joe_padavano

This is the tool I most hate to reach for...

Fremont car, apparent repaint, some aftermaket parts on the engine. Clearly the car has been gone through (repro underhood sound deadener mat. RPO L34 350 4bbl motor. Obnoxiously droning Flowmaster exhaust system. Aftermarket radio. Later-model (1975-newer) SuperStock III wheels with snap-in centers. Build sheet is nice. The "numbers matching" engine appears to be a restamp. Below are the stamp from the car for sale and a known factory stamp from a different 1972 block. Note the difference in the "3", for example. You be the judge.

They didn't replace strength. They damped out deflections to reduce NVH problems like cowl shake.

I got my Vacula for $15 at the Long Beach swap meet about 30 years ago. No one (including the seller) knew what it was. I've since bought another one for $25 at Carlisle. 😁

The air leakage around the bleeder screw threads. With the Vacula and constant vacuum that isn't a concern because all the air goes into the bleeder, not back into the system.

You're kidding yourself if you think there's a specific temp for each mark. Use that gauge more as an indicator of trending. If it's constant at a particular mark when you drive, it's fine. If it starts creeping up in traffic then watch it more closely. If you really want to calibrate it, get an IR thermometer and verify what the marks are.

Just to confirm, is this an aftermarket GM-style HEI with coil-in-cap, or is this an electronic points conversion in the stock distributor (which is not "HEI", despite what people call it)?

TVS is thermal vacuum switch - it opens or closes vacuum ports depending on coolant temp. EFE is early fuel evaporation, which is the heat riser in the exhaust manifold outlet that closes when the engine is cold to route exhaust through the crossover under the carb to promote fuel vaporization. Newer cars used a vacuum actuator rather than the old bimetallic spring. EGR is exhaust gas recirculation, which is the vacuum operated valve typically bolted to the exhaust crossover on the intake manifold, next to the carb. The EFE&EGR-TVS shuts off vacuum to both of those systems until coolant reaches a certain temperature. DS stands for distributor source, which is the vacuum source that controls the vacuum advance VMV is vacuum modulator valve, which blends two different vacuum sources to achieve the desired vacuum signal to the vacuum advance can. The emissions controls use a combination of a thermal vacuum valve (DS-TVS) and a vacuum modulator (DS-VMV) to obtain the correct vacuum advance curve depending on engine temperature and load (engine vacuum is an indicator of load on the engine). SVB is secondary vacuum break, which is typically a vacuum diaphragm that controls either choke opening or secondary air valve opening (or sometimes both on a Qjet). That SBV-TVS is the thermal vacuum switch that provides vacuum to the SVB once coolant reaches a certain temperature. As noted above, manifold vacuum is the vacuum level inside the intake manifold. Ported vacuum (also called timed vacuum) is sourced from ports slightly above the throttle plates in the carb. With the throttle plates closed, there is zero ported vacuum. As you start to open the throttle, the throttle plates uncover these ports, which then see manifold vacuum. The timing of this can vary depending on where the ports are relative to the throttle plates. Some carbs have more than one set of ports in the throttle bore to provide vacuum signals with different timing relative to throttle position. It pains me to say this, but the complexity of these vacuum-operated emissions controls suggests that computer-controls are the better way to go. A throttle position sensor, coolant temp sensor, and MAP sensor pretty much give you all the info you need.

Here's a more comprehensive list: https://en.wikipedia.org/wiki/Category:Vehicles_with_four-wheel_steering

There were a number of vehicles with AWS in the 1980s. https://www.caranddriver.com/reviews/a35287962/tested-1988-four-wheel-steering-benefits/ Even GMC offered a pickup with the feature (called Quadsteer) a few years later.

400 Pontiac or 403 Oldsmobile?

I don't know where the OP is located, but while I agree with recoring the original, real radiator shops are a dying breed. Here in the Northern VA area, there is only one left, and it's an hour each way for me.

Wildcats used the B-body platform.

So long as there is continuous vacuum on the system (as provided by a Vacula or similar vacuum bleeder) then this is a non-issue. The air cannot physically get into the brake system, only into the bleeder. The problem I've had with the Mityvac is the risk of air getting back into the system when you pump it.

Considering that Chevy cars of that period used exactly the same brake system as did other GM cars, the different bleeding orders are illogical.

Unfortunately it still doesn't say why. I stopped responding to "because I said so" when I moved out of my parent's house. By the way, the following is from Oldsmobile factory-issued Chassis Service Manuals. The excerpt on the left is from 1970, the right from 1985. No, neither one of these is a diagonal-split braking system. And note especially the part about "bleed the master cylinder last" in the 1970 manual.

That isn't clear. Starting furthest away theoretically will pull more air from the system the first time, but as I and others have said, I've never found a substantive difference one way or another.

I have not had success with the Mityvac units. Air will always leak past the threads of the bleeder screw when it's loose. With a constant vacuum source like the Vacula, this is irrelevant since the air always goes into the bleeder, not back into the system (physics is your friend). I've found that with the Mityvac, when you release the handle to pump it, air can get back into the system.

I have a Vacula pneumatic vacuum bleeder and it is probably the best tool purchase I've ever made. One pass at each wheel cylinder and I'm done. I don't even need to bench bleed the M/C, this will pull the air out. Even the ABS system on my truck didn't phase it. A real Vacula is pretty spendy if purchased new. Fortunately I got mine at a swap meet decades ago for peanuts because no one (not even the seller) knew what it was. There are clones on the market now for under $50.

This is one of those questions like which way does the toilet paper hang. I've got Oldsmobile factory manuals from 1961 through 1985, and even these are not consistent. I'm still waiting for someone to tell me what the effect is that they are trying to prevent by specifying the order. And even then, when one has a dual circuit system (split front/back), why does it even matter at all?

I got my switch pitch converter from Fatsco.

If they also list the same P/N as correct for a 1968 Toro, then it won't be correct for a 66. Might want to double check. Vendor application lists for Oldsmobiles are notoriously inaccurate.

Agreed, but again not RA's fault. The Raybestos and Wagner brake parts I get from RA are the same ones I would have gotten from my local auto parts store.