straight up timing
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Junior User
Joined: Feb 2002
Posts: 84
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From: indiana
straight up timing
Hey all just wanted to get some imput on the straight up timing gear sets that are for the 400. I have been thinking of putting this on my stock motor. How much of an improvement will this be? Will it effect my milage at all? I see that alot of rebuilds put this in but what about on a stock motor. Thanks in advance for the imput.
Six strings and Ford trucks music to my ears.:-X11
Six strings and Ford trucks music to my ears.:-X11
Senior User
Joined: Apr 2002
Posts: 406
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From: cedar rapids usa
straight up timing
By advancing the cam, the valves open and close earlier. Duration and overlap remain unchanged. Advancing raises the cylinder pressure (due to earlier valve closing) This improves low end and mid-range torque at the expense of some top-end power. The result is similar to using a shorter-duration cam since the intake valve closing point is more critical than its opening point.
Retarding the cam so valves open and close later has the opposite effect. This should increase top-end power, at the expense of low end, and mid-range torque. Thus: 1) Advance Cam: More low and mid-range torque, 2) Retard Cam: More top-end power.
Advancing and retarding are easily accomplished with offset bushings or keys for the cam or crankshaft, depending on the engine. The bushings and keys are usually supplied in increments of 2, 4, 6, and 8 crankshaft degrees. Remember that one crankshaft degree equals two camshaft degrees.
Crane also sells an offset crank gear that will move the cam so that it is dialed in straight up. For our trucks anything that increases lowend torque is a good thing. As far as a milegae improvement, I installed a new chain and gear on my stock 351M and yes you can tell the difference in low end grunt but my mileage improved only by 2 to 4% depending on what I am doing (towing, playing, or driving my wife crazy).
Retarding the cam so valves open and close later has the opposite effect. This should increase top-end power, at the expense of low end, and mid-range torque. Thus: 1) Advance Cam: More low and mid-range torque, 2) Retard Cam: More top-end power.
Advancing and retarding are easily accomplished with offset bushings or keys for the cam or crankshaft, depending on the engine. The bushings and keys are usually supplied in increments of 2, 4, 6, and 8 crankshaft degrees. Remember that one crankshaft degree equals two camshaft degrees.
Crane also sells an offset crank gear that will move the cam so that it is dialed in straight up. For our trucks anything that increases lowend torque is a good thing. As far as a milegae improvement, I installed a new chain and gear on my stock 351M and yes you can tell the difference in low end grunt but my mileage improved only by 2 to 4% depending on what I am doing (towing, playing, or driving my wife crazy).
Tuned
Joined: Jun 2001
Posts: 266
Likes: 0
straight up timing
>Hey all just wanted to get some imput on the straight up
>timing gear sets that are for the 400. I have been thinking
>of putting this on my stock motor. How much of an
>improvement will this be? Will it effect my milage at all? I
>see that alot of rebuilds put this in but what about on a
>stock motor. Thanks in advance for the imput.
>
>
>
>Six strings and Ford trucks music to my ears.:-X11
As the previous poster has said there is no reason not to do it, particularly on a motor that is typically desired for low-end grunt. I have heard that going to straight up timing can increase HP by 20-30. Be aware that if you live in a state that cares about emissions, you may be causing problems for yourself...
>timing gear sets that are for the 400. I have been thinking
>of putting this on my stock motor. How much of an
>improvement will this be? Will it effect my milage at all? I
>see that alot of rebuilds put this in but what about on a
>stock motor. Thanks in advance for the imput.
>
>
>
>Six strings and Ford trucks music to my ears.:-X11
As the previous poster has said there is no reason not to do it, particularly on a motor that is typically desired for low-end grunt. I have heard that going to straight up timing can increase HP by 20-30. Be aware that if you live in a state that cares about emissions, you may be causing problems for yourself...
Posting Guru
Joined: Sep 1999
Posts: 2,297
Likes: 1
From: Indiana
straight up timing
[updated:LAST EDITED ON 14-May-02 AT 02:59 AM (EST)]supercab, You are right. But I don't know if the stock aftermarket manufacturers just mass produce them all as retarded. I guess you could verify this by checking part numbers for a stock replacement timing set on a 70 351C verses, say a 79 400. If they are the same number, then they are all retarded.
Tuned
Joined: Jun 2001
Posts: 266
Likes: 0
straight up timing
>supercab, You are right. But I don't know if the stock
>aftermarket manufacturers just mass produce them all as
>retarded. I guess you could verify this by checking part
>numbers for a stock replacement timing set on a 70 351C
>verses, say a 79 400. If they are the same number, then they
>are all retarded.
To be safe, go with a decent aftermarket set that is keyed for 3 degrees advanced, 3 degrees retarded, and straight up. The quality will be better than a stock one anyway. I recall hearing that all "stock type" are retarded irregardless of the year...
>aftermarket manufacturers just mass produce them all as
>retarded. I guess you could verify this by checking part
>numbers for a stock replacement timing set on a 70 351C
>verses, say a 79 400. If they are the same number, then they
>are all retarded.
To be safe, go with a decent aftermarket set that is keyed for 3 degrees advanced, 3 degrees retarded, and straight up. The quality will be better than a stock one anyway. I recall hearing that all "stock type" are retarded irregardless of the year...
Thread Starter
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Junior User
Joined: Feb 2002
Posts: 84
Likes: 0
From: indiana
straight up timing
Thanks all for the info. I Think i will opt for the straight up set.
Got anotherone for ya all though , seem no mater where i time my motor i get lifter noise. It just happens at differant times throughout the driving range, depending on where I time it. seem to be worse on the lower octain gas though. Any ideas?
Six strings and Ford trucks music to my ears.
Got anotherone for ya all though , seem no mater where i time my motor i get lifter noise. It just happens at differant times throughout the driving range, depending on where I time it. seem to be worse on the lower octain gas though. Any ideas?
Six strings and Ford trucks music to my ears.
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Senior User
Joined: Apr 2002
Posts: 406
Likes: 1
From: cedar rapids usa
straight up timing
It's not the lifters you hear its denotation or "ping". That's why it gets worse with lower actane fuel. After you install the new timing gears time the engine to factory specs. Take it for a test drive and see if you still hear the ping. Because your actually moving the cam to increase lowend cylinder pressure, which also improves lowend torque, you might find that you'll hear it pinging on the factory specs. If you do you'll need to retard it(the timing) some. IF you don't hear it pinging you can advance the timing a little in 2* steps until it does ping then back it off 4*. This will be the best setting for perfromance and mileage. Do not use a sitting that allows an engine to ping. Ping kills!
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Posting Guru
Joined: Sep 1999
Posts: 2,297
Likes: 1
From: Indiana
straight up timing
[updated:LAST EDITED ON 17-May-02 AT 01:45 AM (EST)]Back to the straight up timing issue. I recently used a Comp Cam double roller timing set with the three key setting and set it at straight up 0. Like was mentioned above, I recall hearing also that all the stock stuff was retarded. Thats why I said to check part numbers for old and newer applications. Though I have not done so my self. The performance aftermarket parts were not not much more than stock replacement parts. 
