Valve to piston clearances w/ hyd roller lifters

[stroker87]

Ok, here gos!

being I have the hydraulic roller lifters and need to make sure the piston to valve clearances are acceptable (min .037) does it make a difference checking them with out oil in them?

I guess what I'm asking is do they build pressure that would make the clearance between the piston and valve different or is that what the .037 is for?

another question is "if" when I check this I dont have the min amout of .037 how do I get the clearance I need with keeping the quench right?

 

[grumpyvette]

first ID point out that you want a MINIMUM of about .080 thousandths piston to valve clearance, and a minimum of .100 is far more conductive to avoiding problems.
you should read thru these threads, and sub links below because most of the info's in the links and sub-links
heres some especially useful info

viewtopic.php?f=52&t=528

viewtopic.php?f=52&t=399

http://www.centuryperformance.com/check ... g-144.html

http://www.racingheadservice.com/Inform ... arance.asp

http://www.cdxglobal.com/content/sample ... ear_WS.pdf

http://www.chevyhiperformance.com/techa ... index.html

http://www.carcraft.com/howto/116_0701_ ... index.html

ISKY CAMS SELLS CUTTERS LIKE THIS TO NOTCH PISTONS

http://victorylibrary.com/mopar/rod-tech-c.htm

http://victorylibrary.com/mopar/piston_position-c.htm

obviously getting the clearances wrong, or over reveing the engine can cause problems

CROWER AND ISKY sell decent lifters,

ERSON SELLS MOREL LIFTERS
http://www.pbmperformance.com/store.php?catId=420

Ive used them without problems, ERSON sells them, in fact the last couple engines I built Ive used the ERSON lifters MADE BY MOREL,but keep in mind the cam lobe design and spring load rates have a great deal to do with the lifter life span along with the oil flow rates. the more aggressive the lobe design and the higher the spring loads the lower the lifter and cams expected life span will be, especially if you get up into valve control issue inducing rpm ranges

ok first some facts
the valves reach max lift at a time when the pistons not even near TDC

heres a typical cam timing on a good hydraulic roller cam for a SBC that IVE used frequently




heres a cam timing chart

http://www.crower.com/valve-timing-chart


heres a crank rotation and piston angle chart
http://www.iskycams.com/ART/techinfo/ncrank1.pdf

simple math shows the intake valve reaches max lift near 118 degrees atdc
when the pistons about 3" down the bore
the exhaust reached max lift while the exhaust valve and piston were also reasonably far apart or almost 2.5" down the bore , valves tend to come closest to pistons at about 10- 20 degrees before or after TDC while the valves are not nearly at full lift and the duration and LSA of the cam had far more effect than max lift
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read this[/color]
viewtopic.php?f=50&t=501&p=619#p619

 

[stroker87]

Grumpy if i read and under stand this right

1.) should use a "solid roller lifer" and push rod checker tool (setup the rockers with light springs)
2.) since I have "aluminum" rods I need to have .100 on int. & .120 on exh. clearances

now since my rods are H-beam forged do those numbers stay the same, if those numbers are off +10/-10 or so do I have to worry?

 

[grumpyvette]

generally I try for about 0.100-.125 (1/10"-1/8")on each valve to piston clearance, IVE seen guys get away with running .080-.090 but remember it doesn,t take much to loft lifters (let the lobe throw them off the surface contact) at high rpms with hydraulic roller lifters due to thier weight, so Id strongly suggest both careful verification of clearances AND keeping the engine rpms under about 6300rpm, and aluminum rods stretch more than steel so error on the larger end of the clearance range IF YOU CAN
adding a REV KIT LIKE AFR SELLs MIGHT BE WISE if you are constantly pushing that upper rpm limit

http://www.airflowresearch.com/store/pr ... ts_id=3450

 

[stroker87]

GrumpyVette,

I never really take up pasted 6k, on the dyno the highest is ever was, was 6,300rpm (found out my tech is a little slow) shifts are between 5,600 and 5,900rpms the power "peaked" right at 6k so never saw a need to go over

 

[grumpyvette]

a REV KIT certainly is an option but may NOT be necessary, youll need to try the current combo out once its adjusted correctly with a few test drives to find out, but it generally adds 300-400rpm to valve control, upper rpm limits, it certainlywon,t hurt anything but your wallet if you choose to install a kit if you feel your bouncing off the limit, but if your ignition has a rev limiter set it at 6200rpm anyway

 

[stroker87]

If I use the "solid roller" do i still need the light weight springs? or can I just used the beehives that i'm installing?

 

[grumpyvette]

a solid roller should work fine. a standard hydraulic lifter without oil under the push rod seat,should work reasonably well, remember with the seat in the lifter bottomed out in the lifter theirs not going to be a great deal of difference when your just checking the piston to valve clearance, and keep in mind the valve will usually not be at its closest at TDC, but some where in the 40 degree rotational arc from 20 degrees BTDC to 20 degrees ATDC.
installing a 1/4" thick strip of modeling clay lightly coated with WD40 and spinning the engine over by hand thru its full 720 degree cycle will usually verify the degree of interference or effective working clearance indicated in the clay depressions, after cutting and measuring with a dial caliper or dial indicator.

re-reading the links should help


viewtopic.php?f=52&t=528

viewtopic.php?f=52&t=399

viewtopic.php?f=52&t=90

 

[stroker87]

ok, I'm a little consufed

I think i've bin over loading my brain from reading so much ....lol :?

it would be "ok" for me to use my currant hydaulic roller lifter with the beehive springs or the light weight springs?

OR

get a solid roller lifter?

 

[grumpyvette]

if IT was MY engine the hydraulic lifter and light test spring route would be the way ID suggest,
HOWEVER even the beehive spring and hydraulic lifter route should get you close enough to see if your dealing with a potential problem, with piston to valve contact or very limited clearance,
ESPECIALLY if you check with a head gasket REMOVED during the mock-up test to give you a bit of EXTRA clearance once its assembled correctly.
IN most cases with a cam like your running and reasonably low compression as the pistons don,t have significant DOMES, you are most likely NOT going to have a problem, but YOU MUST CHECK!, remember in some cases advancing or retarding the cam timing will give you more clearance.
you need to maintain a good grasp on the concepts and keep track of what your doing, keep records and measure carefully, but don,t get paranoid over every single detail, or you'll go nuts, the truth is that on most things , you'll do during an engine build you need to work within a tolerance, IE a thousandth, of an inch difference in bearing clearance matters, but the same single thousandth, of an inch difference in rod side clearance has significantly less effect but the same single thousandth, of an inch difference in valve to piston clearance is meaningless

 

[stroker87]

can I just get some 2" light duty springs from the local hardware?

 

[grumpyvette]

can I just get some 2" light duty springs from the local hardware?

if they fit the retainers or come close those will be just fine for testing,
generally if you buy two of each of the 1.25"-1.375"-1.5" diam. springs that are about 2" long, one set will fit most engines well enough