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Onan Tech Star 35G Saavy?


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  #1  
Old 01-02-2018, 07:58:20 PM
CubCo CubCo is offline
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Default Onan Tech Star 35G Saavy?

Hello,

This is my first attempt at a "forum."
I have this propane techstar 35g sitting in my shop. I'd like to set it up to be able to use all the voltages and phases on a test stand. Anybody ever done this before?
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  #2  
Old 01-02-2018, 08:16:01 PM
I like oldstuff I like oldstuff is offline
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Default Re: Onan Tech Star 35G saavy?

Sit back and the smart guys will chime in. Don't be surprised if it's not what you want to hear though.
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Old 01-02-2018, 08:19:23 PM
Wayne 440 Wayne 440 is offline
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Default Re: Onan Tech Star 35G saavy?

Well, somebody might as well do it- so,

My advice- before you consider modification of that set to allow "all voltages and phases", read the linked thread below.

https://www.smokstak.com/forum/showthread.php?t=134727

After you have done so, you may (should? had better?) decide to go another route.

If you still want to do so after reading the referenced thread, the first thing you need is the wiring diagram for your set.
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Old 01-02-2018, 08:22:29 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan Tech Star 35G saavy?

Your the Man Wayne, and Yes, somebody had to do it!!!
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Old 01-02-2018, 08:25:26 PM
yellowlister yellowlister is offline
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Default Re: Onan Tech Star 35G saavy?

Sell it and buy a Ford powered 30 ek or es.. the techstar is a ticking time bomb and will wake the dead
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Old 01-02-2018, 09:13:10 PM
CubCo CubCo is offline
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Default Re: Onan Tech Star 35G saavy?

Ouch. I feel so welcomed.
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Old 01-02-2018, 09:20:11 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan Tech Star 35G saavy?

Truly nothing to do with you, the TechStar has a very terrible reputation with the Onan folk, not one of I think Cummins best designs.
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Old 01-02-2018, 09:30:50 PM
CubCo CubCo is offline
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Default Re: Onan Tech Star 35G saavy?

OK, so a doctor had this machine in his basement. His brother was the engineer for the local power company and had this unit installed for him.

He paid me to remove this machine and gave me the machine, transfer switch and all the wiring. It also had an elaborate exhaust system. (He gave me that too). He says that he got tired of paying an ONAN tech to service it every month when they've only lost power twice in the past 10 years and only for an hour or so.

So, now what do I do?

sounds like you know what they're going to say.
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Old 01-02-2018, 09:33:26 PM
Wayne 440 Wayne 440 is offline
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Default Re: Onan Tech Star 35G saavy?

Quote:
Originally Posted by CubCo View Post
Ouch. I feel so welcomed.
No offense intended, you are certainly welcome here.

IMHO, it would be a great disservice for us to allow you to remain uninformed about the set you have.

Would be a shame to put lots of work into your project only to find out that the most important part of same is not going to give the service you hoped for.
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Old 01-02-2018, 09:35:50 PM
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Default Re: Onan Tech Star 35G saavy?

no worries... Believe it or not, I'm a 55yo Master Electrician, but I'm very naive. Sad huh?

Thanks... no offense taken. I appreciate experience.
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Old 01-02-2018, 09:41:48 PM
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Default Re: Onan Tech Star 35G saavy?

Well, since you've already got it, and are close to getting it to run, might as well fire it up (keeping clear of the sides), then you'll know what we're talking about.

Then, down the road, when you get a nice, sweet 1800 rpm (or less!) machine, you'll appreciate it more than would otherwise have been possible.
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Old 01-02-2018, 09:44:48 PM
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Default Re: Onan Tech Star 35G saavy?

I would build a covered bunker. If you plan on keeping the thing. Then you will need to warn any neighbor. Within twenty miles about the noise.

CubCo You are welcome here. You will find some very helpful people here. The bad part is you just happen to get the worst thing Onan ever made. I have been with Onan since 1980. Left in 2008 still working on the older units. The very sad thing is. We are not kidding about the Techstar.
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Last edited by Billy J Shafer; 01-02-2018 at 09:59:19 PM.
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Old 01-02-2018, 09:48:50 PM
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Default Re: Onan Tech Star 35G saavy?

Their telling you that big sob runs at 3600 rpm instead of 1800 parts could fly.
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Old 01-02-2018, 09:53:26 PM
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Default Re: Onan Tech Star 35G saavy?

There were 2 of those tech stars at the auction they never got over $350.. so they never sold.
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Old 01-02-2018, 10:05:18 PM
Wayne 440 Wayne 440 is offline
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Default Re: Onan Tech Star 35G saavy?

I am still thinking about the fact that it was in a basement - I made the mistake of starting a Federal Signal 2001SRNB weather siren in my (closed) shop once. Every dust molecule in the building was immediately suspended in the air before I could trip the breaker back off. Maybe the Onan wasn't quite that bad.
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Old 01-03-2018, 08:52:16 AM
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Default Re: Onan Tech Star 35G saavy?

quick primer for the un advised

for a traditional 60 HZ generator the speed will be
3600 rpm for 2 pole
1800 rpm for 4 pole
1200 rpm for 6 pole
etc

so the engine needs to develop peak torque and HP at or just below the speed
engines that develop their peak HP at lower rpm last longer and have
longer stroke, longer rods, bigger crankshafts, and much heavier blocks.
all expensive.


for a near fully loaded generator
picture running a 350 chevy on a dyno
at near maximum throttle loaded down to 3600 rpm for a week.
rule of thumb [I was told] a 24 hour race is like putting 200K Mi. on a car
[I once helped crew for a 24 hr race]
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Last edited by armandh; 01-03-2018 at 09:07:13 AM.
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Old 01-03-2018, 03:22:17 PM
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Default Re: Onan Tech Star 35G saavy?

IF I owned one, which unless I got it for free like you did I wouldn't, I would wire up a momentary switch to run the starter ONLY so I could turn the engine over for 10-20 seconds without starting it to oil prime the engine first.
Think of every time you started your car from dead cold and holding the throttle open to have it immediately come up to 3600 RPM. Not a pretty thought.
BUT, Welcome to the BEST site for ONAN and other old stuff.
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Last edited by Motorhead; 01-03-2018 at 08:18:35 PM.
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Old 01-03-2018, 03:54:25 PM
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Default Re: Onan Tech Star 35G saavy?

They're not kidding about Techstar , remember hearing the guys say a lot of bad things about it over the years.

Problem with making all voltages and phases is you can't make all at once. Don't know techstar but typically there are 6 windings with 12 leads, basically 2 sets of 3 phase. But you have to connected them differently to get different voltages, and phases. If you don't need all the amps at low volatge , I suppose you could configure windings for hi-voltage wye then wire 2 output sockets for hi and low voltage.


Other solution might be a CUSTOM $$$$$$$ switch, (can't change under load).

Best general solution I've seen for "quick" changes (10 minutes) is the setup in military gens (mep-xxx) where they bolt a panel with copper buss bars over copper studs and use different panels for different voltage configurations. Panel basically has fixed jumpers (buss) between copper studs (winding leads)

All in all what your asking to do can be done , but slow and awkward requiring manual re-configureation of winding leads.

Last edited by len k; 01-03-2018 at 04:25:15 PM.
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Old 01-03-2018, 04:31:55 PM
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Default Re: Onan Tech Star 35G saavy?

With enough money and ingenuity, one could use a series of contactors with the requisite control to make it so that you could switch between voltages on the fly.
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Old 01-03-2018, 05:06:44 PM
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Default Re: Onan Tech Star 35G saavy?

I would recommend that you run GOOD oil that has good film retention so it is not starting with a dry cam. I would change the camshaft drive belt if it has never been changed. My understanding that it is a bit of a job to do on an Onan application. The fortunate thing is that engine is a NON Interference engine meaning if the belt breaks during operation, the valves won't be hit with the pistons. It would be a good time to change the water pump too. Don't use the 2 year GREEN coolant. Spend a few dollars more and go with the G-05 5 year or the red diesel truck coolant and distilled water. Remember to that most of the engine parts you can buy a heck of a lot cheaper through the automotive parts supply than Onan where you will pay three times as much for the same part.
Billy S recommends that when you go to an auto parts store to buy parts for it to have the old part in hand and order for the same year to one year earlier and say it is for a Chrysler mini van. That will at least get the counter guy to talk to you. You tell them it is for an Onan and they just shrug their shoulders and tell you they don't know.
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Last edited by Motorhead; 01-03-2018 at 08:21:44 PM.
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