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

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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.

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

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.

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!

Originally Posted by repoman3809

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!

yep i know all about the EX running threw the prop . many time s the flap valves would come apart .many times you would see parts of them when you did a stren drive R&R look like the heel of a shoe... we did not see it ....more to the point did not want that job on some boats and was a winter job. it was not fun .but did not rate as hi on the list as a gimbal housing that bolt threw the transom i did drink abit back then. some of the work really did suck . that job was not much fun

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.

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