1.6 vs 1.7 roller rocker arms - Vintage Mustang Forums

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post #1 of 4 (permalink) Old 03-22-2002, 01:26 AM
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What are the advantages and the disadvantages to using 1.6 and also using 1.7 roller rocker arms on a 317 stroker motor. Any personal testimonials appreciated.Thanks in advance
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post #2 of 4 (permalink) Old 03-22-2002, 01:29 AM
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Little more lift with 1.7's. I put them with full rolers in my 91, I noticed no difference, however my car is mostly stock under the hood.

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post #3 of 4 (permalink) Old 03-22-2002, 04:04 AM
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Going from 1.6 to 1.7 rockers will increase lift at valve by 1.7/1.6 times.
There are many upgrades on my list before 1.7 roller arms. It is not cost efficient upgrade. On street machine you can increase the lift on cam quite a much before 1.7 rockers will become necessary.
But when it's time to upgrade to rollers, then why not the 1.7, because the valve train geometry has to be checked and probably tailored anyway.
The reason for higher ratio is that you get slightly easier profile on cam which means easier job for valve springs than with 1.6 ratio and more lift on cam.
But where the Nascar teams get their over 2 ratio rollers?

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post #4 of 4 (permalink) Old 03-22-2002, 07:51 AM
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Are you planning on using TFS heads on your stroker?

If so, contact them with your query...TFS heads are a very specific subset of Ford aftermarket heads (because of their polyangle valves) and their engineers would be the best source of geometry information (the 1.7's put the pushrod closer to the fulcrum, which slightly changes geometry)

Normally, 1.7's are a way to get a little more out of a cam profile without making internal changes...and, if valve-piston clearance co-operates, are cost-effective upgrade when going to aftermarket rockers from stockers.

I've always run 1.6's on the race car, but I'm just old-fashioned..*G*

BTW, do you have a link for the full specs on the TFS cams?...I couldn't find any specifics on their product pages...

Edited to add the specs magically appeared in a pop-behind window...I just didn't see them...
Here's the specs for the cam I'd recommend if your app is to be a daily driven streeter (and you use the 1.7's)
Valve Setting Intake: .000 in.
Valve Setting Exhaust: .000 in.
Advertised Duration (Degrees): 275 intake/279 exhaust
Duration at .050 in. Lift (Degrees): 221 intake/225 exhaust
Camshaft Lift: .312 in. intake/.319 in. exhaust
Valve Lift with 1.6 Rocker Arms: .499 in. intake/.510 in.
Lobe Seperation (Degrees): 112
Intake Cam Timing at .050 in. Valve Lift:
Opens 3 degrees BTDC
Closes 38 degrees ABDC
Max lift: 108 degrees ATDC
Exhaust Cam Timing at .050 in. Valve Lift:
Opens 49 degrees BBDC
Closes 4 degrees BTDC
Max lift: 116 degrees BTDC
Firing Order: 1-3-7-2-6-5-4-8
Camshaft Notes: Good idle, strong midrange power.
Aftermarket intake, heads, and headers recommended.
Requires modified Mass Airflow sensor. Best with
9:1-10.5:1 compression ratio.

Recommended Components: TFS-514002000
Valve Springs with 1.6 Rocker Arms: TFS-51400413
Valve Springs with 1.7 Rocker Arms: TFS-31400414

As they list springs for 1.7 rockers, I'm assuming they consider them a proper retrofit. You still may want to contact them for particulars, especially if you go with one of the more radical profiles than I listed...

Good luck!

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