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Adjustable Timing Pulleys… who might want some?


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I wasn’t going to post about this tell I was a little further along, but since possible demand may shape how I proceed with the project I guess I’ll spill the beans.

 

On a suggestion from Tex I have prototyped a sprocket for the EA82 (see pics), he will receive the first set for testing (cause he gave me a bunch of parts, thanks again Tex :) ). I have also made contact with Myxalplyx about possibly including them in his Dyno testing. After I’m happy with the design I will hopefully have enough interest to justify a small production run.

 

The units are adjustable +/- 10 deg with locking pin locations for +/- 0 through 5 deg at 1 cam degree increments (1/2 crank degree), one whole belt tooth is 10 deg so this yields a full range of adjustment. The steel prototype came in at 12oz (stock is 9oz), the production version will have an aluminum hub and should be at or below stock weight. One detail that still to be determined is if the mounting screws will clear the stock timing covers, they protrude from the pulley face by about 0.120” and I have not checked the clearance yet (preliminary investigation does not look promising, thanks Shadow).

 

Anyway, let me know what you think and give me an idea what you might be willing to pay for them. Quantity will have some effect on the final price, but unless it high enough to warrant a CNC run it won’t make a tremendous difference.

 

pulley1.jpg

 

Pulley3.jpg

 

Pulley2.jpg

 

Gary

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Adjusting the cam timing is used to move the powerband up or down the RPM range, it is completely different from ignition timing which is simply choosing when to fire the spark. These can have a great benefits for offroading when you want your powerband lower, as well as if you are a drag racer, where shifting the powerband can help you tweak your 60 foot and trap times, as well as full out road race/high rpm fellows who want to move the range up.

 

I got a sneek peek at these and I must give kudos to Gary on them, he does excellent work. Someone offering access to these kinds of parts for an EA82 doesn't come along very often, so if your serious about your EA82 now's the time to start looking into these high performance options. I have a feeling the EA82 platform is going to start to take off this year with a lot of solid EA82's being built up.

 

YES!

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I remember back on the EZboard a couple people did this for their own application. If memory serves they did 3 degree advance at the cams. Results were good performance but 'ran hot'.

 

Those are well crafted; good work man. Hopefully Tex and Shadow can test them fully and find out if the engine will run hotter. After all the bugs are worked out this should be another real performance upgrade for the EA82.

 

I'm continually ammazed by the diversity of knowledge and craftsmanship we have in the USC. While a lot of clubs just buy bolt ons from some 3rd party manufacturer; we have people who love Subarus so much they craft quality upgrades and share them with the community to further the greatness of Subaru :drunk:

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WJM makes a good point, if you change the driver side cam timing you will need to reset the ignition timing, in some cases you might even need move it a tooth (but I doubt that).

 

Shadow, thanks for the kind words.

 

I know price is the bottom line and I know that most of us playing with old Subies don’t have unlimited budgets. Here’s the breakdown… I need a stock set of pulleys for each set, these would normally be a core charge/exchange deal so no real added cost for these (BTY, I could use some of these to get started if anybody has some lying around). The material for the hubs isn’t very expensive, about $20 a set with hardware. My best estimate for total production time is about 8 hours a set, but hopefully less once I get going, I usually get about $25 an hour for home shop work... all that comes to $220 a set. I think that’s going to be a little high for most people, I’m thinking something around $140-$150 would be good, I don’t mind de-valuing my time a little and if a make enough of them at a time it will cut down on the setup time in each part. So for now lets ballpark somewhere between $150 and $200 a set. Does that scare everybody off?

 

This all assumes that they prove to have an advantage, I’m sure for those with aftermarket cams they will, but I’m not sure how much they might add to the stock set up.

 

What do you guys think about making up some and taking them to WCSS7? How many do you think I could sell?

 

Give me your thoughts

Gary

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Your esstimated price sounds resonable at $150 - $200. Maybe you could do a core charge of $50... so $150 for ppl who supply you pullies OR $200 for those that want to keep their stock ones. Breaking down the price like you did really helps ppl understand where cost comes from.

 

The advantage is proven in my book. I remember on the old boards the ppl who did this noted significant increase at the 'seat of their pants' dyno :lol: This mod has been done on other engins also; it works :drunk: Its kinda funny you made this thread; not 12 hours after Arch and I were talking about this very same thing in my garage!

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I think this is a great idea. Are the pulleys the same for an xt6? I believe that the EA-82 is a great motor and its fullest potential has not been reached yet.

 

I have a plan on the back burner for a screaming xt machine....I am leaning toward a 6 but if this has good potential I might go the ea-82 route (unless these would work on an xt6)

 

I think an even $200 is a very fair price and $50 core (total of $250 if you don't have core) I believe that time is money so if you are going to do it you might as well make it worth your time......

 

Matt

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Those look great, the ability to precisely set the cams is just what these motors need. Nice work.

If I can move my power band lower then I'd be in, possibly for 2 sets. I can send pulley's down in advance if need be when the time comes.

Price sounds reasonable.

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... (BTY, I could use some of these to get started if anybody has some lying around)...
In a recent (December) thread, someone local mentioned that they had "piles" of the crank sprockets, so perhaps they have piles of the cam sprockets, too.

 

Want me to find the reference and ask ther person?

 

BTW, preeeety. I would still prefer variable sprocketry, but this is definitely a step in the right direction.

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  • 1 month later...

First let me apologize for the delay, I expected to be further along with this project by now, my extra curricular work always seems to get bogged down by stupid life stuff. :-p

 

I finished the fixture plate for the mill work so all I need now is some material for the hubs and few sets of stock pulleys… and a bit of inspiration which bumping this thread should provide.:) My plan is to do three or four sets in this first run and get some out to my testers, maybe even try a set on my stock RX for durability testing (I drive 900miles a week). If all is good I hope to have more sets available to sell by WCSS7.

 

Thanks for the bump

Gary

P.S. If I have time I’m going to try to bring a few more wears to WCSS, like light flywheels, wheel spacers/adapters and strut bars. Let me know what you think people might want.

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