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Problem with damper installation

1

180 Out

Member
I am putting together a 5.0 roller cam engine for my '65 fastback. I am using the front cover from the 289 that was in the '65. I am using a Summit Racing balancer, like this one: http://www.summitracing.com/parts/SUM-163302/. Following the enclosed instructions, I boiled the balancer for 15 minutes, then I oiled the crank snout and the inner diameter of the balancer. I used a proper installer tool to snug the balancer up tight against the timing gear. Then I switched to a torque wrench set at 90 ft/lbs. After maybe 360 degrees with the wrench, maybe more, there was a scary crack sound.

I thought maybe the damper bolt had broken. Well, with nothing to lose at this point I went ahead and continued tightening with the torque wrench. It had been very high effort to pull on the wrench handle prior to the crack sound, but after the crack sound it was lighter. Now I'm thinking stripped threads. But no, after a few rotations the effort got high again and I got the wrench to click, indicating I had reached 90 ft/lbs. But here's the weird part: the crank is locked up solid. It wouldn't rotate at all. I used two long bolts threaded into the balancer and put my biggest longest screw driver between them as a lever and the crank would not rotate at all.

I removed the balancer today and the crank turns just fine. I have not checked runout again, but I will do that next. I had checked runout during the build, and it checked good.

Well, sorry for the long post, but I wonder if anyone else has had this experience and if you have an idea of what I'm doing wrong.
 
I have no experience with this happening to me and it's a total stab in the dark, but two scenario's come to mind.

1) If the the balancer snout is too large of a diameter it could be binding against the timing cover/seal inner diamater. The crack you heard might be the timing cover cracking as the larger snout is forced thru the seal opening.

2) you dislodged the seal from the timing cover and it caused binding against the crank/balancer.

Good luck.
 
I tried to install a new timing cover over the winter (since I had to rebuild the valve train) and it was a little too deep for my SFI damper. I could not get it to torque down without binding against the timing cover. Put the old TC back on and all was well.

It's not you exact situation, just another idea.
 
Yes, sounds like the damper bottomed out somewhere. Is there any scraping marks against the timing cover?
 
Check the lower gear on the crank, you may have broke it.
Verify the snout of the old bal is the same length as the new.
From your discription it went too far and pinched the gear to the block, That is why it stopped the crank from turning
but turns with the bal off.
 
Thanks for all the replies. I think Mach1Rider matches my guess of what happened too. That "crack" sound I heard was the sound of something breaking. The front cover shows no cracks, but I'll be taking it off to see what's what and my guess is I'll see a broken timing gear.
 
I think this project might be the victim of my own bad vibes. Ever since I saw this

wrl-120010_w.jpg


on the Summit Racing web site -- it's a 371 ci World Products long block with the same deck height as a 5.0 -- I've been thinking well, if the project I building blows up on me I can always go for one of these. They're even $600 off MSRP, according to Summit: http://www.summitracing.com/parts/WRL-120010/?rtype=10 . That wouldn't be such a bad consolation prize.
 
I am using a 1990 5.0 HO in my '66 with the old 289 timing cover. I wound up having to use a special 50 0z balancer (from ebay) that was shorter, because my pulley's would not line up without it. I made a thread on here about the problem at the time if you dig around you'll find it.
 
Thanks for the tip gwstang. I think I found your thread: http://www.stangfix.com/testforum2/index.php/topic,10702.msg133009.html#msg133009 . My Summit balancer came with the spacers to position the pulley. But I'll measure it and the OE unit to see how they match up.

If I understand the front dress of the crankshaft, it's still mysterious to me how I could go wrong. The crank sticks out past the first main bearing and it has a step machined into it. The timing gear indexes against that step, and the damper then press fits onto the crank snout. The balancer installer tool snugs everything up, and the torque wrench then helps to ensure you've put proper bolt stretch on the balancer bolt. What could go wrong? I'm still in the guessing game stage here, but my guess is that I somehow messed up the timing gear, like I didn't put it on square. Kind of unlikely, but that's the kind of thing you come up with in the guessing game stage. I'll take pictures and post them up when I take it all apart.
 
Yes you have the right idea about the crank but,
The area where the timing gear goes is somewhat beveled to match te shape of the rear face of the gear.
The balancer does press against it but the cranks snout should be flush with the balancer at the inside end of the hole
when it is seated completely and the greatest amount of the tork that is placed with the bolt is spread across the heavy washer
and the endface of the crank.
If the bal snout is too long when you drew it down farther with the bolt to seat the heavy washer it presses the gear farther onto the bevel of the crank and SNAP goes the gear. I bet if you take the bal off and look inside with a light you will see the gear has split in 2 peices.

Also roll the crank completely while checking the lower gear for a single splitting crack.
 
I found the problem. silverblueBP and cmayna were on the right track. Just below the water pump the front cover casting has a pair of bosses. It's my guess that these are the entry points where the molten aluminum was poured into the casting sand. One of them is lower than the other, and this lower one was interfering with the outer ring of the damper. (The outer rings on the original equipment 28 oz. units are so much thinner than the one on this fancy 50 oz. aftermarket unit that they don't have this problem.) Here's a pic to show how my first installation of the damper broke off part of this boss:



I cut and ground it down to look like this:



I'm not out of the woods yet, though. I should have cut it down another .050. Fully torqued to 90 ft/lbs, the crank turns freely. But there's almost no clearance between the cut down boss and the damper. I don't think it would be a good idea to run such a tight clearance. So I've pulled it apart again, and I'll cut down the boss some more and put it back together again next weekend.
 
No matter what, your photography is very nice. Yes see no reason to not grind that boss down flush.
 
Might not be a bad idea to clerence both of those boss's down just to be sure.
At least it is an easy fix. :beer
 
If one of the bosses cracked when you originally torqued the damper down, I would be concerned that there would be other cracks in and around that area. You might not be able to see them; I'd recommend a magnaflux on the timing cover or complete replacement.
 
Who sells the old timing covers? I would consider getting one if they're not too spendy. I don't think you can magnaflux aluminum.
 
Packy of Mustangs R US in San Jose probably has a pile of them. Is it a stock 65 289 timing cover? I can call and get price and availability from him as well as maybe another guy here locally.
 
Hi Craig. Thanks for the offer. Of course Midlife's comment about unseen damage to my front cover got me stewing, and with the itch to spend money starting to infect me again, I went ahead and ordered a brand new unit from Summit Racing. About $95 delivered.
 
"180 Out" said:
Who sells the old timing covers? I would consider getting one if they're not too spendy. I don't think you can magnaflux aluminum.
Click to expand...

They should be able to magnaflux a tc cover. They magnaflux aluminum heads and block all the time.
 
"180 Out" said:
Hi Craig. Thanks for the offer. Of course Midlife's comment about unseen damage to my front cover got me stewing, and with the itch to spend money starting to infect me again, I went ahead and ordered a brand new unit from Summit Racing. About $95 delivered.
Click to expand...

Doh,

I have a new unit sitting in the garage. My SFI damper hit it and I ended up going back to the original one. Could have saved you some cash if it worked.
 
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