I need a 500 cfm
Thread Starter
|
Junior User
Joined: Mar 2012
Posts: 67
Likes: 0
I need a 500 cfm
I have a 1982 f100 with a 302. I recently rebuilt the motor and got a 4 speed for it. I put a rv cam and aluminum intake with 650 cfm carb on it. Those are the biggest upgrades really. I'm pretty sure the carb is too big for it though. The truck now has no acceleration or power except in 1st gear. I really Boggs down in 4th gear. I'm pretty sure it's because of the big carb. Does anyone have any tips?
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
While 650 CFM is probably a bit more than the engine needs, it isn't causing the problem. That's because the carb only gives that CFM with the secondaries open, and they aren't open until you both give it full throttle and wind the engine way up. In fact, you can't cause the secondaries to open unless the engine wants them - assuming you have a vacuum/velocity-operated carb.
Tell us more about your engine, like the cam and the intake manifold, awa the carb.
Tell us more about your engine, like the cam and the intake manifold, awa the carb.
Thread Starter
|
Junior User
Joined: Mar 2012
Posts: 67
Likes: 0
448/472 valve lift on the rv cam. The intake a dual plane pro comp aluminum intake. I recently put new rod, main, cam bearings. New sealed power pistons with Hastings rings and all new valves. And a bunch of other stuff. It's pretty much a new motor on the inside
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
448/472 valve lift on the rv cam. The intake a dual plane pro comp aluminum intake. I recently put new rod, main, cam bearings. New sealed power pistons with Hastings rings and all new valves. And a bunch of other stuff. It's pretty much a new motor on the inside
- Whose RV cam? I'll look at the spec's and recommended applications.
- Is this the intake? Pro Comp Intake If so, it says "180° dual plane medium rise design for outstanding power from 1500 to 6500 RPM." That means it isn't going to pull very well until you wind it up - which, by the way, is not what trucks need and may be part of the problem.
- Did you have the block bored or did you just put in new rings?
- And, did you have the valve seats ground or just put in new valves?
I just want to make sure we aren't missing anything.
And, while I am asking questions, have you changed out the ignition system? That truck probably came with the DS-III ignition and EEC computer. If you didn't change that then that is part of the problem.
Again, we need all the details or we will be chasing our tails. Please describe all that has been done. And, by the way, telling me the lift on the cam is a good example of part of the information. First, I have to assume that those #'s are at .050" lift since you didn't say. Second, there are many different "RV" cams, and some are mild and some aren't. So, please tell us the details. I want to help but you have to help me by telling me what you have. I will not guess as that will just cause more problems than it will solve.
Posting Guru
Joined: Feb 2010
Posts: 2,006
Likes: 2
From: CASA GRANDE AZ
Trending Topics
Thread Starter
|
Junior User
Joined: Mar 2012
Posts: 67
Likes: 0
I'm not sure about the cam brand I bought it off of eBay lol. And yes that's the intake I have. The blocks not bored. And it has a eBay brand hei distributed
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
I was afraid of that. There's no reason to do any more diagnosis until you do at the very least a compression check, and preferably a leak-down test. I seriously doubt that you have reasonable compression on any cylinder, much less all of them. Without compression, good compression, the engine will never, ever run correctly.
Moderator
Joined: Nov 2007
Posts: 22,415
Likes: 92
From: Denver Metro Area, CO
I was afraid of that. There's no reason to do any more diagnosis until you do at the very least a compression check, and preferably a leak-down test. I seriously doubt that you have reasonable compression on any cylinder, much less all of them. Without compression, good compression, the engine will never, ever run correctly.
Yeah, truly rebuilding an engine requires a machine shop and very accurate measurements of all the parts and is best left to the experts who know what they're doing.
Merely replacing parts isn't likely to get you good results.