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On 2006-06-18 22:54, Motorhead wrote:
I've been throwing around the idea of swapping from 1.6 to 1.7 rockers on my 289. I think my engine could use a little more lift and a tad more duration on the camshaft, and this would be a real quick, easy, and inexpensive way to do it without tearing the engine apart, having to do another cam break-in, etc... Here's my current combo:

289, .030 over, H-beam rods
KB Hyperutectic flat tops with big valve reliefs
9.3:1CR
Comp 282S Camshaft (236 duration, 528 lift)
Windsor Jr. iron heads, light porting work done by myself
Weiand Xcelerator intake
Holley 750dp with choke horn milled and 1" tapered spacer
Long tube 1.5" headers (a little small, but choices are limited for a V8 Ranger)
Dual 2.5" exhaust with Dynomax UltraFlo dual 2.5" in and out, and dumped in front of the right-rear wheel.
T-5 trans.
4.10 rear with 245/45/R17 tires/wheels
About 3200lbs with me in it.

I need to check the valve springs I've got to see if they could handle ~.560 lift that I would get with the 1.7s, but if you take into account the .020 lash that's only .540 lift, so if the springs are rated at .560 I should be OK right? Also I was curious about valve float... I run this thing up past 7000rpm and it does a fine job of it right now, will the bigger ratio make it more or less prone to valve float? Seems like it would make the spring have more leverage on the pushrod/lifter so should have less tendency to valve float, but at the same time the valve itself has more lift now so I dunno. Also there is the issue of piston to valve clearance, but the shop that put my longblock together said I had tons of room (didn't give me an exact number), and I've got 1.94 valves with the big reliefs in the KB pistons, so I think another .040 lift shouldn't cause any real problems there.And last, what would be a good set of 1.7 rockers without breaking the bank? I see Ford Racing has a set of extruded aluminum full roller 1.7s for about $300 (M-6564-D351), that's not too much but cheaper would be good if I could get something that's good quality for less (keep in mind the ~7500rpm redline). Thanks!

_________________
'86 Bronco fullsize, 460, E4OD
'85 Ranger, 340hp 289, T5



<font size=-1>[ This Message was edited by: Motorhead on 6/19/06 1:59pm ]</font>
 

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Discussion Starter · #2 ·
<font size=-1>[ This Message was edited by: Motorhead on 6/19/06 1:58pm ]</font>
 

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I'd say do it. The springs won't be a rpm problem but you'll have to check for coil bind and make sure the spring's retainer isn't hitting the seal or valve guide top. Should give you a little more bottom end HP/TQ.
 

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ohio crankshaft. check their website. used to sell a set of rollers for about $130.
 

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Tighten your rockers about .002 that will be the cheapest and easy way to get a little more duration out of your cam

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<font size=-1>[ This Message was edited by: tonys10sec306 on 6/19/06 7:40pm ]</font>
 

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Not much help but I run 1.7 trick flow rollers in my 282S cammed 393. I installed them when I built the engine and had more than enough valve to piston clearance (running 2.055/1.600 valves and probe pistons.) I've been told that increasing ratio does little to nothing to decrease piston to valve clearances. Also when I built the engine, I used the "premium" recommended spring from Comp Cams. I checked for coil bind using the paper clip method and have plenty of room.

I also run my valves at .019" hot (with aluminium heads.) I've taken the car up to 6200 no problems, but of course that is not in the same RPM league as your 289.

Many people swear by Harland Sharps.

The trick flows are based on the well known Crane Golds, as probably are the Ford units you mentioned. The trick flows are know for there "sewing machine" sounds, which I have at certain lower RPM's.

A ratio change may not even make a difference in your car's performance, so as Tony mentions, you should first try tightening the lash and run it.

I never tried 1.6's with the engine, as I had innitially had no rocker arms to try and figure that I might as well step up to the 1.7's when I spent the $$. Now that I am itching a little for a new cam, I wish I would have opted for the 1.6's in the first place.

_________________
Dennis

65' Stang

393W Stroker, Wide Toploader 4 Spd, 9" 3:70 Posi

Victor Jr. Heads, Stealth Intake, 750dp, 236/561 Solid Cam, 9.6CR, 1 3/4" Headers, Lakewood, Subframes, Caltracs



<font size=-1>[ This Message was edited by: dennis111 on 6/20/06 12:40am ]</font>
 

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Same cam an I considered this mod for my 331. Wish I had done it when I built the engine, but no lack of power as is. Just the same, two things I would have done differently...1.7s and beehive springs.

Main reason I don't want to do it is that the engine is just running too good to mess with the internals, albeit a minor mod.

The springs are the biggest question. I got the premium Comp springs too, and they will not be binding at .540 lift, but...Comp recommends .050 clearance before spring bind and this mod, as I recall, will reduce clearance to less than .050. The Comp guys recommended I switch to the 292S springs, but I would switch to beehives if I did it. Beehives may require the spring seat to be milled down a bit though...fagetaboudit!

I set my lash cold to .018 and I have iron heads too. The lash only changes a few mils when the engine heats up for an all iron engine. Reduced lash makes a difference...I can hear the difference in the idle quality...it idles more radically with .018 lash than it does with .022 lash believe it or not, and it's much quieter.

You'll probably obtain about 5-8 HP more from this mod and the increase in HP will come mainly from the increase of lift on the intake valves. You can save money and just do the intake rockers if you wish.

I believe they obtain 1.7 ratio by shortening the fulcrum arm between the pushrod cup and stud which moves the pushrod outboard. Make sure the pushrod is not coming in contact with the outboard side of the pushrod hole in the head.

_________________
Tracy Blackford: Corona, Ca
'65 FB Mustang 331, 282S cam, ported 351W heads. T5z, 3.50 9" posi.
346 [email protected] on a warm spring day (335 RWHP SAE corr.)




<font size=-1>[ This Message was edited by: blkfrd on 6/20/06 4:19am ]</font>
 

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First off...If you are looking for some good rocker arms that won't break the bank, get some Scorpions. 1.7's can be had for under $250. I spin my Scorpion equipped 410 above 7k every time I get behind the wheel.
I don't have the answer for springs, but I like the road that blkfrd is leaning towards. Those beehive springs do look quite inviting. I had a 294S in a 347 for a while. It behaved pretty well, but I always thought the valve springs were holding it back (I was using 986-16's)
I also agree with tonys10sec306. You might want to run a little tighter lash to start with. A couple thousandths does seem to make a difference in the seat of the car.

By the way...what are you doing for a living now days? I'm guessing the whole deal in Oregon must not have panned out. Pullman Washington? Shoot me a PM. I think we might work in a very similar field.
 

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Discussion Starter · #9 ·
Thanks for all the replies guys, sounds like this is something that I'll be heavily considering in the future. I know what you mean about adjusting the lash to change the duration... last time I adjusted the valves I did them a little on the tight side of .020 and I could tell the idle was a little rougher. Hard to tell the difference on top-end with just the seat-of-the-pants meter though... but I'm sure that my head flow has room for improvement, and one easy way to get more airflow is open the valves more. I just really need to find out what valve springs I've got... I bought these heads used off eBay with the cast Crane aluminum roller rockers and a set of pushrods that were so short they had to be from a roller cam. I kept the springs, as the shop told me they were fine with my camshaft, but they never did tell me what the seat pressure and spring rate were. I don't know if they're the springs World Products ships with the heads or some other brand, don't even know the diameter (although that's quick and easy to check). Other than measuring the diameter, is there any way to identify the springs without taking them off?
 

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You might also consider advancing or retarding the cam itself for a different power curve.
 

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I like them on my 289. Never had it at the track before to tell the real difference. Couldn't really feel it either. Just seems to run good for what it is.

Faster valve action with them. Valves open higher sooner if that makes sense. Will be open a little longer as well. Not much change in idle for me though.
 

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I know this is on OOOLLLLDDDD trhead, but im curious about the 1.7 ratio as well. If it opens teh valve for more lift, then its doing the same thing a aftermarket cam is doing. And seeing how i really only want a mild "rv" cam, wouldnt it be easier and cheaper (price and labor) just to do a 1.6-1.7 rocker swap? By what you all describe it going to give me bottom end power and thats what ive been looking for so....?
 

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Excuse me? Whats with the sarcastic face there? I was asking an honest question but i guess its not worthy of a real reply, just forget it.
 

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The extra lift is worth about 2 deg. in duration. They really won't make much difference. Best regards. John--Las Vegas.
 

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I have tested this on my dyno many times, and it is always a waste of time and money. If yoiu get any gain at all, it is SO SMALL and at a high RPM, you would NEVER be able to feel it in the seat of your pants. It will usually LOOSE HP up till 5000 RPM, then MAYBE gain 2 or 3 or 4 HP above that. IT NEVER make more than a few HP differance. On most engines, it will cause the pushrods to bind in the hole in the head ( or the guide plates ) Save you time and money. DONT DO IT>

JOE SHERMAN RACING ENGINES
 

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Hey Joe why are rockers used on Nascar stuff, Sprint engines, and some Drag race stuff close to 2:1 ratio? Just curious.
 

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Many people get confused between street engines and race engines. What works for RACE ONLY engines usually DOES NOT WORK in street only. I use high ratio rockers on EVERY RACE engine I build, BUT, if it is for street, the extra ratio never seems to add anything on milder engines. My 800 HP small blocks run 850 lift cams, which require 1.75 or 1.80 ratio ( intake only ) to get that much lift. I have been around this stuff all my life ( old ) and I can see how it is tempting, but again, the results are just not there

JOE SHERMAN RACING ENGINES
 

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Thank you Joe. That wa smy confusion. I figured if a cam and different ratio rockers were both going to give me lift, that doing the rockers would be a cheaper way to achieve the same goal. But thank you for the detailed description why not too! i sure dont want that happening. Well let me ask youthins why i have you, when i do a cam/lifter swap (and like i said a very mild one) i need to change the springs and timeing chain right? What about the push rods and rockers. Would they be ok? The cam im using will is a 204/214 duration at .50 and 448/472 lift. Is that still mild enough for stock components? I read somewhere thathe stock cam specs were like 380ish lift and only 198 dur at .50? Does taht soud right to you? Thats awfully small.
 

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Many people get confused between street engines and race engines. What works for RACE ONLY engines usually DOES NOT WORK in street only. I use high ratio rockers on EVERY RACE engine I build, BUT, if it is for street, the extra ratio never seems to add anything on milder engines. My 800 HP small blocks run 850 lift cams, which require 1.75 or 1.80 ratio ( intake only ) to get that much lift. I have been around this stuff all my life ( old ) and I can see how it is tempting, but again, the results are just not there

JOE SHERMAN RACING ENGINES
This has to be some of the most useful best advice I've seen in a long time. I've always contended that 1.7 were for people that either had the wrong cam or didn't want to change the one they had, but now I know that they aren't even useful for that.
Thanks for clarifying the real use for higher lift ratio rockers.
 
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