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10-28-2015, 05:27 AM | #1 |
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Location: Fort Worth, Texas
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Harmon Collins Cam
Have a Harmon Collins cam for early flathead. Numbers on front of cam are 7RA 3/4. Cam lift measures 320. Anyone have the opening and closing timing specs for this?
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10-28-2015, 08:18 AM | #2 |
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Re: Harmon Collins Cam
Are these numbers around the outside of the timing gear flange?
I ask as the h&c cams I've seen are marked around there, they had "Harmon & Collins" then a number like 6352, then 3/4, I just made that 6352 number up for an example. I'm not with my notes right now, I can have a look after work, see if I got the specs. Martin. |
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10-28-2015, 08:49 AM | #3 |
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Re: Harmon Collins Cam
Yes they are on the flange. Harmon Collins logo and then the 7RA 3/4.
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10-28-2015, 12:28 PM | #4 |
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Re: Harmon Collins Cam
7RA would indicate it is for a 49 - 53 engine. Specs I have are: IO-19, IC-59, EO-59, EC-19 for 248 deg duration and .320 lift. Overlap is 33. Clearance is .011 intake and .013 exhaust.
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10-28-2015, 01:50 PM | #5 |
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Re: Harmon Collins Cam
Great stuff flatjack, I looked, haven't got those specs.
The 3/4 h&c spec I have is 19-59 54-14 .320" lift. But have a full race h&c spec of 19-59 59-19 .320" lift? Martin. |
10-28-2015, 03:04 PM | #6 |
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Re: Harmon Collins Cam
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10-28-2015, 03:46 PM | #7 |
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Re: Harmon Collins Cam
H&C had at least 5 grinds they marked 3/4.
The one Flatjack9 noted is one of them. |
10-28-2015, 05:39 PM | #8 |
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Re: Harmon Collins Cam
"Specs I have are: IO-19, IC-59, EO-59, EC-19 for 248 deg duration and .320 lift. Overlap is 33. Clearance is .011 intake and .013 exhaust."
Shouldn't that figure out to 258 degrees of duration and not 248 ? Sal |
10-28-2015, 06:22 PM | #9 |
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Location: Central Ohio
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Re: Harmon Collins Cam
Yep . . . but I've seen so many different claims over the years on different cam specs, who knows. I tend to put them in engines and degree them - then I really know.
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10-28-2015, 06:56 PM | #10 |
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Re: Harmon Collins Cam
That's the way to do it. I have a block set up on my bench specifically for checking cams.
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10-28-2015, 07:44 PM | #11 | |
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Re: Harmon Collins Cam
Quote:
2015-05-11 22.32.30 copy.jpg |
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10-28-2015, 10:11 PM | #12 |
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Location: Oshkosh, Wi
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Re: Harmon Collins Cam
Yep, looks like mine.
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