Anyone on here familiar with that engine?
4.5"x5.5" V-8 double over head cam front and rear timing gears, pre cup injectors called a 1676 in a truck 54B. A 42H in a 980 wheel loader. Never seen one. Bob
I know where one is, just setting in a set of KW frame rails. Only one I've seen. Thanks Bob.
That is a good place for it. Bob
From what I have been told through the years it was a turd.
Well I have to admit I did rebuild a couple of those 42H engines. Lots of timing gears up both ends and the balancer weights down near the bottom. One thing that I thought was neat or strange is you did not use a feeler gauge to set the valves by the service manual. The adjusters had swivel feet on them that pushed down on the valve stem and the screw to adjust them had notches around them with a spring finger that held them from turning! Procedure was to use bolt in flywheel housing to lock in position to set valves, if I recall you did half them then rotated crank 180º and did the others. The actual settings were done by turning adjuster down till there was slight drag on the swivel feet then back off a specified number of "clicks". One thing that no one ever explained to me is why the rods had a very thin edge on the big end that ran against the crankshaft. At least one of the ones I worked on had groves worn in the crank from this thin edge. Crank was sent out to a shop that rebuilt it not sure if it was welded or chromed but brought back to standard. That must have been 30+ years ago so memory is a bit rusty! Also seem to recall that there was a larger version of that engine, something on the 5.4 bore size that was made in 8 and 12 cylinder versions. Seem to recall one of those was used in a 773 haul truck.
Was it moreless the 3408 predecessor?
It's a 4.5" bore so more like a 3308 that wasn't. Bob
The D346 is a 5.4" bore V-8 overhead cam. Bob
and was rated at 340 hp in highway truck app.
Very few were sold for on highway, had to be a fuel guzzling engine. Too many moving parts.
And with all those gears and cams I imagine it was not cheep to build. Also as I recall at idle it made all kinds of rattling noises. Separate intake and exhaust cams so every time the lobes for one cylinder went past full open the cam followers would snap the cam it the direction to take up the back lash in the straight cut gear train. There was also a 5.4 bore 4 cylinder inline "D340?" engine that was the same with the snappy clattering noise at idle. I believe the six cylinder truck engine version was a 1693 if memory is working the version used in off highway equipment was call the D343.
More than a 2 stroke Detroit?
twin gear trains.
That That is correct and I have two 1693TA/D343 engines. They have a sound of their own at idle.
The D343 was a 6 cylinder double over head cam.
Yep! Worked on many for those in the 988 Front end loaders before they came out with the 988B which had the 3408 V8 The 769 and 769B Haul trucks used the D343 as well as well as other machines.
The 5.4" x 6.5" engines. The D343 I-6 has one timing gear train on the back of the motor and uses a cam follower that sits on the valves under the cam. These are the ones that the valve lash is adjusted with a philips screwdriver. The D346 v-8 D348 v-12 and D349 v-16 have rocker arms under the cams and a gear train on both ends of the motor and that makes a lot of noise. All are spacer plate motors and overhead cams. The I-4 was used in a 619 scraper wheel tractor and used that serial number, and was not a spacer plate motor. Bob
1693TA in my 1978 Mack RL755LST: Factory set at 425hp and runs very well.
D343 Originally from a Oshkosh P-40 airfield crash truck. I'm told this one is set at 550hp and it runs very well/strong, but I have no proof of anything but the size of the radiator in the truck would surely support the rating: I found two snapped studs for the cam boxes when I went adjust the valves so removed the camshafts to extract the broken studs: Valves with adjuster caps you adjust with a #3 Phillips screwdriver for clearance to the base circle of the camshafts: Here is an adjuster:
Pull the rack screw.
If you moved the motor make sure the cam gear and the cam are timed before you torque the cams down. What's the serial number on the red engine? Bob
I brought it to TDC on #1 and ensured all marks aligned before pulling the cams. I have not rolled it over at all since being put back together. Interesting engine for sure. I could use a conventional fan drive assembly for the front of it too as it swung a 30' diameter "pusher" fan blade. This truck was responding to an "inflight" emergency on an airfield and exploded the transmission behind it breaking the flywheel from the crankshaft hub. I have photos of that mess but haven't found them yet. I installed a replacement 15" flywheel and indicated to ensure the crankshaft was not bent before starting the engine on the floor. Nothing ascertainable wrong and the engine settled down to a nice idle once the injectors purged the air. Didn't let it run very long as know well how these engines were on heads. I'll get the serial number and arrangement tomorrow when out to the shop.
Kind of gives a flash back to working on the old 988 Cat loaders! Recall one problem we had with the bolts that held the cam housing and cover on was one or two of the long 3/8 inch bolts were in slotted holes in the valve cover. In your pictures I think it's back near the breather. Dirt and water would get down the side of the bolt(s) and cause them to seize up and a simple job of pulling the valve cover to replace a bad glow plug would get bigger fast. I did have an extra long grade 8 bolt that I ground a couple groves in like a tap that could help clean out the threads if I was lucky and original bolt did not break when removing the cover.
That is what started this one. The two bolts at the left rear and kind of close to the hot side of the turbocharger snapped off. They were corroded almost 1/2 way through the shanks and snapped very easily but flush with the head surface. One other bolt was already broken and there was a slight oil leak. I couldn't see any other way to remove the cam boxes without removing the cams first. I was surprised this happened but didn't really have any maintenance routines for the engine so made a tool to remove the rear plug to remove the cam driveshaft, ensured any marks I could find were in mesh, and pulled it apart. It was easy to extract the broken bolts with just a bit of heat on the inside of the "bosses" and that gave me no problems. I did "meter" the glow plugs to ensure they were good and found none open so buttoned it back up. I hung that engine from my gantry with a crane dynomometer and it weighs just over 3550 pounds as seen in those photos so no slug for sure.
As I recall the cam drive shaft has a missing spline or some way to prevent installing it out of time. Not sure if I ever thought of it at the time but I would now be tempted to fill the notched out area of the valve cover with some high-temp silicone sealer after it is assembled to keep dirt and water out.
Yes, there is a missing spline precluding incorrect installation. There is a plug in the rear drive cover and I welded a nut to a grade 8 bolt and this became my tool for removing that plug which has a female recess. IIRC you then thread in another bolt or stud into the end of the driveshaft and it pulls out with finger pressure. I did run a slender bead of blue RTV when it was assembled. Also purchased sealing washers for under the bolt heads holding these things down. They were just a bit large for the recess so did not get used. That was following another's advice with past experience working with the engine series. I'd never seen one till purchasing that Mack tractor several years ago and the red engine just kinda fell into my lap from working on an airfield and knowing the ground operations guys.
The problem is not installing the quill shaft it's bolting the cams down then rolling the motor over to line up the shaft. The shaft only goes in one way but rolling the motor to line it up tends to bend valves. Check the quill shaft is not twisted when you have it out . Bob
Or one could do it the way the factory recommends, this is the way they said to do it back in 1972 when my manual was printed!:
Not sure what anyone wants to see but here goes: My home brew tool which worked very well although I thought I'd used a grade 8 bolt:
And just because nobody can do without some Detroit Diesel photos, here are a couple of my 12V-71T:
I think i still have a manual for that engine some where
As I recall the engines in the 988 had a lifting bracket that bolted on the back of the flywheel housing to cover up that camshaft drive shaft.
I ran into one of these blocks in a yarder years ago, it was set up as a D343 . The cat parts guy did some head scratching looking up the motor by serial number. 27U military serial number 1693 truck engine similar commercial 65B 2219 1693. That flywheel housing for a brakesaver . I bet that engine is 425HP. like data plate says . Bob
No brakesaver was on the engine. Was an automatic transmission however. My truck 1693TA has a Brakesaver and the much larger oil cooler supporting it. Red engine does not have this larger oil cooler, nor plumbing anything like the truck engine. The crash truck was "upped in power" considerably by the local Cat dealer, "Altorfer" when the airfield took possession of the truck from the air guard base across the field. A new and larger water and AFFF tank was fitted requiring more power was the reason I was told. Probably an overstress to the balance of the driveline components because when it came apart, it was violent. Wish I could locate photos as the damage to the truck is almost unbelievable.
Bob, Came across these engines also in Madill Yarders, had pictures of one in a Loggers yard, complete with the rad. Tried to buy it yrs ago not for sale. They Scrapped it a few months ago, it was 425 hp, they had a cat decal on them saying 9Lxxxx, hope I still have the pics, my favorite cat engine series D337f,1693,343, cracked heads were a problem
I meant a 27U numbered block ,The Cat parts guy finally figured out it was a military serial number and was originally a 1693 in an Oshkosh fire truck. Bob
I meant it has a brakesaver flywheel housing which is different D343 flywheel housing. If cat changes HP on a motor they usually restamp the data plate. The 550 HP sounds like a tall tale as that is more than a marine engine would have. I would hope they would have better sense than to that much more HP on that drive train. Bob
Thanks, It very well could be an exaggeration; but I have no direct history on it at all. I do remember the truck smoked like a locomotive under a hard pull and ran very well. These trucks are always "floorboarded" every time when making a response to get into position so live a hard life. The chief of the department told me the story of he sent it into the shop after the tanks and turret gun were replaced to be turned up in power and that 550hp figure is what it came back with. The radiator core size they installed was just over 5ft wide, almost 6ft tall and six rows. Wouldn't know where a conventional fan drive assembly could be had would you? The hub pilot on this one if far too large in diameter to fit a conventional fan:
Radiator was overkill.
Certainly was large, and heavy. I commented that it probably never got hot.
Went by the fuel shop yesterday (Altorfer) to drop off some injectors for rebuild and asked the guy whom has been there well over 35 years if he remembers the airport crash truck being "hopped up". He told me he did the work on the pump and injectors. Also referenced the service manager, (then technician and hot rodder) I should talk to as one of the two guys that actually did the work on the engine; (the other has passed away). The manager tells me the story I've been told is correct of the work on the engine after the larger tanks were installed. They suggested driveline upgrading but the customer, (airport authority) dismissed the idea citing cost. That was from memory as the truck was worked with about 1987-1988. The radiator and shrouding were repurposed from a stationary power generator installation and adapted to fit the truck supplied by the airport authority. I didn't think to ask but the rear guard, or plate for the rear of the truck must have been locally fabricated as it looked nothing original. Also didn't ask about a restamp of the data tag, but I think I will as he was interested in the engine and was surprised it still existed. We parted company as he took a call that was involved but thought we'd converse again. It must have done well for a period of years as the transmission, (or more correctly) transfer case came unglued in 2007 which was shortly before I received the engine. The above is just a regurgitation of what I've been told as I've not seen the engine run in many years now. It just sets on the floor in the back of my shop but it's not going anyplace soon either. This truck was replaced by an E-1 "Stryker" unit and they sure keep that one spit and polished. It has a 600 Caterpillar engine as does almost all equipment on that airfield citing Cat hangers their corporate jets there. Moline has all John Deere equipment over there due to that corporations presence.