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Discussion Starter · #181 · (Edited)
So, here's some input on the original harmonic damper. Because of this thread, I literally picked up the phone and called a guy who has owned a company that engineers and builds the rubber part of harmonic dampers and we just hung up. He says his are designed for a 20 year shelf life with zero degradation of the damping frequency. He also did a 5 year study of his products in use on cars and there was "barely any shift in frequency". Further, he told me that 30 years ago or more, Toyota had an embarrassing recall on a non bonded harmonic damper (friction fit) that came apart. From that day forward, they led the industry in bonding 100% of their dampers - this one included. Bonding is a cost add and chemically bonds the rubber and steel and that's a step up from other makers where they also use a higher grade polymer - not just ordinary rubber. So he says unless the engine has had a major heat event (fire, or catastrophically overheated) the damper will be fine.

Having said all that, I'm confident in using the original harmonic damper. Especially now that it's snappy black again and has a yellow timing notch!! I"m glad this topic came up because that's a ton of money for a damper and, learning a bit about the physics involved, my guy says it's unlikely whomever is making those dampers is getting the rubber durometer correct for the engine. He has looked at and measured aftermarket competition and they're a joke - no engineering at all.

It requires a lab to engineer the precise durometer for each individual engine for a part that goes out the factory door on your engine. Aftermarket parts don't have a buyer who gets the part, hooks up his engine to a vibration detector in HIS lab and says "Are you kidding me - the engine has only a 10% reduction in 1st and 2nd order vibrations - that's crap." No, they have people like you - consumers who open the box and say "cool, it's got red designs on it and says 'race' in a blue anodizing, so it must be effective." Uh, nope. Buyer beware of solutions like shocks, and springs and mufflers that are the same part number on 15 other vehicles.... You are often DOWNgrading your vehicle putting that stuff on it.
 

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My take on the dual PCV outlets is that both are high spots on the engine and would tend to collect moisture that needs to be ventilated. The other thing is that the stock ventilation does not have a check valve in the pipe to the accordion tube like the mk4, so it is probably not as effective as a normal non-turbo setup where full vacuum is applied to the crankcase. Here the crankcase is always at or near atmospheric by virtue of the accordion tube "leak."
 

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I"ll check my factory manual and confirm.

On the ATI damper. I did some research to see what's available and that product was the only one I could find. Simply put - no way I'm spending $400 on a damper. I have Toyotas running smoothly at 300k miles with the original damper. I'm sure the durometer of the rubber is not exactly what it once was in absorbing engine power pulses, but I expect a smooth engine when I'm done. It will be resting on new motor mounts, and I've done a very precise valve adjustment, and I expect no issues out of the original damper. Happily, a straight 6 engine is a naturally harmonically balanced engine (vs V6s which are horrible, etc). So unless you're sending me an ATI damper, it's not happening!! Heh....

Edit: Yes that metal union pipe on the rear of the head by the EGR cooler is the hot water exiting the engine going INTO the heater core in your dash.
you missed it when toyota was selling the OEM dampers. $600 at that time. The ATI is good for 550 hp sustained (Nascar style). Toyota never made theMA70 damper to support more than OEM power (harmonics increase with power increase) which for the i6 folks (including the BMW guys) there had to be another option as the i6 are a wet noodle from a crank harmonic perspective.
 

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So, here's some input on the original harmonic damper. Because of this thread, I literally picked up the phone and called a guy who has owned a company that engineers and builds the rubber part of harmonic dampers and we just hung up. He says his are designed for a 20 year shelf life with zero degradation of the damping frequency. He also did a 5 year study of his products in use on cars and there was "barely any shift in frequency". Further, he told me that 30 years ago or more, Toyota had an embarrassing recall on a non bonded harmonic damper (friction fit) that came apart. From that day forward, they led the industry in bonding 100% of their dampers - this one included. Bonding is a cost add and chemically bonds the rubber and steel and that's a step up from other makers where they also use a higher grade polymer - not just ordinary rubber. So he says unless the engine has had a major heat event (fire, or catastrophically overheated) the damper will be fine.

Having said all that, I'm confident in using the original harmonic damper. Especially now that it's snappy black again and has a yellow timing notch!! I"m glad this topic came up because that's a ton of money for a damper and, learning a bit about the physics involved, my guy says it's unlikely whomever is making those dampers is getting the rubber durometer correct for the engine. He has looked at and measured aftermarket competition and they're a joke - no engineering at all. It requires a lab to engineer the precise durometer for each individual engine.
ATI did, i worked with them on it back 2008 ish time frame with specific CAD and engineering diagrams that I approved to make it happen. That first damper cost me about 3x what it cost today to make but with that, ATI did infact nail the numbers correctly based on the engine and OEM damper i sent them :)

On the bonded portion, i would triple check that again when it actually started as the 2jz damper had a horrible rap for delaminating the shell from the hub at elevated power levels.
 

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where does that hose for the heater union run to coming out the top .... i cant figure out ..

For a visual, see @Snipe_sas 's thread here.

You will see that the coolant line goes to the top metal tube under the exhaust ports as seen here.


So that's a large air hose that I'm not even sure goes yet but will be dealing with soon. I've been puzzling over the dual vents as well (one on each valve cover) as I'd think that either would be sufficient for crankcase ventilation. It is an interesting setup and I'm sure it will all be clear at some point. I assume you're asking about the valve covers? If it's the heater union pipe on the head, I believe that feeds hot water to the heater core through the firewall.
The two breather setup for the 7M has been known to puke out oil. Instead, an alternative is to run a catch can. Also, with all the time and money you are and have spent on the engine, I would also encourage you to get a new damper, even at the cost :D
 

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Discussion Starter · #187 ·
Figgie,

Interesting and thanks for the input. I stand corrected about the ATI harmonic balancer. Looks like they did the correct engineering, eh?

Chevydude - wow thanks for the link on Snipe's "New Old Build" going on over in the Builds section of this forum. You guys and gals have got to go see that engine. It's a work of art and I can't believe I had no idea another engine build on a 7M was going at the same time as mine. Wow. Just wow....
 

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Figgie,

Interesting and thanks for the input. I stand corrected about the ATI harmonic balancer. Looks like they did the correct engineering, eh?

Chevydude - wow thanks for the link on Snipe's "New Old Build" going on over in the Builds section of this forum. You guys and gals have got to go see that engine. It's a work of art and I can't believe I had no idea another engine build on a 7M was going at the same time as mine. Wow. Just wow....
I hope so otherwise they took my moneys!

In all seriousness, I discussed with both ATI and fluiddamper about the 7M's base and resonant frequency based on the length, mass and stroke but then including the delta between power stroke #1 and the flywheel as that will produce the biggest base/resonance on the crank with the others producing less freq since they are closer to the flywheel (who would have thought that music theory would actually prove to be useful outside of music). Long story short, ATI for the 7m can live at 550 fwhp sustained without issues with the current size of the damper (5.5"). It can blow past that in short bursts but now inspections etc need to happen. Bonus part (that i did not require or ask for) was SFI certification for those that are drag racing or that are doing ANY type of racing where SFI certification is required. I know that there is a 1k HP 7m Supra running a custom 8" damper since that time and a couple of 800+ hp supras on the same. Most anyone on 7M high HP build is on the ATI.
 

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Discussion Starter · #189 ·
Nice info. Good to know the ATI can handle a hopped up 7M. Mine is stock, plus whatever effect I got mildly porting and polishing the head, (or the placebo effect of that!). So I'll be fine and atop that I'm pretty anal about proper belt tension, quality belts, tuning and cooling etc, - all of which can also help a harmonic balancer live happily ever after. My buddy lives this stuff all day every day and has for over 40 years. Literally all they produce is the engineered rubber part that solely determines the damping of harmonic balancers based on the engine's unique characteristics. He has a lab, they sample each batch and test it in the same lab, plus send samples out to outside testing for comparison. It's quite a science as you've noted.

It's also worth noting that when you make a significant change to an engine like advancing the timing, installing a hot cam, install lighter pistons/rods, or increase the power pulse strength through forced induction you need to change the damper to match the now very different frequencies. Greater torque on the crankshaft causes whipping/flexing the factory setup could not achieve, ignition timing alters where in the crankshaft angles the force hits, etc, etc. So when I asked him about hopped up engines he shook his head and explained a damper is set up for an engine family as it is delivered from the factory and these engines are built by the tens of thousands to as close a tolerance as possible. So his calculations and the damping effect itself are based upon the vibration profile of factory parts, factory timing settings, etc. He expressed doubt about the effectiveness of a damper that would be claimed to be effective across a range of such dramatic modifications - providing damping on a stock 230hp engine and a 500hp version of the same engine. I didn't even mention the 800 or 1000hp(!).

I'd be curious what ATI's position on how they achieve such a broad range. An elastomer's damping is essentially fixed. I could see them making the claim it has the STRENGTH to handle a broad range of power output because obviously if it will handle 1000hp it will still handle 230hp. But not the effective damping. In racing there is less concern about vibrations, belt wear and component bearing wear as things are closely tended, replaced and monitored so it may be ATI is correctly giving the racing world what it wants/needs.
 

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Nice info. Good to know the ATI can handle a hopped up 7M. Mine is stock, plus whatever effect I got mildly porting and polishing the head, (or the placebo effect of that!). So I'll be fine and atop that I'm pretty anal about proper belt tension, quality belts, tuning and cooling etc, - all of which can also help a harmonic balancer live happily ever after. My buddy lives this stuff all day every day and has for over 40 years. Literally all they produce is the engineered rubber part that solely determines the damping of harmonic balancers based on the engine's unique characteristics. He has a lab, they sample each batch and test it in the same lab, plus send samples out to outside testing for comparison. It's quite a science as you've noted.

It's also worth noting that when you make a significant change to an engine like advancing the timing, installing a hot cam, install lighter pistons/rods, or increase the power pulse strength through forced induction you need to change the damper to match the now very different frequencies. Greater torque on the crankshaft causes whipping/flexing the factory setup could not achieve, ignition timing alters where in the crankshaft angles the force hits, etc, etc. So when I asked him about hopped up engines he shook his head and explained a damper is set up for an engine family as it is delivered from the factory and these engines are built by the tens of thousands to as close a tolerance as possible. So his calculations and the damping effect itself are based upon the vibration profile of factory parts, factory timing settings, etc. He expressed doubt about the effectiveness of a damper that would be claimed to be effective across a range of such dramatic modifications - providing damping on a stock 230hp engine and a 500hp version of the same engine. I didn't even mention the 800 or 1000hp(!).

I'd be curious what ATI's position on how they achieve such a broad range. An elastomer's damping is essentially fixed. I could see them making the claim it has the STRENGTH to handle a broad range of power output because obviously if it will handle 1000hp it will still handle 230hp. But not the effective damping. In racing there is less concern about vibrations, belt wear and component bearing wear as things are closely tended, replaced and monitored so it may be ATI is correctly giving the racing world what it wants/needs.
well the 5.5" will NOT be able to dampen 1000 hp. Can it survive? Sure, just like the OEM can but is it doing anything useful at those level. Very unlikely.
No way around that science hence the need for the 8 inch custom. I would love to know the durometer rating of the stuff ati uses but all that stuff is "company secrets". lol.

With that said, I am sure with some digging, the Dinan paper on harmonic dampers can still be found somewhere.
 

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Thanks @IdahoDoug for starting and keeping up with this thread and thanks to all the other folks contributing as well. Really enjoying following along as I'm refreshing my own car, great information here.
 

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Discussion Starter · #192 ·
Kind of you to say. Hope it proves fun going forward. Yesterday I moved another car out of my 3rd stall with my son's help and that means the Supra goes in sometime in the next week. For the moment I'm enjoying the space and will just use the empty stall to finish the engine up before pulling the rolling shell in. It's pretty high on its suspension with no engine, no trans, and no fuel tank (off for cleaning).
 

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@IdahoDoug

Joining the new truck fad are we? ;) The MA70 engineless is the precursor to the new fad!

260128
 

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Discussion Starter · #194 · (Edited)
Yeah, that's the stance for sure. I've got a PreRunner Supra about 30 years behind the actual fad! I just realized I need to leave it out there for the time being as there is a hole under the battery tray. Looks like when it sat for 20 years, the battery must have discharged and frozen, then leaked down there. So I'm going to buy a sand blaster and clean that area up, patch the hole and repaint it for protection from the elements. I've heard the grit goes everywhere, so I'll be happy not to have to clean up my garage.

I want to get this done first, because once the engine's in I won't have much space to do it right. And of course the mess is better left outside....
 
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