So I am trying to get through the final stages of my 416 build and got to checking distributor to make sure I had everything right. During the check, I got a sinking feeling that I set the timing chain up incorrectly.

The cam was installed straight up as recommended by the guy who ported my heads and spec'd the cam. So when I installed the timing chain and sprockets, I 'lined up the dots' - cam sprocket at 6:00, crank sprocket at 12:00. The cam has 2 degrees advance built in.

The question is whether I have the sprockets on right. I started to check the position of the distributor rotor to make sure it was facing #1 on the compression stroke and it is. However, the timing marks are now both at 12:00. While doing this, I started looking at the lash. If it was off, I would think the valves would be in the wrong place to set lash but it was correct. #1 piston at TDC on the compression stroke, set #8 exhaust valve and #2 intake valve.

I do have a vague notion that if the marks were at 6:00 and 12:00, the motor would be ready to fire #6. Is that correct?

Here's a pic of where the marks ended up. Motor is at TDC on compression stroke, both valves closed.


Not sure if you can see but this is a pic of the cam lobes on the base circle.


I put the dampener on to double check. It's at 35 degrees advanced here, firing on #1


Distributor is pointing roughly at the #1 intake valve.


So what happened to the timing marks? The one thing I keep thinking is that I found TDC on the wrong stroke when I put the timing sprockets on. I don't remember looking to see if both cam lobes were on the heel. I think I did it with one lifter and a checking pushrod. I believe I rotated the motor until the #1 intake closed then brought it up to TDC.

So is it OK or do I need to start again? I know I am probably over thinking it but better safe than sorry.

Thanks for any input.

- Greg

Remember the crank makes two rotations to the cams one. So the piston will be at tdc twice in one cam rotation. Once after the exhaust stroke when the intake valves starts to open then again on compression.

Assuming you installed the timing set in accordance with instructions provided by the manufacturer of the set then two things, cam rotates once for every two crank revolutions. Rotate the crank one more revolution and your dots will line back up.

Second, you distributor is 180 out. When you get the dots lined back up, pull the distributor and rotate the shaft 180 degrees, reinstall.

Think you're good. Both dots at 12 oclock fires #1 on all mopars v-8's I know of.

maybe a stock timing set, I know for a fact Edelbrock sets are like the OP set his up

http://static.summitracing.com/global/images/instructions/EDL-7800Series-Performer-LinkTim.pdf

So what do you have for a timing set in there?

It looks like you have spent some time and money to make a good motor, now is the time for you to learn how to degree the cam. Buy a degree wheel(bigger diameter is better than smaller) and mag base dial indicator holder and a good one inch dial indicator that reads in .001 increments There are muliple souces for how to degree a cam on the internet and in various cam cataolgs so go for it and learn how to verified if the cam is ground correclty or not, I always check both the #1 intake and exhaust lobes to make sure the cam is ground on the lobe seperation angle the cam grinders says it is on the cam card I have seen more than one cam and or timing sets ground wrong and several have had the marks wrong on the timing gears It is the engine builders, assembler, responibility to MAKE sure every part of the motor fits right and is assembeld correctly Lining up the dots and not checking the cam timing, lobe seperation and piston to valve clearance is a potential disaster waiting to happen

12 and 12 should be #1 firing TDC.

Cam at 6 o'clock is usually #6 firing, even on the edelbrock chain I used on a sb.

You can see the #6 lifter coming off the exhaust lobe in the pic with your alignment rod.

Timing set is a Pro Gear from Hughes. Here are the instructions for the install.

Since there are 2 degrees built in, I used the unmarked key ways and lined up the outermost dots closest to the teeth on both sprockets.

Cab, I degreed the cam and it is where it's supposed to be. Frankly, I was not paying attention to the dots on the sprockets when I did it though because I didn't think it was necessary with a degree wheel.

I guess it just made me second guess myself when I saw it, was not expecting both marks to be at 12:00 on the compression stroke.

Hand turn the dampener with a 1&1/4" socket/breaker bar till the dampener timing slit is at 15 BTDC (forward or backward whichever is closest if the lobes have been gooped) & if that is 6/12 then clock the dist so the rotor is pointing rearward & slightly to the DR side. if you are at 12/12 then install dist tang 180 so the rotor is pointing forward & slightly to the pass side. with the vac can on the pass side with room to be turned some then turn the dist housing slightly till the magnet lines up dead even with the closest tooth & moderately snug the dist holdown clamp. if the rotor is installed forward then start the #1 plug wire there & go on around CW. if the rotor is rearward start #6 there & continue on CW 5-7-2-1-8-4-3. this lets the wires nestle neatly with the shortest lengths possible & maintains the OE firing order & helps prevent future mistakes. good time to check rotor phasing and I would make a mark on the dampener 2&7/32" CW (35 deg) from the timing slit & have your dist man set it to that when it fires. EDIT only way I would deviate from this is if the dist I used did not point the rotor either foreward and slightly to the pass side or rearward and slightly to the dr side as some dists have drastically different top rotor to bottom tang clocking and the rotor could end up anywhere & you can start #1 or #6 wherever the rotor ends up at but the OE routing is the best if possible. Holler how it goes. Looks like you have a nice build there. I would suggest reading "breakin secrets" at www.mototuneusa.com MORE EDIT whether you are on 6/12 or 12/12 the timing tape should be within a degree of TDC. Is it just me or does that chain have a fair amt of slop in it. I would confirm that you have the valves lashed correctly (I do each pair on base circle/takes longer but is less mistake prone at least for me) then remove the rocker assys then goop the cam then replace the rocker assys & this quick/easy R&R wont change the lash cuz your adjusters are tight

RR, there is no slop in the chain. It's brand new and has a tensioner on it that pushes it to the right a little, perhaps that's what you are seeing?

When I degreed the cam, I thought it went in too easy, I got it on the first try. I actually called Comp and Hughes to confirm I did it right and I know I did. I did lift checks and what not and I could swear it was all dead nuts.

I might take the valve train apart one more time just to confirm AGAIN. Getting the tensioner on was a real hassle.

This stuff makes me nuts, all the second guessing.

Alright sounds like it is all good (cant say about the valve lash). Yes I hear those tensioners are a pain. After a successful breakin with no leaks/good leakdown numbers etc & your out there burning some rubber It'll all be worth it! Guys here have come close to pulling their hair out/selling there projects or even worse over issues

I ran into this 'issue' when I started doing the lash. I stopped after the first set of valves and stuck the distributor in to check where it was at. That said, if it was way off, I don't think I would have been able to do the lash because the valves would have been all out of sync.

So if the cam timing is correct, (regardless of the timing marks) then the rotor should be in the correct position, right? (firing #1 on compression stroke?)

I really don't want to take it apart again.

I would keep the dist and the valve timing seperate. On the dist if you are at 6/12 then install the dist (rotor) rearward & plug in the #6 wire & if 12/12 then install the dist tang (rotor) forward & plug in the #1 plug wire at that rotor location. for the valves with the plugs out for easier turning I'd get the rotor at each cap location & at that point the valves for that cyl should be on the base circle with the correct cold lash. & with this hand turning you'd wanna regoop the cam & cam failures are epidemic. I ain't sayin they aint' right as is but just throwin thoughts out there for your perusal. However with thousands of $$$ invested & many man hours you have ONE shot to get an excellent cam and ring breakin as opposed to a good breakin or even an average/mediocre one. You want good leakdown numbers. On the valves there are those EO/IC procedures & iirc with cams over 280 duration you want to use the 8 position (MP?) chart. You could cut a strip of paper 5.694" long to use as a ruler on the dampener to go 1/4 turn to the next cyl.

^^^ This.

I always roll mine over with my finger over the #1 plug hole, when it starts coming up on compression it will start blowing air past my finger. I continue rolling until I get 16-20 degrees BTDC then set my distributor in and line the button up with the #1 tower on the cap. Mine have always started and ran doing it this way.

On setting the valve lash cold set the valves .004 to .008 tighter than the cam card calls for if your running aluminum heads, with iron heads and iron block set them .002 looser cold. Always reset them hot to what the cam card cals for ad then maybe .004 to .010 tighter for testing at the track Do you know the "intake opens set the exhasut lash and then rotate the motor over until the intake valve opens all the way and starts to close" to set the exhaust lash? If not you may want to try this method on the bigger duration cams out there Your being confused is not uncommon , many old time professional mechanincs have thought you should install the distributor firing #1 with the timing gears aligned at 6 and 12 o clock like the instructions on the timing set call for, that is the beginning of the intake stroke on # 1 cylinder, not the compression or firing stroke IHTHs Engine building can be very frustrating, especially the first cuople of times, the advantage of doing this yourself is you know what you did and you may end up learning something new on each build The last thing I do before start up on any new motors is to priem the oil pump while turning the motor over on the starter with all the sprak plugs out and then put the plugs in except #1 and use the starter to find the compression stroke on # 1, set the dirstibutor in and start that rascal up

For the priming 90 deg BTDC #1 compression-preoil pass side & dampener may have partial slits at 90 deg intervals that'll work for this. 20 deg ATDC #6 compression-preoil dr side, use the timing tab as a ruler to go from 15 to 20