Видео

Yes, I did one long ago, sorry if you didn't see it. Try this: ruclips.net/video/MjxPVDOW5Vw/видео.html I did find that I had missed checking the boxes for the playlist though, so perhaps it was hard to find.

Well, it does provide some extra challenge, but a good mechanic ought to be able to get it run. I know it is tough to get it perfect, or make it run as well as today's cars, but this one did run reasonably well for a number of years.

Yes, you sure need to be careful with flame and brake fluid.

Yes, these engines were a little temperamental. There aren't many adjustments, so we need to be sure the computer system and sensors are working right. The service manual is definitely critical to sorting it out.

You're welcome, the MAP sensors are not well understood, yet very important.

Yes, those vacuum gauges are quite useful for diagnostics and adjustments, aren't they? I still use mine often.

On the headliner, I need to give credit to my son. He has an '87 we're working on and he gave me the trick. He said that he used Office Depot thumbtacks. I bought a pack of 100. They're 5/16 long and 1/2 inch head. When I started, the entire headliner was hanging and just propped up by various things. I went through and just went across every few inches and put rows of them in front to back. They are long enough to hold into the backing board and they hold rather well. I suppose there is a possibility to puncture a wire like for the dome light, so care is required, but it was a good fix for now. On the diesel question, let me think about that. I didn't work directly on the engine, but I did work on vehicles with them and have some experience.

@bitsofwisdom460 Much appreciated. I think they started development in 1973. I'm sure it was long before you arrived

You're welcome.

More to come as I dig in...

Not sure if I understand, but timing advance will be higher at closed throttle, possibly up to 40 to 50 degrees at light loads. When the throttle is opened for acceleration, the advance will come down a lot and then track with increasing engine speed. I don't know the exact curves, but at WOT, might start out at 10 - 20 degrees coming off idle and end up at 30-35 at max RPM. The curves depend on load, engine speed, knock resistance and emission requirements.

The engine will develop vacuum while cranking. Ignition timing effect won't likely show up because once the engine fires, it will go from cranking to start very fast. Valve timing issue like jumped timing chain would likely show up if ignition was turned off, but it might be hard to know what is normal cranking vacuum for a reference. I was asked to look at a car (friend of a friend) years ago that wouldn't start and the cam was jumped so far that it was pumping air back out the carburetor. I didn't measure vacuum, but it appeared there was none at all.

You're welcome. That spring can really cause trouble.

I hadn't thought about the heated models, but I see the risk of running them down with the heaters. Lithium chemistries are all sensitive to low temperatures and to low voltage. The advice to not leave them discharged is very valid and charging at low temperatures can damage them also. The chemistries that I used in my automotive applications would run to well below zero F, but the lower the cell temperature the lower the allowed charging current. Too much current would damage the cells and cause potential safety hazards due to the damaged cells.

I would not expect that changing the PCV hose would affect the vacuum because the valve should regulate flow. Some engines have a fixed PCV orifice rather than a variable valve, but either way I would not expect a larger hose to affect flow significantly. I don't know what is normal for that engine, but 2 in. hg. certainly seems way way too low. If you are using a sensor into the intake manifold, I would check to be sure that the passage you are using is clear and not also feeding another device or system that could have a vacuum leak. For example, some passages feed the brake booster, HVAC, or purge system and can have a bleed orifice. It is also possible that the sensor / gauge has an problem affecting accuracy or calibration. Sometimes it helps to cross check with a good mechanical gauge. You might have a real vacuum leak in the intake manifold and need to check gasket seal.

@bitsofwisdom460 Thank you for your advices.

Yes, big cams will really drop vacuum. That will affect anything that uses vacuum, like brake boosters and the like.

Thank you. And yes, some of those fittings and connections are really tough. I try to not sugar coat the projects, you see what I am really dealing with. I just sometimes need to shorten those sections because you wouldn't want to watch the entire struggle...

Yes, vacuum or pressure can be measured in mm or inches of mercury. And yes, you have the right idea, the difference between inside and outside is a relative pressure measurement. That is what I was trying to explain: the difference between relative and absolute pressure. MAP is absolute, vacuum is the difference between atmosphere and inside the manifold (or other container). You can measure relative pressure with a mercury column, it just requires a different reference point. The best way is to use a tool called a U-tube manometer. I can't show a picture here, but if you take a clear glass or plastic tube that has a tall and narrow "U" shape, then connect the top of one of the sides of the "U" with a hose to the container and leave the other tube open to atmosphere, the height of the fluid column in the tube in mm is the relative pressure. I have seen these used with mercury. I use this method with water instead of mercury for very low pressures like air filter pressure drop.

I don't have any technical data to know whether old filters age sitting on the shelf. I can only say that over the years, I don't recall ever having that concern raised. No one ever came to me with a test failure because of an aged filter, but perhaps we never went that far. Regarding the newer, smaller filters: while I like to keep the older size on my Camaro, I think we need to trust the filter manufacturers at some level. They do have an obligation to have adequate designs, although I understand there can be quality variations and not all brands are equal. There is continuing work on filter media and folding patterns and I expect that there is continuous improvement in the field. Most engine manufacturers run various validation tests before they approve an engine with a smaller filter. I know that I saw many engines run hundreds (thousands?) of dyno and vehicle hours with the latest small design filters before they were released to production.

Yes, I agree that the overlap will reduce vacuum at idle and it will recover at RPM. It will improve most at part throttle when the cam is in an efficient / tuned range. But I'm not following your concern about exhaust systems and bearing damage. The greatest negative load on the pistons will typically be on closed throttle "overrun" conditions. Taken to the limit, assume a vehicle pulling a trailer on a mountain downgrade in low gear with the engine at high RPM and throttle closed for downhill braking. I can say from experience that the engine can pull 26 to 28 in.hg. or maybe a little more depending on altitude. You can sustain this condition for miles. Now compression on most engines will be on the order of 100 psi or so, PLUS combustion pressure and the reversed load due to vacuum and with fuel cutoff would be no more than 14 to 15 psi. I don't understand how a higher cam overlap would cause a problem in this condition, but perhaps I'm missing something.

@bitsofwisdom460 it is complex. A manifestation of CFD. Long exhaust = short duration. Long duration = short exhaust. Oil temps will increase exponentially when it is in the zone. Dont run long duration cam in a car with full length exhaust and some gear. 80 mph is hot oil in 60 seconds.

That would seem to be a good strategy. Regarding harm, it would seem to be dependent on the circuit. If the driver is a pull down to ground in the ECM and you are grounding the coil on the ECM side, it would seem to be safe as you are applying the same condition as the ECM. I think the concern would be if the coil resistance was low and the driver was handling more current in normal operation.

@@bitsofwisdom460 Thank you for answering, Sir. I was just thinking if the coil were shorted in the process that more current would go to the driver than what it is designed for and damages it. Thank you once again. I am surely going to use that strategy one day if need be.

Well, just to be very careful about this, especially for anyone else reading this discussion. It would work on a driver circuit that provides a ground for a relay or other coil that has power fed from the other side of the coil. If it was a high side driver that provides power to a coil, a short to ground would likely damage the driver.

Yes, I expect you are correct. There are probably counterfeit listing labels used. Years ago I had an imported ceiling light fixture that became a safety hazard after a few years. It had a UL label, but I went in to change a light bulb and found all the insulation flaking off of the internal wires - inches of bare wire. It was a miracle that we didn't have a fire. I contacted UL and they had me send it to them for investigation. They wouldn't give me details of their findings. They did say that had cases where some companies made substandard products and by the time UL could investigate they would go out of business and re-form under another name. In this case, the fan was definitely no UL listed, but had a European listing. Recently, I had a comment from someone who told me that the certificate had been revoked, but I haven't had time to verify that.

It can be hard to see the 6 degree mark, my light is bright enough and I can just see it. It would help to put a white mark there as well. With the engine off and cold, you ought to be able to get in there, clean the pointer, and put a dab of paint or white marker on the correct spot. I haven't been in there recently; I think that there are bumps / marks every two degrees, but only numbers at zero and perhaps 10 degrees. So you need to count up from the zero mark.

@bitsofwisdom460 thanks I really appreciate it i believe I finally got it right thanks to your video and your response to the question i was asking so thanks you for your help

I think that's great! We can have our brand preferences, but there are many great cars out there. And, I worked the C5 driveline when it was in development. The C5 was a great advancement from the C4. Don't misunderstand, I thought the C4s were great cars and a lot of fun; but the C5 chassis had such great handling, stability and balance. It was impressive how it would stick in the corners.

Yes, in short, the vacuum booster becomes a controlled vacuum leak in that condition. Back in the day, I worked for a brake system supplier and had design responsibility for boosters. This gets a little hard to explain, but here goes... Essentially a typical vacuum booster stores vacuum (or has lowered air pressure) on both sides of a large rubber diaphragm. When you depress the brake pedal, a valve allows air to enter back side of the diaphragm. When you release the brake pedal, the booster needs to refill that large metal can with vacuum (removing the air) and that air flows through the hose to the intake manifold of your engine - on the back side of the carburetor or fuel injector so that it isn't measured and no fuel is added to compensate. Normally this is only a short pulse, but if you repeatedly pump the brake pedal, air will continue to flow into the engine downstream of the fuel metering system as manifold vacuum is depleted. If the booster valve has a leak, it can be a constant air bleed as well.

That is the best explanation I have ever gotten. Thank you very much, Sir.

Thank you, we are doing well and had a great Christmas and New Year. I hope that you and your family had a great holiday as well. I'm glad that you enjoy the content. You are right that it has been quite a journey. I still have work I want to do on the Camaro, but other projects and personal commitments / travel often take time away. There will be more to come on all fronts.

Thanks Mike. It was a lot of work, but I also must give credit to the original owner. The interior had quite a bit of wear, but he really kept the body in good condition. For a car spending life in Michigan, road salt is usually death to the body. The original owner obviously kept the car out of the bad weather since the floor pan still has the original paint on the bottom rather than rust. It made my life much easier not having to fight body rust. As they say... "been there - done that"

You're welcome. Happy New Year

Thank you, you're right it really has paid off. There were some times when I wondered. As I dug into the project, the work grew, but sticking with it was the right thing to do.

Thank you! Merry Christmas and Happy New Year to you as well. You are correct it was quite a struggle at times. It was really demoralizing when the first engine failed. That 20 miles on that engine came in 2 or 3 mile increments interspersed with diagnosis in the garage. Just couldn't understand why it wouldn't run right and kept getting worse. Then the realization that after all the careful work, I needed to pull it back out.

Thank you. They really are great cars. When I started on this one, I didn't have a full appreciation for them. I have really come to appreciate how good they are.

I don't recall seeing that, I'll have to check that out. Thank you for the info.

Yes, it has been amazing. It was great to have a car so well cared for as a starting point, but it was a lot of work even then. It still can be refined, but it's great to have it on the road.

Im in Michigan too, I got a 94 Z28, not the most admired car but it’s my first car. A lot to learn trying to fix summer cars that were driven during Michigan winters.

Thank you very much for your comments. I'm glad it was helpful.

Yes, getting that starter off isn't an easy job, and with the ground clearance on these cars being very low it is even harder.

Thank you for watching, Greg.

Thanks!

Both the IROC and the Mach 1 are great cars. I wish you success in your projects.

There are other brands of test kits that ought to provide similar answers. I picked the WIX kit because it was one that was easily available off the shelf at local parts stores. O'Reilly Auto Parts carries it, although often I need to overnight order it. Merry Christmas.

We did not drill any new holes in the frame. We did need to open up the holes a little on the engine bracket for the mount through bolts as noted in the video. The through bolts normally have clearance holes and we added a little more clearance intending to clamp the bracket to the frame mount like the factory does. This did allow us to place the frame mount bolts in the original holes. We did consider the alternative of relocating the frame mounts forward or rearward enough to drill new holes in the crossmember. I'm not yet sure which is better. Since we are using aftermarket steel brackets rather than Chevrolet V8 factory engine brackets, our choice might be different.

@bitsofwisdom460 thanks for the information I'm interested to see the finished product I subscribed to your channel Thanks again

No, it just needs the key on. There is a sequence that the tool will walk you through where you power up the tool and connect with the key on, then start the engine. In this video, I set up to record data with engine off, then crank and run: ruclips.net/video/wzZp1itEePg/видео.html

Yes, and I expect that dealing with manifold absolute pressure rather than vacuum / relative pressure can really be a help in aircraft, because it isn't affected by altitude. A specific manifold pressure should result in equivalent power at any altitude or barometric pressure. Granted it may be harder to get a boost pressure at higher altitude. And gas turbines are a different animal for sure. I was a transmission test engineer and I spent several years in the '80s running M1 tank powertrains in dyno cells for performance and durability. The AVCO Lycoming turbines were needed to test my transmissions. I learned a lot about those engines because they were fairly new and had a few issues. I ended up being an engine test engineer of sorts just for self preservation in getting my job done.

@@bitsofwisdom460 I also had the opportunity to work on a test cell with a turbo I had recently rebuilt. It takes a little nerve and great care to stand inches behind a spinning 14' prop to adjust the fine pitch of the propeller control...

Yes, I expect that would be unnerving. I can only imagine that one. The old Allison test cells where I worked had originally been used as final production test for the supercharged Allison V1710 V12 aircraft engines in WW2. They were set up with large pedestals in the center so engines could swing a full size propeller and flow air through. That section of the test cell was heavy reinforced concrete while the rest was only brick. Rather impressive. For transmission work, they built floors at the level of top of the pedestals for bedplates.

Thanks!

Yes, that did the job and got the tractor back on the "road".