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I can see his point about compression on the loaded side... so I can understand saying that it's going to have more clearance on the unloaded side, under load... but I would assume that the clearance on the unloaded side would be the same regardless of which thickness shell is on that side...
So yeah, I concur with you Eric.

The rest of the article seemed informative, if you have several hundred dollars worth of gauges...
 

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Discussion Starter #123
I've been assembling the short block. Got all the main and rod bearing clearances worked out. They came out pretty good, 1-4 mains at .0026-.0028 with .0036 on rear main. Rear main took both +.001 shells. Rods are all split shell, .001/std at .0026-.0027. Apparently it doesn't matter much, but I put the .001's in the block and rods. I went to set the ring gaps and can't find my ring filer. Haven't used it in a while. I might have loaned it out and never got it back. Anyway the short block assembly is dead in it's tracks 'til I get a new ring filer coming. I should have it Tuesday. I'm going to put the 1,2 7,8 pistons in ringless and check deck heights today.
My cam came in yesterday way ahead of schedule, so I can go ahead and degree in the cam, too.
Here are the cam spec's off the card.

[email protected] .050: 215/224
Adv. Dur. 284/296
Valve lift .470/.490 w/ 1.5 rockers
Centerline 108/116
Lobe Sep. 112
Overlap: 0
Recommended Spring Pressure: 125/350

I checked one exhaust valve earlier with my new height mic and with the .060 thick locator and the recommended retainer, I came up with about 1.882 available spring height, so either .075 or .090 worth of shims to end up at 1.807. With these springs installed @ 1.807, seat is 147# and 331# @.470 lift. Installed at 1.792, I get 154 / 337. That's a little heavy on the seat and a little light on the nose, but I think it will be OK. My Straub in my 383 is .580 lift and only 375 on the nose. .100" or so less lift on this one. It looks like this spring could have used a little more spring rate. If I thought about it, I could probably calculate a perfect rate, but I think what I have will work. I could always send them back, but I don't think it is worth it. What do you think?
 

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I worry a lot about seat pressure it’s what snubs bounce as the valve is closed. Especially for fast ramps and high lifts getting the valve to sit tight on the seat can be a problem. High spring pressure over the top is simply a byproduct of trying to get the valve seated. One advantage of less pressure over the top is with solid lifters you can use the inertia of the valve train to loft the valve beyond the cam’s stated lift. But this is an area of complicated cut and try which is time consuming. For hydraulics this trick leads to pump up which then needs other solutions which are not easily applied. I tend to run my hydraulic engines on this edge but it takes considerable modification to lifters and oil system to keep them safe.

Bogie
 

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Discussion Starter #126
One advantage of less pressure over the top is with solid lifters you can use the inertia of the valve train to loft the valve beyond the cam’s stated lift.
We did this with the Briggs and Stratton 5 hp single cylinder motors for my son's racing go kart. It was pretty wild. You could hear it go into float at the end of the straight and the kart would just jump. You couldn't cheat, because the motor got tech'ed if you won, but he won a lot of kart races with that little trick!
 

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jaw22w: Are you using a dial bore gauge with .0001 accuracy?
Just wondering, since I was looking at them and didn't want to spend that kind of money!
 

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Discussion Starter #131
More progress. I got the cam degreed in. ICL came in at 107.5 on a 108 spec. Close enough. I then mocked up the timing chain cover with the cam button and checked cam end play. I can't get an indicator to the back of the cam while it is on the stand, but moving it back and forth it seems to be in the .005 or a just little plus range. Seems okay to me. I am using a stock steel timing chain cover and was a little worried about flex, but I am also using a short water pump, and the back of the pump is actually pushing in a couple thousandths on the timing chain cover. There is more endplay with out the water pump. So I think I will be okay there.
The heads are together. I didn't have any problems assembling them, and I learned a few things along the way. These ProMaxx Maxx heads really look nice.
My new ring filer should be here tomorrow, so I can continue short block assembly. If I get lucky and the 7.4 pushrods I have on the shelf work, I might make my 2 week target.
 

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If you're using a standard base circle cam, and tie bar lifters that are +.300, I'd expect it to need 7.6 pushrods.
7.8 - .300 + .100 (the valve height should be +.100 on those heads).
My 383 has a .050 smaller base circle cam, and it measured out to needing 7.650 pushrods (+.300 lifters and +.100 valve height).

Is there something I'm not aware of that would make you expect 7.4 to be right?
I don't know how far you can fudge it, I'm just saying it wouldn't be the "correct" length.
Did you do a geometry check when you made that length assessment??

Reason I ask is the 7.800" length is stock FLAT tappet length....stock hydro roller pushrod length is right close to 7.300" length, since the hydraulidc roller lifters are automatically taller than flat tappet lifters.
With a .050" smaller base circle and a +.100" longer valve I'd expect your assembly to fall into the 7.350 to 7.450" range...7.650" seems way off.

That +.300" figure you mentioned for the lifters is just the height of the tie bar fastener location being taller so it clears the taller roller style lifter bores(this is in comparison to older flat tappet blocks with shorter lifter bores and the roller lifters designed around that lower height.)...the pushrod seat is not raised from a typical hydraulic roller pushrod cup height....so the way you showed for math is just not correct....wrong use of flat tappet pushrod length minus bogus +.300 taller lifter height are both false for any hydraulic roller set-up.
That +.300" is only on the outer body of the lifter, not the pushrod cup height.
 

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Well that would be a big misunderstanding on my part then...
The odd thing is that I did do that whole geometry check, and came up close to 7.650...
I guess I'll have to go through that whole check again.
 

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Well that would be a big misunderstanding on my part then...
The odd thing is that I did do that whole geometry check, and came up close to 7.650...
I guess I'll have to go through that whole check again.
I won't say the 7.650" is for sure wrong, just the math you gave didn't track, and that 7.650" is a number I have never seen in an SBC before....so I just wanted to be sure you had figured things out and ended up with a good geometry.
You could have lifters of a design I'm not familiar with, maybe the base circle is smaller than you thought or what it was supposed to be, or who knows and could be I"m just wrong.

Just was a very odd number for what I'm familiar with, so I wanted to bring it up so it could be confirmed.
 

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For the time being, let's just assume I was wrong... in the meantime I'll go through the geometry check again and try to figure out how I made the incorrect number work...
 

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I'm not sure what I had done differently before, but I just ran through it a few times, and it does appear that 7.45 - 7.5 seems like it's pretty accurate.
So based on the correct base numbers, provided by Eric, I'd assume that 7.450 would be where I'd expect to be...

Since this whole process is based on "eyeballing", it now seems to me that it might actually be easier to "have the correct numbers in the first place"... and start with your checker pushrod at the length you expect to need.
Snug up your locknut, then perform the process backward... back off your locknut 1/2 the gross lift, then check to see if the line on your rocker is parallel to the spring retainer.
If it looks good, it most likely is.
If it doesn't look good, then repeat the process in the normal order and see what you come up with.
I'm willing to bet that if you have the right numbers in the first place, the reverse order process will work out.
If it doesn't, then either something is wrong, or you had the wrong numbers for some reason.
So it would be changing it from "figuring out what it should be" to "making sure it is what it should be".

I think I was aware of the correct numbers at some point, but that was last year, before the virus and waiting and waiting and waiting months for my machine work and heads...

To the OP: sorry for questioning what you were doing... I'm glad it at least served a purpose... in reverse.
 

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Discussion Starter #138
I'm not sure what I had done differently before, but I just ran through it a few times, and it does appear that 7.45 - 7.5 seems like it's pretty accurate.
So based on the correct base numbers, provided by Eric, I'd assume that 7.450 would be where I'd expect to be...

Since this whole process is based on "eyeballing", it now seems to me that it might actually be easier to "have the correct numbers in the first place"... and start with your checker pushrod at the length you expect to need.
Snug up your locknut, then perform the process backward... back off your locknut 1/2 the gross lift, then check to see if the line on your rocker is parallel to the spring retainer.
If it looks good, it most likely is.
If it doesn't look good, then repeat the process in the normal order and see what you come up with.
I'm willing to bet that if you have the right numbers in the first place, the reverse order process will work out.
If it doesn't, then either something is wrong, or you had the wrong numbers for some reason.
So it would be changing it from "figuring out what it should be" to "making sure it is what it should be".

I think I was aware of the correct numbers at some point, but that was last year, before the virus and waiting and waiting and waiting months for my machine work and heads...

To the OP: sorry for questioning what you were doing... I'm glad it at least served a purpose... in reverse.
The pushrods in my 383, Profiler heads with HR cam uses 7.45 pushrods. I am just finishing my coffee, then going through the mid-lift method on the new motor. I expect it to need 7.45's but maybe I'll get lucky.
I just remembered that I had to go to a longer rocker stud in the Profilers because of insufficient thread engagement for the polylocks with the mid-lift technique. Hope I don't have to do that here. I also need to check for pushrod to head interference, but these Promaxx heads already have some work done in this area. We'll see. The last three sets of aluminum heads I have used, Dart, Profiler, and ProComp have all needed some massaging for pushrod clearance. I have a set of non-adjustable guide plates, but have never been able to make non-adjustable plates work with any of the above mentioned heads, so I may either have to split these plates or buy a set of adjustable plates. All I have to do is get off my butt and get at it. I'd like to have all this done by about 4 PM when my ring filer should arrive. Ok, coffee's done. I'm after it.
 

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Discussion Starter #139
Yep, just what I figured. The 1.8" studs are too short. They are what came with the Profilers. The start of the mid lift deal is to get the lifter perpendicular to the valve stem on top of the closed valve. When I do that I can't get a poly lock on. It's flush at the top of the stud. I tried to use a dial indicator on the valve and set it at half lift and set the height of the trunnion from that, but my light checking springs pushed the oil out of the lifter. I will just have to wait on the taller studs and do it Foxwell's way (Straub).
Well, my ring filer is here so I can get back to short block assembly.
 

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Yep, just what I figured. The 1.8" studs are too short. They are what came with the Profilers. The start of the mid lift deal is to get the lifter perpendicular to the valve stem on top of the closed valve. When I do that I can't get a poly lock on. It's flush at the top of the stud. I tried to use a dial indicator on the valve and set it at half lift and set the height of the trunnion from that, but my light checking springs pushed the oil out of the lifter. I will just have to wait on the taller studs and do it Foxwell's way (Straub).
Well, my ring filer is here so I can get back to short block assembly.
Dang, I just went through that too short of a rocker stud problem with my build.
I ended up just going a shorter pushrod. But I'm wondering how much I'm leaving on the table would not doing it 100% the right way?
Anyways, did you end up getting Straub's rocker arms that are set up for the + 100 long valves and aluminum heads?
Only reason I'm asking, I got tired of waiting on mine and just threw some crane Gold's on it!
 
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