finding top dead center #1 for timing ignition & cam

grumpyvette

Administrator
Staff member
INSTRUCTIONS, on the procedure
0111gmhtp_pumping08_zoom.jpg

555build1-09122.jpg

Find Top Dead Center
before you can set the ignition timing or install a cam correctly youll need to know how to locate TOP DEAD CENTER on cylinder #1

yeah, it takes a bit of work and a few accurate tools, but you don,t need to do much compared to tearing the engine totally appart to expose the cam, you can meassure lift and duration accurately at a valve retainer or even more accurately with the rockers removed at a push rod tip






a simple dial indicator fixture, on a push rod tip after removing the rockers from the Number 1 cylinder, and a degree wheel on the crank hub,and a piece of graph paper and your time to graph out the lift vs degree of rotation, would give accurate info, that is going to be a whole lot less work and gives you FACTS VS guessing at the answer

http://www.harborfreight.com/multipositional-magnetic-base-with-fine-adjustment-5645.html

any time you change cams youll need to use a matching distributor gear, the cam manufacturer should be able to help tell you what matches, obviously checking clearances helps
and dipping the gear in moly assembly lube before it installed helps
be sure you inspect the distributor gear for excessive wear
especially if you changed from a flat tappet to a roller cam.
if your seeing the timing change a few degrees, back and forth,
slack in a worn, loose timing chain, worn distributor gear or not having the proper shim clearance on the distributor center shaft will provide slop that allows timing to vary several degrees

http://www.harborfreight.com/1-inch-travel-machinists-dial-indicator-623.html

http://www.igagingstore.com/MAGNETIC-BASE-FLEXIBLE-FLEX-ARM-001-DIAL-INDICAT-p/203957.htm
flexmagb.png

flexmagba.jpg

THE PROFORM SOCKETS ARE ALUMINUM
pro-67491_w.jpg


http://www.summitracing.com/parts/PRO-67492/

http://www.summitracing.com/parts/PRO-67491/

when purchasing a crank socket try to find one designed to easily accept and lock down a degree wheel

THE COMP SOCKETS ARE FAR MORE DURABLE STEEL
http://www.jegs.com/i/COMP+Cams/249/4914/10002/-1 LS ENGINES
LSCES.jpg

http://www.jegs.com/i/COMP-Cams/249/479 ... ProductId= BBC ENGINES
BBCES.jpg

http://www.jegs.com/i/COMP-Cams/249/479 ... ProductId= SBC ENGINES
SBCES.jpg



cca-4914_w.jpg

degreewheeladapter.jpg

565pv-check1.jpg

http://www.rbracing-rsr.com/compstaticcalc.html

use of a camshaft install handle generally reduces the chances of damaged cam bearings
CCA-4919_xla.jpg

cca-4919_w.jpg


READ RELATED LINK
viewtopic.php?f=53&t=3554&p=9433#p9433
YOU CAN AVOID POTENTIAL CONFUSION & PROBLEMS IF YOU TAKE THE TIME TOO, DEGREE THE CAMSHAFT IN, instead of relying on "dot-to-dot".
btw when checking for TDC its usually best to pull all the plugs it makes spinning the engine by hand FAR easier
Fasten the degree wheel to the crank, with a washer and a crank damper bolt.
http://www.circletrack.com/enginetech/c ... to_12.html
degreepointer7.JPG

Degree_Wheel.JPG

degreewheeluse.jpg


timingchain4E.jpg

WHEN CRANK IS AT TWELVE AND CAM IS AT SIX THEN #6 CYL IS FIRING AFTER YOU LINE UP YOUR MARKS AND INSTALL GEAR THEN ROTATE YOUR CRANK ONE

REVOLUTION AND THEN DROP THE DIST. IN - AT THAT POINT
scan10001B.gif

mrg-4600.jpg


CLOYESGR.jpg


Proform Parts 66830 - Proform Cam Checking Fixture Kits
pro-66830_cp.jpg

4-stroke-process.jpg

CamTimingGear04.jpg


ordety.jpg

Take a stiff 1/8-inch TIG welding rod or similar material and sharpen one end to form a pointer, and wrap the other end around your needle nose pliers so that a 360 degree loops formed so a bolt and washer can secure the pointer wire to the block in a convenient bolt hole location.
Attach this pointer so that it rests very close to the damper and the point is at the degree wheel edge to eliminate parallax viewing error.
IF THE HEADS ARE OFF THE BLOCK
Obtain a stout strip of steel about seven inches long, drill three holes, two for head bolts and one centered on piston.
Put a bolt in the center hole to stop piston movement.
OR IF youve got the tool required, ...A deck bridge you can bolt it in place and insert a bolt that prevents the piston from reaching and passing thru top dead center in its rotation,
deckbridge.jpg


deckheight.jpg


This strip or the correct tool,is then placed across the center of No. 1 cylinder bore and bolted on each end to secure it to the block.
Caution: Be sure that the strip of steel is rigid enough so that it will not be deflected when the piston contacts the center bolt stop.
Incidentally, the positive stop should be adjusted so as to stop the rotation the crankshaft in normal running direction (clockwise) until the piston crown lightly strikes this stop.

Now, radially turn and lock the degree wheel to the crankshaft at 40 degrees before T.D.C. at the pointer.
Rotate the crankshaft backwards to the positive stop.
If the degree wheel reads 40 degrees from T.D.C. you have hit Top Dead Center exactly, and the zero mark between the two 40 degree readings is absolute T.D.C..
However, if your readings were unbalanced, you will have to split the difference (your errors in degrees) by moving the degree wheel radially on the crankshaft.
Then, try again until you get exactly the same degree readings against the positive stop on either side of T.D.C.
NOTE: The lower the positive stop is located below T.D.C., the greater the degree readings will be.
The results will always be accurate.
T.D.C. always lies equidistant between the two positive stop readings.
http://www.totalengineairflow.com/tools

MOR-62191a.jpg

4914r.jpg


IF THE HEADS ARE ON THE BLOCK


youll screw a piston stop into a spark plug thread hole and accomplish the same thing

pistonstop.jpg


yes all the instructions and details are located in the links so youll want to read thru them

http://www.frontiernet.net/~ennis/tdc.html

http://www.iskycams.com/techinfo_index.html

http://www.lunatipower.com/Tech/Pistons ... eight.aspx

http://www.2quicknovas.com/2qntdc.html

http://www.romac.com.au/Std_&_Offset_Crank_Info.pdf

viewtopic.php?f=44&t=464

viewtopic.php?f=52&t=90

http://www.classiccarauto.com/impala/ho ... _tdc.shtml
YOULL WANT THESE TOOLS TO DO IT EASILY

http://store.summitracing.com/partdetai ... toview=sku
cca-4795.jpg


http://store.summitracing.com/partdetai ... toview=sku
cca-4914_w.jpg

http://store.summitracing.com/partdetai ... toview=sku

sum-g1057_w.jpg


ttp://www.fourwheeler.com/howto/67578/index.html


http://www.2quicknovas.com/happyTDC.html

http://www.summitracing.com/parts/MRG-4599/?image=large

mrg-4599_w.jpg


http://forum.grumpysperformance.com/viewtopic.php?f=50&t=723

http://www.summitracing.com/parts/MRG-4598/

http://www.rodandcustommagazine.com/tec ... index.html

http://www.hotrod.com/techarticles/sett ... index.html


they make these for BOTH SBC AND BBC , and IN SEVERAL DIFFERENT DAMPER SIZES ,SO BE SURE YOU ORDER THE CORRECT ONE FOR YOUR APPLICATION
 
Last edited by a moderator:
I want an accurate measure on TDC; the process looks pretty simple except for the feel when the piston hits the stop when using this tool. How hard is it to feel the top while turning the crank (plugs out) without damaging anything?

Brad
Now lets go through the procedure one more time.

1. Install the piston stop in cylinder #1.
2. Turn the crank by hand until it stops.
3. Put a mark on the balancer exactly in line with "0" on the tab
4. Turn the crank in the opposite direction until it stops again.
5. Put another mark on the balancer exactly in line with "0" on the tab.
6. Remove the piston stop.
7. Use a tape measure to find the point exactly midway between the two marks.
8. Put a third mark on the balancer at the midway point. THIS is the mark you will use for setting the timing. When it is lined up with "0" on the tab, #1 will be at TDC.
cca-4795.jpg
 
Last edited by a moderator:
while your verifying tdc, if your turning the engines crank with a breaker bar on the front crank/damper bolt its done, with the engine out of gear, slowly and carefully turning the assembly and its rather obvious when its stopped solidly, against the piston stop, you then mark the line on the damper, reverse, rotation and use the second mark when it stops as a second marker,the true TDC is 1/2 way between the marks, obviously having a degree wheel installed, and a stiff wire as a pointer on the rim of the degree wheel, makes this far easier
 
Last edited by a moderator:
"HEY GRUMPYVETTE??
I tried to use a spark plug hole piston stop on my 496 and had to use a 4" bolt to bottom it out (the included stop didn't bottom out). Trouble is no matter what I did to turn over the engine it never stopped. (My guess is that the piston stop bottomed out in the head not the cyl. and piston top). I turned over the engine 720 degrees but not stop at all.
So here is the question:
Can someone explain this better than I have? Is there a special BBC head on piston stop? "
http://www.summitracing.com/parts/SUM-G1057/?rtype=10

the problem you experienced is not rare with flat top, or dish pistons in a BBC simply because the spark plug entrance angle is very shallow in the heads of most bbc engines. before you start,be sure to take the rocker arms loose and remove the push rods on that cylinder on that big block Chevy because if you do not TAKE THE PUSH RODS FOR THE CYLINDER BEING POSITIVE STOPPED, OUT OF THE ENGINE WHEN YOU DO THIS OPERATION, its possible to cause internal damage, bend valves etc.
thats one reason most guys do that with the heads off. a piston stop with a bent bolt in the plug adapter, thats inserted then, you turn the bolt so the bent part is facing down and the lock it with a outside nut, can be custom made but bend the bolt so you can have the screw slot aligned with the bend as it helps you get it indexed.
[/color]Id also label BOTH ends of each ignition wire, any decent label maker can produce sticky number tags far cheaper that the kits but even the kits are cheap
wirenum1.jpg

wirenum2.jpg

viewtopic.php?f=50&t=6098&p=18837&hilit=label#p18837
3M sells these really handy number tape tags

12174.jpg


http://www.clarcorpindustrialsales.com/ ... -p/wmd.htm
at about $30- $45 for a fully loaded dispenser it seems expensive but its really a bargain


checkingdeckheight.jpg


pistonstop.jpg



bentpstop.JPG


openchamber3.jpg
 
Hey grumpyvette?
I had to buy an adjustable timing tab for my new 8" balancer. So I used a degree wheel and found TDC (0* degrees) and pointed the red arrow in the picture at it. However, the white 0* mark on the balancer doesn't match the true 0*on the timing tab ?. Should I etch a new line on the balancer at the true 0* mark and paint black over the existing timing marks, as you can see the damper is about 4 degrees out from the timing tab arrow?

Any help would be appreciated.

BTW I assume you gentlemen do know theres
even a correct and very inexpensive tool for spinning it from the flex-plate or flywheel


https://www.summitracing.com/parts/wmr-w80510/overview/

https://www.summitracing.com/parts/sum-900178/overview/

55580530.jpg

Timingpt.jpg


the REASON you have an adj pointer,is that it allows you to move the red arrow pointer to point to the TRUE ( 0 or TDC) on the damper, so obviously in this case the timing tab red arrow gets moved about 4 degrees to make the lines on the damper, arrow and reality match, it makes no real difference if the dampers a few degrees off provided the timing tab used is matched so it shows exactly the correct timing, theres no need to mess with the damper; just set the pointer to point at the 0° mark on the damper when the piston is at TDC.

the marks on the cheap stamped metal tabs are rarely correct
mrg-4593_w.jpg


the arrow adjusts to show reality using the marks on the damper
spe-4237_w.jpg

stock_tab_2.jpg

timing-marks.jpg

KEEP IN MIND that theres TWO totally different damper and timing tab locations that are correct on the SBC engines and you must use matched components for almost all years the ting tabs and dampers show TDC to be at about 2 o,clock, but theres a few applications that used a 12 o,clock timing tab and damper combo and you can,t mix&match the two types

use the correct damper instal tool NEVER beat a damper with a hammer
p168788.jpg


if you find having the timing tab marked distracting you should use an adjustable pointer like this one below

ati-918950_w.jpg


while you have the engine on an engine stand with the heads off ,and having the correct crank snout adapter and a decent degree wheel and a stiff coat hanger wire makes it easier to locate TDC
pro-67491_w.jpg

degreewheelindicator.jpg


checkingdeckheight.jpg


pbd1.jpg

pbd2.jpg

pbd3.JPG

555-81625.jpg

MOR-62190.jpg

image_1450.jpg

CCA-4926.jpg

degreewheeladapter.jpg

ctrp_1012_01+race_engine_rebuilding_tips+.jpg

cam_checker1.jpg

camposition.jpg


degreeten.png

http://garage.grumpysperformance.co...ectly-and-get-it-to-last-cam-install-info.90/

http://garage.grumpysperformance.co...ifter-for-checking-cam-timing.3745/#post-9950

http://garage.grumpysperformance.com/index.php?threads/degreeing-in-a-cam-correctly.3097/#post-8240

http://garage.grumpysperformance.com/index.php?threads/cam-degree-equipment-tools.1759/#post-4440

http://garage.grumpysperformance.com/index.php?threads/precision-measuring-tools.1390/#post-12997



cambreakin.jpg

62191_ATA.jpg

scan10001B.gif

SUM-G1056_xl.jpg

cambutclear.jpg

http://garage.grumpysperformance.com/index.php?threads/how-to-pick-timing-gear-set.4548/#post-43700

http://garage.grumpysperformance.com/index.php?threads/timing-chains.2209/#post-32459

http://garage.grumpysperformance.com/index.php?threads/timing-chains-stretch.5734/#post-17492

http://garage.grumpysperformance.com/index.php?threads/cam-spacer-buttons.1793/#post-4553

http://garage.grumpysperformance.co...ear-articles-you-need-to-read.282/#post-57371


SPRAYING ALL VALVE TRAIN COMPONENTS DURING ASSEMBLY WITH MOLY REDUCES FRICTION
molysp3.JPG

molysp2.JPG

molysp1.JPG

pre-spraying all bearing and valve train components with a moly based spray, helps embed micro moly lubricants in the metallic surface micro fissures , a good paste lube like cranes assembly lube over the spray surface helps insure a good lubricant surface coating, that is far stronger than just the ZINC and PHOSPHATES in oil
crn-99004.jpg
 
Last edited by a moderator:
Back
Top