Injection pump timing- yellow dot?/ overheat

[mortskeg]

Having found many a post reminding me to "check my pump timing" and after receiving my neato german diesel timing kit in the mail today I set out to do just that. My truck is an 81 so it orig. had the 1.6D in there, pretty straight forward to find the specs for this engine. However, I have now procured a 1.5d engine to replace my ailing 1.5 gasser, and have come to find out that two different injection pumps were used on these models.

My manual gives adjustment (mm of lift) specs for "pump without yellow dot" and for "pump with yellow dot". This has caused me some confusion as there are some round plastic pieces on the pump that could be construed as being yellow, as well as smatterings of yellow paint here and there, I belive to show if the fuel enrichment screw has been tampered with. I was able to find one tidbit of info on the net (VW gtd page) that states:
quote:"the way you tell a 1.5 pump from a 1.6 is the 1.5 (most of them unless repainted when rebuilt) will have a large yellow dot on the bottom faceing the front of the car on the timing advance piston cover."

From this description I figured that if my pump was a yellow dot model then it should have a dot here: (see white arrow)
http://img.photobucket.com/albums/v400/glen_ekstrom/yellow.jpg
which mine does not, but you can see the yellow plastic.

So I am asking you diesel gurus out there- is my pump a "without yellow dot" model as I suspect? I found that my lift was set at around 1.25mm and the truck was running well after being warmed up, although with excess soot when given the goose. This is much closer to the "with yellow dot" spec of 1.15+/-.02mm than that of the w/o yellow of .86mm. I went ahead and set the pump to the .86mm spec but haven't run it yet as I was also RTV silicone-in' my oil pan and wanted to let the goo cure before dumping a bunch of oil back in 'er. Thanks if you know your 1.5 D's.

[mortskeg]

Well I guess I can't be bothered to wait so I fired it up this morning after letting it sit for the night for the oil pan seal to cure, drove it around the block and determined that it was really running like sh^t. So by process of elimination I ruled out the possibility that my pump was a "without yellow dot" pump and should not be timed to .86mm of lift.

After correctly timing the pump to 1.15mm the thing runs much better and has no more of the hesitation when cold as it did when I first ran the engine (timing was at that point to far advanced).

I will write Bentley in the morning and ask them if they can change their manual to read "pump with faded yellowish plastic cover thingy" so that others will have an easier time identifying their pump[:p] I have also written "yellow dot 1.15mm" on the front of my pump in black permanent marker so at least this pump should be good for the duration:D

[Darth Garry]

You should engrave it on the pump, permanant marker isin't as permanant as you would think.

Morts, my dad told me that on the 1.5's he would sometimes advance the timing a little more beyond spec (above 1.15) to give it a little more peppiness, and supposedly they burn a little cleaner. But he was drunk when he told me so don't take it to the bank.

I timed my Turbo pump to 1.02, but that's a no brainer, only one to choose from.

Garry

[mortskeg]

Cool, thanks. I was thinking about your 1.02 pic when I was timing mine to make sure I wasn't cheating myself by going on the shallow end.[:p]
quote:my dad told me that on the 1.5's he would sometimes advance the timing a little more beyond spec...But he was drunk when he told me so don't take it to the bank
You may ask his lush-drunk as$ http://www.websmileys.com/sm/drink/trink42.gifha ha what he (or you) thinks about my 1.5 running a little warm on the highway. In town driving it runs cool as a cucumber, but on the highway it seems like it wants to get into the elec fan realm. Something that my 1.6d only did going up hill. I tried experimenting with cruising in 4th vs. 5th (FO trans) and cold start knob in and out, but it didn't seem to differ much. I was browsing the GTD site and it seemed as though having the fuel turned up could cause excessive heat. I don't really want to pull the pump off and have it re-calibrated $$$ though. At least I know that the pump timing is right. That was easy enough to do. Any thoughts dark siders?

[DieselsRcool]

Mort
Check to see if your alt belt is good and tight. You also may have a waterpump with a slipping impeller(common). There have been lots of problems with the impeller slipping on the shaft when they get warm. Even new ones.

You probably are aware of it but here's a good VW Diesel site too.> http://www.vwdieselparts.com/forum/viewforum.php?f=8&sid=f824479a717b9ae4cd889ebb0e4dd503

[mortskeg]

Hey I don't think I've seen that sight. Looks like I've got some reading to do. Well I tightened the alt belt (probably too much but I wanted to make sure of no slippage) and the engine is still doing the same thing. Tomorrow I will see what the dealy-o is with the impeller (maybe just replace the water pump half-unit job) and test the thermostat, back-flush the rad and heater core and see what happens. If it still runs warm on the highway I'm guessin it's a fuel thing but I'll keep you updated.

[mortskeg]

Since it looks like I've hi-jacked my own topic I will add overheat to the title:D. I took out the thermostat this morning and couldn't get the impeller to slip at all, so ops check good on the water pump. I decided to see what would happen if I took it out on the highway without my new thermostat to see what would happen. Even cruisin under load at highway speeds, the temp needle wouldn't make it past the first line on the gauge, and my oil temp wouldn't go past 80C compaired to around 105C with thermostat installed (I don't have an oil cooler).

I can't imagine that a fully open thermostat would cause so much of a restriction that it would make that big a difference running without one. This is a new unit too, I had just bought it when I swapped the engine. I tested it on the stove and it starts to open right where it should at around 180F but I am going to pick up a 70C thermostat at the parts store today and see what that does for me. I'm guessin it's not a fuel issue, but purely a problem with the new thermostat (maybe I put it in crooked?) I don't know.[|)]

[vwabbitman]

u sure its not you thats crooked. i think all of us diesel guys are a little crooked...sometimes.

[Darth Garry]

What do you guys mean by "impeller slip"? Now that I have a new water pump in the 'doza I want to make sure it doesen't happen to me before I bolt it all together.

Garry

[mortskeg]

I guess it's a pretty common problem to have the waterpump impeller slip on the shaft; however, I couldn't tell you if it is more common on the water pumps with plastic or metal impellers as i have seen both. Also, I personally have not experienced this yet in 9 years of watercooled vw driving, 5 engines and 7 water pumps.
The gas bently has a procedure in it whereby you use about 5 screwdrivers and 10 hands to jam everything you can get into your water pump and pulley bolts/cap screws and see if it's slipping, but to me it seemed like a good way to loosen the impeller and make it fail prematurely but what do I know. For some reason I think they left it out of the diesel bentley but I may have just overlooked it.
I just like to get one screwdriver on an impeller blade and see if I can manually move to water pump pulley while holding the impeller still. But whatever works.:)

[DieselsRcool]

I've not had the problem myself but have read of guys having the same high speed overheat proble. Then checking the impeller when cold and finding no problem. After searching for the problem to no avail, then dropping the pump in boiling water, the heat causes the impeller to expand slightly and then slip. Sounds like you have isolated the prob to the stat but at least keep waterpump slip/fail in the back of your mind.

I know, one more thing to worry about.

[mortskeg]

Thanks for the good word, Dr. C. The water pump on the 1.5 gas I took out of my truck looks new so I can rob it off that if need be. I did get my wahler 70 deg cel. thermostat in this morning and it did the trick. No more hot on highway. It looked as though the wahler had a little bit larger diameter opening but I don't know why it made such a big differnce as my 82 deg thermostat was opening correctly. Anyhow problem solved......... for now. ha ha.[:p]

[DieselsRcool]

Ahhh... Nothin finer than when the ole putt-putt is runnin good.[8D]

[Darth Garry]

I'm thinking about what thermostat to put in the 'truckdoza, whether to go with the 70 or the next step up. I won't be driving the truck in the winter, and may be driving it through a few deserts on my trip next year. Any advice?

Garry

[mortskeg]

Well with my GTI and the old 1.6d I think I had about a 80 or 82 (180F) thermostat and the temp gauge would always run straight up and down, right in the middle. This seemed to work just fine. The fan switches I had would kick the fan on about 2 bars before the red zone, this was unsetteling when I first got my GTI but I got used to this as being a normal VW thing.
When I first got my pickup (1.6d) the thermostat was stuck wide open so the thing would only heat up when I was going up a good hill. As I was new to diesels I though that the engine was so efficient that it didn't produce enough heat to warm up. Well after enough trips over the cascades with no heat I finally figured that this was probably "not normal" and replaced the thermostat. The reason I bring this up is that I didn't notice any change in fuel economy with the engine operating at the proper temperature. I though that it would improve but it was 40mpg before and after.
About 2 years ago my fan switch died in my pickup, and the one that they sold me actually comes on sooner than the old one- closer to halfway on the temp gauge rather than waiting until 2bars from red. I don't really like this as it makes the fan run more than i think is nessessary, especially when I had the 82 deg. thermostat in it.
Today I took the truck out on the highway for an extended cruise, the 70 deg wahler stabilized the temp at about 1/3 of the way up the temp scale which is enough to keep the cab warm with the heater turned up, but you can tell that there is less heat avail. Also my oil temp runs over 10 deg cooler (close to 20 cooler) with the new thermostat at 90-95 deg on the highway.
So anyhow there is alot of info here but this is what I would suggest-IMHO: as long as you are running a thermostat you should avoid issues like uneven (shock) cooling and other exessive stress on the engine, of course just being liquid cooled avoids most of this. I can't see where the temp changes the economy much, so if it didn't change for me from no thermostat to 82deg, then I don't think there will be a problem with the 70. Having it run cooler may give me a little cushion if my fan switch decides to crap out again, I will be able to trouble-shoot sooner, rather than having it not kick on at 2 bars from the red and then- "oh there's the red". I don't know why my 1.5 is so picky but the 82 deg just didn't work for it on the highway. I guess wahler is good stuff, according to the parts guy.
If you decide that the warmer thermostat is for you, I would just make sure that you have the fan switch that kicks on at the higher temp. Otherwise your fan will start to run right after the thermostat has fully opened or just before. Eitherway the result is fan running way too much for my personal taste. Of course when I had my thermostat stuck open I wasn't even sure if my fan worked (never kicked on). Alot of jumbled thoughts here, hope they help.[:p]

[Darth Garry]

Thanks for the words man. It makes sense. I'll probably go with what my local parts guy has, the 78 degree one, cooler than stock, but not way cooler and see how that goes. You aren't joking about the fan especially in a 1.5 diesel. I could feel when the fan came on by feeling the lack of power. It's pretty funny actually. There was someone on the forum who could feel the difference in power between high beams and regular beams, now that's sensitivity. I also wired in a manual override switch on my fan so should I desire, I could turn it on at any time(like when I'm about to start climbing a big hill), which would help stabilize the temp even more.

Anyways, thanks.

Garry

[DieselsRcool]

Garry
You beat me to it. I was going to say I added a manual fan switch/relay to mine. One hot summer day(sounds good about now huh?) I was sitting in stopped traffic and I noticed the temp climb past where the fan usually kicks on, but no fan. Oh..oo.. No place to go and the temp was now over 220F, so I turned the cab heater way up, heater fan full on, with the windows rolled down, and the temp dropped back to 180 after about 3 min.:D

Something to remember.

[Darth Garry]

I've had to do that a few times (the turning the heater on trick). It makes a miserable day even more so, but the truck lived to see another day!

Garry