78 460
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78 460
Hi Guys
I don't know if this is the right forum for this question but here go's.
I have rebuilt my 78 460 30 over rv cam. The fine machine shop we have here didn't have the cam sheet or cam gear sheet when I picked up the block and parts.
I put it to gether with the double roller three key set at o. I feel the engine isn't running with the power I had before so pretty sure it is retarded but don't know how much. With the research her I think I should have used the triange key way.
I also have a holley 750 vacum secondard carb that the idle is so rich it will run you out of the shop really quick.
I guess my question is do you think my cam timing is wrong and should I go back in and varify that it is key I used is truly the 0 setting before fighting carb problem. I also have no idea why the damn thing is so rich at idle. It is new carb. The idle adjustment on passenger side has some afect but the driver side you can close all the way. Don't see any dripping do the carb throat.
Any ideas.
Thanks
I don't know if this is the right forum for this question but here go's.
I have rebuilt my 78 460 30 over rv cam. The fine machine shop we have here didn't have the cam sheet or cam gear sheet when I picked up the block and parts.
I put it to gether with the double roller three key set at o. I feel the engine isn't running with the power I had before so pretty sure it is retarded but don't know how much. With the research her I think I should have used the triange key way.
I also have a holley 750 vacum secondard carb that the idle is so rich it will run you out of the shop really quick.
I guess my question is do you think my cam timing is wrong and should I go back in and varify that it is key I used is truly the 0 setting before fighting carb problem. I also have no idea why the damn thing is so rich at idle. It is new carb. The idle adjustment on passenger side has some afect but the driver side you can close all the way. Don't see any dripping do the carb throat.
Any ideas.
Thanks
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
Do you have enough vacuum to hold the powervalve shut?
Do you know what # it is?
I'm no expert, but I have one so I've run into things like this before.
*edit*
Whose timing set do you have?
0 should be stock,... retarded compared to pre'72 cam timing.
I just pulled out the Cloyes instructions for the set I installed last week.
Do you know what # it is?
I'm no expert, but I have one so I've run into things like this before.
*edit*
Whose timing set do you have?
0 should be stock,... retarded compared to pre'72 cam timing.
I just pulled out the Cloyes instructions for the set I installed last week.
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Freshman User
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19 inchs
6.5 PV
Holley Carb
Part no. 80508-1
Model No. CFM 4160 750
Primary Main Jet Secondary Plate Primary Metering Block
122-72 134-21 134-1315
Secondary Spring Color Plain
Suppose to be Cloyes timing set I am guessing it was ordered for 78 model. I installed it with the 0 mark lined up with cam gear.
6.5 PV
Holley Carb
Part no. 80508-1
Model No. CFM 4160 750
Primary Main Jet Secondary Plate Primary Metering Block
122-72 134-21 134-1315
Secondary Spring Color Plain
Suppose to be Cloyes timing set I am guessing it was ordered for 78 model. I installed it with the 0 mark lined up with cam gear.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
Not sure about the internally balanced motors but,
I would then start by checking that the marks on the harmonic match TDC #1.
I know mine's slipped.
Seems like plenty of vacuum.
Others are viewing this thread and no one's spoken up....
I would then start by checking that the marks on the harmonic match TDC #1.
I know mine's slipped.
Seems like plenty of vacuum.
Others are viewing this thread and no one's spoken up....
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I think you are right about that when I first setup the timing didn't like the throtle response, so set timing hot just where it would start well without kick back.
I have also noticed that the engine doesn't ping even on the regular fuel. Before the rebuild it would with 200 thousand miles on it. This adds to my belief that the cam is retarded even more than the normal 4 degrees.
I have also noticed that the engine doesn't ping even on the regular fuel. Before the rebuild it would with 200 thousand miles on it. This adds to my belief that the cam is retarded even more than the normal 4 degrees.
Senior User
Joined: Aug 2003
Posts: 227
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From: Virginia
These engines do like the better fuel even with lower compression ratios. I don't want to sound like a smart a** but you should have degreed the cam when you installed it. Some are cut with advance/retard in them. The only way to know where the cam truly is installed at is to degree it. I would keep advancing the timing till you got some detonation, then back it off and check it with a light to see the total advance. Should be no more than 38-40 degrees max.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
Originally Posted by hotrodmerc
I don't want to sound like a smart a** but you should have degreed the cam when you installed it. Some are cut with advance/retard in them. The only way to know where the cam truly is installed at is to degree it.
Call the machine shop, see what they ordered....
Demand It!
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Hotrodmerc you are not a smart a** you are 100% right. I haven't been able to find out what cam they put in so guess I am screwed. I lost my temper with owner and if I return will call law.
I don't know how much distributor advance I have now. I set it just below the point where it kicks back on starter.
I don't know how much distributor advance I have now. I set it just below the point where it kicks back on starter.
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Senior User
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From: Virginia
I know it's hard to find a good machinest you can trust and does good work.
I hate to say it but I think you are kinda screwed without alot of work being involved to remove the cam. I think that would be my next project if it doesn't run as well as you think it should. Timing is about all you have to go on without pulling the cam. You might get a part # off of it if you decide to pull it. Good Luck
I hate to say it but I think you are kinda screwed without alot of work being involved to remove the cam. I think that would be my next project if it doesn't run as well as you think it should. Timing is about all you have to go on without pulling the cam. You might get a part # off of it if you decide to pull it. Good Luck
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Not knowing anything about the cam grind is a bummer, but all isn't lost. You already have the good chain and gear set, so get a RV cam and get on with the good life. For all you know it was a reground cam anyway, right?
As for the carburetor issue, at a minimum the metering block has to looked at since your idle screw does nothing, but once you're in it that far, you might as well go whole hog with a rebuild kit. If that's the original carburetor with 200k+ miles, the throttle shafts/bores are probably worn and could be a source for vacuum leaks.
As for the carburetor issue, at a minimum the metering block has to looked at since your idle screw does nothing, but once you're in it that far, you might as well go whole hog with a rebuild kit. If that's the original carburetor with 200k+ miles, the throttle shafts/bores are probably worn and could be a source for vacuum leaks.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 38
From: EXTREME southwest CT
BTW,
Are you sure you don't have a stuck float in your new carb?
You'll never know how the cam is if your motor's drowning in fuel.
Or vice versa.
Do you have the old carb still, to see if the situation clears up some?
Check TDC, how old's the damper?
Do whatever you can before pulling it back apart.
Sorry about the "demand it" comment, I should have read more into your machine shop.
Are you sure you don't have a stuck float in your new carb?
You'll never know how the cam is if your motor's drowning in fuel.
Or vice versa.
Do you have the old carb still, to see if the situation clears up some?
Check TDC, how old's the damper?
Do whatever you can before pulling it back apart.
Sorry about the "demand it" comment, I should have read more into your machine shop.