OK, dad's '55 is now up and running. Got the '66 Corvette 327 installed, figured out the lifter problem (I think...), got it running/idling and actually took it out for a drive the other day. Idles OK, runs fine but GUTLESS. No power at all. I need some help on where to start. Here's a list of the problems I've noticed: - Smokes a little out the drivers side exhaust. Burning oil smoke, not gas smoke. - Front carb (dual carbs) is leaking gas pretty bad while sitting. Couple puddles in the manifold, and I'm ***uming it's leaking into the runners as well... - If I step on the brake and give it gas it knocks. Acceleration without braking is fine, just no power. - Vacuum at idle is only about 5-7 inches. I tried swapping out that front carb with a brand new one, didn't make a bit of difference in the performance. Also, I've tried to find a vacuum leak and can't find it anywhere! I've sprayed all around the manifold gasket, carbs, etc. and nothing. So, I guess my questions are: - Can the low vacuum cause the lack of power and the knock? - How do I find the vacuum leak? Thanks in advance for the help guys. This car's almost completely done and it's a very cool traditional hot rod built by an old hot rodder. Any help from you motorheads would be great. big mac
First put a timing light on it and dial in the timing ,Second fix carb .and adjust floats Knock sounds like timing is to far advanced..........Also try plugging your va***n advance to full ported va***n ,Do the above first.........................also what carb , distributor . trans and stahl. and also rear.......
Is the vacuum reading steady or does it have a pronounced bounce? If so, you may have a valve not sealing. A compression check would confirm it.
What cam? What type of lifters? How did you set the lash/preload on the lifters? The carb flooding could be excessive fuel pressure.
1.st step do a compression test, its free and tells you an awful lot about your engine. There is lots of stuff going on, they could all be related or not. steady low vacuum usually late valve timing, (could be valves too tight) Dripping carbs and still running I would guess there is a large vacuum leak
In an intrest to help you and your Dad I took a look back and found this history concerning this engine 7/25/09 please help oil in water. http://www.jalopyjournal.com/forum/showthread.php?t=382897 suspected head gaskets but no update or confermatiom after 7/26/09 Then this one: 8-25-09 Dad's '55 is alive http://www.jalopyjournal.com/forum/showthread.php?t=392003 Thanks to those that helped ID the oil problems. It's all fixed now and running like a champ. Then this one: 9/20/09 Valve adjustment/Carburation help needed http://www.jalopyjournal.com/forum/showthread.php?t=399967 Adjusted valves too tight. So what happened or what was done to this engine after 8-25-09 when it was "running like a champ" No sence in tail chasing, right? You might have to return to the headgasket problem of July and go from there, confirm solid or hyd lifters. cam timing, ect.
In an intrest to help you and your Dad I took a look back and found this history concerning this engine 7/25/09 please help oil in water. http://www.jalopyjournal.com/forum/s...d.php?t=382897 suspected head gaskets but no update or confermatiom after 7/26/09 * The cam journal/cover was missing. We pulled the motor/trans, separated the two, and sure enough there was no plug. That fixed the oil issue. Then this one: 8-25-09 Dad's '55 is alive http://www.jalopyjournal.com/forum/s...d.php?t=392003 Thanks to those that helped ID the oil problems. It's all fixed now and running like a champ. * "Running like a champ" was me being over-excited that it finally fired up and idled. It was idling just fine, didn't heat up, etc... I had not driven the car at this point. Then this one: 9/20/09 Valve adjustment/Carburation help needed http://www.jalopyjournal.com/forum/s...d.php?t=399967 Adjusted valves too tight. * Turned out that the lifters were frozen. Replaced all the lifters, re-adjusted about 50 times. Thanks for looking into this so much. It's been a nightmare thinking we are "done" each step of the way, only to uncover one more problem. To answer some of the other questions: - Stock distributor/vacuum advance - Not sure what cam - Hydraulic lifters - vacuum wipers - vacuum brake booster - Fuel pressure regulator Thanks again folks. I'll try all the suggestions and post some pics when this thing is really "done"....
Did a compression test tonight: all cylinders are between 110 - 125. The plugs are very "sooty". Two of the plugs were black and oily, but all the others were real dry and black (sooty). Timing may be too far advanced? Initial timing is about 13 and total about 24. We're not sure what cam is in it though. BTW, my dad says a big "Thank You" to all you guys helping out with this. You HAMB users have literally saved this car a couple times! Here's the most current pic. You can see why we're so excited to get this thing on the road!
The pictures don't do this car justice, but it is VERY traditional. A crate motor would have killed that theme. I have nothing against crate motors. My '54 belair is running a zz430. The motor we put in this car is a '66 Corvette 327 that was "built" a long time ago, greased, wrapped in plastic and stuck in storage. It was untouched and brand new when he got it. Old school "crate" motor I guess you could say....
Additional info: One of my dads friends mentioned possible corrosion problems with these aluminum manifolds. The drivers side corneer near the firewall shows some pitting. Could this be the cause of the vacuum leak? We're thinking our next steps should be to pull the manifold and run a single carb setup on a new manifold to see if that fixes the vacuum problem. Thoughts? Are we going in the right direction?
I didn't see it mentioned yet. You really need to find out what the cam profile is. The more lift/duration you have will affect the vac*** reading. The 5-7 might just be correct for the cam specs. Also I have seen an internal vac*** leak from the intake. Like landseaandair asked does the needle bounce on the vac*** gauge? A pretty reliable way to tell if you have a leak somewhere.
Needle is holding steady. Do I need to pull the cam then? Is there a way to find out cam specs without pulling it?
Sometimes I have seen the #'s behind the cam gear. If you are lucky you will just have to pull the WP/timing cover. If not, wellllllllll!!!!!!!!!
OK, I guess that's the next step. Thanks everyone. I'll post more info as soon as I find something else out.
steady vacuum gauge = no vacuum leak. black fouled plugs is too rich, i think you might be over carbed......try a single 4bbl. IF 5-7 lbs at idle is regular for that cam it would have a VERY aggressive idle (lumpy and choppy).
A vacuum leak does not always make the needle on a vacuum gauge bounce. If the leak is a steady leak it will have a low reading that is a smooth a silk. Have you tried to spray test for vacuum leaks? If you have plugs that were oily, there is a chance that the intake is leaking around the runners past the gaskets. If you spray carb cleaner around the top side of the intake and see no change in idle, pull off the oil fill cap and spray the carb cleaner down the fill tube. If the gaskets/intake is leaking on the bottom side, then you will get the change in idle when the spray gets ****ed in. I have a offy dual quad intake that looks to be the same as your edelbrock, on a 331 with a fairly healthy hyd flat tappet cam, and it sounds to me that you do not have too much timing, but too little. Not that this will cure your problems, but you might want to get your total up to 32-34 degrees. Your initial sound good, mine is 12, but my total is 34. It idles with 9" of vacuum. Have you done any tuning/jetting/rod changes to the edelbrock carbs? Is the rear carb equipped with idle mixture screws? My set-up has Carter carbs, but they are original dual quad carbs and the front carb does not have idle mixture screws/circuit in it. When you run two fours on these style intakes, they tend to be a little finickey to tune if you have mixture screws/idle circuit on both carbs. If your rear carb has mixture screws as well as the front one, try turning the front carbs mixture screws all the way in and adjusting your idle circuit with the rear carb only. This is how that intake was originally desinged to be run. You can open the primary blades(idle speed screw) on the front carb a little to get idle air in, but not much would be required to get it set. Use the mixture screws and Idle speed adj. screw on the rear carb and see if this helps your idle and loading issue. If your rear carb does not have mixture screws, swap the carbs around. One these intakes the idle carb is the rear one. This might not be the cure for all your issues either, but it may help altogether. If you get a dial indicator and a magnetic base, you could get a close idea of your cams specs by measuring the lift on the tip of the rocker arm above your push rod or measure the travel down(openning) of the valve with the indicator located above the tip of a valve on the rocker arm. If you have a degree wheel you can get the duration dimensions exact, but if not you can get a close idea just by marking and seeing how far the balancer travels from the beginning to the end of the movement on the rocker arm after you check for lift. Just rotate the engine until the indicator needle begins to move, mark your balancer, then continue in the same direction rotating the engine until the indicator needle stops moving, now check to see how far you have rotated the balancer from the point you marked it at. Make sure when you mark the balancer, you mark a spot on the timing tab or something that is stationary near the balancer so you can gauge how many degrees of rotation you have rotated it. This will get you plenty close enough to decide what the cam probably is. Make sure you always rotate the same direction, otherwise the "play/slop" in the timing chain will effect the reading you get. If you spray test for a vacuum leak and still find nothing, I would sort the carbs out next. They can cause the low vacuum and sooty plug condition. If this does not make any difference, then I would measure the cam before pulling it out to check it. Usually the cam part number is on the rear of the cam not on the front, so you would have to take the cam out of the engine to read the part number. Even if the cam has enough overlap to cause the low idle vacuum, the plugs should still not be sooty. I think I'd look into the vacuum leak, especially from the underside of the intake, and then work out the tuning on the carbs.
I just noticed another small thing, you have the vacuum advance hooked up as well. I am not running a vacuum advance on mine. I use only mechanical advance as that is what the factory set up is. When you but the car in gear, step on the brakes, and push the gas, your vacuum is going to drop more than likely to ZERO, and with that your timing will retard...causing even less timing. With this lack of timing and lots of fuel you will get detonation. Detonation/know is not alwys because of too much timing, rich condition can cause the knock as well. I would unhook the vacuum advance, and get the total mechanical advance set at 32-34 degrees. I know you said it ran good at first, or at one point, but as the plugs start to get fouled/sooted up the performance will fall until the point you are at. I would get the timing and carbs set up correctly....I think that will be more of your problem than the cam.
I am looking back at what has been done to try and correct this engine. It appears that the cam is an unknown. You mentioned that all the lifters were "frozen" Any chance at all the cam is designed to run SOLID lifters? And now it has a new set of hydralic lifters? That would affect the cam timing to the valve along with valve lift. I agree with some of the other posters that yo need to know what cam is in there and what lifter belong with said cam.
How many miles are on this motor? Not many would be my guess. If the rings have not seated yet, this could be the cause for the smoke you have seen. The 327 is not a big torque motor either, so after reading your initial post again, I would say you really have to get the timing up to 32-34 and get those carbs set up for your application. It sounds like you bolted them on out of the box, and with your setup you WILL have to do some tuning to them to get them to run and perform. Once you get the primary side of them sorted out, then you can go out and run it some. Once you feel comfortable with running it hard, open it up and see if it starts to pull better as the rpms go up. This thing might not want to really start running until 3-4000 rpm. What transmission are you running? What torque convertor? stock or stall? What gearing is in the rear?
Unless the cam is extremely huge, you can run hyd lifters on solid cams all you want. The only reason you would need to run solids is if it was so big that you would be running strong valve spring pressures and high rpms. I have built many engines for stock car racing where you are required to run hydarulic lifters, so I use solid cams to get bigger/better grinds and run hyd lifters on them to p*** tech. I have had cams specially ground for hyd applications, but if it is under 570-580 lift I'd run hyd lifters and not have a problem at all. Hyd and solid cams are both ground with a tapered face so that the lifters will rotate, so as long as the profile of the grind is not too big(lift wise) the lifters will not be an issue. The lifters will not affect cam timing at all. The lift will actually be more as you normally would set a lash gap on the solids, but it will not be enough to cause any issues unless as already stated the cam was huge. If it was that big, it would not have started and idles fine as stated above, it would have idled rough.
you could possibly be running a hyd lifter on a solid cam. i just went through this with a 327. adjusted the valves starts up great shut it down go to start it the next time low compression readjust(loosen) valves start up over and over. bad vac*** gas puddles run on ect.
Wow, tons of good info. I have a good list of things to test now, so I've got some work to do then I'll get back on here. Evil- you are correct, I have no clue what cam is in it. The motor has 0 miles since rebuilt, but it sat for a long time. I believe it's a stock rear end, trans is a TH400. Not sure what stall. Hope that helps. Thanks everyone.
BIGMAC...doe's the vette. engine have a 30-30 solid lifter cam.WHY? because if it doe's, you can't run a stock gear in the rear end. believe me she will fall flat on her ***. O after you reach 80 m.p.h. the torque will be there...POP.
333 Half evil is right. Too LITTLE timing for a 327. Crank it up to 36-40 degrees total and try it. Also edelbrock carbs can't handle over 5psi fuel pressure. I have a stock sbc pump and 2 carbs and ran into a leaking issue also. Found out I had 10 psi fuel pressure. Regualted it down to 5psi-no leaks, runs way better. As far as power, crank up the timing. The smoke is probably due to the fact that the excessive fuel (due to retarded timing) is washing past the rings.
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