351C-4V Knocking, oil compression lost

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   Went to take my car on a maiden voyage of sorts. It's an essentially new 351C, all new parts built from the ground up. Car developed a ticking (probably from the lifters), and that turned into a loud knocking noise at higher rpms. Losing oil, white smoke from exhaust, and oil compression went from being about 75 psi to under barely 40, at idle it's VERY low. There's definitely a problem with compression in the engine too -- the transmission isn't downshifting into first when the car comes to a stop.

When I started hearing the knocking, I immediately pulled over and got a tow truck. The car is extremely low on power, it could hardly move into the gas station I pulled into from a dead stop. I have no idea what happened, could someone point me in the right direction? Thanks in advance. 

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r9b2 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 16-June-2021 Location: Maine Status: Offline Points: 84	Post Options Post Reply Quote r9b2 Report Post Thanks(0) Quote Reply Topic: 351C-4V Knocking, oil compression lost Posted: 03-November-2024 at 1:30PM
	Went to take my car on a maiden voyage of sorts. It's an essentially new 351C, all new parts built from the ground up. Car developed a ticking (probably from the lifters), and that turned into a loud knocking noise at higher rpms. Losing oil, white smoke from exhaust, and oil compression went from being about 75 psi to under barely 40, at idle it's VERY low. There's definitely a problem with compression in the engine too -- the transmission isn't downshifting into first when the car comes to a stop. When I started hearing the knocking, I immediately pulled over and got a tow truck. The car is extremely low on power, it could hardly move into the gas station I pulled into from a dead stop. I have no idea what happened, could someone point me in the right direction? Thanks in advance.
	1973 Ford Torino Base 2D 351CJ Project 1975 Ford F150 300I6 4spd 4x4 Project 1973 Ford F100 429 1966 Ford Mustang I6 2025 Subaru Forester

Rockatansky Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 30-July-2010 Location: On The Road Status: Offline Points: 6398	Post Options Post Reply Quote Rockatansky Report Post Thanks(0) Quote Reply Posted: 03-November-2024 at 1:58PM
	pull the plugs and run a cranking cylinder pressure test, drop the oil and cut the filter open white smoke, watch out for water / coolant shooting out the plug holes maybe pull the valve covers off and try to discern whether all the rockers are going full swing during the compression test Edited by Rockatansky - 03-November-2024 at 2:04PM
	72 GT Ute

Booyah45828 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 28-February-2022 Location: Ohio Status: Offline Points: 163	Post Options Post Reply Quote Booyah45828 Report Post Thanks(0) Quote Reply Posted: 04-November-2024 at 5:06AM
	Drain the oil and see what you find. Hearing that you have knocking, low oil pressure, and low compression my gut tells me you've got bottom end damage. It sucks that this was just rebuilt.

r9b2 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 16-June-2021 Location: Maine Status: Offline Points: 84	Post Options Post Reply Quote r9b2 Report Post Thanks(0) Quote Reply Posted: 17-February-2025 at 4:40AM
	Just a quick update on this since I forgot, the camshaft was toast (just after about 1-2 hours worth of run time). It was mostly the exhaust lifters that got cooked as well, which was causing the oil problem as well. Currently looking into a better camshaft, only problem is that all I know is that it was a Comp Cam; the guy who supplied the parts for me unfortunately passed away and never gave me a cam card.
	1973 Ford Torino Base 2D 351CJ Project 1975 Ford F150 300I6 4spd 4x4 Project 1973 Ford F100 429 1966 Ford Mustang I6 2025 Subaru Forester

Booyah45828 Members Profile Send Private Message Find Members Posts Add to Buddy List Member Joined: 28-February-2022 Location: Ohio Status: Offline Points: 163	Post Options Post Reply Quote Booyah45828 Report Post Thanks(0) Quote Reply Posted: 18-February-2025 at 7:03AM
	Was it a custom or shelf cam? There's only so many shelf options from comp that you should be able to single it out pretty easily with some measurements. If it's custom that's altogether different, and the actual cam specs might never be found. With such a short run time, are you going with a roller cam this next time? I'd suggest doing so if you weren't. With it running rough, you likely sent shrapnel throughout the engine, so this will probably need to be removed and rebuilt again.