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Username Post: Setting Initial Timing?        (Topic#341791)
farm rat 
Forum Newbie
Posts: 37

Reg: 09-13-16
01-09-17 12:54 PM - Post#2670299    

Ok, so when I built my motor this summer with new cam and etc. the one thing I was worried about was getting the initial timing set so the engine would fire right off for the cam break in.
With intake off I stuck an extension in number one hole until I could feel the piston coming up. I made sure my timing marks were lined up and both valves were closed. In my mind I was at TDC on the compression stroke.
Put the intake on and installed the distributor to where the rotor was pointing at number 1 on the cap. Locked everything down. Sure enough when we went to fire it up I was 180 out. WTF??

Now I read in the sticky on common mistakes that if you use the dot to dot method when installing a cam (which I did) you will be 180 out.

What am I missing here??? What should I have done?

This is something that has bugged the crap out of me ever since.



 




LUVmachine 
Frequent Contributor
Posts: 1159
LUVmachine
Age: 35
Loc: Redding Ca
Reg: 10-02-14
01-09-17 03:58 PM - Post#2670324    
    In response to farm rat

Been there and done that. It's just part of the learning curve. Most of what I know is because I learned it the hard way.

71 C-10 454 with weiand 177
72 406 sbc powered Chevy LUV sleeper (SOLD)
2010 GMC Sierra crew cab 4X4
http://s626.photobucket.com/user/GJohnson81/libra r...


 
Rick_L 
Honored Member
Posts: 26966
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
01-09-17 05:15 PM - Post#2670347    
    In response to farm rat

You should have used the "dot to dot" method to install the cam.

But when you go to install the distributor, if you have the engine in the "dot to dot" position, you are 180 degrees out.

That's Ok, all you need to do is rotate the engine 360 degrees and install the distributor. This puts the engine at 0 degrees TDC on the #1 cylinder on the compression stroke.

You didn't say how you determined that #1 was on the compression stroke, but you missed it.



 
bobb 
Super Senior Member
Posts: 5264
bobb
Loc: paradise
Reg: 09-05-03
01-09-17 08:25 PM - Post#2670379    
    In response to farm rat

you should have installed the cam, adjusted half the valves, turn the engine 360, adjust the other valves, and you would have been at #1 tdc. then turn the engine to + - 10 degrees btdc, drop the distribitr in rotor at #1, turn the the distribitr back and forth with the key on so you can hear the spark as you advance it. when it sparks thats where you snug it down for initial firing. i know this is oversimplified but thats it in a nutshell.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
0utlaw 
Very Senior Member
Posts: 2691
0utlaw
Loc: New Hampshire or Florida
Reg: 09-10-02
01-10-17 03:35 AM - Post#2670405    
    In response to farm rat

You verified TDC so....similar to last post,
dropping in the distributor is EASY
When you feel no.1 piston come up, it must be on the compression stroke.(use a screw in gauge if needed) At that point the timing mark will approach TDC. Turn the motor by hand until you are at 8 or 10 btc. I drop in the distributor so the rotor can sweep by no 1 with plenty of swing room. Then I attach a timing light to number 1 with the trigger jammed, turn on the ignition and sweep the distributor. When the light flashes, I have a perfect STATIC timing. I lock it down. Turn off ignition. It assures good runability on start up. And almost guarantees no backfire in the carb.



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 16869
grumpyvette
Age: 68
Loc: FLORIDA USA
Reg: 03-16-01
01-10-17 06:59 AM - Post#2670421    
    In response to 0utlaw

IF you find the engines hard to start after a cam instal, theres a very good chance you installed the cam using the DOT-TO-DOT method and you forgot to rotate the engine one full revolution BEFORE dropping the distributor into the engine, you might be reading the info incorrectly, cams are generally installed using the DOT-TO-DOT method for easy installation without a degree wheel, this places the cam timing at TDC on the number 6 cylinder, simply rotating the engine one complete revolution after the cams installed using the DOT-TO-DOT method, brings the #1 cylinder up to TDC , thats when you drop the distributor into the engine with the distributor rotor facing cylinder #1
(remember the cam rotates at 1/2 the speed of the crank, so every other full rotation brings the cam and crank timing in alignment at TDC for number 1 cylinder.
If theres one constant fact I learned the hard way early on in this hobby its the fact that , most of us learn from our mistakes,and yes IVE made my share, but I do learn not to repeat the same ones twice,
30 minutes spent reading instructions very carefully can save hours of wasted effort




http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...


IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 01-10-17 07:10 AM. Reason for edit: No reason given.

 
farm rat 
Forum Newbie
Posts: 37

Reg: 09-13-16
01-10-17 07:58 AM - Post#2670429    
    In response to grumpyvette

Well the motor was on an engine stand when we did this.

So to maybe over simplify.

Install the cam dot to dot. Set the valve lash by however means. I actually found a rotation online that mimics the firing order when adjusting the valves and was pretty straight forward. Once the valve lash is set return the crank to dot to dot, then rotate one revolution back to TDC and THEN install the distributor.
Sound right?



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 16869
grumpyvette
Age: 68
Loc: FLORIDA USA
Reg: 03-16-01
01-10-17 08:16 AM - Post#2670433    
    In response to farm rat

yes that sounds correct!

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
farm rat 
Forum Newbie
Posts: 37

Reg: 09-13-16
01-10-17 09:17 AM - Post#2670440    
    In response to grumpyvette

Thanks Grumpy



 
0utlaw 
Very Senior Member
Posts: 2691
0utlaw
Loc: New Hampshire or Florida
Reg: 09-10-02
01-11-17 07:42 AM - Post#2670562    
    In response to farm rat

Some guys rotate engines around by hand and adjust valves cold. Others actually run the engine and adjust valve lash hot and running. So I chose hot and running with the idea that I could get a valve closer to acting like a solid cam and lifter setup. And that different metals expand at different rates. I adjust till the click stops and turn 1/4 of a turn. I feel that you get more out of a motor this way.
Do I get oil mess? I first take out any slack on valves that are up. I do it on a slightly warm engine with a homemade shield to stop spitting. One side at a time...leave the other cover on. Back off and adjust all of them till the click stops. I then do the final 1/4 turn on each one.....with the engine off. This way I never get a motor trying to stall every time I adjust a valve. I, then restart and quickly double check my work.




 
busterrm 
Frequent Contributor
Posts: 1209
busterrm
Loc: Wichita Falls, Tx
Reg: 08-30-10
01-11-17 08:51 AM - Post#2670569    
    In response to 0utlaw

The method I use, I get #1 @ TDC on compression stroke, both valves are on the cam's base circle. Adjust both valves, rotate engine 90 degrees adjust next in firing order, etc. When I am adjusting #1 is when I slide in the distributor. I keep going through valve adjust, distributor eventually drops against the block, after all valves are done I run plug leads. I get three tasks done in shot order and accurate.

==== BOB ====
If I can't smoke the tires I want more!

1976 Chevy Nova
2007 Chevy 1500 1/2 ton
2008 Harley Davidson XL1200 Sportster


Edited by busterrm on 01-11-17 09:01 AM. Reason for edit: No reason given.

 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 16869
grumpyvette
Age: 68
Loc: FLORIDA USA
Reg: 03-16-01
01-11-17 09:02 AM - Post#2670572    
    In response to busterrm

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
0utlaw 
Very Senior Member
Posts: 2691
0utlaw
Loc: New Hampshire or Florida
Reg: 09-10-02
01-11-17 05:23 PM - Post#2670641    
    In response to grumpyvette

Hey Grump...lots of good info
Great effort! OUTLAW



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 16869
grumpyvette
Age: 68
Loc: FLORIDA USA
Reg: 03-16-01
01-11-17 05:28 PM - Post#2670642    
    In response to 0utlaw

always glad to help!
  • Quote:
when your checking, a valve train, and spring clearances, your far better off too deal in proven facts,and verified measurements, guessing will only get very expensive when you find out your wrong

http://garage.grumpysperformance.com/index.php?threads/checking-pist on-to-valve-clearances.399/

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 01-11-17 05:32 PM. Reason for edit: No reason given.

 
Bel Air kiwi 
"2nd Year" Silver Supporting Member
Posts: 2082
Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
01-12-17 12:05 AM - Post#2670685    
    In response to grumpyvette

Hi Guys, to put this in plain English. 1 and 6 pitons are at tdc at the same time, but always supposed to be 180* opposite on the cam. The only way to get that wrong is to install a cam with a different firing order, and that's not easy on a SBC.
Whether you put the cam in correctly for No1 or No6 only really matters if the distributor doesn't match.
Because cams turn at half crank speed in a 4 stroke what is 1/2 turn out when cam referenced is 1 turn out when crank referenced which is why what the guys are telling you above works for the SBC.

If its a different brand, firing order, or number of cylinders it wont be always six paired with one. Some makes have two firing orders in the same family. Eg Windsor v Cleveland V Late Windsor.

When you have the cam in, the partner cylinder to No1 has the valves rocking and No1 has its valves both shut for the distributor rotor to point at No1 cylinder cap post for firing, however many degrees it should be statically advanced.

Everybody I know has goofed this at some stage including timing the cam out 180*, the dizzy out 180* and the firing order wrong or turning backwards. Paired cylinders are easy to spot on a dizzy as they are opposite each other and you have to change the crank and cam to alter this so its very uncommon. Other people or you getting the firing order wrong is far more common.
Its only easy when you do it all the time.

Cheers Kiwi


48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars


Edited by Bel Air kiwi on 01-12-17 12:10 AM. Reason for edit: No reason given.

 
farm rat 
Forum Newbie
Posts: 37

Reg: 09-13-16
01-12-17 10:07 AM - Post#2670754    
    In response to grumpyvette

To add to what I posted above, should I add a little bit of advance on the crank before setting the distributor?

In other words, line dot to dot, rotate 180*, then keep going to about 8-10 BTDC THEN drop the Dist.?



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 16869
grumpyvette
Age: 68
Loc: FLORIDA USA
Reg: 03-16-01
01-12-17 01:48 PM - Post#2670787    
    In response to farm rat

ID suggest verifying TDC and the use of timing tape on the damper and a decent timing light rather than guessing.

once youve located TRUE TDC, you either install timing tape on your current damper, or a marked cover

then graphing your advance curve

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...


this is usually a good start point


IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
farm rat 
Forum Newbie
Posts: 37

Reg: 09-13-16
01-12-17 01:56 PM - Post#2670789    
    In response to grumpyvette

Well not that it's perfect, but one of the things I did with this build was to install a new harmonic balancer as the inside sleeve was squeezing out of the old one.



 




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