1998GsRIntegra

I got bored towards the end of the day today and I decided to take a crack at making up a secondary cam belt tensioner. The result after a few hours was not the prettiest, but it is cheap, rock solid(seriously, I could probably lift the engine up by it), and it actually works. Warning:Shitty welds below;Eyes may be burned Prior to this, I hadn't touched my welder since I got it for Christmas because the engine you see the tensioner bolted to was taking up all the space on and around my welding table. Needless to say, I am terribly out of practice. Now that I've gotten the lame excuses out of the way...Lol

The idea behind utilizing a secondary tensioner is fairly simple. When running higher lift aftermarket camshafts you end up with timing belt "slap" on the front side of the engine because the opening and closing ramp angles on aftermarket camshafts are typically fairly steep. In some rare cases, this can cause the belt to skip a tooth or even derail completely. To correct this, most people use the "screwdriver" method to over tension the timing belt. The problem with doing so is that you end up taking away any oil clearence you had in the cam journals. In short, you starve the cams journals of oil. About a year ago I saw a video that illustrated the concept/scenario of a tensioner perfectly. After several hours of searching I have found it again so that those who are like "wtf is this foo talkin' 'bout" can see what I'm talking about



So what you'll need to make my bling shitty version:

-An old(or new if you're so inclined) factory timing belt tensioner. You don't need the little spring, just the tensioner itself, the grade 10 bolt specifit to it to go with it, and a 14mm nut w/ lockwasher. Everybody has at least one old tensioner laying around from a timing belt job. In my case, I discovered I have seven. Yes, I need to do some parts department clean up again.

-Two short(1" longish) grade 10 14mm bolts. If your like me, you have boxes labeled with 10mm, 12mm, 14mm, and 17mm that contain about 5 lbs worth of bolts and nuts each from various projects. Alternatively you could stack up washers if you can't come up with short bolts.

Parts total should be $0 at this point if your doing things right.

-A section of 3/16" thick flat bar that is about 1" wide. About 2ft's worth should provide you with enough material for several screw-ups. Any lowes or home chepo should have it. Cost: about $5

-Power-drill and various drill bits. If you're to the point that you need a secondary tensioner you own a power drill and a bit set for it. If not, go rent one from harbor freight.

-A way to cut the metal. Bandsaw, sawsall, hacksaw, angle grinder, beaver, ect.

-Welder, or a friend with a welder. Shouldn't be too difficult to accomplish. Hell, give the guy at your local machine shop a case of beer to weld it for you if you are anti-social and don't have/want friends. And if you're just that ghetto, give good old JB weld a whirl.

So, if you don't live under a rock, your into this for about $5 at this point. Give yourself a big for being cost effective!

Here's some pictures of mine for you to copy/improve upon.

I think two things are fairly obvious. 1.) I need to work on my welding. 2.) which picture shows the belt tensioned and which shows it untensioned. You can also go any where in between as far as adjustment is concerned. I just made the bracket so that with the tensioner fully loose, the belt has 0 added tension, that way the tensioner is really easy to put on and take off. Also, and I just thought of this, by doing this, you actually are installing a spare timing belt tensioner. If you are at the track and your tensioner takes a dump, simply remove and replace with your secondary tensioner. You will no longer have your secondary tensioner goodness, but at least you'll be able to safely drive home.

On the off chance someone actually wants to make one of these for their engine, I'd be happy to post some more detailed pictures and try to give some dimensions on the pieces. Maybe I'll make another one with decent welds after I've had a week to get back into welding.

And yes, the engine is in our cabinet shop.

lzylst

iTrader: (1)

Could it be made to mount to the lower p/s bracket holes so it sits out of the way for a cleaner look? Or does that change the effectiveness of adding tension at a certain position of the t-belt?

1998GsRIntegra

Yes I wouldn't see a problem with that. Regardless of where you mount it, you can adjust the lengths of the pieces to get the tensioner basically in the middle between the cam gear and the crank pulley if that makes any sense. If you try to make one, you'll see where the tensioner should be mounted to be the most effective in taking up excess slack in the timing belt.

just-ef-it

Vibrant racing makes one

mark@silbernage

T.O.O. makes one too (Endyn), which I picked up when the problem you described broke my timing belt at about 4k miles after the rebuild.

Nice job - particularly using the stock tensioner, so you know it's made for that job in every respect. Pretty nice welding too.

Well done!

EsotericImage

iTrader: (8)

^^
Is that for all B's or just the Vtec kind?

I remember seeing one years ago, but it was for vtec heads only.


Edit: the Endyn is Vtec only, Vibrant is all B's

1998GsRIntegra

Thank you Mark!

This was a "spur of the moment" project in every sense of the phrase. I figured, as you said, the stock tensioner pulley is made for the job, and on top of that it's adjustable. A little bit of finagling later, and we have a bracket to bolt it up to.

NAH2B

adding deflection between the exhaust cam and the crank is a bad idea, especially if you don't plan to dial in the cam timing on the dyno afterwards. plus there is no need it.

1998GsRIntegra

Randy, can you elaborate at all? Thanks in advance.

odz-fab

your reducing deflection...wich is a great thing..
facts for a secondary tensioner like the one made here:
yes it advances both cams and total timing by a small amount.
ideal to add befor degreaing cams or reset timing after its been added.
it only adds tension if your a tool and dont reset your belt tension after installing!
thinking the stock tensioner eleviates belt slap by adding more tension with a coat hook is a terrable idea and false information. that much tension will destroy your cam journals.
i like DYI's ! so good job! save money and being involved

evan221

need to get one of these

BryanM.

iTrader: (1)

I am a little surprised that these aren't made to be PS pump compatible (maybe there is one that is?). The Endyn version is so close since it has a 2 piece design, you could almost sandwich the mounting plate between the upper PS mount and the head. Belt clearance would be tight but hell, it already is very tight in that area.


And op's version is just a couple mods away from being able to put the PS mount over it.

DA-NINE

Could you explain your thought?


The way i see is that you time the engine before you install the secondary tensioner. so the cam/crank relation is how it should be. THEN install the secondary tensioner.

If you install the tensioner then the belt (effectively making the distance between the crank and cam pulleys longer and throwing timing out of wack) then yes you would need to degree your cams over again.

OMG

that's a band-aid for improperly tensioned belt. I removed the secondary tensioner on my buddy's car and set the tension properly; it's 10 times better now

DDTECH

Something as little as timing belt tension can throw off cam timing, that's what he's getting at.

DDTECH

Rocket, while I agree, I don't think this particular product is a bad thing. It doesn't actually "push" hard on the belt, rather just keep alittle guide on it, Its not like an actual tensioner, at least that's how I've seen it. I've tuned a few cars with it, customers seem to like it.

whitesihatch

thanks OP

blackeg

maybe its just me, but applying tension to the belt following the helms leaves a lot of slack on the return side and it kinda freaks me out watching the belt flex and twist and wabble around either when the motor is cold or when it hits the limiter. i almost feel like going from tension to no tension when the motor cuts out adds wear to the belt from stretch/compress cycles if that makes sense.

this tensioner looks like a great idea to add after the belt is already tensioned just to keep it from flopping around not to add tension

BryanM.

iTrader: (1)

^ that's what I'm thinking too. Seems to me all it would need to do is just barely contact the belt to keep it from whipping. It would be more of a guide than a tensioner as someone else said.

And how does belt whip not effect cam timing?

1998GsRIntegra

In hindsight I probably should have called it a guide, not a secondary tensioner, because that's really what it is. I currently have it setup to apply a small amount of pressure to keep the belt from slapping around excessively. It just makes me feel better after seeing how much the PROPERLY TENSIONED belt was slapping around at certain rpm windows.

m4xwellmurd3r

Weird, I just rebuilt my engine amd had no issues with belt slap. I have a gates racing belt and a NEW oem tensioner spring. I had one spot that had a touch too much slack so I just pulled the tensioner a little (with my hand) and that was enough to kill the slop without over tightening the belt

I think the biggest issue is people reuse those springs thinking they retain strength after years of use

blackeg

Exactly. I kinda feel the spring is a joke. I often go by belt deflection when hot keeping it tight but not to the point where it whines when u rev it. Im not sure if its just me but my benson sleeved turbo motor expands a ton when warm and when the belt has good tension at 180-210f oil temp it is looser than Lindsey lohan when cold

m4xwellmurd3r

Its not that the spring is a joke, honestly I probably couldve killed the slack by putting the slack on the long end, pinning the exhaust cam, and rotating very slightly so the tension side slacks.

Im not even sure it was too loose. I have some belt whine but nothin like when I hangered it last year. The new spring has gobs more tension than the one I replaced.

I think the little whine it has is mostly normal. The belt isnt tensioned much harder than what the spring can. I just used a finger and pushed the tensioner a bit and it pulled out the slack.

After I did it I rotated the engine and the tension is equal all over.

DA-NINE

yes this is what a the secondary tensioner is fighting. slack in the belt from rising and falling valve train.


you would have to degree the cams with the tensioner on if its designed as an actual tensioner. i think they are trying to project it as more of a guide roller type deal

JDogg

s2000 motors and k-series motors deal with the same... you know how we fix it.. get cams that are made properly, no more slap.

Same thing applies here. If you have a bunch of belt slap your cams are junk or the timing is way off.

The little spring that holds up the tensioner is all you need to tension the belt. No coat hangers or pry bars or secondary tensioners needed. Correct parts go along way.