[brewski]

"No question too basic here" huh? Well let's give that a test!

I've got several issues I'd appeciate getting some help with. I have a 67 Lemans with a 326ci and originally an ST300. I just replaced the ST300 with a TH2004R. While trying to set the 2004r up, I've encountered several problems. I have spoken with the transmission vendor customer support people. One person works very hard to help, but needs the expertise for certain questions from another person, who doesn't want to help. So, I'm coming to the online repository of Pontiac knowledge!

1) The car now has a high-speed vibration it didn't have before. Above 50, it is very disconcerting. I re-used the u-joints and driveshaft, but never had a problem prior to the swap. Prior to the transmission upgrade, I upgraded the 8.2 rear-end to an Eaton Posi at 3.55. I ran the ST300 with that for a short time, but didn't notice a problem. (Other than the engine had to run like hell to get to a decent driving speed! Originally was a 2.56.)

2) The engine has not run "cleanly" since I purchased the car a little less than a year ago. I rebuilt the carb, but it still would not accelerate cleanly. I replaced the carb with a rebuilt unit. Very similar behavior. The choke is difficult to set. If I set for cold start up, it will not open well for warm operation. Set for warm operation, doesn't choke as it should. The REAL problem, right now as I'm trying to test out the transmission, is that the engine will not run up to higher rpms. It misses badly. In gear, I can hardly get the engine to run over 3000. In park, I can race the engine to about 5000 before it misses badly. The basic ignition is set to 6 btdc. The vacuum at idle (from the port on the carb) is around 16. Vacuum does advance the timing at idle when I plug in the vacuum to the distributor. Adding throttle advances the timing. I can't tell how much because I don't have a timing light that will tell me. How should I attack this problem?

3) I installed a B&M Supercooler for the transmission. While trying to install it, I poked a hole in the radiator with those stiff zip ties they send you with the cooler. I took the radiator out of the car and took it to a radiator shop for repair. (That radiator shore is green mister!) They patched the hole then told me that I shouldn't run a 16lb radiator cap on the old radiator, it actually should be an 8 or 9lb cap. So I put a 9lb cap on the radiator and filled the radiator with fluid while the engine was running and after the thermostat opened. Later today, when running the car to test the transmission, after I stopped the radiator puked some of the fluid out on the overflow. Should I be able to run with less fluid, or do I need the 16lb cap that was on it?

4) I installed a tubular cross member for the rear of the 2004R. I ended up attaching it from under the frame. I'm told it should go "over" the frame. I'm assuming when they say "over" the frame, they mean on top of the bottom of the "C" channel side rail. I can't figure how to get this WEDGED inside the "C" channel. It seems to be just a tad too long to turn it diagonally and miss the ends of the channel. I can't quite figure this one out.

5) On this new cross member, I can't get advice from the vendor on how to attach the emergency brake cable. Has anyone done this task before? So at this point, I do not emergency brakes. Made it dicey when testing the transmission out of park!

6) I upgraded the drum brakes with SSBC discs all around, with 2" drop spindles in front. Braking is "dead", totally sucks. Anyone else have experience with this installation? Also, the emergency brake cables are coming up short. Now with the cross member problem, I've got an even more interesting issue with emergency brakes.

7) Anyone want to buy a 1967 Lemans? (I think I'm kidding.)

Thanks,
Don

[chipster]

Well, on the vibration, it could be caused by having the crossmember mounted incorrectly, because the angle at the U-joints will be off. If you completely removed the driveshaft when you changed the transmission, did you mark the rear joint when you removed it, and reinstall it in the same position? Any caps fall off and needle bearings get knocked out of place? Did you check the U-joints for wear? If the U-joints are good you might try disconnecting the rear U-joint from the yoke and turning it 180 degrees and replacing.

[chipster]

On the radiator, back before the closed systems with a recovery tank, you had to leave a couple inches of space from the top of the filler neck to the coolant level to leave room for normal expansion when at operating temp. If it is overfilled, coolant will have to go somewhere. The fact that coolant came out the overflow tube shows that the repair was succesful, so far, but if you poked a hole it the radiator with a nylon tie, and the repair guy said to use a 9lb. cap, you really should just get a new radiator.

[carbking]

I will take a stab at question number 2.

The 1967 Tempest would have come from Pontiac with either a Rochester type 2-GC two-barrel or Carter type AFB four-barrel. Either would have used an integral style choke assembly.

An integral style choke works with the following parts:

(1) A bimetallic spring inside the choke housing to close the choke
(2) A vacuum piston inside the choke housing to open the choke
(3) A vacuum passage to provide vacuum to the back side of the choke piston, and also to draw heated air through the heat tube to warm the bimetallic spring
(4) A functioning (NOT PLUGGED) heat crossover in the intake manifold.

The choke butterfly should be adjusted on a cold engine at an ambient temperature of 68 degrees F. to touch closed, no tension.

The choke spring is calibrated to lose tension with a predetermined amount of heat supplied by the hot air tube, and based on the amount of additional richness necessary considering a functioning exhaust crossover. As the spring loses tension, the vacuum supplied to the choke piston causes the piston to pull against the spring tension, and thus gradually open the choke butterfly.

Most common problems:

(1) The vacuum passage is plugged. This issue will cause the choke to open slower than normal, and will cause the engine to run rich with rough idle, and black smoke. The vacuum passage begins in the primary throttle area of the carburetor and runs through the carburetor to the back side of the choke piston. Vacuum then leaks past the choke piston, creating a negative pressure (vacuum) on the entire choke housing, which then pulls heated air through the external choke tube. The heated air causes the choke spring to relax.

(2) Either the exhaust cross-over is plugged from long years of running too rich a mixture, or some mis-guided enthusiast deliberately plugged the cross-over trying to keep paint on the intake (or the intake was previously used on a race vehicle). A plugged crossover will cause an extremely long warm-up (as much as 1 hour) with extremely lean idle conditions until full warmup. This will cause stalling, especially with the use of an automatic transmission.

Solution: first set the choke as described above. If this doesn't solve the issue, then determine if the vacuum passage is open. If not, open it. If the vacuum passage is open, then it may be necessary to determine if the exhaust cross over is blocked.

Jon.

[brewski]

Chipster, Carbking - Thanks for the input. Chipster, I'll check out the u-joints and make another attempt at the cross member. I know a new radiator would be a good thing, but I'm out of Pontiac funds at the moment. Carbking, I'll give the choke setup another try and verify the passages are open. It is a Rochester 2 barrel. There is a hardline from the carb (thru a rubber hose connection) to the intake manifold, then another hardline from that manifold spot to the choke piston/spring device. With the choke adjusted fully open, the carb wouldn't be a suspect in the high rpm missing, would it? Two carbs, same missing.

[carbking]

The two barrel Rochester uses the main metering circuit for RPM above roughly 900 including high speed. It also uses a power valve to augment the mixture for wide open throttle. It is possible that the use of a Chevrolet power valve (smaller fuel orifice) by a previous rebuilder could cause a high speed WOT miss; but unlikely that two carbs would have the same problem. More than likely, this problem is elsewhere.

Jon.

[RAIV55]

On the crossmember issue: compair overall length of the new crossmember with the old one. If the new member is longer trim to correct length or send it back. As i recall don't the e-brake cables attach to hangers on the original crossmember? Some provision should be there on the replacement. Maybe something else to talk to their tech about.

[RAIV55]

About the traany problems with shifting. Get the engine running right first. I'd assume there is now provision for the TV cable? The 300 ran off vac. the 200's use a cable that increasing gets extended with throttle application.

["QUICK-SILVER"]

Something else to look at. You may have done tried. Do you have a tach? How many rpm's at 55, try same rpm's in park or neutral. If you have vibration converter is probably not centered or pulled up in back of crank. Have seen rings on centering knob on converters. I have seen this many times on converter swaps.
Keep us updated
Clay

["QUICK-SILVER"]

RAIV55 is right detent/TV cable increases fluid preasure and affects shift points plus firmness.

[brewski]

RAIV55 - Yes, I'll need to find out what it will take to "squeeze" the cross member inside the frame rail. There is no provision on the cross member to attach the e-brake hanger, this is one of the things I wanted to talk about with the tech. Talking to the cross member expert where I bought the cross member has turned out to be pretty well impossible. I agree with your comment on testing the transmission, I need to get the engine running right first. I think the transmission is going to test out fine. I just need the engine to run up cleanly and to eliminate the vibration. I have the TV cable adjusted pretty well. Thanks.
Quick-Silver - I have installed a tach in the car. I don't notice vibration running the engine up in park. Just the missing problem at high revs. But your suggestion is something I can try. I initially had the TV cable set too short and the shifts were pretty hard. I reset it correctly using the pressure gauge and it works much better now. Thanks.

["QUICK-SILVER"]

About the miss. What distributor are you running? On point type GM I've seen the ground wire (points to neg. coil) wore out or rubbed raw. Usually touches something and grounds out when vac. advance moves. Like when your trying to drive 55 or accelerate. Same thing happens with pick-up wires on vac. type HEI. Either way your tach hand should jump around when it happens. This problem will show up and feel worse under load or driving. You can try holding foot on brake in drive, work gas up and down slowly, feel the engine watch the tach. You might find something or rule a bunch of stuff out.
I'm still thinking
Clay

[goathead455]

I would check to see if the heat riser valve in the right exhaust manifold is seized shut.
This would explain the lack of power and difficulty to rev.

[matrix]

Points distributor? Had a buddy with the same symptoms with his 70 Lemans. He changed the points with no improvement. I asked him if he also changed the condensor and he did not. Put a new condensor in and runs like new.

[engineer]

crossmember should fit inside C channel. trim to fit. E brake cable, can be run on top of crossmember, thru it or under it. E cable came in different lengths. use longer T400 center one, install and adjust it whichever way it will work. Get a different radiator shop. any one that tells you to use a lower pressure cap on a radiator designed for 16 lb. does not know how to repair a radiator or you need a new core. Just buy a whole radiator from the auto store. For the brakes, if you mean dead as push the pedal to the floor and no brakes, adjust them, if power, check booster and vacuum, and bleed system completely.

[brewski]

An original style points distributor. I'll look into all these areas, hopefully this weekend if it doesn't rain. I'll have to investigate the heat riser valve suggestion. I didn't know there was one! Thanks all.

["QUICK-SILVER"]

About flap in exhaust manifold. Has your car got duals? If so get behind it and listen to exhaust. If warm up valve is shut one pipe should be quieter and exhaust pressure weaker. Valve is suppose to open when engine gets hot, unless stuck. If it is shut when the motor is hot it will overheat intake manifold, boiling fuel air mixture. Between the two, vaporized fuel and restricted exhaust, car will feel like parachute is out.
I don't think this would make it skip or miss, just run weak. I think older models had a spring that operated flap, later models had a vaccum pot that closed it.

[brewski]

Quicksilver - yes the car has dual exhaust pipes. I looked around and I honestly can't find anything around the exhaust manifolds that I can identify as a heat riser valve. Anyone have a picture of it? I do have equal exhaust flow from the pipes.

Another question - broke a stud untightening the exhaust pipe from the left manifold. What is the best/easiest/least-costly way to replace the stud. (These may be three separate questions) The left exhaust is hanging on by one stud now.

["QUICK-SILVER"]

Brewski,
The crossover valve may have been a seperate piece, in between manifold and pipe. Since your getting the same pressure out of both pipes, it's not closed or it's gone. That would not be uncommon, a lot of them got left off when duals were installed.
Hate to say it but you have to pull the manifold off. If you are not good at removing broken exhaust bolts find someone who is. They can be very difficult. Trying to drill and EZ-out might make things worse.
Be very careful with manifold bolts. They are bad about breaking also. Tap on them and work them back and forth if there stuck.
Good Luck
Clay

[BVR421]

a can of PB Blaster will help keep rusty bolts intact