1994 Diesel Suburban Build

[ctmaybury@yahoo.com]

Interesting spot for your battery. Do you have 2 batteries? I have a grid heater on the Cummins, and it is a power hog. I think you said you have glow plugs. They have to be just as big of a power hog. That combined with the high compression (extra work for the starter motor), you might need a second battery.

[COcyclist]

This build looks nice and tidy so far. I will be watching with interest.

Originally Posted by ctmaybury@yahoo.com

Interesting spot for your battery. Do you have 2 batteries? I have a grid heater on the Cummins, and it is a power hog. I think you said you have glow plugs. They have to be just as big of a power hog. That combined with the high compression (extra work for the starter motor), you might need a second battery.

The gel or AGM batteries seem to have more Cold Cranking Amps in a smaller package than the old lead acid batteries. That said, I live in a very cold climate and would want plenty of battery capacity if I needed to park outside overnight. I kept a lithium ion boost pack in my Grand Cherokee CRD before I sold it. It helped if the battery was a little low.

[aardvarcus]

Ctmaybury,

Yes the Suburban came factory with two batteries, but I am planning on only going back with one. The main driver for this was weight savings. (Yes my friends think I’m nuts.) The concern with this as you alluded to would be excessive voltage drop when the starter and other accessories pull large amounts of current. I did consider this and to compensate, I went back with a gear reduction starter versus the stock direct drive(lower current draw), am using an odyssey AGM battery which has very low internal resistance, and am using very large battery and ground cables (1/0 and 4/0 versus 4ga stock) with much lower resistance. With these modifications the starter should draw less and see less voltage drop so I don’t think starting will be a problem. Also since I will be manually controlling the glow plugs, I don’t plan on using them while I start, instead I plan on using them right before I start (like I do on my diesel tractor). And if it doesn’t work I can always add another battery.

Yes it is an interesting spot for the battery, and wasn’t my first choice. I wanted to relocate it out of the engine compartment and get the weight further back and lower down for better handling. I wanted to put it in the trunk, but that will cause issues later when I do some future planned modifications. My second choice was frame mounted, but it was too tall to fit where I wanted and would have been a maintenance and waterproofing headache. I wouldn’t normally suggest a battery inside the cabin due to off gassing, but this one is sealed AGM.

Cocyclist,
Thanks. I am trying hard to not to cobble it just to get it finished. That’s a good idea on the boost pack. I also have considered some assisting capacitors if it needs just a bit more oomph.

Edit:
Oh, and I appreciate all the feedback, it helps me make sure I haven't missed anything!

[ctmaybury@yahoo.com]

That should work fine with one bat. Manual switch on the glow plugs is a good idea. I think I'll do that too. On my truck, the computer turns the heater grid on when iat is low enough, even after the engine is running. The headlights dim and the idle drops about 50 rpm. I don't feel it's needed after initial startup in the morning. If the engine is fresh and compression is good, it shouldn't need the extra heat. Still keeping the second bat though. Live and work in the mountains, sometimes way out in the wilderness. Just put a fresh set in about 2 weeks ago on one of the trucks.

[grabowski]

I drove my '94 K2500 6.5 for a short time with only one battery connected, didn't get very far until it stalled out. I forgot to install the positive crossover cable, both batteries are 880CCA. May want to test how far you can go with one battery hooked up.

Keep up the good work!

[aardvarcus]

So I did a ton of work on the Suburban over the holiday break. Routed lots of wires and cables, fabricated an aluminum upper radiator shroud to integrate my electric fans, hooked up lots of assorted parts, terminated and troubleshot the wiring, added fluids, and generally worked on it as much as I could. Rolled it out of the garage yesterday and started it up.

The engine ran fine, but it was making a thumping noise out of the intake. I am guessing it is a valve not opening, so I will have to pull a bunch of stuff to get back to the valve covers off to have a look. Hopefully it will be a simple fix and not require pulling the heads. Note I never pulled the valvecovers before swapping this engine, the bottom end looked so clean I assumed the rest was in similar condition.

Anyway that sucked the wind out of my sails a bit on the project. I have a few in progress pictures showing the fan shroud but I was too disgusted to photograph it last night. But what fun would a project be without some hiccups.

[grabowski]

Originally Posted by aardvarcus

The engine ran fine, but it was making a thumping noise out of the intake. I am guessing it is a valve not opening, so I will have to pull a bunch of stuff to get back to the valve covers off to have a look. Hopefully it will be a simple fix and not require pulling the heads. Note I never pulled the valvecovers before swapping this engine, the bottom end looked so clean I assumed the rest was in similar condition.

I had the same situation with my military takeout. With a long screwdriver on my ear, I was able to find out which hole was unhappy, #7 in my case. You do not pull the heads to R&R the lifters! Be very careful removing the valve cover so not to bend it. These VCs do not use gaskets, use The Right Stuff 'glue' for the best results.
If you have a point and shoot IR thermometer, once the engine is up to operating temps, you can use that to find the bad hole as well.

[aardvarcus]

Grabowski,
I wish I had read your post before now….

So I pulled the valvecovers off, bending them in the process. They had been installed with very large amounts of permatex, and would not come off by normal techniques.

All the valves and lifters looked fine, and turning the engine over by hand didn’t show any hiccups. After much inspection and deliberation, I put everything back. I tried to get the valve covers flattened out, with moderate success. I used a gasket (as I hadn’t seen the above post) and some RTV to reinstall.

Restarted the engine, sounded the same. I tried 8 or 10 different things to locate the sound. I tried the screwdriver trick with an old stethoscope, all areas sounded the same. I tried pulling the accessory belt, changing the fuel lift pump, disconnecting the fuel lift pump, holding the clutch, and several other things. I timed the noise to try to determine if it was at crank speed or cam speed (it is at neither…).

After discussing it with a friend, I turned to youtube to listen to videos of 6.5l engines running. They all sound just like my engine. After letting two other people experienced with diesels listen, they all say it sounds fine to them.

So at the end of it all, it appears that I was chasing an imaginary problem. A guy who was helping me when I started the engine the first time had said that noise was a problem, and I took that and ran with it. I drove the truck around my property and it seemed to run and drive just fine.

The valve covers are already starting to leak, apparently the recommended 20 ft-lbs of torque crushed and split the fel-pro valve cover gasket. So it will be new valve covers, no gasket, and some RTV sealer.

So the project is going to progress, I need to so some more legwork on the remaining wiring for the lights and accessories, and then a final push to get all the odds and ends installed.

[grabowski]

Where did you get your motor from?

Here is one of my "whoomping" videos: https://youtu.be/Jkf7dFGehis

[grabowski]

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