REAL!!!! GPU Continental cam specs

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Waterthunder
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REAL!!!! GPU Continental cam specs

Post by Waterthunder » Wed Dec 23, 2015 1:58 pm

It's been 15 years since I built my last A/C motor but I have a racing buddy who did the usual. Stroked a motor , ran a longer Lycoming rod, Put in dome pistons and jacked the compression way up. Then ran a stock or mild cam and now wonders why the motor lays over on the big end. After calling 5 or so A/C engine builders nobody could give me the actual specs such as LSA or duration at .050. So we put one on a cam doctor here is what the stock specs were.

INT EXH

DUR @.050 226 223
Lobe lift 358 352
Lobe Separation angle 108

I can see why this motor had so much cylinder pressure and also hit a wall after 2,500RPM's. I told the guy this cam is like a coffee straw and was the restrictor plate on his motor. Your new cam will welcome you to 2016 my friend!
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Waterthunder
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Re: REAL!!!! GPU Continental cam specs

Post by Waterthunder » Wed Dec 23, 2015 4:21 pm

We are going to develop a custom grind and spring kit for this engine. We are trying to come up with a drop in spring package for A/C performance cams. Would anybody else be interested in this? Or atleast replacing their 40 year old wore out valve springs.
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diesel250rr
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Re: REAL!!!! GPU Continental cam specs

Post by diesel250rr » Wed Dec 23, 2015 4:36 pm

I would be interested in getting a crank more so then a cam but I was told you can use an e225 cam I could check my part number on mine but don't know the specs for it

rjonesboy
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Re: REAL!!!! GPU Continental cam specs

Post by rjonesboy » Wed Dec 23, 2015 6:55 pm

I would be curious to see the actual specs on all the ac/gpu cams. Stock, H290, Phase 3, helicopter, and so on. I think there would be a market for an aircraft cam and spring package

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Waterthunder
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Re: REAL!!!! GPU Continental cam specs

Post by Waterthunder » Wed Dec 23, 2015 8:40 pm

I have several friends who want me to come up with a valve spring package so Im working on it. I also want to verify the desired lifter preload is .050 in the A/C motors and I want to find out what is the max seat pressure a hydraulic A/C lifter can handle. I am already verifying spring pressure at closed and max lift. An old saying is "lift is free horsepower" so That is one of many ways I think we can find good power for the A/C guy's. In the past I have machined cam gears so they can be degreed. Were going to try to come up with a entire valve train package such as springs, cam, pushrods and cam.

Like I told a buddy today,,, just from 1990 to today it's amazing how much automotive cam lobe profiles have changed, but (you) still insist on running a cam profile that was designed in the early 60s even late 50s. He agreed and ordered a cam and springs.
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John Fenner
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Re: REAL!!!! GPU Continental cam specs

Post by John Fenner » Thu Dec 24, 2015 9:50 am

Interesting reading this, out of curiosity, is this the 878 part# ?
I never finish anyth,,,.

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Re: REAL!!!! GPU Continental cam specs

Post by FP1201 » Sat Jan 02, 2016 12:06 am

For years I tried and could never get the RPM's out of my GPU that I though it should be turning. Talking to SpeedWheelie about it, he said something to the effect that the GPU (at least some of them) used a cam shaft that just wouldn't let the engine turn up over about 2,600.
With that in mind, I'd say you were dead on with your assertions. These engines were really designed to run at one relatively low, constant speed.
Being how you've got to split the case to install one, would increasing the diameter, and thereby reducing the load on the components be an option?
I think with the shear number of these old engines, if you can produce one that's economically viable, they will sell
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plumcrazy
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Re: REAL!!!! GPU Continental cam specs

Post by plumcrazy » Sat Jan 16, 2016 2:27 am

my pe 90 would not crank after it heated up and i tried every kind of starter and battery turns out it was a stroked motor after i tore it down 180 small journal with 520 high compression pistons cam stock .. when it was cranked it was bad ass but it built heat . just got finished puttin it back together with flat top 550 pistons custom cut... 366 ci and a couple point lower on compression should be a good combo ill let ya know a good grind and better springs would be cool

SWAMPHUNTER45
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Re: REAL!!!! GPU Continental cam specs

Post by SWAMPHUNTER45 » Sat Jan 16, 2016 6:58 am

Dave,

I spoke with Buddy Branch on this and he got a big smile of his face and wishes you the best with the project. Your gonna find a lot of low cost power for the GPU guys! Awesome

Better get with Rick fast and save you another alternate screen name "GROUNDPOWER THUNDER"....lol

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Bruce
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Re: REAL!!!! GPU Continental cam specs

Post by Bruce » Sat Jan 16, 2016 9:08 am

who still runs a stock cam in a 220 if theyre already in there?? yall are a tad late lol
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Re: REAL!!!! GPU Continental cam specs

Post by Rich863 » Sun Apr 22, 2018 10:23 pm

plumcrazy wrote:my pe 90 would not crank after it heated up and i tried every kind of starter and battery turns out it was a stroked motor after i tore it down 180 small journal with 520 high compression pistons cam stock .. when it was cranked it was bad ass but it built heat . just got finished puttin it back together with flat top 550 pistons custom cut... 366 ci and a couple point lower on compression should be a good combo ill let ya know a good grind and better springs would be cool


Was this the motor Tom built for you?
:old_glory: :florida:

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Re: REAL!!!! GPU Continental cam specs

Post by Sisk Rifles » Mon Apr 23, 2018 11:05 pm

Is there a chart with the torque curve in these engines showing various cams ? I have a carb’d 520 in my 182. It is faster at 2350 rpm’s than any setting up to 2700. Doesnt matter how much fuel you give her either. Could it be that around the 2350 rpm is peak torque , then falling off at higher rpm ?

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