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Discussion Starter #1
I am in the process of an engine rebuild and the engine builder calls to ask if I want the cam re-installed at 7 degree retarded. That sounds like a lot to me. The car made good power. I liked the curve. However, I wonder if it would perform better if installed per the cam card. The cam has 2 degrees ground in advance. The engine builder recommends installing it as directed. I don't know why the cam was installed 7 degrees retarded. I do know that it was supposedly installed dot to dot and they didn't degree it. What do you guys think?
 

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Lol, I just went through this with my little sbc, I lined up the keyway dot with the cam dot, it ran good but seemed lazy down low, pulled it apart and installed it correctly and picked up 4 tenth’s in the 1/8
 

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Discussion Starter #4
Tell the whole story, engine, power, cam numbers, ect, so people might have something to go on.
Stock bottom end Gen 2 Viper (V10, 488 ci), 243/251 .667/.645 113 lsa 111 icl, 11.3 compression, revs to 7k, made 642/585.

Engine was being rebuilt due to a few valve spring retainers breaking. Mainly just torn apart to see if there was any damage. Engine checked out fine.
 

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Somebody put the cam in lining up dots. Dots can be off. My own custom solid roller cam core has the keyway 6* out from where it is supposed to be. Makes degree’ing their cam a real bitch. Throw away the dots because they are no where close to where they should be.
nobody should be in business putting a hi-perf cam in without using a degree wheel; especially a Viper engine.
follow the new guys instructions and do it right. Expect to go through rear tires at a faster rate.
 

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agree with the previous comments, though I am not familiar with viper engines I consider the dot to dot as a starting point only mostly they are close rarely are they right.
 

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agree with the previous comments, though I am not familiar with viper engines I consider the dot to dot as a starting point only mostly they are close rarely are they right.
This^ And I’d care to guess that even installed straight up will be a huge improvement. Never heard of anyone installing a cam that much retarded. Not saying it doesn’t happen on purpose, I just ain’t heard of it.
 

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I am in the process of an engine rebuild and the engine builder calls to ask if I want the cam re-installed at 7 degree retarded. That sounds like a lot to me. The car made good power. I liked the curve. However, I wonder if it would perform better if installed per the cam card. The cam has 2 degrees ground in advance. The engine builder recommends installing it as directed. I don't know why the cam was installed 7 degrees retarded. I do know that it was supposedly installed dot to dot and they didn't degree it. What do you guys think?
Stupid question:
If the cam has 2* advance ground in, then was your "net" retard at 5* or was it actually 7* ?

Are you going to gain more P/V or lose it installing the cam straight up ?

If you take the 7* retard out of it how much rpm will you lose on the top ? Or will it not matter because it will have more average pwr across the range ?
 
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Better make sure you check your valve to piston clearance. They may have had a reason for installing the cam like that. Not saying it's right, or a good reason, just saying.... You mention breaking retainers. That's a big red flag.
I was thinking the same thing while you were typing .....
 
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Discussion Starter #11
Better make sure you check your valve to piston clearance. They may have had a reason for installing the cam like that. Not saying it's right, or a good reason, just saying.... You mention breaking retainers. That's a big red flag.
I don't think that will be an issue because I've had this cam for years and never broke retainers until I switched to titanium. P/V clearance was always good before and I made no changes to the valve train geometry. Viper pistons are deep in the hole, .035", so there should be a lot of room. I will have them double check for clearance though.
 

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Discussion Starter #12
I'm not 100% sure, but I believe when you retard or advance you gain or lose clearance on the intake and the opposite on the exhaust. I'm not sure whether I netted 5* or if if it was still 7*.
 

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Maybe the engine builder thought the cam was a little small for YOUR expectations & retarded it a few degrees to increase top end HP.
 

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Maybe the engine builder thought the cam was a little small for YOUR expectations & retarded it a few degrees to increase top end HP.
I didn't design the cam, he did. So he thought it was optimal for my set up I suppose.
 

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Where is this engine builder, what State. Who's cam, grinder. We have quite a few Vipers go thru the shop and all made power. So but more info and we can help some more.
 

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Stock bottom end Gen 2 Viper (V10, 488 ci), 243/251 .667/.645 113 lsa 111 icl, 11.3 compression, revs to 7k, made 642/585.

Engine was being rebuilt due to a few valve spring retainers breaking. Mainly just torn apart to see if there was any damage. Engine checked out fine.
"a few valve spring retainers breaking." means that there is/was something wrong in the engine. Your new engine builder should be able to determine why the retainers broke and if there is really any (valid) reason for the cam to be installed so far retarded.
 

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Stock bottom end Gen 2 Viper (V10, 488 ci), 243/251 .667/.645 113 lsa 111 icl, 11.3 compression, revs to 7k, made 642/585.

Engine was being rebuilt due to a few valve spring retainers breaking. Mainly just torn apart to see if there was any damage. Engine checked out fine.
What do the piston to valve clearances check out as ?
 

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Sounds like my former builder, no real reason why pick up tubes not welded to pump on sbc, no reason for shaft rockers spilling its needles out, (retainers hitting, not clearanced as per instructions), then leaving needle bearings in head and pan , while off, and reinstalls with bearings , still in pan, my list goes on, wrong pistons, paid for good ones , got junk ones. I hope its not the same idiot in new jersey, alot of fucking assholes out there just assembling shit
 
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