August 9, 2021 - The adventure begins! This is the way the Blazer's 6.5 looked this morning, after spending yesterday installing new cam bearings (then re-installing the cam) and setting the new crankshaft/bearings into the block. The engine shop that did the machining had already installed new cam bearings, but unfortunately they weren't installed with the oil holes clocked correctly. So, those cam bearings had to come out and a new set of std Clevite cam bearings had to be installed before the original cam went back in. Of course, all of the cam bearing journal clearances were mic'ed before installation. I did use a piece of 1000/1500-grit wet/dry sandpaper (used wet with WD-40) to polish the cam journals and lobes first - followed by a liberal application of assembly lube and motor oil.
I think the mistake in oil hole location was due to the fact that the engine block has to be upside down when installing cam bearings. The GM service manual's cam bearing installation instructions call out the "clocked" position as though the block is sitting upright and you're facing the front of the block. The theory in oil hole clocking is based on the fact that the incoming pressurized oil has to be applied to each cam journal just ahead of the highest load region of the cam as it rotates - to allow for the thickest oil film on the journal in that high load region. Incidentally, the highest load on the cam is always on the bottom 120 degrees of the cam due to the force applied by the valve springs onto the lifters (and the side load produced by the oil pump drive & timing set).
Installing cam bearings isn't that difficult when you have the right tool and follow the instructions. Before committing to installing the new bearing set, you could practice re-installing the old bearings (after having removed them), to get a feel for it. The cam bearing installation tool set I used was purchased just for this project. It cost about $100 from an online tool company if I remember correctly. The tool set is easy to use and not hard to figure out. I watched a few YouTube videos... And, I recommend taking a few photos of the original cam bearing installation so you know what "centered" looks like, or how deep to drive them. This sort of info is helpful when doing it the first time...
Since this photo was taken, all of the pistons/rods have been installed along with the 16 roller valve lifters and the oil pump. The new std bore pistons were all outside diameter mic'ed along with the inside diameter of the 8 cylinder bores, and time was spent matching the minor differences in cylinder bore dimensions to the minor differences in piston diameters. The result from all the piston matching is near perfect (GM spec) piston clearance across all 8 pistons/bores, including the slightly larger spec'ed clearances for the #7 and #8 (rear) cylinders. I also spent some time looking through the various and sundry boxes of parts in preparation for the next step in assembly. Haven't found everything yet, but it's early! I wasn't the one who disassembled this 6.5, so my foggy memory, our 6.2L/6.5L Diesel Troubleshooting & Repair Guide and the GM service manuals (for rebuild specs) will have to suffice with the re-assembly process.
Onward and upward... My daughter helped me a few of the weekends during the two separate Duramax head gasket replacement projects we completed recently. After a couple of weekends, she looked over at the 1994 Blazer sitting there in the garage with us, and calmly asked what I was going to do with it - such a poker face... Long story short, it's now hers, and we'll work together to make it go. She's a trooper, likes learning and enjoys spending time with her dad. Plus, she'll have a rig to haul a kayak and do some vehicle camping with her friends. We have quite a road ahead of us. Stay tuned!
Jim
September 2024 Update - What follows is a recent addition to this forum thread, in the form of a video that represents the culmination of our 6.5L Turbo Diesel Blazer Project. There's more to come, for sure, but this YouTube video will help to bring you up to speed about where the Blazer Project was in early September 2024 - some 3 years and thousands of miles after the process of engine restoration began. The video shown here is a great addition to the story, but... this forum thread still provides a lot of detail and granularity that just couldn't be a part of the video. So, I encourage you to read through this forum thread to learn more about the repairs made to the Blazer and its 6.5L diesel engine. As always, your questions, comments, suggestions and advice are all important. If you found something of value here, please "like" the video and "subscribe" to our YouTube channel (move your cursor over the little circle with the red truck in the upper left of the video image), and let us know what you'd like to see in the future. Thank you.
Video Introduction: This "Murdered Out" 1994 6.5L Turbo Diesel Chevy Blazer was brought "Back from the Dead" after the engine sat disassembled in a thousand pieces for over 11 years. My daughter and I worked together to solve the problems caused by melted pistons, a gouged crankshaft, and cracked cylinder heads - resulting in a great 6.5L Turbo Diesel powered Chevy Blazer.
Had fun with this one! Check it out. There are some brand new clips in this 18+ minute video that haven't been shown before... including at the very end where the loaded Blazer is the subject of a video clip that was shot at a scenic location far-far off the beaten path on our way to a high mountain glacial lake here in beautiful western Montana...
Incidentally... this Blazer has an excellent sounding exhaust system that produces a low rumble under acceleration. This sweet sound can be heard in the video when using headphones, but my computer speakers apparently don't reproduce the lower frequency sounds. The fairly short 3-1/2" in 3-1/2" out muffler was a Kennedy product back in the early 2000's. Let me know what you think...
Jim