After double checking everything on my motor to determine where my oil was dissapearing to I have learned that my valve seals / guides are the culprits. That said it's decision time! I've been told that since my compression is at or better than factory specs I could get by with just doing the top end. This currently consist of a factory 72 4bbl Rochester and stock manifold. I have been told that I can go to "Summit" or "Jegs" and buy a top end set up consisiting of a high performance manifold, carb, cam etc., then all I would need to do is get the heads redone. I checked Summitt and Jegs and all they have are Comp Cam set-ups, no carbs or manifolds! Car has 90K on current motor. Any ideas? I want the best bang for the buck and don't want to cheat myself out of something if I undertake this project. I also have acess to a 71 455 motor that I can rebulid as well but think done right, I can get some good performance out of my 350. Ideas and suggestions wellcome.
http://www.taperformance.com/ TA has the Buick parts, alum intake, etc... If you go with the 350, you can install larger valves in the heads to increase performance.:3gears:
Thanks guys, TA was the only place I found as well. They sure make things hard for those of us with Buicks don't they!
Hey Steve, I'm confused about what you are really after. Do you feel you need a rebuild, or just need to have the heads rebuilt to stop that leak? Are you looking for more performance, or just to make it right?
There is more performance lurking in your motor without lots of new parts. The stock intake is good for a street car the Q-Jet gives the best mix of performance and gas mileage if properly set up. The key is tuning everything to bring out the beast. There is a wonderful thread on power timing on this board. It's a great starting point. Most camshafts make more horsepower but it can come at the cost of torque. Torque is what gets you off the line and is what you use most of the time on the street. The heads are the key to opening up the engines potential. A lot can be gained by pocket porting and gasket matching the heads and intake. A good dual exhaust system will help it exhale. The exhaust manifolds can be ported to increase flow or headers can be slipped. The key is to define how you'll use the car and build the engine to suit. There is a thread about a 350 Build that has gobs of torque over a huge RPM range that idles smooth and runs on pump gas. Find that thread and build as close as you can to it for a great street/strip all around engine. John
Basically I thought since I have to pull the heads to address the oil issue now would be the time to make any improvements for adding to that seat of the pants feel. I already have Hooker Headers and a 3" SS Magniflow dual exhaust system with an X pipe, 3:08 posi gears and a tranny shift kit in the Turbo 350. That said, the car actually runs well but the heads need to be done which is why I was looking at the big picture. Any ideas on what can be used to reduce the oil loss for the time being and head opinions would be appreciated.
How did you diagnose the valve seals as being bad? Also how do you use the car, is it a daily driver, weekend cruiser, or?? If the oil pressure is as good as the compression and the seals/gaskets are not leaking you can probably just do the heads & thro in a mild cam and have fun. However, if the car is used alot then itstill might be a good time to do a complete rebuild.
Had brought the car to my old school mechanic after doing the basic test to find the oil leak and try to find if oil was getting into my antifreeze as it turned brown. The brown color was actually found to be scaling from my block, even did a Ph test on the antifreeze and it was OK. As far as my oil loss various test were done including compression at which time it was determined my guides or seats were likely at fault. Made some sense as I recently noted that the car would puff (white / gray) upon initial start up after sitting awhile. Think if I do the heads I will just have them ported a bit and do the power curve keeping the stock cam and carb set up as she runs fine. Any other ideas / sources?? Car is used as a weekly ride, not everyday.
Sounds like a good start. You already have the exhaust (possibly too big at 3" o No: ), and the shift kit. You can do the heads without having to take too much apart (you'd have to pull the radiator to get into the cam), so go for it on the heads! You might consider going with Stage 1 valves since you are doing the heads. I just went to see my cylinder heads at the shop where they are being ported - they look nice!
Did the exhaust in case I ever went to a big block. Actually sounds real nice with the Hooker headers. Heads have to be done but not necessarily the cam.
Are you still using the stock cam? If so then just leave the heads on and have the valve seals installed WITH the heads on. No point in head porting with the stock cam. If you want to add (or already have) a good cam then go for it with the head porting!
So what where your compression results for all 8 cylinders? I would hate to see you do a "Top end rebuild" if all you need is valve stem seals! You can replace the valve stem seals WITH the heads on the car easily: Remove the valve covers, use compressed air in the cylinders to keep the valves from falling down, use a valve spring compressor tool, then replace the valve stem seals.... Easy job with the heads on the car. I have no doubt that you have leaking valve stem seals HOWEVER you may have two seperate issues here: First off how much oil are you consuming? An old engine will burn some oil... Top up the oil to the full mark on the dipstick, drive it for 100 miles then see how much oil it takes to get it back up to the full mark. If you are burning oil it is most likely one of two things: Broken or worn out oil control rings on the pistons, or valve stem seals leaking in the heads. If you have low compression then it is most likely one of two things: Broken or worn out compression rings on the pistons, or valves/valve seats leaking in the heads. A "leak-down test" can help you isolate the problem. My best advice is to first tell us what your compression numbers are for all 8 cylinders. Second tell us how much oil you are consuming per hundred miles, and we can go from there.
Don't have the exact numbers handy but know none was off more than 3 lbs which is what I was told is the in range for a new / rebuilt motor.
Ok, then let us know the oil consumption and we can help you from there. If the engine is in good shape then you could just do a cam and lifter swap along with a timing set at the same time you do the valve stem seals. Or if you want to get a bit more serious then have the heads ported and new valve-job done, as well. keep in mind to get the most out of your mods the Q jet will need to be re-calibrated.
A quart every couple hundred or so, give or take. Most smoke puff is after car sits for awhile which is a least for a week at a time.
Well that is fairly substantial amount of oil loss, i would start with valve stem seals. If you do really want to boost performance though then follow our other suggestions.
A compression test will only tell the condition of the compression rings, not the oil rings. LIKE sean says do the oil seals first with the heads on, it's quick & cheap. If that solves the problem, great, if not then you aren't out anything as you would be doing that as part of a more extensive overhaul anyway. By the way what do your sparkplugs look like, are they all oil fowled or just some of them?
Spark plugs are burning fine. Nice pinkish color, no fouling. As I was going to do some work down the line I was considering doing the heads (have them ported) and maybe a mild cam as suggested. This way I'll get some extra horsepower without sacrificing too much torque. However, just doing the seals and power timing might be an inexpensive option to consider but I have been unable to locate the thread. Still rolling a big block option around in my head but don't know if I want to dump the $$ money needed for a total swap right now. That said I know there is allot of untapped potential in my current 350 from what I've read and been told which may give me what I am looking for.
