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#1
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Adjusting cam timing
I've already degreed the cam and need to advance the cam 2 degrees. My lower timing gear only has 4 degree options adv/ret.
The only way I can see is to use a SBC offset crankshaft key on the cam. So if I use a SBC 4 degree offset crankshaft key on the Pontiac cam, will this give me the 2 degrees at the cam I'm looking for ? |
#2
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I think a mopar key is avail.Tom
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The Following User Says Thank You to tom s For This Useful Post: | ||
#3
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In the old days the mopar keys were used a lot.
If you find a source I would like to purchase at least 3 sets of the parts. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#4
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https://butlerperformance.com/search.html?q=cam+keys
Perhaps a bit pricey?
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Frank M. 75 Firebird 68 Firebird 400 RAIII 66 Chevy II 461 Pontiac in AZ |
#5
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Unobtainium, so far on google.
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#6
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Those are Chevy crank keys.
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#7
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Ah, the old days.... Gone.
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#8
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Cam timking
Does anyone know how much the cam would move if I put a Chevy offset crank key on the Pontiac cam? If it's a 2 degree crank key, how much would that move the cam ?
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#9
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Crank turns two revolutions while the cam turns one rev, so 2° on crank is 1° on cam.
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#10
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Did you already try degreeing it using the +4 advance slot to see what the result was? I've seen some 9 keyway chain sets that only change the camshaft position +2 degrees when using the +4 slot, others advance more than 4 degree when using the +4 slot, just depends on the combination of everything, like the crankshaft keyway, camshaft keyway, the accuracy of the 9 keyway timing set cam/crank keyways. It has to be rechecked everytime that it is advance or retarded to verify that it moved the amount desired.
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1978 Trans Am Pump Gas 461 Stroker |
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#11
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Quote:
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The Following User Says Thank You to Formulajones For This Useful Post: | ||
#12
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^^^^^ x2
The cheby key would move the cam 1* which you probably would not even really find on the wheel. I know when I was dialing mine in....i call it +/- 1/2* = YAY!!! |
#13
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It will double the number on the degree wheel. 2 degree offset key would show 4 degrees advance/retard depending on how the key is installed
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66 GTO, 495, M22, Strange S-60 w/4.10 Sold new at Royal Pontiac. 70 Formula Last edited by Singleton; 01-29-2022 at 11:55 AM. |
#14
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Quoting Jim Hand on 6/15/2000:
"As the cam rotates at half speed from the crank, one degree change at the cam equals two degrees at the crank. Accordingly, a one degree change in location of the cam will shift the lobe center two degrees at the crank. So a two degree cam key will change the cam timing by four degrees!" End quote. The discontinued Mopar offset keys contained a set of 5 color coded keys. The natural metal key is 1 degree, which would give you the 2 degree advance that you're looking for. I'm not aware of anyone else making a 1 degree key
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66 GTO, 495, M22, Strange S-60 w/4.10 Sold new at Royal Pontiac. 70 Formula Last edited by Singleton; 01-29-2022 at 02:23 PM. |
#15
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Last time i needed a 1 degree cam key (2 at the crank) i welded and reground a 2 degree cam key. No issues Works fine and didnt take long. Jon
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'78 Macho T/A DKM#95, 460cid, SRP pistons, KRE 310 D ports, 3" pypes, Hooker 1 3/4" headers, hydraulic roller, 10" Continental, 3.42 gears 11.5 @117.5mph 3900lbs ([_|_] ##\|/##[_|_]) |
#16
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The Mopar 5-pack color coded keys were really great, but I haven't seen any for sale in at least 10 years now. They were sold as a "Direct Connection" performance part. So that goes way back. If you want to go the offset key route, probably the best thing to do is Google "Mercedes offset woodruff key". That will bring up multiple sources for Mercedes offset keys from 1 to 5 degrees that will fit our Pontiacs. Each key is about $10.00. Hope this helps.
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#17
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I see what you are getting at, I need to put the degree wheel on and experiment. Sounds like it's hit or miss sometimes using the multi crank gear positions but I may be able to correct it with a cam key going whatever direction I need it to. Sure wish they made the Mopar keys again.
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#18
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Thanks I'll try that.
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#19
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Quote:
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1978 Trans Am Pump Gas 461 Stroker |
#20
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Look in the Summit catalog they sell a timing chain setup that has +- 2,4,6,8 degree keeways on the crank sprocket.
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