Ok well to start off i have a rebuilt motor with no more then 5k on it. Its a 69 350, ta c110 cam, poston s-divider, 800cfm q-jet, ta headders, crane cams electric ignition, k&n filter, and magnaflow mufflers. The car has no off the line power. It hardly squeaks the tires when i punch it. It runs an 11.46 0-60, 18.50 1/4, and has 90 net hp and 137 net torque. All that info came from my g-tech. The car is pitiful. My total timing is 35*. Ive checked my carb and secondaries are opening, my timing should be right, im running an electric fuel pump, i cant find a vaccume leak. The car runs smooth and starts easy. Im stumped. All suggestions and ideas are welcome.
Are you sure of your total timing? At what RPM is all your timing in? Are you running the vacuum advance? Was the cam degreed in? Have you put a vacuum gauge on the engine? What does it read at idle in Park? Is it steady?
how is ur fuel pressure. are u using new valve springs. what kind of rpm are u getting out of ur motor. good luck and let us know what u find.ralph sr.
Im 90% sure of my total timing, im going to retime it today. All of my timing should be in by 2500rpm's, i put in a crane cams spring kit in not to long ago. Yeah, im running vacume adavnce. Im not sure if the cam is degreed in, what exactly does that mean? I havnt hooked up a vaccume guage yet, ill do my best to get to that today. It shouldnt be the converter or the rear, before i changed cams and intake i was running like 15.7 in the quarter and the car was faster, so that shouldnt be an issue. Fuel pressure should be good. Im using ther stock mech one plus an electric one at the same time. I didnt just replace the valve springs when i did the cam swap, but i had rebuilt my motor not even 5k miles before and thats when i installed them. As for rpm im not getting as much as i used to...when i should be getting more. It seems to fall down after 4500 when before it would go strong to 5k. It seems the i get higher rpm shifts when im in higher gears. Thanks for the help everyone!
did it run like this since rebuild or recently? what timing chain did you use and did you degree cam? did you recurve distributer to go with new cam?
Yes the cam was degreed in. It was put in at 0*, i can change it to 4* i believe. Whats the difference between the degrees? Im not to clear on how it works. What exclactly is recurving the distributer and how do i do it? I used a ta double roller chain. The car has always seemed to run slower than it should be running. Thats why i went with a biger cam and the intake. Now it is slower than ever. Larry- It idles at about 600 in park and it does jump arround a bit, but not to bad. Even if i did have a small vaccume leak, would it be causing this bad of performance?
What pistons are in there ??? If they are stock 8-1 or so you would have a loss at low rpms....how does it run at higher rpms ? remember that as you increase your cam timing ( valve open longer ) that you will lose cylinder pressure at low rpms. hence we run higher cylinder pressures to make up for some of that loss, of course higher pressures make more power so they go hand in hand. Mark
curious why u are using both mechanical and electric fuel pumps on a stock engine. did u have a fuel delivery problem. maybe u can hook a fuel pressure gauge to ur engine and see what u have. keep at it and let us know. good luck. ralph sr.
When you degree a cam in, you verify what is on the cam card. Most cams go in 4* advanced. This closes the intake valve earlier on the compression stroke and builds more cylinder pressure. Your cam has a 110 LSA and should have been degreed to a 106 ICL which would make it 4* advanced. Given the above conditions, you would want about 9.5:1 static compression to make this cam run well. What is your compression ratio. If you or your machinist haven't measured it, then you do not know. You can't use Buick's published compression ratio for that year engine. People think you can, but you can't. Whenever you choose a cam, you must keep the static compression ratio in mind. Just going to a bigger cam without enough static compression will decrease cylinder pressure and decrease performance. Read this. http://www.empirenet.com/pkelley2/DynamicCR.html
Ok, im gonna do my best to answer everyones questions. Mhgs- Im not sure which brand pistons my dad put in there when he rebuilt the motor, but i know he dropped the compression down to 9:1 or 9.5:1 from whatever stock was for a 69 gs350 motor. It does seem to run stronger at higher rpm's, but its still nothing special. Ralph- I dont run both at the same time all the time. I normally just run the stock pump and i have an electric on a togle switch to run when needed. Larry- After reading the cam card it says to put it in at 4*, i put it in at 0*...is this my issue? Like i said in my post to Mhgs, the car has 9:1 or 9.5:1comp, my dad cant remember what he had done and he cant find the origonal paperwork. Thanks for all of the help guys, it is very much appreciated!
Look for the installed ICL (Intake centerline). It should say 106* somewhere on the card. That and your static compression could be your issues. Like I said, it's not good enough to guess, you need to know what your static compression ratio is. Advancing the cam closes the intake valve earlier building more cylinder pressure. If you read that link I posted, you know about Dynamic Compression Ratio(DCR). It should be between 7.5-8.0 for a strong running street car that will run on pump gas. Even at 9.5:1 compression, that cam straight up will only get you to 7.3 DCR. If you advanced the cam to 106* ICL, 9.5 compression would give you a 7.58 DCR. That would be good. The problem is you don't know your compression and it is likely that you have the cam in there retarded. Find the paperwork, it's important.
Larry is correct...with that cam by the specs it has a fairly aggressive ramp which with advancing it the 4 degrees would for sure help you out with a lower compression . Did you have the block decked when it was machined ?....which head gaskets are you using ?, You could try going to a steel shim gasket to give you a little help with cylinder pressure. Mark
You might be unpleasantly surprised about this. Aggressive cam timing coupled with a low stall and/or low numerical gear can be a disaster. To begin with, torque below 2000 rpm is probably a lot less than before, and the gear & stall factors may be forcing the engine to spend more time in that low range than it would like. Many moons ago I learned this lesson all too well on a '70 Olds 350 project, same symptoms as your Buick. Before was decent, after was not. I think advancing the cam will help, along with following the timing suggestions. Again, I'm interested in knowing about what converter & gear you have in there. Devon
Ok i found all of the paperwork. The motor has 9.1 pistons, and the block is 30 over. On my cam card it says Degree intake lobe to 106* for 4* advance. Wildcat- I dont have the stock converter in there, but it has a similar rating to stock. As for my rear end ive never been sure as to what i have alll i know is its an open diff. The gears are whatever came in a stock 69 gs 350.
you degree that cam and put the shim head gaskets in and it will be a whole new ride.......would really recommend a stall converter too..maybe 2500 or so and you will be nothing but smiles Mark
Just because it says 9:1 pistons does not mean your compression ratio is 9:1. It could be less. Even if your compression is 9:1 with a 106* ICL, your DCR is 7.1. Still too many unknowns. That cam has an advertised power range of 1000-5200. A stock converter should be just fine. Putting a high stall converter in would be a band aid, and would hurt the driveability on the street. You won't like it. You still sound a little unsure of your timing also. Are you absolutely sure that your mechanical advance is working correctly and that all your advance is in by 2500? BTW, You haven't filled out your profile. No one knows where you live. Could be someone close by who could help you, but they'll never know it.
Im going to time the car again now. When before swapped cams my timing was in before 2500, whout that be changed now? I may never know my exact compression. My dad did all the work when i was younger. He tells me the compression is 9:1 and because its .30 over that makes it close to 9.5:1, but i dont know. Ill keep everyone updat and i appreciate all the help. I live in clovis california by the way, ill update my profile now.
hey there......well I would start with checking all the easy things first. I would still check your cam timing and up the cylinder pressure what little you can with a new thinner head gasket and then get your ignition timing proper and fuel mixture correct.. Then you can play with the transmission and gears which will really wake it up. But you have to have the motor running proper first.......by boring your cylinders you won't raise your compression ratio in the least...in fact it would lower it a bit but not enough to worry about. Mark
