ok i just came from outside and i checked my retainers and measure the heights two ways.....one with dial caliper and a machinist ruler to really get to the machined spring area.

and the results was this

intake retainer sits right at .060" ABOVE the exhaust retainer.

so the exhaust retainer is closer to the head.

this is with it set on TDC ready to fire number 6 cylinder.......i know my mark is right on the hormonic balancer and timming tap. this was checked several times during the build of the motor with a magnetic base dial indicator.

so this means my cam is retarded right?

i'll post the original question below for others to see what motor this is.


ok so can anything be said to how much is this cam retarded with a .060" difference in retainer heights........what should be my next step? advance the cam........til when?

It's getting close to go back out and start playing with my cars. And on my 80 z28 i was wanting to make some changes. It's a driver i take to work when weather is nice and it is raced during the summer at the track when i dont want to haul the "race car" out.

i'm always tinkering with it to improve the e.t. and mph. and i do alot of highway road trips with it too. hence the gear ratio.

my car is 3900 lbs with me in it and about 5 gals of fuel.

i currently have a 2.41 posi in it. but i have another rear end ready to go in that sports 2.73 gears.

last year i was crossing the finish line just at 5,000 rpms using 1st and 2nd gear only with a th350. and was shifting into 2nd gear at 6,000 rpms.

after some caculations i decided to step up the gears to 2.73 to allow me to cross the finish line at over 6,000 rpms to bring it in closer to the cams pulling power. assumming i can pull better mph out of it this summer. i'm looking for around 102-105mph trap speeds.

i know my combination is not the norm. since im running highway gears. and more compression then a street car really should have but it is working out ok. i can still run 87 octane.

my cars specs as follows:

-396 bored to 414ci
-closed chambered heads,oval port, ported and cleaned up thru out the runners. exhaust was polished, intake runners finished with 80 grit, all corners radiaused, bowl blended after 3-angle valve job, chambers polished,2.19/1.88 valves with 20* back cut.
-on the money 10.2 to 1 compression,domed KB hypers. cranking compression 155-160psi
-delta cams recommended a regrind with the following specs.
lobe center sep.....110.3
valve over lap......14.7
intake
valve opening........7.4 btdc
valve closure........45.3abdc
lobe center..........108.5 atdc
duration............232.7
cam lift............318
lift................547
lobe area...............25.95

exhaust
valve opening..........51.5
closure................7.4
lobe center............112
duration...............238.8
cam lift...............320
valve lift.............550
lobe area.........27.04

number are stated @ .050 lift on intake and exhaust.

-torker 2 low rise single plane
-highly modified 3310-2 750 holley with 72/76 jets
-msd 6al box, hei accel coil,timming set at 20* initial and 36* total at 3,000 rpms.
-summit headers 1 7/8" pri. tubes
-2 1/2" exhaust dumping at axle thru turbo mufflers
-cast crank, polished and lighten stock rods,arp bolts everywhere, balanced, crank scrapper,windage tray,rear oil pump baffle. high volume high pressure oil pump from melling.
-heavy duty pushrods,stock rocker arms,single spring with damper, lift good for just over .600
-th350 tranny with 2100 brake stall convertor.
-2.41 posi unit.

as combo stated above it ran a best of 14.47@98 mph with 2.15 60 ft running thru the mufflers on 245/60-15 street tires. shifting at 6,000 rpms and running thru the lights at 5,000 rpm.

since then i have installed/added:
-2800 rpm brake stall convertor
-roller tip 1.72 rocker arms
-K&N filter on my stock air cleaner assy (factory cold air induction set up on the 80 z28's)

now with the cam that is in there it provides little vacuum (5.5 inches @ 600 rpms) at idle. i was thinking about adding Rhoads lifters to increase vacuum and to smooth out the idle since it is rough. from what i understand they would give me my cams full value back around 3000-3500 rpms........i really dont want to give up to much on the top end because this thing pulls hard and i was planning on pulling the 6000 rpm rev limiter chip out and put in 6600 rpm chip to allow me to run it over 6000 rpms. the engine is pulling very hard to 6000 so i know there is more in it..........

i was also thinking about getting me a rpm edelbrock intake and finding a way to make it fit under the hood. from what i understand this should help out with the lower rpms but not give up to 6500 rpms.......

i guess what im looking for is a smoother idle for around town driving giving better street matters........but i dont want to loose the power it has on the top end specially now since im looking at crossing the finish line above 6000 rpms.......

i also thought about advancing the cam 2* to see what that does and even changing out my head gaskets to steel shimmed to raise the compression more about .5 to maybe increase low end torque.

right now i can run the 87 junk fuel and load the motor going up a hill and i dont have any pinging........not sure thou if another .5 in compression would send it over the top with pinging problems even with 91 octane.....

basically the bottom end is soggy to 3000 rpms and im just looking at ways to clean it up with out loosing the top end pull.

comments are welcome maybe even cam change if it doesnt effect to much on top end charge.

Originally posted by ddeennis:
advance the cam........til when? Until you reach the best static compression reading on your compression gauge. Do not advance more than 6 deg without checking piston to valve clearance. Beware of lifter bleed down during the testing skewing your results.

Originally posted by TJC:
</font><blockquote>quote:</font><hr />Originally posted by ddeennis:
advance the cam........til when? Until you reach the best static compression reading on your compression gauge. Do not advance more than 6 deg without checking piston to valve clearance. Beware of lifter bleed down during the testing skewing your results. </font>[/QUOTE]you said beware of lifter bleed down.....during the test i just did? checking the retainers?...........being that both valves are still open some it shouldnt matter should it?

or are you talking about valve clearence when i advance the cam?

right now my cranking compression is around the 155 psi mark give or take alittle from each hole.

how far do you think i should bring this up? i can run junk 87 octane fuel now. but i dont want to go to far up i guess i still want to ran no more then 91 octane. i guess i can just go a few degrees at a time and see what the results are.........

[/QUOTE]you said beware of lifter bleed down.....during the test i just did? checking the retainers?...........being that both valves are still open some it shouldnt matter should it?

or are you talking about valve clearence when i advance the cam?

right now my cranking compression is around the 155 psi mark give or take alittle from each hole.

how far do you think i should bring this up? i can run junk 87 octane fuel now. but i dont want to go to far up i guess i still want to ran no more then 91 octane. i guess i can just go a few degrees at a time and see what the results are......... [/QB][/QUOTE]

If you do repeated compression testing, your lifters will have a tendency to bleed down and cause your readings to read falsely high. You should see about 5 to 7 psi increase for every 2 degrees of advance. Do not exceed 170 psi. Do not exceed 6 deg advance without checking clearances. Make sure your valve lash is set correctly before you start testing. Your idle speed should be increased to about 900 with that cam.
Also, I have experience with SBC torker II manifolds, and they are junk. They have a really narrow power band in the 3500 to 5000 range, and nothing down low. A ported Performer would work much much better. ( not the rpm )

Dennis, I don't know if you can guess at this by that measurement, but its so close to mine, that I'd have to say retarded like 6-8 degrees. If there is a big offset bushing like mine had, flip it over and check again!

Also, with the cam in -7 or so, the P/V clearance was bigger on one side, once you advance it, it gets tigther on the other side. I forget which way it goes, retarded, closer exhaust, advanced closer intake? In my case, exhaust were tight the first time @-7 and intakes had near .200 clearance. Didnt'/couldn't check them the second time after advancing the cam to +7. HOPE the two moved the right way, tightening up the intake side. Didnt have much exhaust clearance to work with!

Dennis,
Before you change anything you need to be sure the intake & exhaust valves are set at the same installed height or you can get real goofy readings measuring from the retainer to the head.
Pull the rockers & check the height of the pushrods in relation to each other & see if you are getting the same relative readings but as was said, it sounds like it is retarded a bunch.
For info the exhaust is closer to the piston when the cam is retarded. ;)

Yeah, to reiterate what Mike said, I did have some variance in the relative installed heights (maybe .020" ) that was zero'd out of the height measurement . Good point. Should have thought to mention it. graemlins/clonk.gif

thanks for the replys guys, weather its lower .060 or .030 its still retarded and i will have a better look when i tear into it and see from the lifters i guess to how much difference it is..............this just helps to explain all other things, you know what i mean.......low cranking compression, low 5.5 inches of vacuum...........

the timming chain is a one way deal so there wasnt nothing for me to mess it up.......lol

the intake my not be much to speak of by others.....but you know what it has ran faster then a stock low rise cast iron unit and the old streetmaster intake.............and since im dealing with hood clearence issues its not going anywhere.........i think once i get the cam phased in alot of things will fall into place...........

i will post the results of my finding as soon as i get them done............this method saved me alot of time and money.........i checked a friends 350 build up this way and his showed advance with the intake retainer closer......

ddennis,

When you take the front cover off, here's the first thing to look for....
With the gears 'dot-to-dot', see if you have the mark next to the keyway lined up with the dot on the cam gear. If you do, and this is why I came up with the 'quick-n-dirty' method in the first place, the cam is retarded about 18°. The correct place to line up with the cam gear's dot is on a tooth about 2 teeth counterclockwise from the keyway. This tooth has the identical mark on it as is next to the keyway.
This is the very first thing to look for.
The second is that, if you've used an offset bushing or key, you've put it in backwards.
The third is that you have a reground camshaft. Reground cams, even UltraDynes, are ground where the new lobe goes on easiest. The cam may be advanced, or retarded, and only actual degreeing-in will help.
This is one reason that when we refinish a damaged cam lobe, we do the ENTIRE camshaft. Otherwise, that lobe may be no longer in sync with the rest.

Hope this helps,

UDHarold

udharold...........the timming set i have on the motor is the same one i have used for years even on other motors. it is a basic design with only one setting. there is only one way to put it on. and i know i have the dots lined up for i check this many times. and since i install all of my timming chains with the dots together so the engine is ready to fire on the #6 hole. this makes it easier to see the dots lined up.

my retainer heights maybe off some causeing a higher then normal reading for the test...but in any case the cam appears to be retarded to some degree.

when i crack into the motor more i will be able to make better measurements and see where everything is at.

i'm very please to know of your method which saved me money in the long run i think just knowing my cam is retarded, instead of trying to cover the problem up with intake changes and variable lifters and so on.

i will break into it soon and post more details of what i find.....

for the time being im looking for a timming chain that allows for adjustments and hormonic balancer since mine is well used and leaking some from the front seal.

and since this is a reground cam (my first) it maybe it has some retard build in as you say. combined with my use timming set.(it had alittle slop but it wasnt bad) adds up to retardedness (is that a word...lol)

thanks for all the help guys........

i will look for what you are saying udharold and let you know.........im sure it will be a few weeks before i break into.

MOVING INTO MY NEW HOUSE graemlins/hurray.gif