim thickness based on how far the pattern needs to be moved. Put the shim under the fulcrum and go back and set it all up again. Find zero lash again and repeat the procedure. I doubt you would run into a situation where you would need to grind the fulcrum but you never know till you get into it. Once you get the pattern reasonably centered ( your probably not going to get it perfect with the shims you get in a kit ) remove the push rod and measure it with a set of 12" dial calipers. Now add the preload figure to that measurement ( I always add .030 ) and this is your new push rod length. This is the reason all your valve tips must be the exact same heights. Finding push rod length is nothing more than centering the tips sweep on the valves stem while maintaining zero valve lash, then going .030 beyond that figure for the preload. Geometry is a whole different story that is a game of compromise for all out race engines running full rollers.
Trying to do this any other way is just going to get you in trouble. Much more than .060 preload is going to cause problems right down to it not even wanting to start or making it run like crap, low vacuum, even back fire. Keep in mind that preload does have an effect on the speed of revs. An old racers trick at the strip is they would back off to zero lash in the pits if they had adjustable rockers. An engine will rev noticeably quicker than one with .060.
A question on what you posted Mark. What if the valve tips are not all in the same spot? What if they weren't ground to the correct length or were not installed properly?
This is one of the reasons I kinda want to yank the heads off... just to see what's what and get accurate measurements before I continue fiddling with things. I do see your point about using an adjustable pushrod and it's a test I do intend to do.
I'm merely debating how many times I want to lift a 100 lb head off an engine LOL.
EDIT: Something else troubling caught my eye.... after staring at my build sheet for a while, I noticed that the part number for my lifters seems odd.... FB900...
FB900 is awfully close to the Sealed Power part number of HT900, but the way it's written on the sheet is definitely FB900... which is meaningless. FB900 does not cross reference with ANY lifters I can identify. Not sure why I wasn't given a "package" of cam + lifters.... and it appears I have some mystery lifters sitting inside my motor. Time to call the shop and ask about that little detail...
What's more troubling is range of lift the lifter has.... 0.060" is all I could get it to move from unloaded to fully loaded (valve was opening because I took out the rocker shims under the fulcrum)... aren't lifters supposed to have approximately 0.200" worth of travel to accommodate a quiet valvetrain???
Maybe my mystery lifters are the problem, and NOT the pushrod lengths???
Originally Posted by ctubutis
Especially in November.
Lol exactly my point
Originally Posted by LiquidCowboy
Probably more like 55-60lbs per head (shipping from AUS ain't cheap) lol
Hahahaha good to know! You just saved me lifting 40 lbs ha.
A coworker mentioned this poem this morning. Very fitting for today... and for bugging FMJ. LOL
SASKATCHEWAN POEM ❤️
It's winter in Saskatchewan
And the gentle breezes blow
Seventy miles an hour
At thirty-five below.
Oh, how I love Saskatchewan
When the snow's up to your butt
You take a breath of winter
And your nose gets frozen shut.
Yes, the weather here is wonderful
So I guess I'll hang around
I could never leave Saskatchewan
'Cause I'm frozen to the ground!
Google what Mark A said about the valve tips centering on the rockers.
Call Comp Cams and ask 'em about their lifter travel specific to their/your cam.
Googled what Mark A. had to say about the valve stem tips. Makes a lot of sense especially for a non-adjustable valvetrain. It's important to get that rocker centered on the tip! I put in an order for an adjustable pushrod kit today to help me out with making adjustments/measurements. May as well get one cause I'll never know when I'll need one again. I read what he said about a week ago, and it's taken me a week to figure out what other goodies I want to put on the same parts order
Called comp cams. The lifters that come in their kit (PN: K32-241-1 - Xtreme Energy 256H) has approximately 0.100 - 0.120 total travel at the lifter (not oiled up).
Part number for JUST those lifters is 832-16. Those lifters are basically a stock replacement and they're not even really that good... Was told the body should be 2.020" (same as OE) in total length.
I was recommended to try Comp Cams lifter kit 840-35 in replacement of my current lifters. They have a total body length of 2.010", but the same travel of 0.100 (approx)., and have much better internals over the stock replacement stuff.
Okay, so I finally have some time to post these results.
Here's the info I have on all my rockers before shims and after shims. Something still aint quite right, but I'm slowly narrowing in on the issue(s). Hmm.... maximum travel of the lifter is 0.060".... Seems odd... If I had the comp cams lifters as I requested, there would be 0.100" of movement @ the lifter... so I'm short 0.040 of total lifter travel (oiled up or not..).
Anywho... take a look below. Comparison is for BEFORE and AFTER I installed the shims. Installing shims gives the appearance that I have too LONG of pushrods.... HMMMMMMM..... That can't be right.....
After reading your chart I have yet another question. (I don't wanna hunt for it through 400+ replies)
New timing set I assume? Multi keyway timing set?
Yes, Cloyes Double Roller. Set to "straight up" (no advance or retard @ cam).
Also 41 overall is a helluva lot of timing at off idle. I'm my race motor I'm about 34 total at 2500.
41 is with vacuum advance connected @ idle. Initial timing is set @ 17 degrees as indicated by the second test.
17 initial seems to have smoothed out the motor a bit, but that's a subjective thing for me to say lol. It's certainly better than the initial timing I had before (below 0 Lol).
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