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View Full Version : Cam troubles once again....



fastsc92
11-24-2003, 10:10 AM
I'm in a bind once again. I ordered Coy's cam, but now its delayed at least two weeks. I called comp cams many times and no one knows what they are talking about. I finally got someone good at comp cams to talk to. His name is Matt and he knows these motors fairly well. He now said that i should go with a .460 lift, 204/214 durration. He said that it would work with stock pushrods. I also informed him about coy miller and that he goes to a .500 lift. He seemed very surprised that it would be that high, but he had the ability to look up previous orders. Most of the cams that coy ordered were .493 lift, 210/220 durration. He told me that the best route to take was to send the cam in attention to him, and they would profile the cam to see what the stock specs are, then figure out if he could get me a higher lift, simliar to coy's cam. I was very happy with Matt and how much he helped me out. Total price for the regrind shipped back to me would be $135. He said that the stock lifters should take up alot of the pushrod slop, that i could use the stock one with a .460 lift. He said as the lift gets larger around a .493 lift that i might need to go a little bigger. He told me that he would personally measure the base circle before and after and add what he took off to the pushrod. Now i'm in a bind of who to get the cam off of, coy or comp. I dunno what to do anymore and i'd hope maybe you guys can help me out once again.

Ken Seegers
11-24-2003, 01:53 PM
I have a cam from crane it is .509 lift with 206 duration at .050. I still have stock valves. I am using (cough....chevy...cough) push rods. They are actually 87 IROC push rods. I am also using 5.0 single valve springs. I can not remember the parts numbers, but I have them at home. The cam from crane was about $150, springs another $70 and push rods $40.
E-mail me tonight if you want the part numbers.

My cam only took about a week to be completed and it is totally streetable.

The cam comp is building is bearly above stock. I think the stock lift is .448 and duration is 192 @ .050.
Good Luck
Ken

fastsc92
11-24-2003, 02:20 PM
I think i'm going to get a from comp, which is the same as a coy miller stage one. .493 lift.....210/220 durration. I should be able to stay with the stock springs as they are good up to .500 lift. I just need some longer pushrods, how long...i dont know that yet. But i'd be interested to know all the parts you used. Also how did you figure out how long of a pushrod you needed?

Ken Seegers
11-24-2003, 07:53 PM
My cam was regrind #00628. The springs were crane cams #99833. The push rods were Chevy SB 85-89 O.E. roller lifter push rods. I just ordered the regular ones from Summit. I believe the length is 7.20" long.

All the info was given to me by Stan Wodzisz. Comp Cams should know what size push rods to use.

Good Luck
Ken

wezar
11-24-2003, 09:02 PM
I believe my cam is the same as Kens. I bought mine from Stan. I misplaced the Spec Card but I have it written down as the regrind 00628 and remember it being a .509 lift. I am using the stock valves too.
fyi. the 90 Stock Cam is .448 Exhaust and .424 Intake
I do have the Crane Double valve Springs and Comp 7.20 pushrods. I bought the Cam and pushrods from Stan. They had been used with the stock rockers and Crane single valve springs by Stan.
I added the Motorsport Roller rockers and found out the hard way that you need to have milled Rocker pedestals (or longer pushrods).Crane instructions to set preload

http://64.90.9.168/cranecams/pdf/453e.pdf

I am very happy with the cam. It idles at around 750 rpms with a little rumble and pulls very hard through 5k.

SilverCasket
11-25-2003, 07:35 AM
FastSC92 - I don't know what your looking for or if you posted it in a previous post, but I have a 555 lift on the intake & exhaust. Idles great. Pulls everywhere. .. Durations is about 240 on either side. .. Seems a bit much & I don't know if anyone else has had trouble at these levels, my car idles great, doesn't stall & pulls everywhere. .. At that rate though, you'll need good head work & of course great springs. .. I used 7.2 rods throughout with no play. ... Like I said, I don't know exactly what your aiming towards, but this info would be helpful if you are looking for a mean mofo.

Anthony

fastsc92
11-25-2003, 07:51 AM
I'm aiming for a reliable engine, that will be great at the track and will also be very streetable. I'm using stock size valves, and i'd like to keep the stock springs (new). I just wasn't sure if i should wait for Coy, or go through Comp. I've decided to go right through comp, with Coy's specs (via Comp Cam). I've decided with a .493 lift, 210,220 durration. The lift is higher than stock but not too high allowing me to keep stock springs. The durration is where it's going to make power seeing that the stock durration is around 180-190. I'll just need new pushrods which i got the numbers from Coy. They are actually SBC rods which are 7.200" long. I'm just hoping that its long enough, or not too long. Is there any exact way of finding out? I have a few pushrods that are 7.200 that i'm going to test with, but is there any way to tell for sure once i test these. I know i need the proper pre-load but if i cant get this, does this determine what length pushrods i need?

Ken Seegers
11-25-2003, 08:30 AM
wezar,
if you need the cam card, I can scan it and e-mail it to you. Just let me know.
later
Ken

Rich Thomson
11-25-2003, 08:42 AM
My suggetion is if you want to go with a 490 lift cam and stock rockers and pushrods then be sure to mark the location of the pushrods. Measure the length of each pushrod as the factory adjusted the preload by installing different length pushrods. Stock pushrod length is 7.135". Verifying the correct pushrod preload is a bit more involved. Shims and or different length pushrods can be ordered. The pushrods are 5/16" with an oil hole in the center. I have transferred the Comp Cams video that shows how to install the cam and degree it as well as verifying and setting the pushrod preload. This Windows Media file WVM is 26 megs.



Comp Cams Install Video (http://www.mn12performance.com/mn12-techinfo/cam-install/comp-cams.wmv)

fastsc92
11-25-2003, 09:36 AM
Rich, thank you so much, that should help me out. Thank you once gain.

XR7 Dave
11-25-2003, 02:03 PM
Fast92 that is some really good info you got from Comp Cams. That CMRESI seems to be the exact same cam that I have in my car. I highly recommend it. It is capable of supporting up to 350rwhp as I have shown with my car. It also idles smooth and provides both instant torque and great mileage. It will actually work with stock pushrods but you will need new valve springs. It is interesting to note that this cam made the same HP (at a lower rpm) and 25ft lbs more torque than the cam that Steig uses in his packages. It also idles at about 15" vacuum. :)

fastsc92
11-25-2003, 02:10 PM
Now thats strange because Coy told me the opposite. He told me I would need longer pushrods, but i can keep the stock springs. I'm going to install everything and see if the springs bind, and then check the pushrods via the pre-load of the lifters. This will tell me if i need new springs and if i need longer pushrods.

fastsc92
11-25-2003, 02:12 PM
oh quick question Dave. Hows does it sound at idle. I want a smooth idle, but of course i also want people to know it has a cam. I was hoping for a slightly lopy idle, just enough to hear.

XR7 Dave
11-30-2003, 08:51 PM
It will have a *just* noticable lope. Most people will miss it entirely. I used the stock pushrods on mine. Stock is 7.135" and the next step is the 305 chevy ones at 7.192" Basic math will tell you that going from .447" lift to .493" lift at the valve will mean going from .260" at the cam to .285". So you have ground .025" off the base circle but your pushrod choice is .060". I didn't like the .105" preload resulting from the longer pushrods, nor did I want to shim the rockers as that changed geometry and is a pain in the neck anyway so I decided to go with .035" preload instead of .060". In simple terms that means that my valves are "1/2 turn past clatter" for the GM guys instead of a full turn. Being that 3/4 turn is considered right for the GM guys, I figured 1/2 turn couldn't be all that bad.

I've been running it that way for about 30K miles with no complaints (well past 6000rpm too). ;) I wouldn't trust the stock springs because as I said this cam will rev past 6000 and with nitrous on board I'd just think it is too risky that you'd over-rev it. The old springs are probably tired anyhow.

fastsc92
11-30-2003, 09:09 PM
ya, i actually am getting new stock springs. But i guess i could hold off on them. I just dont want to do any machine work to the heads, like i've been told that i would have to do if i got comp. 942 springs. It was just weird because coy told me that i wouldn;t need springs at all, just pushrods. Now i dont know what to go with. I never rev the motor past 5500. I shift at 5000. I figured new stock springs would be fine. Now i'm in a bind once again. Two conflicting stories.

pearl95sc
11-30-2003, 11:01 PM
Get new springs. On my 95, which I came to fine the motor had less than 30K on it, I had 2 bowed spings. I only put about 20K on the car since I got it. Alyn.

fastsc92
11-30-2003, 11:12 PM
i'm getting new springs, but the question is do i get new stock springs, or aftermarket springs. And would i need to machine the heads to accept the springs. And in addition to that, are aftermarket springs even required for this cam? Coy miller says no, but others say yes......

MIKE 38sc
11-30-2003, 11:22 PM
If youre planing to rev the engine higher than the stock redline I would go with the 942's. But if you plan to stick to the factory redline the stock springs will be fine.

fastsc92
11-30-2003, 11:50 PM
to add more fuel to the fire, It turns out that the 942 springs can take a max lift of .500. Here is the link i found which says that. This place is the cheapest i could find for a set of 16 springs. I'll call comp in the morning to verify the max lift that the springs can take. http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=2274

MIKE 38sc
12-01-2003, 12:41 AM
Whats the problem with that?:confused: Yes there good for up to .500 lift.

fastsc92
12-01-2003, 08:35 AM
I was just surprised because everyone informs me to go to a different spring such as the comp 942, and in turn, these have the same max lift as a stock spring.

MIKE 38sc
12-01-2003, 10:49 AM
Yes but theres more to it than how much lift they can handle.
The 942's are a little bit stiffer springs but the 942's require more machine work to the heads to get the proper installed height and they will need some new spring seats as well.

Rich Thomson
12-01-2003, 02:26 PM
The 942 springs are 115lb @1.7" installed height. The 3.8L head has a factory installed spring height of 1.645"@94lb. I believe the 942 spring installed at 1.645 height is 130lb. The 942 spring coil bind is 1.125". The stock spring coil bind is ???? (anyone). According to Dr. Fred the 942 spring installed on a 3.8L head is good for 530 lift. After that coil bind is a problem. The rule of thumb is .050 clearance for coil bind. I know many SC's are running the 942 springs on stock heads with non adjustable roller rockers. As for the pushrod height you will need to either get an adjustable pushrod to determine proper preload which is about .030" to .050" when installed or machine / shim the pedestal height to achive the proper preload.

I am working on a How-To article that will show and explain the stock cam setup and .520 lift cam install using the pedestal roller rockers and the 942 springs. If you have any tech info on this please e-mail or PM me. I am getting most of the tech info from Dr. Fred and Coy.

Rich

XR7 Dave
12-01-2003, 03:57 PM
Coy is right obviously, you don't have to get aftermarket springs. Just keep in mind that with the added performance of this cam you will find that 5500rpm comes real quickly, especially on the juice. I have the same cam and I see 6000rpm all the time.

fastsc92
12-01-2003, 03:58 PM
how about the machining of the heads to accept the springs, is it nessesary? I will take many pics of this swap if you'd like to use them. I'll be doing it sometime around the 13th. It wont be a .520 cam, but it will be a CMRE stage 1 cam with new springs, and i'm going to degree it. I can take pics of the whole process or just the degreeing on this motor if that would help you any.

MIKE 38sc
12-01-2003, 04:21 PM
Talk to Dave Neibert about the machine work. He tried using the 942's without it and has since had the machine work done on his heads. He can explain firsthand why it needs to be done.