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Over the past 6 years I have been somewhat intrigued by the diesel engine since purchasing a 2005 Duramax to help move from California to Wyoming. Since then I have owned 6 other diesel engines in various shapes and sizes to help cull my insatiable curiosity including a couple of tractors for the property. A few years later and 1200 miles away in Ohio brings me to my current project, one that many of you would prefer to cannibalize and put a carburetor on,. The engine everyone loves to hate, the Oldsmobile 350 diesel. I am building this project for the same reason GM did back in the late 1970's, fuel economy. When this engine is finished being built I am stuffing it into a third or fourth generation F-body mated to a T5 5 speed and see where it goes from there.
I am in the early stages of the build but off to a good start
Block is bored .020 over
Dualoy pistons from UEM
Total Seal rings, 2nd ring gap-less
New seats and guides in the cylinder head.
4 new intake valves and 1 exhaust valve I made from an old intake valve.
Pump and nozzles are being gone through and refurbed at International Fuel Systems in Findlay OH.
Many Olds diesels had head gasket sealing problems. A fix is to use high-strength ARP bolts or studs for greater clamping force.
However, unless your block was machined with ARPs in place, that option is behind you. I mention it so you can keep it in your memory banks in case the problem ever arises with your engine.
A fix is to use high-strength ARP bolts or studs for greater clamping force. However, unless your block was machined with ARPs in place, that option is behind you.
It's my understanding that it's not REQUIRED to use a torque plate when machining the block and installing ARP head bolts/studs. In fact, I know it's not necessary for ARP head bolts. I had my 455 machined without a torque plate and used ARP head bolts without complications. Plus, there are many folks out there that install head studs on IDI diesels without removing the engine for even a cylinder hone.
Greg, here's a good thread on our website about the Olds diesel:
One thing ABSOLUTELY REQUIRED when you install this Olds diesel in a vehicle is a water separator. Olds never used a water separator from the factory and that led to pre-mature engine failures. Here's one I use in my IDI truck:
Also, when you reassemble the engine you can set base injection pump timing by lining up the marks on the timing gears; however, to properly time the IP you will need a piezo-electric adapter for your timing light. Here's a good thread at a diesel truck website I frequent:
Have that cast crank checked closely for cracks. Exhaust valves are generally better steel than intakes; consider finding a correct exhaust valve instead of using a cut-down intake.
Here is a picture of the intake valve I cut down and turned into an exhaust valve. I can still find new intake valves on places like ebay, but new exhaust valves are non existent.
Have that cast crank checked closely for cracks. Exhaust valves are generally better steel than intakes; consider finding a correct exhaust valve instead of using a cut-down intake.
They are both stainless valves from the factory, so good to go. But yes, it's not uncommon for a manufacturer to use steel intake valves and stainless exhaust valves.
It's my understanding that it's not REQUIRED to use a torque plate when machining the block and installing ARP head bolts/studs. In fact, I know it's not necessary for ARP head bolts. I had my 455 machined without a torque plate and used ARP head bolts without complications. Plus, there are many folks out there that install head studs on IDI diesels without removing the engine for even a cylinder hone.
Greg, here's a good thread on our website about the Olds diesel:
One thing ABSOLUTELY REQUIRED when you install this Olds diesel in a vehicle is a water separator. Olds never used a water separator from the factory and that led to pre-mature engine failures. Here's one I use in my IDI truck:
Also, when you reassemble the engine you can set base injection pump timing by lining up the marks on the timing gears; however, to properly time the IP you will need a piezo-electric adapter for your timing light. Here's a good thread at a diesel truck website I frequent:
FWIW, I use the Snap-On MT 257A. It's not cheap but these tools are getting harder and harder to find.
This engine will be getting ARP head studs, and you are correct, I don't need to use torque plates prior to the installation of the studs. We don't have an Olds torque plate right now anyway but I may see if I can borrow one from a nearby machine shop we work with sometimes. If I use new main bolts or rod bolts then the mains and the rods should be inspected and measured and resized if necessary.
I appreciate all the help and ideas, I purchased a water separator for a Massey Ferguson some years ago and never installed it, so I am going to go ahead and use it in this project. I also have an electric carter lift pump that may work to replace the original mechanical pump on the side of the block.
As far as a piezoelectric timing light I asked around some friends and I think I have one sourced I can use, but honestly thats a ways off right now.
Have that cast crank checked closely for cracks. Exhaust valves are generally better steel than intakes; consider finding a correct exhaust valve instead of using a cut-down intake.
also, I haven't had a chance to mag the crank yet because I currently have the pump for the wet mag tore apart to repair some leaks, and of course just for the fun of it I cracked a flange while getting a little rough with a hammer and chisel trying to get it separated. Now I can enjoy welding up old nasty cast iron!
Greg, I'm sure that water separator will work well. If you don't have an electric fuel pump already here is one that is highly rated at the diesel websites I frequent:
The injection pump is up at International Fuel Systems in Findlay Ohio. For a rebuild with some upgrades I was quoted $825 for just the pump, I find out about the nozzles tomorrow.
I have tools and the means to rebuild it myself so that will most likely be my best option. At first I though I didn't have the time to do it here, but $825 is a good way to change my mind!
$825 isn't too bad for an IP rebuild. It costs about the same to have the IPs on the Ford IDIs rebuilt.
I'm not sure about the Oldsmobile injectors but the injectors used in the Ford IDI trucks are pretty simple to rebuild. The problem is sourcing spare parts for them. Do you have multiple sets of injectors to salvage parts from?
I don't have any parts around for the injectors. International Fuel called today and let me know that pattern wasn't great and the pressure was a bit soft. But but the good news was the parts are now considered obsolete and they cant find parts for them anymore.
They are going to go through them and see if they can make them a bit better.
Greg, hopefully you can find an Oldsmobile diesel in a salvage yard. Here's a website I used to find a spare 7.3l IDIT for my 86 f250. I found it near Ft. Worth, TX. I also found a salvage yard in Dallas, TX that had a Bullnose Ford with an IDI diesel. Somebody already took the IP, but I got a good set of injectors I can use as cores.
Pop-Pressure in the IDI injectors is adjusted by adding/removing shims. You might ask the service shop if they can source shims by size that would work in your injectors. Interestingly, I did see an Oldsmobile diesel IP recently near me on Craigslit. I tried to contact the poster via. e-mail (no phone number given) but I never got a response. I thought it would be good as a core for my Ford diesel. BTW, if your IP has a Vacuum Regulator Valve (or GM equivalent) on it for the OE automatic transmission make sure you keep it even though you're going to a manual. Those things are GOLD!
Well, @#$%@#$. I just threw away a complete set of diesel heads a few months ago.
I do have the injection pump and high pressure lines. Just held onto those for wall art......
(my intent was to use that engine as the basis for my next gas build. Unfortunately, the #4 main cap was sitting in the bottom of the oil pan.......)
Greg, hopefully you can find an Oldsmobile diesel in a salvage yard. Here's a website I used to find a spare 7.3l IDIT for my 86 f250. I found it near Ft. Worth, TX. I also found a salvage yard in Dallas, TX that had a Bullnose Ford with an IDI diesel. Somebody already took the IP, but I got a good set of injectors I can use as cores.
Pop-Pressure in the IDI injectors is adjusted by adding/removing shims. You might ask the service shop if they can source shims by size that would work in your injectors. Interestingly, I did see an Oldsmobile diesel IP recently near me on Craigslit. I tried to contact the poster via. e-mail (no phone number given) but I never got a response. I thought it would be good as a core for my Ford diesel. BTW, if your IP has a Vacuum Regulator Valve (or GM equivalent) on it for the OE automatic transmission make sure you keep it even though you're going to a manual. Those things are GOLD!
Thanks for the link! I do not think the pump had a vacuum regulator valve on it but I will check when I see it again. I am still waiting on the injection shop to get back to me about the injectors, I think I should have everything back in about a week. I would like to source some spare parts since the shop did say these injectors are no longer available from Stanadyne. The one I have came with pencil injectors and I guess they were only used on cars in 1978 and 1979 and then they went to poppet valve after that, so my options would be finding later heads or good used parts.
These are the rocker arms I purchased from Speedmaster. Just finished drilling and tapping the holes for 7/16 on the VGS 20 and decided to snap a photo. These are the shaft mount ones for the Oldsmobile gas engine, lucky me, Olds decided to share the valve train with diesel engine too! To me these are not true shaft mount rockers like the Jesel ones, these just have a tie bar between the two rockers that keeps them from rotating thus negating the need for guide plates and hardened push-rods.
Will most likely need a set of tall valve covers, but those are minor details.
Here is a link if you are interested. Got mine on Ebay for $163 shipped.
Check out the junk yard in Modoc Indiana. Looks like it is 1.5 hours from you. They have at least three diesel 350 Oldsmobile cars there that still have the engines in them. While you are there, it is worth a full day to look around. They have never scrapped a car since the 50's and it really cool to see all the vintage cars.
Check out the junk yard in Modoc Indiana. Looks like it is 1.5 hours from you. They have at least three diesel 350 Oldsmobile cars there that still have the engines in them. While you are there, it is worth a full day to look around. They have never scrapped a car since the 50's and it really cool to see all the vintage cars.
They are pretty close, I wonder if I can talk the Mrs into a little day trip
Greg, those rocker arms are awesome. Make sure you post some pics if you go to that salvage yard. I hope you can convince momma to let you get some cool swag.
I was taking a closer look at my cylinder heads and found something interesting, one of my heads is missing an oil drain back hole!
With the top end over oiling issues that the Olds suffer from, I will need to find a way to remedy this issue.
Got a chance to degree the camshafts today, I did the stock 1978-79 Flat tappet cam and a 1980- later roller cam. The roller cam was designed for a .921" lifter, but the block uses an .842" lifter. In theory a bigger lifter should increase duration a a bit. If anyone knows what the stock duration is for an early 80's roller cam diesel is let me know.
Also, Thanks Gene for getting that Cam out to me, I think thats the one I am going to use!
Greg, are you going to use a double roller timing chain? I imagine even the Oldsmobile diesel had nylon teeth on the timing gear which would deteriorate and come apart in the oil pan over the years.
Greg, are you going to use a double roller timing chain? I imagine even the Oldsmobile diesel had nylon teeth on the timing gear which would deteriorate and come apart in the oil pan over the years.
from what I can tell the diesel uses a unique timing set. The cam gear has a bit of an offset to clear the fuel pump drive. The stock timing set is all steel, replacement sets are readily available and I am going to need it, there is a good 3/8" of slop in this chain.
Sorry for the lack of updates everyone! Bottom end is together as of this past weekend, roller cam is installed, waiting on lifters now. I will have pictures for you guys in the next couple days.
My big question would be... are you adding a turbo?
No turbo right now! Going to keep it NA until I get it running and find a car to put it in. After that, If I do put boost to it I am thinking about a supercharger, just to be a little different.
Er... What's with the big holes on the driver side of the block? One on the side below the water inlet, the other down along the pan rail below the rear water drain....
Er... What's with the big holes on the driver side of the block? One on the side below the water inlet, the other down along the pan rail below the rear water drain....
Good eye! those holes are for auxiliary oil drain-back lines from the heads. The factory failed to drill the original holes correctly in the heads, so I decided to take a note from the racing world and put some exterior lines in.
September 8th, 2019 | 04:51 PM
