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1/8 Scale Dragster Build


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It might be the picture ... and I might be wrong ... but I think the blower drive belt should go to the inside of the tensioner. Both engines.

You are correct. The tensioner ALWAYS runs on the smooth backside of the belt (the inside of the belt would be toothed to engage the teeth on the drive pulleys). That would probably take the excess slack out of the belts on the model as well.

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It might be the picture ... and I might be wrong ... but I think the blower drive belt should go to the inside of the tensioner. Both engines.

You are correct. The tensioner ALWAYS runs on the smooth backside of the belt (the inside of the belt would be toothed to engage the teeth on the drive pulleys). That would probably take the excess slack out of the belts on the model as well.

matt, your drive belt / tensioner arrangements are correct. these two gentlemen are incorrect. if you'd like photographic proof i can supply literally thousands of pictures. love the build!!!

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On the older BDS type blowers, like these, the belt is usually run as you have them. On the newer systems, with serpentine belts, it would more than likely be on the inside of the tensioner.

Looking forward to seeing this model progress.

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It might be the picture ... and I might be wrong ... but I think the blower drive belt should go to the inside of the tensioner. Both engines.

That's true Ted, The drive belt was hard plastic that I covered with black electrical tape. There was no option to run it inside the tensioners. Thanks for the reply.

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Thanks for all the input, I thought I put the belts on wrong. They only went on 1 way. I'm trying hard not to screw this build up. The instructions are the worst to work with, I have to take extra time before gluing. I will take more pics as it progresses.  

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matt, your drive belt / tensioner arrangements are correct. these two gentlemen are incorrect. if you'd like photographic proof i can supply literally thousands of pictures. love the build!!!

OK...I'm wrong. Just goes to show that speaking before double checking makes one look like an idiot.

However, in the old days, Gilmer belts were routinely tensioned on the smooth side by some builders, the reasoning being that a vibration was introduced into the assembly from the teeth running over a smooth tensioner pulley. The rest of the reasoning was that the high-frequency vibration could cause early failure of the bearings on the blower snout. Putting the tensioner on the back, smooth side of the belt also gives more "wrap" and tends to engage more of the teeth both on the crank and blower snout pulleys, which has the effect of lowering the loads on individual belt teeth. Though these are the only shots I could find of that arrangement in a 30-second search, I've seen it often, and recently...but I was entirely wrong about "always".

            Image result for blown 392 chrysler   Image result for GMC 6-71 blower                      

                                                              Image result for GMC 6-71 blower

Older design belts could be tensioned from either side, but from my research just now, I see that the manufacturers of newer design belts recommend tensioning on the tooth side only. 

 

NOTE: I'm NOT arguing with comp1839. He's actively involved with drag-racing today, and knows his stuff. I've been away from the sport for over 20 years.

 

 

 

 

Edited by Ace-Garageguy
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A quick look over on the H.A.M.B shows this street blower set-up on a 292

http://www.jalopyjournal.com/forum/threads/blower-set-up-for-292-312-y-block.441284/

Just popped open one of the kits - it has a couple of tan rubber bands for the blower belt and a full 360 degree belt guard on the chrome tree.

Matt, I'm liking your project - it's going to make me move mine up on the build schedule.

 

 

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A quick look over on the H.A.M.B shows this street blower set-up on a 292

http://www.jalopyjournal.com/forum/threads/blower-set-up-for-292-312-y-block.441284/

Just popped open one of the kits - it has a couple of tan rubber bands for the blower belt and a full 360 degree belt guard on the chrome tree.

Matt, I'm liking your project - it's going to make me move mine up on the build schedule.

 

 

Dam, I made the belt guard the belt. I thought the bands were just to hold the frame together after it was glued. No wonder the pulleys didn't line up with the so called belt. MY Bad. I should be able to fix. Thanks.......

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Dam, I made the belt guard the belt. I thought the bands were just to hold the frame together after it was glued. No wonder the pulleys didn't line up with the so called belt. MY Bad. I should be able to fix. Thanks.......

The rubber bands probably work better to hold the frame together...  I don't like the idea of tension on the rubber band belts pulling the glue joints apart over time on the engine assembly  Making a belt (more electrical tape?) might be a better solution  - anyways, thank you for the inspiration. - looks like a fun kit.

Edited by Muncie
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I saw all the slack in the belt and thought it looked wrong.  It is loose at both the top cog as well as the bottom.  The only thing I could see to tighten it up was the tensioner.   I tried to be as gentle and discrete as possible.  Sorry to cause a ruckus, won't do it again. 

Edited by tedd60
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ted, we ALL make mistakes and this board would be worthless if we aren't learning something. let's not forget that the system that you and bill were describing is a setup that was widely used. just not the ONLY system used. the o.p. setup is in fact correct as as is.     thank you bill for acknowledging your error.

pic of vintage like matt's.

pic of modern blown alcohol altered.

 

and just so you know i was thinking of you bill here is a modern alcohol funny car(just a few years ago) you might recognize the name ....frank manzo. he runs a toothed idler (at least when this pic was taken.)

.

 

hope this helps.

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ted, we ALL make mistakes and this board would be worthless if we aren't learning something. let's not forget that the system that you and bill were describing is a setup that was widely used. just not the ONLY system used. the o.p. setup is in fact correct as as is.     thank you bill for acknowledging your error.

pic of vintage like matt's.

994517_545726552151352_741941947_n_zpsuy

pic of modern blown alcohol altered.

040_zpsa2umm05p.jpg

 

and just so you know i was thinking of you bill here is a modern alcohol funny car(just a few years ago) you might recognize the name ....frank manzo. he runs a toothed idler (at least when this pic was taken.)

. 063_zpseg3xtqz6.jpg

 

hope this helps.

Manzo,...The KING of T/A!

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To the O.P.

I would maybe look into a rubber band about the correct size and width if there is one available. Or electrical tape can work also as a belt. Unless you are going for a 100% box stock build (like you were going to go to contest with it) I have one of these started but never got to the engine stage as I never cared for the engines in the kit. It is still a nice kit however and with a little bit of work can be made to look great! Yours is coming out fantastic thus far. Keep up the great work!

Paul

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I saw all the slack in the belt and thought it looked wrong.  It is loose at both the top cog as well as the bottom.  The only thing I could see to tighten it up was the tensioner.   I tried to be as gentle and discrete as possible.  Sorry to cause a ruckus, won't do it again. 

No "ruckus", nothing to be sorry for.

The OP learned something and will have a better model as a result, I learned something (several things, actually) and we're all adults here...at least those of us who appreciate constructive criticism and correct information. 

Nobody got rude, nobody felt threatened or had to resort to calling names, and most importantly, again, the OP will have a better model as a result of the exchange

If we can't offer helpful advice because somebody might act like a baby, it's a sorry thing indeed.

And if you ever see anything that looks wrong on MY models, PLEASE SPEAK UP.   :D

Edited by Ace-Garageguy
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