mustangmuncher

I am considering this cam, big question on my mind is power band, but the biggest question is the oil pressure/engine safety with it. Is there anyone on a stock cube engine who hasnt had to rebuild the engine or just simply had to be easy to avoid blowing the engine?? Could anyone direct me to the GM part numbers for 1.6 roller rockers and if they sell valvesprings/pushrods that I can use? If not what valvesprings/pushrods/lifters would you recommend? Any part numbers? What were your results, stock heads? Home ported heads?? Thanks

-Eric

n20ta2

Well,results are below with home ported heads.Power band is good,it starts pulling hard around 3000-3500 and will spin as high as you dare with a good set of lifters rockers and springs.As far as oil pressure is concerned Im not sure what your getting at-it shouldnt be any diff than with the stock cam.I cant help you with rockers as im running a set of crane rockers with guide plates 1.6 ratio.Go with the reccommended seat pressure springs,any mail order/speed shop can give you a reccomendation,I no longer have the box mine came with so no part#there.

mustangmuncher

With the oil pressure, I an trying to get at the fact of people spinning bearings and the like, and having to rebuild.

1 Nasty Bird

Wait till winter and pull the motor and have new bearings and rings thrown in for a few hundred, toss on a good valvetrain and spin it up till you see pigs grow wings.

mustangmuncher

Has anyone had similar problems with the CC306?

n20ta2

Its a myth,it shouldnt make any difference unless you mean spinning the motor at a higher rpm causing problems,you will have the same oil pressure you started with.You should be ok but if you have a high milage engine its best not to beat it if you cant afford to fix it.A cc306 is still an aggresive grind and wont be any diff then adding a 847.

atljar

I beat mine like a red headed step child and the bottom end is still good. All the info you asked for is in my signature, OR on the mods page of my website.

NAZTLT1

It really depends on a couple of things. Dirt and carelessness are your biggest enemies but high rpm driving can bite you in the a$$ too. My motor failed after just 800 miles, 200 of which were low rpm break in miles. I am confident that my install was clean. However I am every bit sure that my engine failure was due to reving the motor way past what a stock bottom end is intended to handle. Haven't pulled my motor apart yet but upon inspection of the oil filter I found the oil to be a gold metallic brown. A sure sign of bearing failure. This motor has 80k on it 35k of which were blower miles, so I was on borrowed time anyway. I kinda threw caution to the wind on this one hoping it would last out the year with plans of building a bottom end over the winter. I was prepared to accept the fact that my engine might not take kindly to the new top end. As for the 847, awesome cam, pulled like a **** from 3500 all the way to 7k on the factory tach which was probably only really like 6800, but still enough to kill it with stock ported lt1 heads and a good solid valve train. If you can afford it, do your bottom end or at least new bearings and rings if you can, if for nothing else peace of mind do it. You will benefit in the long run. Many people are successful for long periods of time like atljar, equally as many are not like me. Just because you have a cam that can make more power at higer rpm's doesn't mean your bottom end can keep up with it. Much depends on the life the motor has had before the introduction of the new cam. As I have said in other similar posts. It's really a gamble. The odds for success are in your favor but the risk is still high. Just my 2 cents.

PS:The oil pressure was the same as before the cam install until the engine failed.

Good luck.

atljar

^----- What evan said is very true.

Brettinator

Hi I'm Brett ...and I too have an 847 .....crowd applauds and group therapy begins ...

Ok looks like you've got a bit of feedback to your question and I'll try and answer a few as well.
1) Powerband range is about 2,000 - 7,000 rpm (on my setup at least)

2) I installed my 847 in my 82k mi engine with bone stock LT1 heads and it lasted 2 hours prior my main bearings shredding into pieces. The cam bearings were in excellent shape so the cam itself or bearings didn't net engine failure, so my analysis concluded that the cam capability far exceeded the engines output due to mileage....so it died!!!

3) Now the following has been on my car for about a year: The Crane 847 cam, Comp HiTech Stainless 1.7RRs, stock length 1-Piece Comp Cmoly Pushrods, Comp R hyd-lifters & Crane 99893 valve springs. All worked well for about a year, month ago I broke 3 springs, replaced the springs with some Crower solid roller springs (specs matched the Crane springs), Tit retainers, 10 deg locks. The new valve specs were close but with the added spring pressures (I'm assuming) caused a collapsed Comp R lifter which threw the #5 intake R-Rocker in a bind snapping the Rocker stud. No biggie but I optioned to step down to the 1.6 & 1.5 RR combo to relieve a little stress on the Comp R hyd-lifters. Car runs fine with 1.5-RRs on the exhaust side, especially when stock LT1 heads stop flowing around 500 or 550, I was running 1.7s on heads that couldn't use them, sure I think they gave me some umph, I could tell the sound difference, but never dynoed it and frankly think all I was causing was extra wear n tear for very little performance.

4) Shorterm plans: I'm selling the GM-847 cam & possibly the 1.7RRs in place of a small base circle solid roller custom grind stroker cam (specs are Black Helicopter To Secret, sorry) and ditching the hyd lifters for solid rollers, changing my pushrod length to accomodate and my AFR heads will be here Oct 1st. My bottom end is fully forged top of the line everything yada yada yada, she's got the best parts, but it's stock cubed and that's the way it's staying till next summer (stroker time).

So I hope this bit of history helps you decided on your cam choice, the 847 cam is a beast, custom grinds are also a good choice. Stick with 1.6 RRs, get GM guide plates, not Comp, Crane, etc for your STOCK LT1 heads, reason is that the GM guide plates better align the roller rocker tips on the valve stem laterally. I cannot stress enough having the correct valve train geometry. My car ran 12.56 @ 114.6 consistently with my 847, stock heads & 1.7RRs. I'm targeting mid 11s with my AFR heads and custom solid cam on stock cubes, just a goal is all and several have done it with a little less than what I've done to my car.

Good luck

93ZM6Tally

I agree with most of what was said here. Oil pressure shouldn't be different because of a cam change so I really don't think that should be a factor that you consider. What is a factor is that to take advantage of the Cam's power band you're going to have to rev the car higher - which of course is more stress on the bottom end, and everything else for that matter. FWIW I've been running that cam for about a year with 1.6 RR, Crane 11983 Springs, CC 10 degree locks, CC retainers and locators, not titanium, sorry but the part numbers escape me, but they are pretty much what I've seen recommended for the 11983 springs by users on this board. I've certainly revved my 90k bottom end close to 7k usually by missing a shift w/o problems so far. I really believe a lot has to do with the quality that your bottom end was assembled with at the factory. Get an engine where the GM guy was lazy or drunk and maybe you could be in trouble - so far I've been lucky, but I don't expect my bottom end to last forever. Which is why I've started building a forged stroker bottom end. Good luck. The cam isn't as un-street friendly as some people say, I've got plenty of brakes, idles fine and sounds good.

Brettinator

I think you mean 99893 springs from Crane, not 11983. And your right this cam is not unfriendly, all about proper tuning, I'm runnin a bit on the rich side and with longtubes, no cats & open Borla it sometimes pops on downshifting but it's not that big a deal.

mustangmuncher

How do you guys think making 6,500 rpms a shift point? It is an automatic, and I think 6,500 is an ok/good limit to put on the bottom end. My friend who copies everything I do is going to buy a Z28 after he rode in mine, instead of finishing up his 12 second DSM. I want to do something he wouldn't do, since he really can't risk any engine failure at all if he gets it. So the GM847 sounds like the perfect cam for me. Does summit racing sell the comp r lifters? I live 45 mins from there in Ohio, and would love to be able to just drive and buy, no waiting or anything. Plus a chevy dealer within a few minutes sells all the GM performance stuff. Just to add in, I was planning on running Pacesetter longtubes/y-pipe with an electric cut-out on a stock cat-back (so if I want quietish I can have it, plus sleeper look) I was thinking about TCI's Street fighter torque converter (3,000 stall) or maybe a stock stall, not sure how much a stall affects things, and plan to research that more. Thanks for the great responses too everyone. I am going to check out altjar's site now. What rocker arms would you guys recommend?
-Eric

93ZM6Tally

You are correct sir. And I'm not even drunk.

93ZM6Tally

6500K sounds fine. You can buy everything, including the cam from Summit, using the Crane part number, although I think you'd get it cheaper from Jason or Dal. I would go with CC Pro Magnums, can't do much better for the price. I also like Non SA types, but I've used the SA's without a problem. I just like the stability of guide plates, but you would need to modify your heads slightly.

I run a manual, so I don't have an issue with a stall. If I was you I might consider a 3500 stall, just depends upon your personal definition of driveability.