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1972 351C Pinging Problems

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    Posted: 14-April-2019 at 12:02PM
Please help.  Can you elaborate on the pinging from advanced timing?  Through research I found that it should be 36 BTDC at 2500 rpms.  I did that and backed a degree all the way down to 28 and I can't get rid of pinging/rattling when I accelerate.  I'm not sure of the specifics of the guts of the engine but it is a 1972 351 Cleveland probably bored .30 over.  I was told it was a Scat rotating assembly with pistons, and some other go fast parts but I'm not sure how that affects factory settings.  Thanks in advance.

ADMIN NOTE:  This was moved from this post here:  http://forum.grantorinosport.org/72-gts-deuce_topic6182_post192692.html#192692
Moved and started a new thread to get better response.


Edited by 72FordGTS - 16-April-2019 at 12:17PM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 14-April-2019 at 12:49PM
what is the vacuum source for the advance pot on the distributor?

have you tried driving it with the vacuum disconnected and plugged?

some idea of what parts are in your engine would help, like what's the real compression ratio,

not somebody's pulled it out of their Censored guess?



Edited by Rockatansky - 17-April-2019 at 10:55AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Big Bird Quote  Post ReplyReply Direct Link To This Post Posted: 15-April-2019 at 2:04PM
Could be a bunch of things causing pinging:
Crappy fuel.ale gas/low octane or just crap gas
Timing, not just total advance but how fast it comes in.
Fuel mixture. Overly lean pings more. Also gets hotter and that may be related
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Regul8r 2 Quote  Post ReplyReply Direct Link To This Post Posted: 15-April-2019 at 2:14PM
1st you have to set BASE timing, then you check the mechanical advance without vacuum hooked up mid range RPMs and then see what it is with vacuum at higher rpms.

Now having read that it might have a SCAT rotating assembly I would be REAL curious as to the Compression Ratio. anything over about 9.2:1 will require mid to high range octane gas.

To elaborate on Octane.
Cheap gas, lower octane, means the gas is more "volatile/unstable" more easily burned and exploded.

Higher grade, higher octane, means the gas can withstand the heat and pressure in a high compression, high performance, high revving and hot engine. This means it will not PRE-IGNITE or "PING" before the spark is delivered. Once the spark is delivered the gas will BURN like it is supposed to and not explode.

Pre-ignition is the gas burning and exploding on its own because of the high compression or heat in the engine because it is Volatile/Unstable this is called DETONATION! and is NOT GOOD! lol
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 16-April-2019 at 12:16PM
Do you know if the engine has the original balancer?  If it does you might want to check if TDC is still accurate.  A piston stop is a cheap tool and it will quickly find true TDC. 
What distributor and ignition system are you running?  What conditions are you experiencing the pinging?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 4:54AM
First, thanks for moving this to a place that doesn't require a huge search across the forum.  To answer the questions posed by all the respondents with the parts I know or was told was used on the engine build.
1.  I use either Shell Ultra or Sunoco Premium with a bottle (7 oz) or two of Lucas octane booster
2.  The ignition is is a Pertronix with distributor
3.  Heads are Trick Flow 195cc 62cc (whatever that means) with 1.73F Trick Flow rockers
4.  Supposed to be a crane cam of some sort
5.  Edelbrock air gap intake manifold
6.  Scat Rotating assembly with some different piston (I'll have to look that up)
7.  Holley 750 double pumper with electronic (is that correct?) choke and vacuum kick down
8.  The vacuum advance for the distributor is coming from the carburetor 
9.  and I couldn't guess what the compression ratio is
Now, I'm not sure about whether it is the original harmonic balancer.  What I'm pretty sure is that it has to be misaligned.  I say that because no matter what I do I get the "rattle" that I am associating with the described ping even though I set the timing as 36 BTDC at 2500+ rpms with the timing light.  The rattle/ping only happens when the engine is under load and is more pronounced when stepping on the pedal during a hard take-off.  I took a timing light and did both with and without vacuum advance.  I am really trying to work through the problem so that I can continue to have the vacuum advance part of the system.  When I look at the balancer at the 2500+ rpm I can't get the rattle, under load, to minimize until the balancer is on the high side of 0, like around 8 - 10 ATDC.

It is my intent to buy an extended TDC indicator and piston stop to better determine the TDC while I install a new balancer.  Any assistance or recommendations would be welcome.


Edited by Timustbe - 17-April-2019 at 8:45AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 12:22PM
that 36*@2,500 rpm is what they refer to as total timing... you need to check #1 TDC see if is it lined up with the 0 or TC on the balancer stock will say like 8*BTDC but with performance parts added you'll be more like 10-12* +? that's your base timing! without the advance hooked up with it idling
there shouldn't be any vacuum out of that hose until you open the throttle just a bit
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 12:50PM
John, thanks.  I found it idling at 0 according to the balancer to keep it below 40+ BTDC when accelerating to the >2500 rpms.  I'm ordering the extended tdc indicator, the piston stop and probably a new balancer.  Any recommendations for the balancer?  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 1:12PM
I think you are on the right track.  You need to verify that you have correct TDC.  Once you know for sure that you have TDC, then like the other guys set, start by setting the base timing.  Make sure you disconnect and plug the vacuum advance line when you set the base timing.   Then once that is set you can check your total timing and report back here.
 
Here is a video on how to find TDC with a piston stop.  Keep in mind this is a Chevy in this video, so the number one cylinder is the opposite of a Ford.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 2:30PM
'all in' at 2500 is too fast for a heavy car driven on the street, it's more of a race timing curve

and with those heads and suspected Too High compression ratio 36* may be out of the question also

i would set the curve with less total timing and taking longer to get there, like 30* all in by 3500 rpm

and again, i'd disconnect the vacuum and plug it until you get the mechanical side of the distributor figured out. having the vacuum operating while sorting the mechanical curve will just confuse things or make it impossible depending upon your vacuum source. you want a 'Ported' or 'Timed Spark' vacuum source, not manifold vacuum which is also available from the carb base plate

i see the famous facebook 750 double pumper on your list of goodies,

what rear gears are in the car, what transmission and what converter if automatic?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Regul8r 2 Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 3:17PM
I am confused...
What is your BASE timing and how did you measure it.

Car warmed up, at idle, vacuum line disconnected from the distributor and plugged(I know it should not have vacuum but I always block it off anyway).
AT that warm, idle, no vacuum you should have it a 8-12 degrees. THAT is base timing.

Now with the vacuum still off and plugged, raise the RPM to 2500.
What is THAT timing reading.

THEN raise the rpm more up to 3000-3500 with the vacuum hooked up.
What is THAT reading.

IF you give us those 3 readings and the rpms at those readings we can help you figure it out.

I see your last post says it showed 0 at idle but was OVER 40 at 2500??
SOMETHING IS WAY OFF!
That is why I ask what are the 3 reading at the 3 rpms and ONLY the top/high rpm with the vacuum hooked up.

Is the vacuum line hooked up to the right port on the carb?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 17-April-2019 at 5:03PM
yeah something's wacky there Shocked i wonder if the pointer is wrong or the balancer? but if it's all in at 2500 sounds like they used lighter advance springs so it comes on quicker???
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 18-April-2019 at 12:01PM
Yes Johnny it's the advance weight springs vs rpm and the actual weight of the advance weights if that makes sense. you can fine tune by drilling holes through or grinding a little material off the weights to effectively make the springs stronger ... if that makes sense too?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 18-April-2019 at 12:48PM
Thanks again all for the feedback.  I have to say first that the car was configured this way when I bought it a little over a year ago.  I haven't put many miles on it because of the ping, mostly around the neighborhood and town.  I'm curious about the "Facebook 750 double pumper" comment.  Is it too big or completely wrong for the car?  I'm not sure what the previous owner, and I don't mean the dealer I bought it from, intended to do with the car so all the parts were on it when I got it.  I wish there were more detailed records but sadly there isn't.  I also can't say what the torque converter is but it's a single wheel squeal, 3.25 ratio, and a C-6 tranny and the tranny is something for another time. 

  Now, back to the timing.  I'm pretty familiar with running a timing light and I can certainly set the timing to something in particular so I will take your recommendation of 10* at idle.  I'll get that one and the 2500 without vacuum and then the third one with around 3000 3500 rpms and report that up.  About the right vacuum port off the carb, I have to say yes.  It is plugged in according the diagram.  I also have to say that I'm pretty sure it is the factory pointer since it is fixed (nonadjustable) and bolted to the engine block.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 18-April-2019 at 1:35PM
what i mean by the 'facebook 750 DP' is it's like a cult on there,

everybody jumps straight to the 750 DOUBLE PUMPER like it's what all the cool kids use for a carb.

and Yes IMO it's completely wrong and too big for your combo, but then again so is the engine build but we'll get to that. 3.25 open rear, C6 probably stock converter i'd use a 650 vacuum secondary Holey or maybe  an Edelbrock 750 especially for a guy that doesn't know a Holley upside down blindfolded backwards in the dark. Edelbrocks are much more user friendly and easier to tune on many levels. almost all tuning changes can be done w/o spilling fuel or w/o opening the top of the carb at all. double pumpers are for manual transmission monster builds that can take a hot supper and want more. 2500-3000 rpm stall converter and 3.73's minimum IMO. to me it sounds like the PO went for the monster build but got in over their head with just the engine alone and never completed the rest of the driveline. why use a Scat rotating kit unless it's a stroker? increasing the stroke of the engine causes the compression ratio to skyrocket all things being equal, but they're not. the PO also used small volume combustion chamber heads which also cause the compression ratio to skyrocket. what pistons? we don't know but it's could be the 4th of July going by the compression ratio calculator. i wonder if it'll run on 100 octane race gas? the cam is still the 23rd wonder of the world, a complete mystery. if the PO used a 'matched to the rest of the combo' race cam you'd probably have less problems, but i suspect the PO used a mild cam hoping to 'keep it streetable' aggravating the need for high octane fuel even further. now top it off with a timing curve set for Don Garlits and you don't drive the car.

10* at idle with the vac disconnected and plugged is a fair starting point, but that assumes the pointer is accurate for TDC, 2 things i would do; verify the accuracy of the pointer, and perform a cranking cylinder psi (compression) test. this is done with the carb linkage propped open at least part way to allow the engine air to compress and with the spark plugs out to go easy on the battery and get good cranking rpm . crank each cylinder tested at least 4 pulses on the gauge, and take note what the gauge reads for each pulse. youtube is your friend if you're not familiar with the correct way to do the compression test

sorry to hear that you're in a facebook build pickle. (it's not the happy dancing pickle)

if there's nothing amiss, the engine build sounds very conflicted.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 19-April-2019 at 2:13PM
Race gas?!?  Do you think it is worth trying?  We got a small oval race track near me that has a Shell station nearby that sells race gas.  I could set the timing based on the recommendations and fill the tank with race gas to see if I still have the ping.  I wouldn't do it always, I'll probably downsize since I'm a amateur hobbyist with a lot of want and not much skill.  I'm looking to do a Jasper trans rebuild, I'm hoping it is the original trans, and put a decent limited slip since I think, I'm not sure, the PO may have upgraded the diff to 3.55 maybe.  I appreciate the scolding for having parts on the car beyond my skills and the car's capabilities.  I wanted a performer and never intended on taking it back to factory.  I figure over the next few years I'll have to pull the engine and evaluate the internals just to know what it has.  I am probably most curious about the Scat rotating assembly since everything I read about it suggests it is a significant performance mod.  Again, thanks for the berating and in spite of it I will still enjoy the car until I get it just they way I want it.  I will; however, stay carb and never go to fuel injection with this.  I want the old school it has. 
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 20-April-2019 at 11:04AM
no scolding or berating intended, just trying to impress upon you how unmatched it all sounds like it must be. no beating around the bush. until you verify TDC there's still a possibility that the damper timing marks are causing your pinging issue, but the PO's recommendation to use octane boost suggests otherwise

did it ping when you first looked at / drove the car to buy it?

or did he have it all juiced up on octane for your first impression?

many refuse to accept that the stock or 'cam only' 351C can be a beast, they'll insist it needs 'fixing' because they've bought in to all the magazine BS over the years about all the 'problems' a Cleveland has. i think those 'problems' and bad press stem from mismatched combos like you may be experiencing? the 351C has been penalized and outright banned from almost every racing sanctioning body on the planet because it's a monster from birth. but it is fairly easy to tie it's show laces together, moreso than other engines. the 351C doesn't behave or respond to modification the same way small chevies, Fords or even Windsors do because they are so different. there are so many aftermarket parts that will diminish the performance of a 351C rather than enhance it. have you seen any of George Pence's articles he writes? what's nice is he has no bias, he doesn't want to sell you anything and he digs on 351 Cleveland history





you're really willing to wait years to tear into it and find out why? i wouldn't wait a week.

Censored yeah i'd put some good fuel in it and see if it changes it's tune LOL

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 20-April-2019 at 3:04PM
Start with the basics and I am sure we can help you out. There is a lot of knowledge and helpful people on this board. Rockatansky is one of the most knowledgeable Cleveland guys around, definitely the most on this board IMO.  Who knows maybe you will luck out and it won't be a bad combo of parts, just a bad damper.
Are you sure the carb is a double pumper?  A lot of guys call all 4150 carbs double pumpers even if they have vacuum secondaries. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 20-April-2019 at 4:40PM
Aw Embarrassed Shucks

Yes many mistake a dual feed 4160 vac sec carb for a double pumper because the rear float bowl also has a fuel line plumbed to it, but no secondary accelerator pump. Tim i know it's a lot to take in all at once but take notice to George's explanation of Dynamic Compression Ratio

your combo might be fixed with a cam change, maybe not optimal but better
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Post Options Post Options   Thanks (0) Thanks(0)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 20-April-2019 at 5:30PM
Originally posted by Rockatansky Rockatansky wrote:

no scolding or berating intended, just trying to impress upon you how unmatched it all sounds like it must be. no beating around the bush. until you verify TDC there's still a possibility that the damper timing marks are causing your pinging issue, but the PO's recommendation to use octane boost suggests otherwise

did it ping when you first looked at / drove the car to buy it?

or did he have it all juiced up on octane for your first impression?

many refuse to accept that the stock or 'cam only' 351C can be a beast, they'll insist it needs 'fixing' because they've bought in to all the magazine BS over the years about all the 'problems' a Cleveland has. i think those 'problems' and bad press stem from mismatched combos like you may be experiencing? the 351C has been penalized and outright banned from almost every racing sanctioning body on the planet because it's a monster from birth. but it is fairly easy to tie it's show laces together, moreso than other engines. the 351C doesn't behave or respond to modification the same way small chevies, Fords or even Windsors do because they are so different. there are so many aftermarket parts that will diminish the performance of a 351C rather than enhance it. have you seen any of George Pence's articles he writes? what's nice is he has no bias, he doesn't want to sell you anything and he digs on 351 Cleveland history





you're really willing to wait years to tear into it and find out why? i wouldn't wait a week.

Censored yeah i'd put some good fuel in it and see if it changes it's tune LOL

then Remove, Disassemble & Inspect ... RDI


Incredible amount of information in the threads that George started. Thank you for the links.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 21-April-2019 at 11:11AM
Yep, absolutely sure it is a Holley 770 cfm four barrel carb, at least based on the part number stamped on it, 86770-2  2585.   https://www.holley.com/products/fuel_systems/carburetors/avenger/ultra_street_avenger/parts/0-86770BL.  I'm confident that there is huge knowledge here.  I'm still waiting on the extended TDC indicater and and the piston block.  Once I get those I'll be able to set the 10* and try the race fuel. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote qcode72 Quote  Post ReplyReply Direct Link To This Post Posted: 21-April-2019 at 2:56PM
Iwould go to harbor freight tools and purchase a cheap inspection camera.Then pull a plug out.use the camera to view the top of the piston.This can tell if the piston dome or dish. The heads are Trick flow 62cc. chambers will give you 10 to 1 or 11.to 1 compression. Trick flow built a 351c for summit racing in Hot Rod Magazine.The build is on the net. this matches your motor.I have viewed your car in Pittsburgh it seemed to be somewhat radical.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 21-April-2019 at 5:33PM
62cc heads on a typical stock stroke / flat top bottom end i get 10.25:1

who would use a stock stroke if they're buying a Scat kit?

3.75" stroke bumps it up to 10.95:1, 3.85" stroke makes 11.2:1 ... with flat tops

still livable with a cam intended for those CR numbers, but we really have no idea if i'm even in the ballpark

BTW, Holley 86770 is not a Double Pumper, it's a 4150 style (secondary metering block) vacuum secondary
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 22-April-2019 at 12:46PM
Good to hear?  Is my carb okay or am I still looking to replace it with something not so radical?  To everyone, I appreciate the help.  I bought the car "as is" and was excited about having a 1972 Ford Gran Torino Sport again.  I'm sure "we" can work through the problems and when I get it running well I will give each and every one of you a ride in it.  I like the inspection camera suggestion and I really wish I understood the math you used to determine the "suspected" compression ratio, almost as much as I wish I really new what the internals were.  I keep you all informed and for you viewing pleasure here is the source of my headaches.  Oh, I did get the airco working and expect to put some miles on even with the ping unless it is absolutely not recommended.  And yes, I would do it light footed.  Thanks again.

Edited by Timustbe - 22-April-2019 at 1:19PM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 22-April-2019 at 12:50PM
In case that one wasn't enough here is the driver's side.
Tim Northcutt
'72 Ford Gran Torino Sport (Pearl White)
'07 Jack Roush SC F-150 (red)
'02 HD Road King Classic (Luxury Blue and Diamond Ice)
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Post Options Post Options   Thanks (1) Thanks(1)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 22-April-2019 at 1:47PM
Nice.

Here is a competitively priced (cheap) camera for inspecting cylinders.https://images.app.goo.gl/TKMsvtvYgtckrn9D9

Should be good for checking intake valves from the carb.

Edited by handsofstone - 23-April-2019 at 1:59AM
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 23-April-2019 at 6:28AM
I figured it might not be a double pumper.  Many mistake all 4150's as double pumpers because of the dual fuel inlets.  Rock will know better about the carb, but depending on your build a Street Avenger 770 doesn't seem like it would be out of line with a healthy Cleveland. It is really just a Holley 750 VS that is calibrated a bit differently.  You can get the specs from Holley if you want to know how it's setup.  At least it is a vacuum secondary, which will work much better than a double pumper with a big heavy car and an automatic. I have a 670 SA and I have been happy with it, but my engine has a mild cam and isn't built for high RPM.

Once you confirm TDC and can set the timing correctly, then see how if ti still pings.  When my distributor was seized, my engine was pinging too.  I still drove the car, but disconnected the vacuum advance and used octane booster to minimize the problem.   It was fine until I got the distributor freed up, but I also planned on rebuilding the engine, so I wasn't overly concerned about long term damage.
Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timustbe Quote  Post ReplyReply Direct Link To This Post Posted: 30-April-2019 at 2:04PM
My fellow Torino enthusiasts.  I am probably going to replace the harmonic balancer and am wondering at the better recommendation.  I see them for $60.00 to $400.00.  With fluid and without.  Does it make a difference since my engine is already kind of out of kilter I'd like to start anew if I'm going to do this.  Any guidance would be appreciated.  Thanks in advance.
Tim Northcutt
'72 Ford Gran Torino Sport (Pearl White)
'07 Jack Roush SC F-150 (red)
'02 HD Road King Classic (Luxury Blue and Diamond Ice)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 30-April-2019 at 2:14PM
I doubt a fluid filled balancer does much. I would get the correct balancer and pointer. That's just me.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 01-May-2019 at 6:23AM
My engine builder, TMI, just used a stock replacement style balancer on my engine.  He builds tons of engines, so I trust it would be sufficient in most cases.
Vince

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