SMI-FST

I have a 65 327 and I am planing to put the "151" hyd. cam in it over the winter. I have done a lot of projects over the years but never cam, lifters, valve spring instal. Can I do it with the engine in the car? Anything that I should watch out for? Anything I should do "while I'm in there? Any one know of a good step by step manual?

Thanks to all and I hope you all have a great and safe Holiday season.

Bernie

wallyknoch

If the engine is a low HP type, convert the heads to a solid lifter style with new springs and retainers. The exhaust valves have rotators and they need to be removed to avoid coil bind. A very good choice of camshaft. It`s the 327/350HP cam. PS replace the timing gears and chain also. :) :thumbs: You will like it. :flag

JohnZ

Good tech references if you haven't done this before are the Chassis Service Manual, Chassis Overhaul Manual, and David Vizard's "How To Rebuild Your Small-Block Chevy" (HP Books).

The "151" cam is a great choice, as it requires no special head machining and uses stock springs and retainers; I doubt if your engine has exhaust valve rotators - they were used primarily on trucks. Buy new stock valve springs and pay attention to correct installed height when you assemble them. :thumbs:

SWCDuke

All SBs use the same springs and other valvegear from the pushrod on regardless of OEM cam or lifter type. There was a change in valve spring p/n circa '67 with slightly different specs, and these are service replacement for earlier springs.

The exhaust valve rotators were not incorporated until circa mid seventies, and there is no need to retrofit them to pre-emission control engines.

Duke


[Modified by SWCDuke, 9:59 AM 12/17/2002]

Plowboy

I replaced my '66 big block cam a couple months ago. We did the work without pulling the engine. The only problem was that the crossing support rods (in front of the radiator) for the radiator mounting box did not allow us to pull the cam out. Naturally, the point where the supports cross is directly across from the cam! You get the cam about 2/3's out and there's no more room
You do not want to remove the mounting box, IMO, and risk screwing with the integrity of the body, ie front fenders.
We solved the problem by removing the front motor mount bolts and raising the engine with a floor jack just enough to clear the support rods.
You may or may not have the same problem with a small block. But, if you do there's the solution to the problem short of pulling the engine or messing with the radiator mounting box.
:cheers:

JohnZ

Based on personal experience, I'd recommend buying a Cloyes timing set and installing the "151" cam 4 degrees advanced (the Cloyes crank sprocket allows you to do this); results in a significant improvement in low-end torque over installing it "straight-up". :thumbs:

mrg

Would this be advisable on the 30/30 or LT-1 cam too, John .. ? ..

mrg

JohnZ

Dunno - have never done it on either of those cams - Duke may have some thoughts on it based on his simulation research. :thumbs:

66427-450

Advancing buys you a little bottom end, at the expense of top end..... right ?

So, if your cam is a little "top end strong" for you/your setup, then you trade some of it for aditional bottom end by advancing.

Consider your application. It all depends on how you drive, and what you want....... obviously you are looking for more power, or you wouldn't be changing cams. Are you more interested in performance above 4000 revs?, or below?

Experts, correct me if I'm wrong.




[Modified by 66427-450, 1:00 PM 12/21/2002]

mrg

Ok ... Thanks for replying, John .. I was thinking it might be beneficial to move the start of the torque curve down a bit lower, since I really don't plan on winding up much past 5500, or so .. Seems the "151" is more than adequate to the task, sure .. I was of the mind that since there seems to be more than enough cam timing with the solid lifter cams going out to 5500 revs, adding some cam timing advance couldn't hurt ..

mrg :rolleyes:

mrg

Ok ... Thanks for replying, John .. I was thinking it might be beneficial to move the start of the torque curve down a bit lower, since I really don't plan on winding up much past 5500, or so .. Seems the "151" is more than adequate to the task, sure .. I was of the mind that since there seems to be more than enough cam timing with the solid lifter cams going out to 5500 revs, adding some cam timing advance couldn't hurt ..

mrg

JohnZ

Half of the chore of choosing a cam is deciding how you want to drive your car; most people "over-cam" their engine when picking a cam out of a catalog, or pick one because it made big numbers in a "magazine motor" which only saw a six-second dyno run for the article. After all, how much of your driving time is spent at wide-open throttle at 6500 rpm around town? :eek: 99% of your drive-time is spent at relatively moderate speed and rpm, and that's where you want the "fun" to be - "fun" on the street is TORQUE, not horsepower - that's what plants you back in the seat when you put your foot it in it. The "151" is the best hydraulic cam Chevy ever made, and it will gain a fair amount of low- and mid-range torque if it's installed 4 degrees advanced; any loss at high rpm is negligible, and you don't spend much time at 6000 anyway compared to the amount of time you spend at 1500-5500. Let the "Harry High-School" guys fight with their square-lobe solid rollers that won't idle under 1200 rpm, and enjoy a cam that really suits your "normal" :rolleyes: driving experience. :thumbs:

wallyknoch

Merry Christmas all, :cheers: :cheers: John`s message sound exactly as if I dictated it to him. The 151 will give you all you need. Don`t listen to the pump jockys, normally their mouth is faster than the car. :thumbs: :D I just installed the 151 in my low HP 84 and for a hydraulic camed car a reall nice improvement. Best choice out there. :cheers:


[Modified by wallyknoch, 12:20 PM 12/22/2002]

66427-450

:lol:
".... Harry High-School" ?
".... the pump jockys, normally their mouth is faster than the car...." ?

Guys, There's no reason to get Personal/Nasty :lol: It's all about respecting the opinions of others. Besides, someone may ask you back up them words :)

PS: "..... 99% of your drive-time is spent at relatively moderate speed and rpm, and that's where you want the "fun" to be......"
OK, I understand where you're at :sleep: We operate on different wave lengths, and that's cool.

Peace - :seeya




[Modified by 66427-450, 1:35 PM 12/22/2002]

SWCDuke

The 30-30 cam is hopeless. It was probably designed to give SCCA racers a little more top end, but it just killed low end torque- WAAAAY to much overlap for a street engine with cast iron exhaust manifolds. It disappeared quickly from service and the LT-1 cam became the replacement. I recommend the LT-1 cam for ALL solid lifter engine rebuilds. The LT-1 cam was developed for use with cast iron exhaust manifolds and it has a fairly early phased exhaust event and longer than inlet exhaust duration to compensate for the relatively restrictive SB exhaust port. It has the fattest torque bandwidth of any cam I've ever analysed via simulations. I think it's superior to most current aftermarket cams, especially with OEM exhaust manifolds, because it was developed with manifolds, not headers. Aftermarket cams have too much overlap IMO. Aggressive overlap is okay with headers and a very low restiction exhaust system, but excess overlap really kills the low end torque with cast iron manifolds.

The LT-1 cam makes about the same bottom end torque as the 151 with a stronger mid range and top end. the 30-30 will make marginally more top end power with a little less rolloff, but is down 20 percent on torque at 2000 revs relative to the 151 and LT-1.

If you just cruise around and really want low end torque and don't plan to rev above about 5000 the 300 HP cam is the way to go. It will make a small block a real stump puller.

Advancing or retarding the cam from its design timing is a crutch. The primary valve event that determines the shape of the torque curve is the inlet valve closing point, and this is why advancing the cam makes more low end torque, but you also open the exhaust valve sooner and alter the overlap event.

The best way to select a cam is to design for torque bandwidth and 80 percent peak torque should occur not later than 2000 for a street high performance engine. If you want real grunt you design the cam to make 80 percent peak torque at about 1500. Once you have selected a cam to give the bottom end torque characteristics you want, you spend at much money as your budget allows for top end power by working the heads inlet and exhaust system.

Duke



[Modified by SWCDuke, 12:00 PM 12/22/2002]

66427-450

I remember when my cousin bought his Z-28 back in 1968 (the 302 came with the 30-30), pretty dead below 4000 rev's (less CID even made that cam seem even more radical)....... but before long, he had installed headers, slicks, 4:88's, some rejetting and distributor work........ that 30-30 really came into it's own then. A VERY nice combo, I gotta tell ya, the 327 vette's were in trouble, that Z flew. Many big cube "muscle cars" fell to that little 302

It's all about getting the right combination...... that gives you the performance YOU want. I understand what you're saying Duke, and I agree...... but that 30-30 cam has it's place. (come to think of it, I think headers came in the trunk of that Z-28 ? could that be true?)

PS: I think he even tighten up on the lash a touch, to squeeze a bit more out of that stock cam (of course more serious cams came later on.....)


[Modified by 66427-450, 3:30 PM 12/22/2002]

SWCDuke

The 30-30 will respond very well to headers because of all the overlap, but I don't think many vintage Corvette owners want a race cam with a power band from 4500 to 7000+ or 4.88 gears. The 30-30 was a good race cam for classes where headers were allowed, but it is a lousy street cam.

Don't know about the headers in the trunk of Z-28s. Headers and the 2x4 carb system were released and available through GMPD. Maybe JohnZ can tell us if you could actually order them as an RPO for "trunk installation".

Duke

67HEAVEN

66427-450

Looks like we went to the same high school. :D

My plans call for radical everything, even though my racing days are long over and this car will only see a couple thousand miles a year, if that.

I'm not interested in "street-racing" either, so responsiveness at stop lights is also of little interest. I don't care about reasonable idle, reasonable gas mileage or "drive-ability". I don't care about hearing the tunes......I'll only hear them when the ignition is off anyway.

What I do want, in my "juvenile" old age is to replicate, as closely as possible, the experience.....the "feel".....the "sounds" that I remember blasting around Mosport, Shannonville, etc. all those years ago.

In fact, if it isn't a bitch to keep running at the lights, if my back teeth aren't rattling, if blood isn't oozing outta my ears.......well I'll figure the whole project was a complete waste of time. :lol: :lol: :lol:
:thumbs:

ghostrider20

{Quote}
The 30-30 will respond very well to headers because of all the overlap, but I don't think many vintage Corvette owners want a race cam with a power band from 4500 to 7000+ or 4.88 gears

I do I do I do I do.

In all reality the 30-30 is not a good choice for the all around street car. I have one in my 365hp motor. The low end torque is leaves alot to be desired. If you want to launch hard you have to either ride the clutch (not) or let the clutch out at 5000 RPM. This causes tire spin and that hurts the launch as well. I have 4:11's in my car so around 30mph the car is reving pretty stong and if your side by side with someone you can mash the pedal and go like hell. It's just getting into the power band that is the problem. Shift out at 6500 RPM and it drops back to 42-4300 PRM and you are right at the bottom of the band. So the big issue is getting the car rolling.

Mark

mrg

Pump jockey .. ? .. :lol: Geez, I can't remember the last time I actually saw one of those guys .. ? .. Sure remember being one, though, back in the "good old days" ..

I always wondered why a buddies car, a '64 Nova with the 365 horse 327 was such a dog, down low .. At the time (1967) Goodies Speed Shop was offering brand new 365 horse long blocks for 500 bucks, so it just seemed a "natural" to drop one a' them baby's in that Nova .. All we knew at the time was that the 30/30 cam was a pretty hot setup .. Little did we know ..

Does the LT-1 cam have some idle lope to it .. ? .. Thanks for posting the info, Duke ..
mrg