Hey guys, I was wondering. If someone were to be playing with an oldsmobile diesel 350 (the LF9 from the late 70's early 80's) how would I hook up a tachometer to this? I can't imagine a simple way without putting a CPS in or something like, being that it doesn't use an electronic ignition system. It's non-computer controlled so a tach output was never included in one. Does anyone have any ideas?

I don't even know if a tach option was available on the Olds diesel.

Typically, a diesel can get a tach signal from a bunch of different locations depending on the engine. Normally there's some sort of engine position or tach sensor mounted on the engine. It could be looking for a signal from the crankshaft/flywheel, camshaft or injection pump. I've seen some diesels getting a tach signal from the alternator.

Yeah I don't think there was an option for a tach, that's why I was curious. I'll see if I can find one to go off the alternator. I can't imagine there are any sensors on that thing, but it does have electronically controlled EGR vacuum solenoids, etc.

You'll need an alternator with a tach output. Depending on the size of the crank and alternator pulley, the tach signal may not be accurate.

I have no manuals on the Olds 5.7 diesel to see if there's a tach sensor. It's not a popular engine.

Yeah they came from the factory with weak head bolts causing many cylinder head blowouts. The motor is from a 1982 cadillac deville and is probably staying there to be restored. The head bolts were replaced with the aftermarket kit to fix this issue. Ill have to search the internet more in-depth to see what other people have done, I just wanted to see if anyone here had any experience with the engine

The original engine? Pretty rare for them to last until the '83 model year when they started sorting out the problems (like aforementioned head bolts which were torque-to-yield; and 10W-40 oil which crudded up the roller lifters and caused cam failure, solved by going to 10W-30 oil).

Yep, it's the original engine. It either has 83,000 miles, or 183,000 miles (the tach only has 5 whole number digits). Hey, since I'm on here, can anyone locate the camshaft profile for this engine because I was wondering if I could swap it out for a closely related gasoline 350 cousin, for better power.

I wouldn't go swapping a gasoline camshaft into a diesel. Valve timing is completely different. Because of the high compression, chances are the valves are close to making contact with the piston already.

Kinda bringing back the dead but. The Olds 350 Diesel engine is a highly desire block in the Olds world. Almost as popular has the 455. Joe Mondello has an article to bore and stroke this engine to a 440cid. Using a Olds 425 crank. And still be street driven. Can go bigger but then its not streetable. But this is pretty exp. Becuz of the machine work. But you might know someone in the machine shop or work in one. Who knows. But there are several option. A guy recently. Took his Olds 350 diesel and bore and stroke it to a 425 and is running in the 9's. His article been publish in several big name site. But there at several more story. Of ppls just converting them to gas. And having a nice 13 sec car. But u need to check out a Olds forum not a Camaro forum.

www.Oldspower.com
www.realoldspower.com

I have a 1981 Cutlass with a 350 Olds. In fact it alrdy sold and I havn't even removed the engine yet. I have a nice 455 ready to install. I figure I would never have the time and money to make my 350 diesel to it full potential so y not make some money and let someone whos does have it.

But far has a tach. Your alternator should have a tach wire slot. But if yours is like mine you don't becuz someone most likely installed a reg alternator off a gas burner.