Chad's 68 Camaro V3.0 build. LS3 & TCI goodies

[Chad-1stGen]

Originally Posted by Matt.A

It is something no one ever really thinks of, but when it comes to building a car, putting a fuel pressure gauge in the engine compartment often comes in handy. Also make sure all of your sensors are working properly, i.e. there's no oil on a MAP sensor, everything is plugged in tight, etc.

As for oil pressure, does Mast have a particular set of numbers that they like to see?

Hope you get all these issues sorted Chad!

Matt

Thanks Matt. Me too. Mast indicated that warm oil pressure at idle would normally be in the 35-45 PSI range. They didn't give me a high RPM or WOT range.

Originally Posted by Vegas69

If you haven't learned this handy little fact yet, here it is. NEVER assume anything.

Ha, I get what you mean and can logically agree with you but you know that is honestly easier said than done sometimes. Probably going to order a fuel pressure gauge for the fuel rail tonight. I had one on my old motor. I can't believe the difference in cost between a mechanical fuel pressure gauge and electric one that you can have in the car though, wow.

[Chad-1stGen]

Well I eliminated the fuel pressure as a cause unless 1.5 more PSI is a problem, though I can't see it causing vibration.

Rented a tester kit from the local parts store tonight. Mast requires 58.5 PSI at the fuel rail and I have dead on at 60 PSI according to the tester. Since I can induce vibration just by increasing RPM's in neutral there wasn't a need to test it under load. When blipping the throttle I see a split second 1 PSI dip.

On to tripple check the engine mounts and trans mount and then it's time to pull the tranny and check the clutch.

I was thinking I can take the clutch off and run the motor with just the flywheel to see if I still get horrible vibration at 2K RPM's. If it's still there then I may need to borrow a flywheel or get the balance checked at a shop.

Will keep you guys posted.

[Vegas69]

At least now you know the pressure is out of the equation. Pull a few plugs and see how the mixture looks as well.

[Chad-1stGen]

Originally Posted by Vegas69

At least now you know the pressure is out of the equation. Pull a few plugs and see how the mixture looks as well.

I actually decided to run a compression test as well. I'd say the car is running a tad rich based on the exhaust fumes. Plugs generally looked good with 2 or 3 plugs looking noticeably rich. Not carbon build up rich but more black in color.

[makoshark]

Are you running a pilot bushing or bearing in the end of the crankshaft? I had a similar vibration on a car once after installing a new clutch. I chased the vibration down by a damaged pilot bushing due to install. I replaced it with a bearing

[chr2002ca]

I went down this road also Chad when I first put my GM crate motor ZZ454 in years ago. Same exact vibration problem, except I had an automatic. Did nearly all the same things you're doing. Compression check, fuel pressure check, spark plug and wires check(and distributor), harmonic balancer check, mounts check. I eliminated some vibration when I found a bad spark plug wire arc'ing over to my block causing a misfire. But still had some vibration so I then detached the torque converter from the flywheel and shimmed the transmission back to allow the engine to run while detached from converter. I noticed very little vibration then. So, to make a long story shorter, most of the issue was with my flywheel and how the converter was bolting to it, and a new flywheel solved that. I still had a slight harmonic vibration between 1500 and 3000pm after all that, but it was basically just a result of a big cube motor and I came to that conclusion when I sat in somebody else's ride who had the same ZZ454 and it felt exactly the same at the steering wheel.

It drove me nuts for quite a while so I hope you get it sorted out soon and it's something simple.

[Chad-1stGen]

Originally Posted by makoshark

Are you running a pilot bushing or bearing in the end of the crankshaft? I had a similar vibration on a car once after installing a new clutch. I chased the vibration down by a damaged pilot bushing due to install. I replaced it with a bearing

I don't know. I had a shop assemble the sub and they installed the pilot bushing/bearing. I'll know soon enough I think.

Originally Posted by chr2002ca

I went down this road also Chad when I first put my GM crate motor ZZ454 in years ago. Same exact vibration problem, except I had an automatic. Did nearly all the same things you're doing. Compression check, fuel pressure check, spark plug and wires check(and distributor), harmonic balancer check, mounts check. I eliminated some vibration when I found a bad spark plug wire arc'ing over to my block causing a misfire. But still had some vibration so I then detached the torque converter from the flywheel and shimmed the transmission back to allow the engine to run while detached from converter. I noticed very little vibration then. So, to make a long story shorter, most of the issue was with my flywheel and how the converter was bolting to it, and a new flywheel solved that. I still had a slight harmonic vibration between 1500 and 3000pm after all that, but it was basically just a result of a big cube motor and I came to that conclusion when I sat in somebody else's ride who had the same ZZ454 and it felt exactly the same at the steering wheel.

It drove me nuts for quite a while so I hope you get it sorted out soon and it's something simple.

Thanks Chris.

I think I eliminated tune or engine running incorrectly as a cause of the vibration. I took the car for another diagnostic drive tonight and the vibration is there upon deceleration as well. I even turned the car off in gear decelerating down from about 3.5K rpms and its the exact same vibration. So I'm convinced it's mechanical, rather that anything else.

I have to go out of town this weekend but I plan to pull the motor next week.

Regarding the oil pressure I ordered an adapter for my other sending unit and can play with that next week too. However, when I did my test drive tonight I noticed that at cold oil temps I have a ton of oil pressure (50 idle cold and doesn't drop below 35-40 until a good 10 mins into driving (not idling). If I rev the motor with cold oil it will hit mid/high 70's PSI.