Belt Tension help!!

Hi Everyone!,

This is my first time here. I have a question on how tight to torque the serpentine belt to.
I have a 7" crank and a 2.95" blower pulley and it would always slip. The most tension I tried was 70 ft lbs. I just put on a 3.33" and 45lbs of tension and no slip but only 6lbs of boost. I called Reichard racing and talked to the owner and he said that 70ft lbs was not excessive....... I am concerned tightening it that tight. I found on the ASP website that they recommend 65ft lbs on their COG systems, so I guess 70ft lbs on a serpentine is ok???

I'm going to try a 3" Reichard racing pulley and see what kind of boost I get, and hopefully it will not slip!!

How tight do you guy's run?? Has anyone seen main bearing wear with too tight a belt? If so how tight was your belt?

Thanks everyone!! You guy's can see my car in last Nov issue of 5.0 Magazine. The red S351 Saleen. I'm making around 570rwhp with the slipping belt! I was getting 6lbs at around 4250rpm then it would start slipping.

Sounds like you need the SCH system ;)

http://www.superchargerhelp.com/ebay/bracket2/ysi1.jpg

http://www.superchargerhelp.com/ebay/bracket2/ysi2.jpg

http://www.superchargerhelp.com/ebay/bracket2/ysi3.jpg

The system gives you two 1/2 Billet plates, all stainless hardware, and a tensioner that is second to none! The system will not flex, it is easy to use, and looks great.

Ian

Two things you can try.
1. You can have the 2.95 bead blasted on the ribbed section. This provides a very rough surface for the belt to grip.
2. Tighten the belt. Cog belts run ALOT lower tensions than the 8 rib serpentine setups. I know I had more than 100ft/ lbs at times last year. What I did is I tightened it up (tight) and work down a little at a time. I had mine tight for a while, then loosened it up and saw no drop off in boost so I left it there.

Hope this helps.

I tighten the belt extremely tight,, I used to keep it at about 70ft lbs, but when dynoing the car at LaRoccas,, they were practically standing on the breaker bar and tightening the belt,, they said that both the SC and the crank bearings can handle it,,, You can try a Elk Performance belt tensioner,, I have one on my car, ,and it is great,,, My car picked up about 3/10ths in the 1/4 with a properly tensioned belt,,, the website is www.elkperformance.com... Lee

Ian, Thanks for the response!

I like the look of your product! Do you have one for a 1995 with a 351? The pic's are showing a fox kit probably with a 302??

How much with a polished idler pulley?

Thanks, Tom

Brent, Thanks for the info!!! Have you had any problems running that much tension? Do you know of anyone who has tried the Reichard Racing pulley?? It has grooves machined into the ribs. You can see one at reichardracing.com

Lee, Thanks for your input!! Especially what they said at LacRoccas. I might give them a call. I don't know why I just have a hard time believing that much pressure is o.k. It even said it was o.k. on the website for the tensioner that you have.... they just didn't say how much pressure. So if you had it at 70lbs and they went tighter did they ever say how much pressure to run??


Also have you heard of anyone who has tried a Reichard Racing pulley?

Thanks, Tom

I personally have nad no problems. However this was with 1/2" heavy duty paxton brackets. I ran all year with the belt really tight and it showed no main bearing wear when i tore the engine out. I've heard both good and bad on the reichard pulleys but have no personal information on them. However every post i've read on them says the belts don't last near as long because of the pulley grooves. When you get the slip problem fixxed please report back. I'm gonna run the 2.95/7" asp crank combo on my T-Trim 357 this summer and I'd like to know a ballpark on the PSI before I go out and stomp on it. :D

Good Luck and that is a very nice ride you have!

FWIW The 351's have 3" mains and should have even less strain than the 302 stuff.

Brent, I have a question regarding posting on this site. I just spent 30min trying to post. It shows me online but it won't let me post. I keep trying logging on and off then all of a sudden it works??? Thought you might know since you are the moderator.

Anyway thanks for the info on the bearing wear when you tore the engine apart. How many miles were on it at teardown?? and you had about 100ft lbs on the belt? Also I was thinking the same about the 3" mains.

I should get the Reichard 3" pulley midweek and I will let you know how much boost. On his website he says he can modify your pulley, so I called to see if he could do my Vortech 2.95" but he said that the grooves for the belt are not as deep so they don't grip as well so he stopped doing it. Maybe that causes more belt wear.

I went and looked at you car, look's great! How fast in the 1/4mi?? I might make less boost than you since I have a 408 with ported Victor Jr's and a Hogan's intake and my cam has 245deg in 254 deg ex. and if you are using a 2.95" it will spin it a little faster but at least it will give you an idea! That is what I'm kinda worried about, not knowing how much to expect! I am going to the dyno Friday for some tuning but it is a Mustang dyno with the double rollers and I just spin the tires at anything over 1/2 throttle. I tried letting the air out of the tires and having 2 people sitting in the trunk but it didn't help. We are going to try a new wideband o2 box mine is not working right.
Anyway thanks again for all the help!!
Tom

Any questions on computer problems you probably better pm Ian. I'm just a gearhead that took a typing class in high school to fill credits. :p

My stock shortblock had 117k on it when i took it out other a lil blowby it was lean and mean! Bearings looked great front to rear, rods and mains. The car went 11.77@117 with my ol systemax/twisted wedge combo and stock pullies. I then added the 8" renegade crank and the car went 11.20's @123-124mph. This was with the Novi 1000. :D I didn't need a real tight belt with the 8" crank and 3.5" blower pulley but i kept it pretty tight anyway cause I bracket race alot. And it was consistent! never more than .17 off. Put the big torque on that belt and lets see some numbers!! :D Sounds like you'll have a mean machine.

I'll certainly appreciate any info on the boost level as it "should" be close enough and if I should have a little more of course.

Brent, So the main's looked good on a 302 with that many miles....makes me feel better!!
You haven't ran the 351 with the Victor Jr heads yet? If not It will be a huge difference!! I had a 69 Fairlane with a .060 over 289 for 297ci and with 3.5 gears and a 2200 stall It couldn't even spin the slick (open rear) off the line, then I dropped in a 351 and it would just fry the tire so I put in a detroit locker to hook up both. What I'm getting at is the torque difference is HUGE...50 cubes is an AMAZING difference. I don't get why more guy's don't put in 351's or stroke the 302's when they go for a rebuild??? The 351 is SO much stronger of a block I think it's well worth the extra weight!!

I should look into a 8" pulley too. ASP charges $125 for a 7" for a 94-95 but I didn't see a 8" listed for my year. It's different than the fox body pulleys. The Reichard blower pulley was $150...kind of a rip off considering how small it is compared to a crank pulley. If it works it will be worth it.
Tom.

I haven't got my 351 project off the ground yet. Lots of little things to be worked out. I hope the reichard pulley does the trick for you. I certainly feel the same on the 351's over the 302's as you do.

8" crank pulley's = OWNAGE! More RPMS and even less slippage. I'll probably end up running the 3.33 and 8" crank by the end of the year. ASP can make whatever you want.

i was tightening my 8 rib belt to 120lbs on my t trim and r302 block.

it was great having the 2.95 and 7inch crank..saw 15lbs on the gauge.

i saw a post somewhere that said bob kurgan torqued his to almost 200 lbs of torque.

thanks to ian, i wil be trying the new belt tensioner he has. looks good and i am sure it works great.

especially after this weekend at world ford challenge. twice going down the track i shredded one cog and threw the other one off the car completely.

good luck

I recently had a 3" renegade pulley and swithched to a RR 2.7. I needed to wake my blower up sooner. (YSi) With the same tensioning that was on the 3", I have no slippage at 6,000 RPM on the RR 2.7. Sweet pulley. I would have a little slippage with the 3" above 6,000 RPM.

Also I use the AFM belt tensioner. and use the vortech renegade strut support to keep the bracket from flexing and also less strain on the bearings.

How do you guys measure your torque on the belt. I would like to check mine and report back to you on my torque? And also no for myself.

Keep in mind this is on a YSI, not a T-trim, supposedly a lot of drag on these blowers.

Thanks.

nstycpe93. Thanks for the info! I hope the new tensioner works for you!

Blownby- Thanks for the info on the RR pulley!!. I just got mine today, haven't had a chance to try it yet. It look's awesome!! Worth the money just for the look's!! Have you noticed any wear on the pulley itself? It is aluminum without a coating....I was told that plain aluminum would wear. Reichard said it wasn't a problem....

The torque on the belt is done with a torque wrench with the 1/2" drive hole on the stock Vortech bracket. That's the thing about aftermarket brackets that I don't understand. How do you know how much tension you have? with the stock bracket you can try in 10lb increments and find out what work's without going tighter than you have to. I personally want to run the least amount of torque on the belt that I can!! Once I find it than I can repeat it everytime. Without knowing I guess you could go until it didn't slip, then if you take it off you could guess and keep loosening/ tightening until you get it right.
Tom

351saleen,

As for wear on the pulley couldn't say? Only had it on for about 20 miles or so so far. I will be re-tunning the new pulley next saturday so i have taken it easy on the motor and blower. I saw an 4-5 psi increase in boost just at 5400RPM with the new and smaller pulley.

Thanks, for the torque measure measurment.

I will see if I can figure out a way to test the torque. I should be able to tighten it with the AF Tensioner, then use the torque wrench and start low and work up the torque reading until it moves the tensioner brefore clicking. This should give me a pretty good idea as to how much torque is on it.

BLOWNBY- That idea on finding out your torque setting sounds good! Let me know how much you are running!!
Thanks, Tom

s351saleen

Well it apears that I have somewhere in the neighborhood of 80 ftlbs of torque on the belt.
I am using the Napa/Gates belt from Napa. RR seems to think this belt has deeper groves than some of the other belts, thus more grip.

Next Saturday I will get the car retuned with this new pulley and hopefully it will put the rwhp over 700.

BLOWNBY
Thanks for the torque spec! I just put mine at 65ft lbs but I havent tried it yet. Reichard told me the same about NAPA/ Gates belts. I compared my NAPA to a Goodyear and he is right! The Goodyear grooves are not very deep. Also the Reichard grooves are a little deeper than the Vortech. I wish the Reichard "shoulder" on the sides of the belt were as tall as the Vortech to keep the belt in place, but I guess he hasn't had a problem.
My dyno tuning is rescheduled for next Thursday at a Mustang dyno. I will try to get my wide band 02 problem fixed, then I will have to go to a Dynojet to see what it's making since I can't hook up on the Mustang dyno.
Let me know how the tuning went!!!
Tom.