Thread: Harmonic balancer on 454 has 4 timing marks.....

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Here's that shop manual pic I found....
Marks.jpg

Cam sprocket at 6 and crank sprocket at 12 sets up #6 for ignition firing. Cam sprocket at 12 and crank sprocket at 12 sets up #1 for ignition firing.

Originally Posted by techinspector1

Cam sprocket at 6 and crank sprocket at 12 sets up #6 for ignition firing. Cam sprocket at 12 and crank sprocket at 12 sets up #1 for ignition firing.

So it's in time. The pic with the marks is on #1 TDC.

Originally Posted by repoman3809

So it's in time. The pic with the marks is on #1 TDC.

turn it 180 marks will line up and it will be in phase

Originally Posted by pat mccarthy

yep 180 out but still need to fix the low cranking psi on the one bank .mark 5 or 6 block ? if thats a mark 6 with a flat lifer cam in it ?. i am short blocking the 330HP mark 6 merc roller engine right now

My heads spinning right now. LOL

Ok, When I bought the motor I was told the motor was the same gen block as my boats original 1993/454(whatever gen that is).

After recently talking to the dealer who sold me the engine. He said he thought it had rollers, knew it had merlin heads, a high rise weiland intake, an aggressive cam and a built, 30 over bottom end. Said he would get back to me on the exact cam specs(still waiting).

The motor was to be a drop in long block. I only had to add carb and accessories. I trusted the dealer and didnt pull anything off the motor. I just dropped in and hooked up.

After hearing of the possibility rollers the other day, I figured I would pull valve covers and check. Likely was going to do as I was getting ready to pull motor.

Of course, if it does have rollers and the motor is 180 out. I may be able to make adjustments and get back to normal possibly....right?

it not 180 off on cam timming . you need to line the top gear mark at bottom 6 clock and lower crank gear mark pointing to top 12:00 clock one more turn lines the gears in phase this will happen when you turn them crank one more time . if a roller cam engine there is not thust button on the front of the cam gear . not good. the engine i see is a mark5 or 6 if it has hold down towers casted in the lifter valley it a mark 6 mark 5 do not but is about the same block other then that .if a mark 6 roller engine it has a mark 4 cam in it. as the mark 6 has on step nose cam different timming set and needs a hold down plate .there is no cam hold down plate i see at can not be used with the mark 4 /5 cam it can have a roller cam with out roller rockers you will have to pull the intake to see if its a roller cam

well let me know if you need any thing . the 330 hp as a 030 fresh bore very nice all new parts and first time rebuilt fresh 010/010 crank rebuilt rods with arp bolts speed pro hyper flat tops wiill be short block very soon. the other mark 6 roller engine is going to be a 489 with srp flat tops. i will very soon have a pair of 511s or 513s mark 4s they will be four bolt mains blocks i have. i will start on them next week , H beam rods .forged pistons 4340 scat cranks all new parts .i have one 489 I beam billet rod6.385. and scat cast steel crank .Icon pistons forged pistons all fresh machined short block on the E bay right now all done

Everything clear now, Repoman??

Everything clear now, Repoman??

I don't know anymore. Go back to the original post, I put my motor knowledge was 5 of 10, at best. Maybe I should edit that to 3 or 4. LOL

Ok so the crank and cam are in time with each other, but the dist is out. I need to set to cam@6-crank@12, reset dist to #1. And this would solve the hard starting, crappy idle and base timing issues. Right?

It doesnt solve the low compression readings, since cam and crank are in time. Unless the roller rockers are unadjusted or incorrectly adjusted. But likely isnt the whole problem, even if it is a problem. So I still need to do a leakdown and see just what it is causing the low reading. Then proceed from there.

IF, you want #1 cylinder to be the "lead" cylinder that you will set ignition timing by. Then you need to rotate the crank 1 more time.
With #1 cylinder at TDC, and both valves closed, the cam gear dot needs to be at 6 o'clock and the crank gear dot at 12 o'clock.
I would advise you to do this so that ALL OF US here are on the same page. What that picture shows is that cylinder 6 is the "lead" for timing the ignition.

I am using the term "lead" for lack of a better word. This is probably why your timing is shown so far off. Hope that helps...

Originally Posted by 34_40

IF, you want #1 cylinder to be the "lead" cylinder that you will set ignition timing by. Then you need to rotate the crank 1 more time.
With #1 cylinder at TDC, and both valves closed, the cam gear dot needs to be at 6 o'clock and the crank gear dot at 12 o'clock.
I would advise you to do this so that ALL OF US here are on the same page. What that picture shows is that cylinder 6 is the "lead" for timing the ignition.

I am using the term "lead" for lack of a better word. This is probably why your timing is shown so far off. Hope that helps...

Come on fellows, this is not rocket surgery. When you assemble the motor and put the dots together, cam at 6 and crank at 12, the motor is set up at that point to fire #6. You have to rotate the crank one full turn, so that the cam is at 12 and the crank is at 12 in order to fire #1. I have no idea why the engineers at GM marked the sprockets that way, but they did and we have to know to rotate the crank one full turn after we put the motor together so that we can fire #1. One more time, 12 x 12 to fire #1.

If it wasn't a science the poor OP would have a running motor by now!

I was under the impression 12 and 12 was to fire #1. 6 to 12 was to ease the installation of the cam, given that the dots were right next to each other. This would fire on #6 TDC. Then you rotate one turn to 12-12 and now your firing #1 TDC.

Techinspector1 seems to agree with this, so does the tech manual pic I found(top of page, post 46).

I guess I'll try and find a 454 Haynes manual.

In the meantime. Tomorrow I'll likely be pulling the valve covers, doing a leak down test. I think the proper way to do that is start TDC on #1, check valves r closed, test #1. Then move crank 90 degrees(to #8, next in firing order), make sure valves r closed, test. So on and so forth.

your making this way to hard here ?? who cares if 12 and 12 is tdc on 1 you do not need to know that. what you need to know if the cam timing is in phase with gear marks and when you degree the cam that the numbers come in to the sheet on the cam card or work out the numbers. honestly i could care less to were the chain is marked to what cylinder is at tdc when there marked as long as the cam is in phased . built a hell of alot of engines not giving it any thought . dumb ? there dumb thing that make engines fail like no piston to valve clearance . rods out of round. the long list of dumb thing. dwelling on this is not helping you. if the cam is in phase . the engine still has one low bank that has nothing to do with wasting time on why the marks should be at 12to 6 for #1 and not #6 you have ether bent valves/pushods on the one bank very will could be bent intake valve .or a wiped cam on one side. hard to think all holes are low on one bank less that head had wrong springs on that bank or adjusted so far down all valves are not closing . if you did wipe the lifters do not force many out if you do you will cut the bores up.

Repoman, seems to me you have a good handle on #1 at TDC now, or close enough to true TDC for the valves on #1 to be closed, and your step-by-step process should give you some more idea about exactly which cylinders have problems, and whether it's valves hanging open or not. It doesn't sound like you're planning to pull the timing chain, so talk about degreeing the cam or setting up the engine is not really of much value for where you are in the process, IMO. Now it may be that whoever installed that hot cam didn't degree it right way back when, but for now you're assuming that the engine was set up right because it ran right at one time. From what I've read you spent some money on what you were told was a good engine from your boat dealer, you're finding that it may not have been quite as good as you were led to believe, and now you're trying to understand just how bad it is before you decide to pull it out and either start fresh, or maybe have that one rebuilt. I would be doing exactly the same thing before I made a decision on several thousand dollars!

If your Saturday is going to be dedicated to this mystery I hope you have your answers early, and can then move on with a decision that gets you back on the water enjoying the boat. Best of luck to you!