Sadly everything was good to, the duster was running great making lot's of power plenty of traction and new clutch felt great. I was doing some test launches with the 2 step and the cal tracs. First few launches were awesome and a handful. Last launch the engine coughed and shut off, attempted to restart and the engine just sounded like it was free wheeling like no compression so I had figured I broke the timing chain. Pulled everything apart found that the cam sprocket came lose after a few years and sheered the locating dowel on the cam off. I already had planned to drive 5 hours down south back home so I attempted a fix to get the duster home. I drilled through the cam sprocket and into the camshaft, then tapped the hole for a set screw. The fix actually worked fine except for my alignment being off a few degrees soooo the camshaft timing is now retarded. Just figured i'd let ya guys know I had never heard of this before so I will be making sure everything is loctited from now on. The scariest hole drilling i've ever done lol. New cam and timing set after graduation (Dec 12th) hopefully

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That washer was just there to see the hole i was drilling I installed everything with the factory bolt and washer again. Current cam is erson 220@.50 464lift 114lsa. Any ideas if I should stick the same cam back in or attempt a small upgrade?

Kev

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Sorry to hear that, but nice fix and description! This is a known problem. I always overtorque my bolt by about 10 ft-lbs and use Loctite and I've never had trouble.

The first Bob Dally Bonneville 66 B'cuda 170 motor had this happen 3 weeks before Speed Week 2011 and I shipped Bob another cam so he could run the car since he couldn't get a cam made/bought in that time.

Careful assembly is often the most important part of a rebuilt engine (or replacement of anything, really).

Your engine seems to make gobs of power, so I'm not sure a different cam will help. However, it's always nice to try a new experiment when the opportunity arises.

Your cam is about perfectly what I would choose. However, if you want higher or lower RPM range you could modify the cam for that using a duration @ 0.050" change. Or, I would try adding some intake dur and subtract about the same on the exh.

Lou

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Home of Slant6-powered fun machines since 1988

I had a similar situation happen 10 years back on a much milder setup but was due to clutch dumps with the Hpak at high rpm. I employed the "Doc Dodge Fix"....

Drill the other side of the gear and cam 180 degrees from your current fix, this will create a back up pin in case one or the other loosens or fails, it also halves the load placed on just the single pin especially if your rpm change is sudden and abrupt.

Ya the whole thing surprised me since I've launched the car a million times before that lol. Oh well I'll get it sorted out when I move back to Clearwater. Ya I enjoy the way the engine pulls and daily drives so I'm hesitant about changing anything on the cam specs except maybe more lift if possible? That would give me an drops in power down low or anything right? I was not happy to find the dowel pin broke off but I guess it was better than eating pistons or something more major.

Kev

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My Lancer broke the cam dowel pin at the Samoa race this year...
I made the mistake of using a different washer under the cam gear bolt and the bolt loosened, then snapped-off the dowel.

I was able to drill and "easy-out" the dowel stub and get it back together for the next race but there were a couple of bent push rods that had to be changed-out. ( a zero deck K1 / Wiseco engine)
Lucky for me that the engine ran on all cylinders, once reassembled... I guess the big valve notches in the Wiseco pistons did their job

As already noted... this is a place to pay close attention when building a SL6. Seems like "over-doing it" is what is needed, with the single bolt / dowel cam gear retention system.
DD

Speaking of that washer, I can't believe they are not available. I did a timing chain on a 2002 dodge PU with a 5.9, and it uses a bolt and washer very similar to the slant six. Called the dealer to get a couple, and they are NS-1, even though they were used by the factory through the 2005 model year. The same part would work on any small block Mopar since the 273, as well as the slant. Called Called ARP and they don't have anything either, and the same with several cam mfgs I called. The bolt is not a problem to get, but the washer is just not available, as far as I know. I have a couple of washers that have stress fractures.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

would a simular sized grade 8 washer do?

https://www.boltdepot.com/USS_flat_wash ... ellow.aspx

What grade and size is the bolt? (and what is the torque spec for tightening the bolt?)


The pin is only for location purposes.


The torque load on the cam is due to the friction between the cam and cam gear due to the clamping force of the bolt.

If the bolt is too loose, there isn't enough friction and you'll shear the pin.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

The factory versions I have are harder than Grade 8, it would be temporary but I wouldn't trust it for the pounding the cam can give the gear if the bearing clearances are loose and the chain has a little play during repeated 6200 rpm clutch dumps...

It might play OK for a tame low rpm street driver or used with a nice stout cam button, though...

Kev, out of curiosity, what LSA is that cam of yours? 112?

Yep, but remember ma mopar learned quickly and made the Hemi and the late 440-6packs a 3 bolt cam gear to share the load since the torque can overcome the interference fit and single pin on the cam. Since only a proud few of us are putting that kind of number to the ground (and most an automatic) luckily, a two pin solution works as a solution for the rest of us.

The factory supplied hardened cam bolt washer is actually a conical spring washer or "belleville washer".
It has a slight cup shape, that holds tension on the bolt, once tightened.
DD

My current cam is on a 114lsa. I torqued everything to spec but I don't recall putting and blue goo on the bolt so I assume it just worked itself loose. The bolt and gear were just loosely hanging together when I pulled the front cover off.

Kev

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Actually the bolt is not the problem. You could use a regular 7/16-14 NC grade 8 bolt. The washer is the problem, as Doc stated, it is special. I hope ARP (or someone) starts making those.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225