Bob Turner

Mark,

I saw that you were interested in installing this cam in your BB. I am as well. I have the cam kit and heads together and now I am ready for the shortblock.

Chevy High Performance used this cam in a 454 and got 480 hp. They used 9.0 to one compression, Demon 850. Performer Rpm intake. I am not sure what else, but I am going to use 2.19"/1.88" valves, roller rockers.

One disadvantage to using this cam is that you have to take out the inner valve springs for break-in, and then reinstall them with the heads on. :eek:

I guess this relieves some of the spring pressures on the lobes.

I am going to give it a shot, though. Don Shuette, a Corvetteforum member, wrote to me regarding the swap last march, so I thought I would share his experience with everyone (as far as reinstalling the valve springs after break-in) He has a '68 with a 427 4 speed.

Here is an excerpt from that email:

"If you're just going to drive the car mainly for regular driving and an
occasional trip to the drag strip, I'm still leaning towards the flat
tappets. However, if you have the money to burn on the rollers, go for it.
You have to remember that you'll have to have the lifter openings indexed to
make sure they are perpendicular to the cam if you use rollers.

You're right on the flat lobes; if it's broken in correctly, it shouldn't
have a problem. Like Comp Cams' manual states, and like their tech guy
stated, and like my mechanic mentioned, you MUST take out the dual valve
spring for the initial 30 minutes because the big blocks are susceptible to
flattening out a lobe. I think it was only "slightly" a hassle dealing with
the dual valve springs because I didn't realize I needed to remove them
until the heads were already on the motor and the motor was in the car.
Thus, I had to do it the "hard" way twice. However, if you bring each
cylinder up to top dead center, buy the little air hose adapters at a auto
store to put compressed air in the cylinders, have a good air compressor,
get the good valve spring compressor tool from Comp Cams (item number 5318 =
$27.57, $33.96 with shipping), remove the little sliding t-bar from the
valve spring compressor and use a socket wrench, and use a magnet
thing-of-a-job to pull the locks out, this will make the install of the dual
valve springs much easier. First hint, I found that wiping the oil off the
locks from the initial break in once you remove them and then applying a
little standard grease to the inside of them helps them stick to the valve
on putting them back in. Second hint, for cylinder #3, the steering gear
box will not allow a "regular" type air hose with fitting to attach to the
adapter, so I also used a little coiled, plastic air hose which fit in
better. Now that I'm really thinking about it, if each cylinder is at TDC,
you may not need to use compressed air because the valve won't drop too far,
but it could be a pain in the but to now need a third had to hold up the
valve. Result: Use the compressed air.

Next hint, it's easier to attached the compressed air line to the adapter if
the line is not "compressed". Thus, once you connect the air hose to the
adapter then connect the air hose to the compressor.

Should have been an earlier hint: Before you add the compressed air to the
cylinder, stick the car in gear or the cylinder will move down (forwards or
possibly reverse) due to the compressed air. And, with the motor being
broke in for 30 minutes, it is a little looser. THIS FREAKED THE HELL OUT
OF ME because I wasn't looking at the motor when I added the compressed air
for the second cylinder to do (#8) and I looked to feel and verify where the
timing line was on the dampener and the thing was back showing tdc for
cylinder #1 and I SWORE that I had already advanced the crank 90 degrees. I
then figured out that the compressed air moved the motor. Another trick I
found is that once you start on cylinder #1 at tdc, use three other pieces
of masking tape on the dampener to roughly estimate where 90, 180, and 270
degrees is from the ground in line to make it easier when you rotate the
crank by hand (ratchet) and you are trying to roughly determine when the
next cylinder is at tdc.

Geez, I think that's about it for the dual valve spring install. When you
compress the springs, the retainer will be compressed down but the locks
usually stay stuck up on the valve and a light tap with a small screwdriver
will drop them down a little for the magnet to pull them up.

Ummm, idle . . . yeah, some might think it has some radical to it. I LOVE
it. My dad LOVES it; he just got the chance to be reunited with the car
that he sold in December of 1973. He ran the damn thing harder than I was
yesterday. Anyways, I let him drive it for most of our ride after we
advanced the timing a little more from the first drive yesterday, and he
complemented me twice on how good a job I did. Anyways, back to the idle.
On a scale of 1 to 10, 1 being stock 427/390 idle, 10 being totally radical
drag car, 7 being radical street cam, this is somewhere between a 5 and a 6.
I've slacked and haven't had a chance to put a vacuum guage on the car yet,
although I do own one. It is lopey, especially at a low idle of 750 or 800,
but I REALLY LIKE it. You get a nice sound back at the older mufflers in
the rear and you get a good sound underneath at the exhaust manifolds. If
you'd like you can call me at some arranged time and I can start the car and
put the phone at the engine, underneath the car and at the rear. I'd rather
chat on the phone and answer all questions right away instead of back and
forth through email, although I wanted to put this together for your
knowledge and for anyone that might ask of it in the future. You're right
the 454 should lighten up the lopey a little bit."

Credit to: Don Shuette, Omaha, Nebraska


Anyone else want to jump in and share their experiences?


Bob :cheers:



[Modified by Bob Turner, 10:10 PM 1/23/2002]

Don Schuette

Geez, Bob, I didn't realize you saved all that and I would be quoted down the road? Just kidding. I'm glad you saved it.

As you know, after all that fun with breaking in the lifters and 300 miles of use, I had a connecting rod go funny, and now have everything back from the machine shop and the motor is about 1/3 back together.

I love this cam.


Don

Marks69BB

Bob - Thanks alot for posting this! It will definitely be part of my mass of cam info I've been collecting. You mention that Chevy High Performance got 480HP out of a 454 with this cam; is that dynoed at the flywheel or at the rear wheels. If it's at the flywheel, I'm running an estimated 450HP already at the flywheel which currently translates to the low 300's at the wheels with my current mild hyd cam that peaks at 3500RPM. If that's the case, I'm wanting more mid and high RPM HP (500+flywheel, 400+rearwheel) to hang with the vipers and BMW M5s among others with 10-11 second ETs. As you can see in my sig, I have the goodies already; with my rectangular port heads (have 2.19/1.88 valves already but no roller rockers yet) and intake, I should be putting out that kind of HP with the right cam. Maybe I should go more radical, I just don't want it too radical so it's still streetable. For comparison sake, new Z06s are in the mid 350s in rearwheel HP from the factory with no mods; Vipers are in the 420s RWHP from the factory.

Don - Have you ever dynoed the car? Really interested in before and after the cam changeout. If so, was it engine dyno or chassis dyno (Flywheel or Rearwheel HP)?


[Modified by Marks69BB, 9:42 AM 1/24/2002]

Bob Turner

Don!!

Glad to hear you are getting that thing back up and running. I guess you probably won't be able to drive it until spring, so what's the hurry?? I am still waiting back on the machine shop for the cc'ing of my heads. I like their machine work but they suck on customer service. You have to call and get on their case to get anything done!!

Bob Turner

Mountainmotor,

I am using the 924 valve springs. I didn't think I needed the 930's if the 924's work fine.

Bob

Bob Turner

Marks69BB,

Your welcome. I believe they meant 480hp at the flywheel. What are your current cam specs?

The 274, as you know is running 230/236 duration at .050 with a 110 LSA and .552/.555" lift.

I would think you would want something like the XE284H with 240/246 or maybe even a roller setup. I will be happy with the 274 since it will be my first BB. I would like to do a 540+ one day when I have more $$.

Keep us updated on your thoughts and cam selection.

Bob :cheers:

mountainmotor

Mark,
I like your car.You will need to change the 308 gear to achieve your goal.

Bob,
The reason I asked about the springs in the private instant message was was to speed up the posting process.
The 924 springs are the premium choice here.The 930 's have a higher spring rate that the XE lobe design prefers for longetivity.But think of this.Comp has to warranty Cams that are used with the 930.They would not have that spring in the catalog if it would not work.With that said the 924's are even a better bet towards long term reliability.I still think in my opinion that break-in without removing the inner spring will work without any problems as long as the motor is primed with 30w Valvoline Racing oil and some kind of Engine Oil Supplement"I use STP 4 Cylinder".Carb bowls should be primed and ready to go as well.I would imagine a better than plain 10/30 or 10/40 oil will be needed all it's life to survive.This might need to be taken into consideration with the bottom end bearing clearances.Extended idle time will need to be avoided as well .
I assume the installed height of the springs are 1.880.Because of the weight of the BB vave train it would not be wise to set them any higher to relieve nose pressure on the cam.The pressure at max lift is not that much at approximately 290 lbs any way.If it were a Small Chevy with the lighter parts 105 seat pressure would work fine.
To aid in longetivity while using a Flat tappet Hydraulic Cam in a Big Chevy there are 3 plugs in the block behind the timing chain.The driver side plug needs to have a # 20 size drill hole in it to let the trapped air out of the journal during start up.Mostly when cold or after oil changes..The Blue pressure spring installed in a stock Melling oil pump is the ticket.

You could always use a set of 1.5 Rockers designed specifically for break-in of cams used in the Big Chevy with high spring pressures.Pricey though at 200 bucks.

Let us know how it turns out and what you decide to do break-in wise


:seeya

edited to correct mucho mispelling :rolleyes:


[Modified by mountainmotor, 6:00 PM 1/24/2002]

Marks69BB

Bob - It is a very mild mystery street cam that, judging by my HP peaking at ~3500RPM and loads of torque, is probably ~205/215 duration at .050 with a 110 LSA and around .400" lift. Probably recommended for RVs and tow trucks! :crazy: I agree that I may need to step up to the XE284 but I'm worried about streetability, my 3.08 rear, and enough vacuum to run my PB and other stuff. I was trying to stay away from roller cams now since $ is tight right now and I could always do it later. Does anyone think a solid cam is feasable? All I've heard is the old story of their high maintenance which is not appealing to me.

Mountainmotor - Thanks, I do too! You are right, it's either the 3.08s gotta go or I throw in a richmond 5 or 6 sp to get the gearing for faster ETs. I'm basing my cam choice on my chassis dyno results to get the mid to high RPM HP to the right level since the gears are removed from the picture. The rear gear or tranny swap will be the next step.





[Modified by Marks69BB, 12:50 PM 1/24/2002]

mountainmotor

Mark,
The Richmonds are neat but I think you might be surprised in the times the BB Chevy can lay down with a 4 spd and 3.36 gear.Man you have the hood for clearance so the sky is the limit for your car.

I really prefer a flat tappet solid lifter motor.More vacumm with not really much maintenance when when a nice lobe is used.

The Forum needs another 10 sec Streeter. Go for it! :) :chevy

Bob Turner

Mountainmotor,

Can you explain a little more about that drill bit #20 hole you were talking about?

I am still weary about breaking it in with the inner springs. I am sure there are other cams out there that don't require you to remove that spring, so I will do some comparisons.


Marks69BB,

I wouldn't use a solid because of the attention needed for them but I think you should look at the 274 and even Edelbrock's 240/246 112 LSA Performer RPM cam (with aluminum heads, they get 540hp). Edelbrock states that this cam is streetable.

:cool: Bob

BigBlockVette

I installed the XE 274H Comp Cam with the 924 springs in my engine when I rebuilt it in summer of 2000. So far, I have put on about 1,200 to 1,300 miles on it. I did not remove the inner springs when I broke in the cam!!! I never heard of this back then. So far no problems, hopefully none in the future. I do like the cam so far.

Dwayne

mountainmotor

Quote:
"Marks69BB,

"I wouldn't use a solid because of the attention needed for them but I think you should look at the 274 and even Edelbrock's 240/246 112 LSA Performer RPM cam (with aluminum heads, they get 540hp). Edelbrock states that this cam is streetable."

If a Vette gets driven 5k a year that's a 45 minute valve adjustment.Not exactly high maintenence nor time consuming in my eyes.He has the ingredients for a fast car.A hydraulic cam will hinder this in a variety of ways not always seen.

540 hp is small block type power these days.

Quote:
"Can you explain a little more about that drill bit #20 hole you were talking about?"

Just explained it .You might get another opinion though

BigBlockVette,
You are good for the go it sounds to me.If it were going to fail it would have 1000 miles ago :cool:


[Modified by mountainmotor, 7:35 PM 1/24/2002]

Don Schuette

Wow, I come back a day later, and all these responses.

Mark, in answer to your question regarding a dyno, no I did not have the chance to dyno with the original motor. However, I just found out I have friends that are real good buddies with the best dyno shop in town, and I'm looking forward to it, even if the sand isn't off the streets by then. The dyno shop is only three miles from my house. I'll get the dyno printouts and keep everyone informed.

It will be a chassis dyno. I guess it's not just a "run of the mill" dynojet, it is supposedly a better quality and better reading dyno that the major car manufacturers use. For a small fee the guy will let you make a nice run or two. And, for some extra cash, he'll fine tune everything for the best. I guess he has all the right gear to read the exhaust also to see if you're running the right fuel misture, etc. We'll see. I guess he is a member of one of the local corvette clubs also and has a 1985 all tricked out for SCCA and NCCC.

Later,

Don


[Modified by Don Schuette, 10:48 PM 1/24/2002]


[Modified by Don Schuette, 10:49 PM 1/24/2002]

Bob Turner

Mountainmotor,


Your right about the small blocks being able to put out that kind of power. I stand corrected! I guess I am coming from the perspective where I have never driven a car with a BB, so I am impressed with a BB that puts out 480-500hp. Mark should be looking for 600+hp out of his motor.

Regarding the solid cam, I have been misinformed on them. I thought they were a real pain, but you and others have started to convince me that they aren't that bad to maintain. :cheers:

It looks like BigBlockVette had good luck at break-in.....interesting!!!!


Don,

Where are you with the motor as of today?? What do you think of BigBlockVette not removing that inner spring? I am surprised in a way that all of a sudden Comp Cams recommends this procedure after all these years of manufacturing.......

Bob :cool:

Guest

Gentleman, excellent reading here, I'll keep checking back.

Mark, can't wait for a ride in the crush mobile once you get all these goodies done. :yesnod:

Don Schuette

Big Block Vette: Regarding not removing the springs, you'll notice that the XE274H is the lightest cam of the Extreme Energy series to require the dual valve spring, so Comp Cams is just being cautious. There was another thread a few weeks ago wherein someone looked at the lift of the cam and the particular springs being used and stated that the pressures on the valve train wasn't that enormous with this cam, and it probably wouldn't be necessary to break in without the inner spring.

Bob, no further than the cam is in, timing chain and cover on. Now to the pan and the rest.

Don