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

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First I guess I should mention my motor knowledge is 5 of 10....at best.

Recently I was forced to replaced a blown 454 in my boat. Due to limited funds I bought a complete, but used marine 454 off a local reputable marine dealer.

The motor that came out was a carburated 1993 stock 454(think Mark IV). Regardless the dealer matched with similar carburated 454.

The new motor is more extreme though: Mid level cam. High rise intake manifold. Merlin heads and a built bottom end. I also upgraded the 650 Holley, with a rebuilt 850 marine Holley.

The new motor starts and runs, but it's a chore.

In order to start. I have to mat the throttle(or pump 20 times). Once running the motor does rev. Of course the boat is out of the water and free of load. I can get to rough idle around 1200rpm(after warming up).

I've adjusted carb every which way. Not much difference. I've checked fuel pressure, sits about 5-1/2 psi. Vacuum at base plate of carb is low(fairly steady 10 inches at 1200 idle).

So to my big problem. Cant really check the timing. The harmonic balancer has 4 marks. Not sure which one is TDC. That's where I could use some help(of course any other suggestions would be great).

As for the four timing marks. One long line(the one the installer set to TDC). An then 3 shorter lines about 5 degrees apart(middle line is longer than two outside lines). These three lines sit maybe thirty degrees before the long line. Making them above TDC, since the long line is TDC.

I verified the long line to be TDC by lining up with the timing tab and pulling the dist. The button was on #1 with the long line on TDC. I also made sure the motor wasnt 180 out by using the finger test.

I assume the installer should have set TDC to the middle of the three marks. I just don't wanna chance changing without some knowledge. I searched all over the internet and couldnt find anything in regards to more than one timing mark.

Thanks for ANY advice! Chris

Here's a pic I made of the timing marks and balancer....

BB timing marks.jpg

first you need to find tdc see what mark is O why not ask the guy that built the engine ? i always check TDC and set it when head is off . if that is a stock GM damper should only be one line if a sfi damper many are fully degree

Use this tutorial to find TDC with the heads on....
http://www.crankshaftcoalition.com/w...op_dead_center
I suspect the carb will be unwilling to accept any adjustment until you get some ignition advance dialed in. Fuel pressure is perfect, leave it alone.

Use a couple of small tie wraps to secure the mechanical advance weights to the shaft so that they cannot swing out and advance the timing and put 34-38 degrees of advance in at the crank. Start at 34 and dial in another 2 degrees after trial runs, up to 38. Connect vacuum advance line to the ported vacuum port of the carb, not manifold vacuum and limit ported vacuum to 12 degrees or less. Crane makes an adjustable vacuum can that may work for you. If the motor kicks back against the starter when cranking, cut the feed line to the coil and insert a momentary push button normally closed switch that you can hold in with one thumb while your other hand cranks the motor with the key. Once the motor is spinning, release the momentary button and the motor will be running. No muss, no fuss. As far as not firing right away when cranking, install a manual choke on the carb and pull it to full choke before cranking. I used to also install a microswitch on the choke shaft assembly that would close a circuit and illuminate a small amber light on the dash, letting me know that the choke was engaged in case I forgot it and began driving with the choke on after the motor was warm. A fellow could also incorporate a turn signal blinker switch if he wanted to make it easy to see and get his attention. Sling that automatic choke arrangement over the fence.

The motor needs to breathe, so install a minimum 14" x 4" air filter assembly. In my opinion, all the hype about those oil-impregnated filters is a bunch of hogwash, but if you buy into it, go for it. Otherwise, just use one 4" conventional filter element or stack two 2" ones on top of each other.

What I've outlined here is all low-buck stuff that you can try and then reverse if you don't like the outcome. The one thing you MUST do though, is find TDC.

Once you have TDC nailed down a good dial back digital timing light will make your life a whole lot easier. Here's the one I picked up, and it has worked fine for me - Equus Products 3568 Digital Timing Light: Tools : Walmart.com This page is from WallyWorld, but I picked mine up from one of the local automotive box stores for about the same price.

boat engine do not use vacuum av as they are most always under a hard load. there should be NO vac pick ups at base carb if so it its not a marine carb . the carb vent tubes need to be J bent to dump fuel in the carb if floats hang or fuel pump fails . this is a must less you feel very lucky .coast guard find any car carb . air filter . fuel pump. alt . dist .. they will have your nuts. sure fast way to get fired at the boat yard i work at some hot shot lasted one day. cost guard would be the least of it. if the bilge gets fuel in it from using car parts on it you can blow the boat up .BOATS are not CARS NO paper filters EVER on any boat they can burn .FLAME ARRESTER ONLY . you can pass way more air threw one then any paper and you can not burn one .you guys really need to watch what you post you could very well help him burn his boat to the water line ..

Originally Posted by rspears

Once you have TDC nailed down a good dial back digital timing light will make your life a whole lot easier. Here's the one I picked up, and it has worked fine for me - Equus Products 3568 Digital Timing Light: Tools : Walmart.com This page is from WallyWorld, but I picked mine up from one of the local automotive box stores for about the same price.

you need to watch this as the old mecruiser boxs Thunder bolts your not to use a timing light likes this on them

Originally Posted by pat mccarthy

you need to watch this as the old mecruiser boxs Thunder bolts your not to use a timing light likes this on them

Help me understand, Pat. The timing light gets battery power, and then senses spark with an induction clip around #1 plug wire - no other connections. How does the box affect this type of light, and what do you use instead?

this was over 20 years ago when i work at one of the largest fresh water marinas around Brennan.s over a mile of yard with docks . it was not hard to work on five boats a day for just tune ups. this is what i was told ... but why ? ask mecruiser they told use NOT to use them. that was back 20years ago and merc was sick of buying back engines with holes in the pistons ..THEY TOLD US NO MORE PERIOD .they said the dealer would cover it . they wanted fuel checked for Octane and timing set were they wanted it . very well could of been them not wanting some super turner with a wiz bang new at that time. timing lite screwing around ?? they said not to use it on the thunder bolt box and thats was a good enough for me..seen some smart a$$ use a snap on one.i told him not to use it on the engine . boat came back in a week with holes in the pistons ?? was it the light ? .the thunder bolt . had a built in curve . the light would change the curve by the way the timing lite work ? i just know what they told us

Originally Posted by pat mccarthy

NO paper filters EVER on any boat they can burn .FLAME ARRESTER ONLY . you can pass way more air threw one then any paper and you can not burn one .you guys really need to watch what you post you could very well help him burn his boat to the water line ..

Thanks Pat, edited post.

Wow a lot to take in. Thanks guys.

As for the carb. Both the 650 and 850 are marine Holley 4011 series. They both have the J tube's, as well as vacuum hookup's at the base and above t-plates(ones plugged). Both are also electric choke. Have a flame arrestor(feel like it's choking motor, it's small).

After the motor rebuild, figured stock carb was to small. I had Holley run the numbers. They verified the above mentioned. I then found my 850 on Craigslist. Had Holley run the number for it. It was an 850, but used the same rebuild kit as the 650. Again they verified the above mentioned. Really the two carbs appear identical. I was upset, I probably could have just upgraded jets.

The original dist didnt have a vacuum advance. The motor installer upgraded the dist. The new one does have advance, but just capped it off. That would be the only thing that's likely not marine.

I didn't wanna get into the motor to much. I was just hoping it would be an easy switch over. Seems that's not gonna be the case. Its hard to check the TDC, because of a water impeller mounted to the crank pulley. I have to key bump. I cant move crank by hand. Plus I've been working on it by myself. It's gonna cost me to get the installer back. He's thinks it was good to go. Obviously not the case.

Originally Posted by pat mccarthy

this was over 20 years ago when i work at one of the largest fresh water marinas around Brennan.s over a mile of yard with docks . it was not hard to work on five boats a day for just tune ups. this is what i was told ... but why ? ask mecruiser they told use NOT to use them. that was back 20years ago and merc was sick of buying back engines with holes in the pistons ..THEY TOLD US NO MORE PERIOD .they said the dealer would cover it . they wanted fuel checked for Octane and timing set were they wanted it . very well could of been them not wanting some super turner with a wiz bang new at that time. timing lite screwing around ?? they said not to use it on the thunder bolt box and thats was a good enough for me..seen some smart a$$ use a snap on one.i told him not to use it on the engine . boat came back in a week with holes in the pistons ?? was it the light ? .the thunder bolt . had a built in curve . the light would change the curve by the way the timing lite work ? i just know what they told us

Sounds to me like the factory had an aggressive timing curve in the box, and if someone "reset" the base timing it threw in too much advance and things went south. There's simply no way that an inductive lead could "change" anything electronic. Had to be the guy "checking" making changes he did not understand in the earlier days of electronics, and burning up engines. That's how it sounds to me, anyway, but I'm not in any way a boat guy.

Found several pics I took of the motor before the install. I was able to zoom in and cut the pictures to show the balancer marks. After finding the pics, it's obvious the "other three lines" arent factory to the balancer. From my prospective with the motor installed in the boat. The lines looked straight and factory. The attached pic, shows a different story(pic 1).

Since I know the installer set TDC to the long line and the motor seems to not be 180 out, I guess I need to put a timing light on it(or set to ear, considering Pat's comments).

I also realize I need to find a way to make sure TDC is TDC. I'll figure something out.

Also looking at internet pics of other factory balancers(which this one appears to be). I noticed the long timing mark appears to match most other pictures found. The mark is in the same spot, relative to the four holes in the side of balancer(pic 2). So likely timing marks not slipping, due to bad balancer.

So seems the motor is to far out of time or the 850 is just to big.

Though on initial startup the cam was big enough to draw water back into the motor. I had to change exhaust to "thur hall". The cam overlap sucked water back into motor, because factory exhaust was routed into the water, though outdrive. New exhaust exits rear of boat into air and corrected that problem. So with such a cam and considering boats typically run higher RPM's. The carb such be right on.

Guess maybe a leak at the base of carb should be considered also.

Know more tomorrow evening, as I will be messing with it. Thanks again guys. I know this isnt really a boat forum. I appreciate the advise anyways!

the long mark is the one you set your timing. other marks are not stock as whey look like they were put in with a ax. if a mark 5 engine with a tin front cover they had a two timing tabs on the cover one like all bbc at around 3:00 and one down around 5:00 look s like that damper had them marks re marked for total curve 32 the 35 the 36 ???.measure from the gm O tdc long mark and i can tell you if them hash marks are 35 or 26 or ??? them holes are nothing but holes used when mass was balanced and is very common to see a row of holes . but may not be in the same place is there more of balancing deal

Originally Posted by rspears

Sounds to me like the factory had an aggressive timing curve in the box, and if someone "reset" the base timing it threw in too much advance and things went south. There's simply no way that an inductive lead could "change" anything electronic. Had to be the guy "checking" making changes he did not understand in the earlier days of electronics, and burning up engines. That's how it sounds to me, anyway, but I'm not in any way a boat guy.

well i was a boat guy but that was 20 +years ago only job i hated and loved equally.no i did not know how the box worked .i have abit better idea now? not really.way to many things to think of were i used the msd.s marine dist like the auto dist it.s curve can be tuned in has it.s springs and a limit bushing .the thunder bolt was potted no way to move the curve . yes a pick up should not hurt the box and yes i used a induc pickup timing lite every day back then .but thats was not the deal it was the way the timing lite work out the curve out on the timing lite with the dial in lite . like said box.s was some what new and so were the timing lites but mecruiser told use not to use that timing lite on them boxs so as a mecruiser mechanic i was happy to play along,as there was many things get drilled in your head most of the time you walked the mecruiser line . but that was not always the case with me... as for the thunder bolt box. dist/box. i had one in a 396 and my 454 worked very good on the street set the base timing like the many boats and used it . what total timing was? boxs did go by engine hp and rate of curve by part number. traded the two set ups .for two gm HEI built buy accel .to a guy with a offshore cat race boat