Cam question...
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,699
Likes: 1
From: Westampton NJ
Cam question...
Hey all, I'm still trying to figure out the engine internals without a lot of disassembly. So, with these measurements, hopefully someone can give me an appproximate value for my cam.
.098 HP / LB from Lars' Vericom computer (with me and Lars in the car, and a half tank of gas)
3.55 posi
M-20
Engine (externally) is a 350, numbers matching block.
The engine is a dog at below 2 grand...just a feel of overall lack of low end torque. It will take a good bit of feathering to keep the car from bogging off the line, and the carburetor and distributor are set up right. If I sidestep it at about 2200, it squeals the tires and roars off the line, anything less and it doesn't quite go as easily.
The engine has a real rough idle...at 750 RPM (stock idle speed), it has a noticible rocking motion that transfers to the whole car...which is kinda cool. It pulls very little vaccuum...it only pulls about 8" at idle, and as soon as you get in the power band, it pulls 12".
Random: It has hardened chromemoly TRW pushrods (stock length) and stock stamped steel rockers (I'm thinking of going to roller rockers), dual damped valve springs, and non-stock valve guides (that appear to be some type of steel, gray in color not bronze).
Any ideas? If you need anymore information, I'll let you know what you need.
.098 HP / LB from Lars' Vericom computer (with me and Lars in the car, and a half tank of gas)
3.55 posi
M-20
Engine (externally) is a 350, numbers matching block.
The engine is a dog at below 2 grand...just a feel of overall lack of low end torque. It will take a good bit of feathering to keep the car from bogging off the line, and the carburetor and distributor are set up right. If I sidestep it at about 2200, it squeals the tires and roars off the line, anything less and it doesn't quite go as easily.
The engine has a real rough idle...at 750 RPM (stock idle speed), it has a noticible rocking motion that transfers to the whole car...which is kinda cool. It pulls very little vaccuum...it only pulls about 8" at idle, and as soon as you get in the power band, it pulls 12".
Random: It has hardened chromemoly TRW pushrods (stock length) and stock stamped steel rockers (I'm thinking of going to roller rockers), dual damped valve springs, and non-stock valve guides (that appear to be some type of steel, gray in color not bronze).
Any ideas? If you need anymore information, I'll let you know what you need.
Moderator
Joined: Jun 1999
Posts: 7,117
Likes: 51
From: Dove Mountain Arizona
Re: Cam question... (rainman69)
You're not ever going to know really, without pulling the cam. Just a ball-park here but if it's 'dead' below 2500 it sounds as if your intake duration is more than 234 deg. Probably more like 238 deg. This amount will make it rock 'n roll at idle, but be a rocket above 2500 as you have said. Keep the intake in the 230 deg range and it will have more low end and still rev past 6K easily. Remember, the only way to know is to take the cam out. :cry
Melting Slicks
Joined: Oct 2000
Posts: 2,268
Likes: 0
From: Roanoke Virginia
Re: Cam question... (MasterDave)
You bastich! You stole my cam! :lol: :yesnod: I have a similar "mystery cam" in my car, haven't taken it out but I did "degree" it when I had the heads off. My methods were about as accurate as I could get, and this told me that it's a mechanical dual pattern cam, with long duration at 0.050" (about 250* intake, 270* exhaust) and 1.5 ratio lift of about 0.45 intake, 0.50 exhaust. This tells me that it's probably (given the age of all engine components) somewhere along the lines of the early 1970's LT-1 or second generation GM performance mechanical cams. With our mutual friend Lars' help, I set the initial timing fairly high (per LT-1 specs) and picked up a lot more low end torque and responsiveness. Found that this cam likes 18-20* initial timing at 700 rpm. I backed my total down to 32* (400 SBC) and it's now a blast to drive! :yesnod:
