| Caddy 500 camshaft recomendations [message #267726] |
Wed, 17 December 2014 20:26  |
mild bill
Messages: 98
Registered: November 2014
Location: Edmonton, Alberta, Canada
Karma:
|
Member |
|
|
Starting to think about my 1973 caddy 500. Stock soap bar Pistons, small chamber heads.
Trying to decide on camshaft. Want to run regular gas so not so sure I want a torque cam, don't want excessive cylinder pressure going up mountains when things get hot. Wouldn't mind more lift and duration, don't think torque would drop significantly at cruise rpm with potential gains in second gear.
Don't want so much lift or ramp rate that I would have to worry about wiping out a cam or stressing stock rockers.
How bad is a stock re grind, can't seem to find numbers for them? It seems like a safe bet with great torque at cruise with a slight decrease of torque say in second gear, 3500-3800 rpm.
How many rpm would a gmc do at say 50 mph in second gear?
My fear of a torque cam comes from my neighbours GMC, I fear perhaps PO put in a torque cam and he has been running regular gas. He has additional problems, it's equipped with a very early fuel injection system that he seems unable to get information for. He said he contacted the manufacture and he said they do not provide any information for that system anymore. The module is mounted on a piece of plywood under the passenger seat and he has nice headers on it but burns almost as much oil as gas (doesn't smoke) however going up steep hills he says say press on the gas at 2200 rpm the engine detonates like crazy, puts the pedal to the floor and detonation stops even without dropping to passing gear.
I went and checked it out for him in the driveway last week and set his initial at about 10 degrees, didn't take note where it was set initially however way advanced. Revved up the engine and while he has a fuel injection distributor that has no mechanical or vacuum advance his computer is not giving any advance and will however drop advance with manifold vacuum drop so Map sensor is working at least so guessing he had his initial set at somewhere around 25-35 degrees. Anyway he's looking for an engine to build, wants me to build and change but I don't se me having time in the near future. Oil analysis doesn't look good and I suggested picking up a leak down tester and checking, mine is home made and one gauge is toast.
Anyway I want to replace the original 25 year old camshaft, wouldn't mind more power but not at the expense of Valvetrain reliability and detonation. Can't find any real numbers as to what the re grind is, if it's th '73 cam I could be happy with that as that's what the MTS 5 is based on.
Also, Falcon engine parts on ebay, any good?
[Updated on: Wed, 17 December 2014 20:30] Report message to a moderator |
|
|
|
GMCforum
Search
Help
Register
Login
Home
