Rebuilt '79 351w block, used accessories from '86 351w, flywheel was the exact same item on both engines so I used the unbent one from the '86, used the '79 harmonic and cannot get the timing set.
When I start turning the dizzy, it starts running bad by the time I get it to the markings. Thing dies by the time I get it to 20 BTC.
Timing gear marks were perfect straight up; dizzy, if not perfect, can only be a tooth off. That leaves only the harmonic and the position of the markings.
This has really got me stressed. Could time it by ear, but having spent so much time re-doing this engine I would like to have it correct.
If ALL 351w engines are supposed to use 28 oz harmonics, why are they different from '81 back? Friend of mine says because the accessory set-up was different, which didn't make sense to me.
Anybody know what the differences are in the '86 and '79 harmonic balancer?
Different crankshaft, maybe?
TIA for any help,
Munrow

 

I don't know the differences between the two balancers, but you can check the timing marks by manually rotating the crank to TDC to see where the marks align with the pointer. If they align, then your problem is something else. If they don't align, just get a timing tape.

 

Swapped balancers, markings were in the correct position. When comparing the two, using the keyway as a reference point, almost three inches difference between where the markings start. Still trying to find out why such a difference in the markings. Is it the crank?
Munrow

 

Welcome to the mysterious world of Ford external balance and part interchange ability. Your stress levels are only going to increase as you continue to try to gain information on these issues. I know; I've been there.

Ford balancers, cranks and flywheels/flexplates are a system. You've discovered that dispite the same external balance the systems in these two engines is not the same. Unfortunately, this is not an area where guessing and assuming are safe paths.

You say that the two flywheels were the same. Why? Because the bolt patterns, tooth count, size and bolt patterns where the same or because the part numbers were the same. If the part numbers were the same then you can safely conclude that the external balance on the later flywheel is in the same relationship to the crank as the earlier flywheel. If the part numbers were not the same, that safe conclusion is now nothing more than a guess and you may in fact have the flywheel and crank balances out of sync.

If your flywheel part numbers were the same, you can safely conclude that the external balance relationship to the crank is the same for the two balancers. And what that means is that the keyways on the crank snout and both balancers are in sync. And if that is correct, then the difference between the two balancers is not the location of the keyways in ralationship to the internal and external masses. The difference between the two balancers would then be that the outer rings of the two balancers are moved in ralationship to the keyway. The only reason to change the relationship of the outer ring between the balancers is to align the timing marks to a different location of the timing pointer on the timing chain covers between the two engines.

Compare the two timing chain covers. Is the pointer on one in a differennt location than the other. If so then that is the difference between the two engines. If not, then the internal/external mass relationships between the two crank systems is more than likely not the same. If the pointer locations are different, then (if the balance relationships are the same) all you have to do is apply a timing tape on the balancer to align with the pointer after bring the crank to top dead center.

I apologize for this being so long, but this balance thing is a complex issue. I'm trying to help you through this in a logical manner.

As to getting a difinative answer to your question, there are two basic sources. The first is from someone who has gone through the exact parts interchange you did and happens to stumble onto your post. Hopefully someone out there who has done this will post up. The second source is an engine builder. Don't hold your breath for that one. Engine builders, like all other professionals, rely on knowledge and facts to solve problems. They fix problems for a fee, as it should be. But lessons cost extra, and they don't usually give lessons because then we have the knowledge and don't need them to fix our problems.

Hope you get this figured out.

 

Thanks for the input, and, believe it or not, the Ford lessons.
Both engines had the same timing cover, same part # stamped on them. Neither flywheel had any markings anywhere. It was truly dumb of me to think the crankshaft and not the timing pointer location would be the difference in the balancers. I don't know exactly which Ford pickup this engine came out of. Didn't stick around long after getting the engine for $250.00. Hauled butt like I stole something. Few months later when I called to find out, no records were available. Trying to look up parts at any of the major autoparts stores online is a real pain. I've been using a '79 (cause of the block casting marks) F-250 as the vehicle for AdvanceAutoParts and Autozone. The latter lists the engine (factory 2-barrel) as a 351M. Scared to even ask about that.
Thanks again,
Munrow

 

hey dude after reading along with your post i really think thats what my struggle has been...the flywheel I believe it got switched with a 302 fly I have a 351w in my 70 f100

 

Okay, a 351M is NOT a 351 Windsor. The strokes are the same (3.5") and the external balance weight is the same (28.2 oz), but the designs are different. A book could be written on the subject, but it isn't necessary here. And I don't have the 351M knowledge to do it anyway.

I've been thinking about several things you could check to come to some logical conclusions, but without the knowledge to be sure of those conclusions they will be nothing more than guesses and we can't do that here.

I need to ask some questions. Why did you use the balancer that came from the '79 and not use the balancer that came off the '86? Also, did you use the crank form the '86? I think you did, but I need to know for sure.

If you used the crank from the '86 and if you have the '86 balancer (even if it is not in good shape), bolt it on. Then, remove the passenger side valve cover and the number 1 spark plug. Rotate the crank to top dead center. You'll know it's at TDC because the piston will have reached the upper limit of travel (it does this twice, once on the compression stroke and once on the exhaust stroke) AND both valves will be closed on the #1 cylinder (both rocker arms will be up and somewhat loose - on the exhaust stroke, the intake valve rocker arm will be up and some what loose and the exhaust valve rocker arm will be down and have tension on it, not loose at all). I want you to check this because you need to make sure the camshaft is in sync with the crankshaft. If the cam and crank are not in sync then this is not going to work regardless of what balancer you put on.

If the cam and crank are in sync, then look at the timing marks in relationship to the pointer. They should align.

If all that looks good, then you can get the correct balancer from the casting code on the balancer. It will tell you what year and what vehicle it was designed for and then you can use that to get the right part from AAP, AZ, etc. Unless the guy behind the counter is personally knowledgeable, he cannot get you the right part unless you can tell him what color seat covers came on the vehicle. It's not quite that extreme, but you get the point. And just to be sure, take your old balancer ('86) with you to compare the two.

Why didn't I tell you to do that first? Because I have no clue as to what cam you have in your engine or what the firing order is for a 351M. If the #1 cylinder TDC doesn't check out, then you can stop right there because you either have the wrong cam or the right cam but it is not aligned properly and you'll have to determine which it is. If you used the cam from the '86 the TDC should check out but you will still have to determine the firing order.

Back to the relationship between the pointer and the timing marks. If everything is in sync with the '86 balancer on, if the pointer and the marks don't line up then the '86 cover on the "M" had a bolt-on pointer. Again, I don't know because I don't know "M"s. If the marks are off but all else is right, then you can either hunt down the right bolt-on pointer (if that's the case) or put timing tape on the balancer to align with the pointer (much easier).

This should get you closer to a solution. Hopefully.

 

Sorry if I caused confusion. I said that Autozone, when looking up the crankshaft and flywheel, listed the engine as a 351M. It is not. All 351W parts fit/work perfect.
Both timing covers have a part# indicating '83 (E3....).
I got and used a balancer for a '79 because when looking up the part online, all the places showed a different part# for '79 and '86.
I used the crank that was in the '79 block. I believe they are interchangeable because AAP, AZ, and Summit showed the same products available for either engine.
If you noticed my second post here, I swapped back to the '86 balancer and all is well on the timing marks issue. However, I greatly appreciate the interest/advice/help.
I'm going to have to re-do it because of not having checked the crankshaft well enough. Got a clatter at certain RPMs, and, when giving steady gas anywhere over about 2200 RPMs. That, plus vibration would seem like crankshaft/bearing issues.
Couldn't find a micrometer locally, so, assumed because of the state of other parts of the engine (cylinders perfect .30 over, no ridge at tops) that whoever had worked on the engine, recently, it would appear, had changed the crank. The journals looked perfect, the old bearings didn't look like any of the photos of wear problems in the Haynes Ford Overhaul Manual. Tiniest, tiniest bit of oil shortage markings, according to the manual.
Oh well, this was good practice. If I can change the crank without having to take out the pistons and heads, I'm going with the stock crank. If I have to entirely dis-assemble the engine, a stroker she will be.
Again, thanks for the input, time spent on this, etc
Munrow

 

You're more than welcome. I'm glad you got the timing issue resolved.