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GM 602 crate how to check for a cheater cam?

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GM 602 crate how to check for a cheater cam?

Postby drifter » Fri Jul 09, 2010 2:02 pm

On a 602 GM crate engine how can tech check to see if a racer has a reground cheater cam in his crate engine at the track? I know you can degree the cam but if you were to do this to the top 3 or 5 it would take a while is there a faster way? I know these guys are sending there stock cams out and getting them reground
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Re: GM 602 crate how to check for a cheater cam?

Postby CamKing » Fri Jul 09, 2010 4:15 pm

It depends on the track.
Some places just put an indicator on the retainer, and check the max lift.
Some also check the lift at TDC.
Some tracks have the Audie system that connects right to the engine, and can do a complete readout of the cam profile in a couple of minutes.

PS, there's a way around all of them, you just have to know which method they use.
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Re: GM 602 crate how to check for a cheater cam?

Postby levisnteeshirt » Sun Jul 11, 2010 12:58 pm

a vacume gauge

if you checked the manifold vacume at lets say 3 different RPM levels , with odd timing settings ,, like only 5 degrees ahead, then 2 ,, record what a stocker does ,

then check the winner against those readings ,,,

i don't see how anybody could hide a cam with different specs against a test like that

alot of circle tracks around here ,, and crate racing is getting big ,,, but so are the cheaters ,,

i gotta believe there is no way to hide a cheater cam against a test like that

someone could argue low vacume readings is because of a worn engine or streched timing chain ,,, but a worn engine shouldn't be winning IMO

i had one friend mess with a 604's cam , it picked up by putting it on a 110 ,, then they went back to a stocker ,, didn't want to chance it
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Re: GM 602 crate how to check for a cheater cam?

Postby Keith Morganstein » Sun Jul 11, 2010 1:06 pm

levisnteeshirt wrote:a vacume gauge

if you checked the manifold vacume at lets say 3 different RPM levels , with odd timing settings ,, like only 5 degrees ahead, then 2 ,, record what a stocker does ,

then check the winner against those readings ,,,

i don't see how anybody could hide a cam with different specs against a test like that

alot of circle tracks around here ,, and crate racing is getting big ,,, but so are the cheaters ,,

i gotta believe there is no way to hide a cheater cam against a test like that

someone could argue low vacume readings is because of a worn engine or streched timing chain ,,, but a worn engine shouldn't be winning IMO

i had one friend mess with a 604's cam , it picked up by putting it on a 110 ,, then they went back to a stocker ,, didn't want to chance it


Ignition timing alone will change vacuum readings.
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Re: GM 602 crate how to check for a cheater cam?

Postby CamKing » Sun Jul 11, 2010 4:46 pm

Keith Morganstein wrote:Ignition timing alone will change vacuum readings.

Jetting will also change vacuum readings.

The best system is the Audie Technology system.
http://www.audietech.com/cam-pro-plus/techinspect.html
They claim, "there's no getting around this", but that's not really true. :wink:
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Re: GM 602 crate how to check for a cheater cam?

Postby levisnteeshirt » Sun Jul 11, 2010 11:18 pm

hmm ,, idle one at 750 rpm with 10 degrees ahead , , 12 degrees 6 degrees

check it at 800 , same deal ,

then lets say 900 ,,

record the vacume readings at each timing setting for each rpm

if they're stock ,, they should be very close

yes i know timing changes vacume , so , you need to map out what a stock , " legal " one does

i go to alot of dirt tracks ,, crate late models are very popular here on dirt ,, i gotta laugh everytime one comes out to hot lap ,, and it sounds like its cammed to death going slow ,,, a game of cheaters ,, enough of that already in circle track IMO

i think thats worth a try anyway ,, you might have to check his TDC on the timing mark to see if he changed it to pass the test , but thats no biggie , then use a timing tape for that balancer to check the timing marks ,

this test might validate if there is a need to dig deeper in the engine IMO
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Re: GM 602 crate how to check for a cheater cam?

Postby CamKing » Mon Jul 12, 2010 7:55 am

levisnteeshirt wrote:hmm ,, idle one at 750 rpm with 10 degrees ahead , , 12 degrees 6 degrees

check it at 800 , same deal ,

then lets say 900 ,,

record the vacume readings at each timing setting for each rpm

if they're stock ,, they should be very close

yes i know timing changes vacume , so , you need to map out what a stock , " legal " one does

i go to alot of dirt tracks ,, crate late models are very popular here on dirt ,, i gotta laugh everytime one comes out to hot lap ,, and it sounds like its cammed to death going slow ,,, a game of cheaters ,, enough of that already in circle track IMO

i think thats worth a try anyway ,, you might have to check his TDC on the timing mark to see if he changed it to pass the test , but thats no biggie , then use a timing tape for that balancer to check the timing marks ,

this test might validate if there is a need to dig deeper in the engine IMO

You're pissing in the wind.
I could design a cam to pass that test, and have at least 10 more hp, in about 5 minutes.
First off, the stock cams aren't all exact. There's a pretty big tolorence to work with.
Second, if you checked the vacuum on a bunch of the stock crate engines, you'd see that they're all over the place, so that would give me a pretty big range to stay within.

I have a series of 602 and 604 crate engine cams, depending on how they're teched.
I'm sure the vacuum on my stage 1 cams would check within spec, without any messing around.
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Re: GM 602 crate how to check for a cheater cam?

Postby Headcase » Mon Jul 12, 2010 4:21 pm

you could use a compression test.....A given engine w/xx to 1 static compression and an intake closing event of xx degrees abdc can only generate xxx pressure....(there are calculators on line specifically for this you would have to plug in your advertised max static compression limit and factor in +4 or -4 on the "intake closes at event" if they are allowed to advance or retard the cam)....anything over that then break out the degree wheel and check the actual timing events and obviously valve lift...you have to get up pretty early to catch those circle track guys....Headcase
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Re: GM 602 crate how to check for a cheater cam?

Postby CamKing » Mon Jul 12, 2010 8:23 pm

Headcase wrote:you could use a compression test.....A given engine w/xx to 1 static compression and an intake closing event of xx degrees abdc can only generate xxx pressure....(there are calculators on line specifically for this you would have to plug in your advertised max static compression limit and factor in +4 or -4 on the "intake closes at event" if they are allowed to advance or retard the cam)....anything over that then break out the degree wheel and check the actual timing events and obviously valve lift...you have to get up pretty early to catch those circle track guys....Headcase

Nope.
There are tracks that check both vacuum at 1,000rpm, and cranking compression, and we get around that too.
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Re: GM 602 crate how to check for a cheater cam?

Postby levisnteeshirt » Mon Jul 12, 2010 8:43 pm

vacume at 1000 rpm , that isn't going to show you much IMO

idle it down to 650 rpm ,, see what it does ,, move the timing so timing won't compensate for overlap ,, set it not where the engine runs smooth , then check its vacume there compared to a stocker ,, thats where you'll see a difference

they let them be rebuilt by approved locations now ,, soo ,, i think the cat is out of the bag really ,, if GM were to attempt to prosecute someone for copyright enfringement ,,, who would they go after ??

Fastrak puts a seal on them now i think themselves ,, once they inspect it

but its so obvious when you hear them run , that something has been done to 'em ,, or they're putting nitro or something in the fuel , because they just run beter ,, they might think they're fooling some people ,,, not people that have listened to engines most of their adult life and know what to listen for

i played with a 604 on my buddies dyno ,,, it made 415 hp ,,, not a very strong engine ,,, it idled smooth , like a pass car ,,, did not want anything other than a 4777 regular 650 dp ,, you name it , they had it there to try it as far as carburators go ,,, 650 hp , 750 dp , etc etc etc , some i hear at the track sound way better than that one did ,,, like its got a way more radical cam in it ,,, more like a solid roller with about 250 @.050 ,, just a whole lot stronger

i think the crate thing sux because its forcing out other classes that did have built engines ,, its why i don't like nothing about them ,,, my .02

i think a gear rule , tire diameter rule and carb rule ,, would be more effective

i wonder if a " stock appearing 604 " class would be more of attractive class to put the engines once they need rebuilt instead of letting them be rebuilt back to so called GM specs and be allowed to go back to crate racing ,, 604 heads block, valve spring diameter, and intake , the rest is up to you
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Re: GM 602 crate how to check for a cheater cam?

Postby JDR Performance » Mon Jul 12, 2010 10:42 pm

They're sealed motors and approved rebuilders are the only ones supposed to have replacement bolts. When they're rebuilt they're blueprinted to optimum legal tolerances. Like anything else there's some extra stuff that's going to be done here and there but the majority of them are found legal when torn down and inspected. Some of the head castings are better than others so they're sought out and used, etc. etc. The bolt on stuff picks up a lot of power on those. Using a good carburetor set up for the crate stuff makes a difference and so does the fuel being used. E-85 and the VP CHP work great. If the stock 4777 made the best power on the 604 dyno test you did you didn't have the right carb there. That alone was losing hp for you. All in all, the crate stuff is very competitive and keeps the car count up. No car count, no track. No track, everybody loses.
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Re: GM 602 crate how to check for a cheater cam?

Postby levisnteeshirt » Mon Jul 12, 2010 11:11 pm

JDR Performance wrote:They're sealed motors and approved rebuilders are the only ones supposed to have replacement bolts. When they're rebuilt they're blueprinted to optimum legal tolerances. Like anything else there's some extra stuff that's going to be done here and there but the majority of them are found legal when torn down and inspected. Some of the head castings are better than others so they're sought out and used, etc. etc. The bolt on stuff picks up a lot of power on those. Using a good carburetor set up for the crate stuff makes a difference and so does the fuel being used. E-85 and the VP CHP work great. If the stock 4777 made the best power on the 604 dyno test you did you didn't have the right carb there. That alone was losing hp for you. All in all, the crate stuff is very competitive and keeps the car count up. No car count, no track. No track, everybody loses.


it wasn't a stock 4777 but a 4777 ,, this was at 2400 ft , don't know what fuel they used , , don't know how much of a factor that would be , but i'm sure it would make a difference ,,, they tried a couple different 750's ,,, my friend won't have alot to do with the crate motors because they want him to cheat for them and he won't do it , i wonder how a 750 vs with annular boosters installed would do ,, when you hear one qualify here , it sounds like they're being lugged down some coming out of the turns , maybe they don't want to change the gear to qualify , , when the track is choppy ,alot of moisture still in it , ( not the best track prep sometimes ) later through the night , seems like they do better , ,, i gotta wonder if a good set up VS carb would do better on the car ,, just a thought

the situation here ,, they canned classes to run a crate class ,, and did a few other stupid things IMO ,,, anyway ,,, now there is a bunch of crate cars there ,, with other cars with built motors at home in the garage with no where to race ,, i think it stinks

how much power are you seeing out of a blueprinted 604 or 602 ??
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Re: GM 602 crate how to check for a cheater cam?

Postby ProPower engines » Tue Jul 13, 2010 12:11 am

We have a crate class here that uses a restrictor plate and a rpm/gear rule. The 2bbl engines pull the crate engines by 2 10th's on both straights with ease. The crate engine is just a stock pu type engine built with all GM's factory tolerances built in. Seems to me if a guy runs at a track that has a crate option for the class a home grown type engine should easily whip it's ass any day. But like most racers they don't look at the total package and if the 10yr old chassis ain't workin no engine is going to make it a winner. yes the will last longer if you don't rev them but they also don't rev like a purpose built engine either.
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Re: GM 602 crate how to check for a cheater cam?

Postby Dodge Freak » Tue Jul 13, 2010 3:02 am

levisnteeshirt wrote:, if GM were to attempt to prosecute someone for copyright enfringement ,,, who would they go after ??



If anybody needs to be sued its GM for how many people / suppliers they screwed over!
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Re: GM 602 crate how to check for a cheater cam?

Postby 3V Performance » Tue Jul 13, 2010 6:50 am

levisnteeshirt wrote:vacume at 1000 rpm , that isn't going to show you much IMO

idle it down to 650 rpm ,, see what it does ,, move the timing so timing won't compensate for overlap ,, set it not where the engine runs smooth , then check its vacume there compared to a stocker ,, thats where you'll see a difference

they let them be rebuilt by approved locations now ,, soo ,, i think the cat is out of the bag really ,, if GM were to attempt to prosecute someone for copyright enfringement ,,, who would they go after ??

Fastrak puts a seal on them now i think themselves ,, once they inspect it

but its so obvious when you hear them run , that something has been done to 'em ,, or they're putting nitro or something in the fuel , because they just run beter ,, they might think they're fooling some people ,,, not people that have listened to engines most of their adult life and know what to listen for

i played with a 604 on my buddies dyno ,,, it made 415 hp ,,, not a very strong engine ,,, it idled smooth , like a pass car ,,, did not want anything other than a 4777 regular 650 dp ,, you name it , they had it there to try it as far as carburators go ,,, 650 hp , 750 dp , etc etc etc , some i hear at the track sound way better than that one did ,,, like its got a way more radical cam in it ,,, more like a solid roller with about 250 @.050 ,, just a whole lot stronger

i think the crate thing sux because its forcing out other classes that did have built engines ,, its why i don't like nothing about them ,,, my .02

i think a gear rule , tire diameter rule and carb rule ,, would be more effective

i wonder if a " stock appearing 604 " class would be more of attractive class to put the engines once they need rebuilt instead of letting them be rebuilt back to so called GM specs and be allowed to go back to crate racing ,, 604 heads block, valve spring diameter, and intake , the rest is up to you



They should make them all run a nascar issued ign box with factory rated chip. ( 6200? ). I have turned down work on more then 1 of those POS !!!
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