CAT 3406 engine

[fastline]

We were looking at an old scraper with this engine. When being started, the owner boosted it with a little ether before cranking. Even after that, it cranked for about 5sec before popping off. I was kind of surprised he used ether at all in warm weather but more surprised that with it, it did not just take right off. Is this typical of the 3406 or is this something to be concerned about? I know on our old excavator with a 3208, I cannot let go of the starter fast enough. It takes off instantly, even in 30* weather. No ether needed.

I listened to another 3406 start today and it started fine. A puff of black smoke and it was going. I know the previous old bird has been doing a LOT of sitting so maybe just a combo of old fuel, injectors, etc? I usually just pay close attention to blowby on a diesel to estimate engine wear but not sure if this points more to IP issues or wear? It seemed to carry more white smoke than normal but it was dark so I could not get a good look.

 

[250c]

I always get nervious seeing the either can come out. I judge the blowby by comparing it @ startup and after it's warmed up if it increases as the temp goes up it means a lot of wear to me.

 

[Nige]

A 3406 should fire up within less than a couple of seconds in temperatures like they are at the moment. Ether means major issues, most likely blowby. Walk away, or better -run. That is unless you can get it at a knockdown price that will cover a rebuild and replacing parts as necessary.

 

[DPete]

Not typical, a healthy 3406 with mechanical injection will start first reveloution in warm weather. It doesn't get real cold here but we have never used starting fluid down to 30 degrees.

 

[Birken Vogt]

I am no expert on 3406 engines but if it is a really old one, like early 80s or late 70s (?) they had some versions that were pre-chamber and not direct injection. Many (most?) types of pre-chamber engines will not start without glow plugs ordinarily when cold, but if the glow plugs are not functional ether will work also.

Just another thought, that if this motor is a 3406 PC, and the glow plugs are not working, it may not be totally shot. But I would still be suspect.

 

[fastline]

I can tell you this is about a 1968 version and pretty sure it is prechambered and I know it does not use glows. Glows with ether = bad things. I need to find more info on these engines. That may be the big difference. I know our 3208 is DI without glows.

 

[D6 Merv]

3406 did not exist in 1968. Only its grandaddy the 1693, or more commonnly D343. 3406 came out about 1978, and yes early ones were pre chambers with glow plugs. All pre chamber cats need heat to start, unless engines warm or real warm temps.
Most early 3406s were truck engine spec only. Cat didn,t start fitting them to scrapers untill later in the piece and most if not all were DI by then. Although alot of people with D336 powered 621s usually repowered them over rebuilding them

 

[fastline]

That is very interesting and might require me looking more into this mess. I know that I looked at one scraper that is supposed to be a 1968 (the one mentioned) and it did not start that with even with ether. The other one was supposed to be a 1972 and started right up. It loped a bit at idle like it was hunting for some reason. Not sure if idle was set to low or what but seemed to smooth out with a little throttle.

 

[fastline]

After a little looking around, it looks like this is indeed a 1693 or D343. I am curious if these are one in the same and if not, how you tell the difference? I know these are not glow engines, I know that. Pretty sure about the PC configuration.

 

[D6 Merv]

If slow to start using ether; leave it behind. Have 2 pre chamber and 2 DI cats and all will start at 32f without smelling salts. Got a old HD6ep that needs a whiff when cold, but its as old as its master, and those single plunger bosch pumps can get abit tired. Also like its master !

 

[D6 Merv]

1693 and D343 are basically the same. 343 was the indusrial engine. 1693 was the name for the truck engine spec.
Only real way to tell difference is through the serial numbers. All these are pre chamber engines with glowplugs. You can,t see the plugs they are under that big flat rocker cover, under the twin overhead cams, screwed directly into the chambers in the 4 valve head.
1693 came out in 380 and 425hp models. very little could touch the 425 in a hill climb. Was alot of DW20s here repowered with 380hp engines. And they really did go like a cut cat ! Have a look at some of the threads in the scraper section. No bull these things could do 50mph ! They were still running them up till 1998 pushing with D9Ls. Looked abit like the spaceshuttle pushing the ark !

 

[Birken Vogt]

3406 did not exist in 1968. Only its grandaddy the 1693, or more commonnly D343. 3406 came out about 1978, and yes early ones were pre chambers with glow plugs. All pre chamber cats need heat to start, unless engines warm or real warm temps.

If slow to start using ether; leave it behind. Have 2 pre chamber and 2 DI cats and all will start at 32f without smelling salts. Got a old HD6ep that needs a whiff when cold, but its as old as its master, and those single plunger bosch pumps can get abit tired. Also like its master !

I am taking this OT a little but for my own edification, your responses are a little bit confusing to me. You state that all PC Cats need heat to start, which I thought was the case, but then you also say that your 2 PC Cats will start to 32° without ether. Do you mean that with the heaters working?

All I was saying originally is that the heaters may have been non functional on the original one in question, and the owner never bothered to fix them, using ether instead. I have been guilty of this a time or two in my life.

 

[fastline]

He said "heat to start" which I read as glow plugs. However, I am still thinking these are not glow engines. For instance, our D339 in the D7 is a PC, non glow engine but because of the pony, you can get it pretty warm before bringing in fuel. However, this might not be the case with all though. I looked at two different machines, both nearly identical in every way and probably even the same model year but one fired right up when cold with just a puff of black smoke. The other was started with a 2sec hit of ether in the intake, then intake closed up and started about 20sec later. It stuttered and coughed on start up and took a bit.

So I guess I am still unsure what is considered normal for these engines. I know from experience with my GM 6.5L TD, 22:1 CR PC turd that if the glows are a no go, you have absolutely no chance of starting without some help. However, I consider that one of the worst diesel engines on the planet.

 

[paulsoccodato]

I have a 1693 in an Oshkosh wt2206 plow truck. The engine has about 17k miles on it and absolutely will not start in any weather without heating the glow plugs when it's cold. After it is warm, it starts without them.

 

[D6 Merv]

Birken. The pc engines have to have heat to start at any temp below 25C All mine will start at 0C [32F] without ether but pc needs heat about 90 seconds of it. DI will start without any assistance. Once engines been running and warm they don,t need any heat.
Quick check for glowplugs is to watch the draw on the ammeter while heating. Each plug should pull about 5 amps. ie if its a 6cyl engine and only pulling 10 amps when switch is in heat position. Chances are only 2 plugs are working !

 

[chevota84]

1693's sound awesome when they're running and are very expensive when they aren't.

Sent from my DROID X2 using Xparent Blue Tapatalk 2

 

[catken]

What model of scraper is this? If you tell what model it is you can get the correct info!

 

[fastline]

This certainly is not a truck application and is a CAT product so I am pretty curious as to which engine was actually being used and at what HP rating. I understood these to be 400-425HP but now not sure.

This is a 633, not a 633C. I want to say they were made 1968-1969 until the C model came out in 1970 with a single air cleaner can. I am not super familiar with them though. I would not know how to ID the specific engines. I cannot remember in the cab if there was a glow position on the switch or not. I was not the starter guy.

 

[tctractors]

Glow plugs are used only in Direct Electric Starting systems fitted to PC engines, in seat starting via Donkey engines or hand start Donkey engines that are fitted as the starting method do not use heater plugs in the main engine, this thread seems to lack information on the Motor Scraper model and any serial No detail?? it would seem everyone is having a pop at what engine might be under the hood of what??? the twin cam D343 would seem to be a fair bet but a bit more info would sort thing, or a pic.

 

[d9gdon]

I saw a 633 scraper last week and it had a D343 in it. There was a 633C sitting next to it that had a 1693 in it, or at least the decal on the valve cover had that on it. I have a feeling that the engine was replaced at some point cause they came with the D343 also.