Too much lifters preload

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Zwap

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Did a little work on my stock 2bbl 383 -66 this winter:
New Lunati 60301 camshaft complete with Lunati hydralic lifters
New timing chain and gears
Used but rebuild 915 heads
Mopar OEM steel head gasket
New 8.575 pushrods
New steel rocker arms

Here's my problem:
When I check lifters preload I end up with about 0.110 preload which is far too much.
The block is not decked and I've been measure the heads and they are not milled.
I've measure the old stock lifters together with the old pushrods and get a total lenght less than 0.020 shorter than my new lifters and pushrods total lenght.
I tried with my old rocker arms but get the same 0.110 preload
I tried to measure the height of the valve shafts and as far as I can see i get the same height compared to my old 516 heads.

Of course I can order a set of shorter pushrods but I can't figure out why?
Is shims out of the question? It's not that easy to find the right lenght of pushrods here in Sweden...
 
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On the lifter, check the height of pushrod seat.
 
OK, but what should i do then? I cant adjust the seat height and the total lenght of the lifter and the pushrod (seated) is less than 0.020 shorter than the old lifter and pushrod, that's the only thing I measured that should increase preload compared to the old setup.
I've read on serval places that factory length of 383 pushrod is 8.575 but on Lunatis page they have 8.555 as factory replacement, that would explain the 0.020, but then I would stil get 0.090 preload, at least 0.030 too much.
 
The camshaft "base circle" dimension can also be a factor in the all this math!
 
Correct, I missed to write that, but I've have check that too, exactly the same base circle.
 
Other factor I see is, on these "rebuilt heads", what is the end result of the seated height of the valves? If they have been ground to death and sunk the valve tip may be too tall, taking away useable geometry and causing too much lifter preload! If it's possible, measure from the spring pad surface (as long as it hasn't been modified) to the tip of the valve and I'll check the gauge measurement we have at work to see how it compares.
 
OK, done that "I tried to measure the height of the valve shafts and as far as I can see i get the same height compared to my old 516 heads."
But I don't remember the numbers, I'll do it again and come back with the numbers.
 
Using a tool manufactured by Miller Detroit c-3648, The range measurement from the unaltered valve spring seat pad to the tip of the valve stem is; 2.125" to 2.090".
 
the last time I used those valves they only came with a .100 longer stem, so check stem height.
 
Max1196 said:
Using a tool manufactured by Miller Detroit c-3648, The range measurement from the unaltered valve spring seat pad to the tip of the valve stem is; 2.125" to 2.090".
Click to expand...

Well, I've measure them to 2.126" which is a tiny bit tall so in theory I could shim them 0.035 and keep valvetrain geometry if 2.090" is whithin tolerance.
Then I shuold get about 0.075 preload, a little bit much but a bit closer and then I don't need to change pushrods.
What do you think about that?
 
RustyRatRod said:
Get shorter pushrods.
Click to expand...

I'm with Rob here, but, I think you are going to do what ever you want.

But think.......if you lift the rocker shaft up from the head you also change the distance to the valve tip. So......if you raise the shaft .035" you will change the preload at the lifter approximately .058".

.035" at the lifter and .023 at the valve side = .058"

.035/1.5 = .023333333 (because of the 1.5 rocker arm ratio).

I'm gong nuts. I'm wasting too much time on these stupid forums.
 
OK, thanks!
Yes, of course you'r totaly right, I didn't think of the 1.5
I think it'll be 8.500" pushrods

I'm glad that you (and others) are wasting your time on these stupid forums :)
 
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Use IQ52's math, that's how it is... Now options can be using a set of FORD 429 style push rods, (yes they have an oil through design but sooo.) View options like Comp. Cams 7843-16 or 7640-16 or something similar.
 
Does "For Use with Guideplates" means that they HAVE to use Guideplates or can I use them without?
The reason I want to use the above TrickFlow pushrod is becuase I can get them localy.
 
Zwap said:
Does "For Use with Guideplates" means that they HAVE to use Guideplates or can I use them without?
The reason I want to use the above TrickFlow pushrod is becuase I can get them localy.
Click to expand...
That just means the stem material is strong enough to withstand the possible wear that could result from the pushrod rubbing on the plate. You're good to go. Check pushrod to cylinder head clearance, they are fatter, .375 instead of .312...
 
I just noticed this!!! Be aware that, that listing is of a quantity of 8!!!
 
Up till 1967 the push rod was longer and the seat in the lifter is deeper to accomadate the extra length Ur push rods are alittle smaller on the lifter end if they are factory. All cam and lifters are made for the 1968 up pushrods. Can u post a pic of ur pushrods. I believe the oal is .075 difference. Kim
 
Yep, I'm aware of that, and because of that I ordered the cam kit with incuding lifters and 1968 up pushrods with 5/16" dia ball in each end.
The old one was like you describe but the total lenght of the old lifter and the old pushrod seated (measured from the bottom of the lifter to the very top of the seated pushrod) is less than 0.020" shorter than my new lifters and pushrods total lenght measured the same way.
I've now ordered Comp Cams 7843-16 which are 8.500" or 8.490" depending on where you read about them, and I hope they are going to solve my issue.
 
The main problem now is that everybody makes 1 lifter for an and be mopars and that lifter is the ab lifter. Be lifters had the seat .075 thou lower in the body. I know this as I have a couple sets of the Mopar lifters and compared them. Kim
 
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