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View Full Version : First D24, advanced situation


hvguy
05-02-2010, 09:58 PM
Picked up my first D24 n/a from sanantonio about a week ago, it ran and drove but needed the cooling system replaced... the guy bought a gasser radiator and just needed to plumb in new lines... also replaced the alternator bracket that held the fan with some other style that oriented the alternator forward about 1/2 inch which mis-aligned the belts...

I ended up using some spare radiator hoses, galv. pipe, handfull of hose clamps and zip ties and BAM! cooling system fixed...

As for the alternator- I cut the back off the pulley to move it in which made the belt rub the bolt holding the alternator X_X so I shimmed the pulley out with 2 washer, I then heated red hot- the alternator tensioner bracket and hammered it flat then shimmed it out with 2 thin washers DONE!

Since I dislike all accessories except P/S and alternator I figured the fan would be a poor choice in harnessing what little power there is; so I zip-tied a pusher-type rad-fan to the condenser and Its back on the road!


Now that things are charging and cooling correctly, I would like to figure out how to advance the pump 1mm... I read somewhere about how to do this but it seemed a little over my head... but even the master had his first time.

I read into there being a cold start advance and I had noticed it on the pump... but fail to figure out how far it advances... I pulled off the little ball on the top of the lever that pushes the throttle and wire-tied it fully forward in hopes it would advance it quite a bit... all I noticed was a noisier idle and no gain in power...

Any ideas as to how I advance the pump? and I will be fitting a T3 garret to it very shortly so any improvements to the pump would be greatly appreciated.:D

pics as to whats going on:
"the lever I advanced is the one pictured with wire wrapped around it"
http://i41.tinypic.com/2urbiio.jpg

v8volvo
05-02-2010, 10:23 PM
Bad idea to do it using the cold start.... it will make it too advanced at idle, but not advanced enough at higher RPM. The cold start advance system bumps the timing up by about .3mm (measuring pump plunger travel at Cyl #1 TDC), but is only effective up to about 2000 rpm, after which point the pump's normal centrifugal dynamic timing mechanism takes over and it reverts to the normal warm setting.

If you want to properly advance the timing..... Well, first start by removing the wire from the cold start mechanism and let it go back to doing its thing on its own. Then you will need to get a few special tools. What you need is the dial gauge and holder that screw into the back of the pump and indicate where the timing is set. Without them you will have no idea what the effects are of the changes you are making, and you run the risk of doing serious damage to the engine, especially if you're not familiar with fooling around with the timing on these things and don't yet have your ear "calibrated" to know what timing settings are OK and which ones aren't.

You can get the dial gauge and holder for a VW 4-cylinder diesel, which are cheap and very easy to find (can get a set off ebay for less than $50). Once you get this tool you will be extremely glad you have it, since you will use it many times and it will make your adjustments much, much easier and more precise. The amount of time you will waste trying to find a way to do without it will cost you way more than the price of the tools. If you want to really get serious you can get the special Volvo tool, which is like the VW one but with a longer snout on the holder so that you can use it without first removing the vacuum pump from the head..... but the Volvo one is much harder to find and more expensive, so you may find the VW one suffices. If you have trouble finding one I have an extra I can sell you cheap.

The other tools you need are a straight 19mm box-end wrench (no angle on the head -- needs to be straight) and a "sprocket buster" tool (essentially a big lever with two prongs on it to counterhold the rear cam sprocket when you loosen the bolt). The rear cam sprocket is held in position on the cam only by the torque of the rear bolt, so what you want to do is change its position in relation to the cam, so that the pump, which is driven off the back of the cam, will be slightly more advanced in relation to the rest of the motor. You'll do all this with cyl #1 at TDC (set this before you even start, to make removing the vacuum pump easier and safer), with the cold start cable tension released by rotating the interlocking halves at the cable end (also before you start), and with the dial gauge in so you can see what you are doing. Book setting value is about .85, and I think anywhere between there and about .97 is good.

HOWEVER-- all that said, if the timing on your car is already correct, you are better off leaving it alone. Can't hurt to check it but if it is within spec I wouldn't touch it. A little extra advance is OK, especially on an older, more tired engine, but as you found it really doesn't make much difference in power. Advancing it beyond where it wants to be starts to reduce power, and can cause problems with overheating, high exhaust temps, and other troublesome issues. Your real power gains will come with the turbo, not from timing.

hvguy
05-02-2010, 10:44 PM
Bad idea to do it using the cold start.... it will make it too advanced at idle, but not advanced enough at higher RPM. The cold start advance system bumps the timing up by about .3mm (measuring pump plunger travel at Cyl #1 TDC), but is only effective up to about 2000 rpm, after which point the pump's normal centrifugal dynamic timing mechanism takes over and it reverts to the normal warm setting.

If you want to properly advance the timing..... Well, first start by removing the wire from the cold start mechanism and let it go back to doing its thing on its own. Then you will need to get a few special tools. What you need is the dial gauge and holder that screw into the back of the pump and indicate where the timing is set. Without them you will have no idea what the effects are of the changes you are making, and you run the risk of doing serious damage to the engine, especially if you're not familiar with fooling around with the timing on these things and don't yet have your ear "calibrated" to know what timing settings are OK and which ones aren't.

You can get the dial gauge and holder for a VW 4-cylinder diesel, which are cheap and very easy to find (can get a set off ebay for less than $50). Once you get this tool you will be extremely glad you have it, since you will use it many times and it will make your adjustments much, much easier and more precise. The amount of time you will waste trying to find a way to do without it will cost you way more than the price of the tools. If you want to really get serious you can get the special Volvo tool, which is like the VW one but with a longer snout on the holder so that you can use it without first removing the vacuum pump from the head..... but the Volvo one is much harder to find and more expensive, so you may find the VW one suffices. If you have trouble finding one I have an extra I can sell you cheap.

The other tools you need are a straight 19mm box-end wrench (no angle on the head -- needs to be straight) and a "sprocket buster" tool (essentially a big lever with two prongs on it to counterhold the rear cam sprocket when you loosen the bolt). The rear cam sprocket is held in position on the cam only by the torque of the rear bolt, so what you want to do is change its position in relation to the cam, so that the pump, which is driven off the back of the cam, will be slightly more advanced in relation to the rest of the motor. You'll do all this with cyl #1 at TDC (set this before you even start, to make removing the vacuum pump easier and safer), with the cold start cable tension released by rotating the interlocking halves at the cable end (also before you start), and with the dial gauge in so you can see what you are doing. Book setting value is about .85, and I think anywhere between there and about .97 is good.

HOWEVER-- all that said, if the timing on your car is already correct, you are better off leaving it alone. Can't hurt to check it but if it is within spec I wouldn't touch it. A little extra advance is OK, especially on an older, more tired engine, but as you found it really doesn't make much difference in power. Advancing it beyond where it wants to be starts to reduce power, and can cause problems with overheating, high exhaust temps, and other troublesome issues. Your real power gains will come with the turbo, not from timing.

aah, that sounds kind.... weird, the cam pulley is just held in place by the bolt? no key way? what should I torque it down to? 150 ft lbs? :p

how would I add more fuel to the engine in order for the turbo to be safely doing its job and not just running super lean. "ive been doing gas engines all my life, diesel is a new monster for me"

I read somewhere about grinding down the fuel pin? or something like that... any .02 on that conundrum?

now that I look at the picture closely... would I be able to just loosten that bolt on the pump housing and rotate it? like a distributor on an older model gas car?

thanks again for the quick response!

hvguy
05-04-2010, 10:44 AM
Anyone have this off-site link to the IP mod? something to do with the fuel pin... google is not helping me any =(

ngoma
05-04-2010, 04:31 PM
aah, that sounds kind.... weird, the cam pulley is just held in place by the bolt? no key way? what should I torque it down to? 150 ft lbs? :p
72 ft lbs is what the 1985 Volvo FSM specs, what year is yours? While you are apparently an ace mechanic, the VW IDI diesel seems to have eluded you all these years. Suggest you get the Volvo Greenbook manual before you start tearing into the engine too far. VW did many things that probably seem "weird" to you, as you are finding out.

now that I look at the picture closely... would I be able to just loosten that bolt on the pump housing and rotate it? like a distributor on an older model gas car?
You COULD do it that way (but there is more than one bolt) but run the risk of over stressing the hi-pressure injector lines (>2000 PSI) and having them crack or fracture. One of the harder replacement parts to find for these.

There are several more knowledgeable members on this forum; state your goals and budget and they can steer you in the direction to get the best results for the buck.

hvguy
05-04-2010, 10:36 PM
72 ft lbs is what the 1985 Volvo FSM specs, what year is yours? While you are apparently an ace mechanic, the VW IDI diesel seems to have eluded you all these years. Suggest you get the Volvo Greenbook manual before you start tearing into the engine too far. VW did many things that probably seem "weird" to you, as you are finding out.


You COULD do it that way (but there is more than one bolt) but run the risk of over stressing the hi-pressure injector lines (>2000 PSI) and having them crack or fracture. One of the harder replacement parts to find for these.

There are several more knowledgeable members on this forum; state your goals and budget and they can steer you in the direction to get the best results for the buck.

Biggest bang for the buck is more of my language =)

everything is done on the cheap... home-made turbo manifolds to intake manifolds, welding differentials or excessive silicone usage.

Im wanting to source enough fuel to the engine to aid the future turbo, and right now there is just enough fuel at WOT to get me to 65mph.

Over stressing the fuel lines? damn, sounds like something I wouldnt want to do... but is it possible to do that with just adjusting the timing? wouldnt it still be injecting the same amount of fuel but just earlier or later?


My current goal as previously stated is modifying the pump to inject more fuel per stroke to aid the added air... how would I go about doing this? As I previously read somewhere you can grind down the fuel pin?

Is there a short tutorial on this? or anyone that can just give me some measurements of how much to grind down and where its located and the gist of how to get to it..

=) thanks again!

BTW, its an 82 245GL wagon w/ m46 tranny oem exhaust system minus the mufflers.

not really any help, but this is what it looks like...
http://i41.tinypic.com/2ztcdiw.jpg

v8volvo
05-05-2010, 12:37 PM
You don't need much torque on the rear cam bolt to make it hold. The Volvo book spec is much higher than necessary. Clean all the oil and crud off the mating surfaces (back of the cam and front surface of the rear cam sprocket) to ensure a good, flat, tight, dry fit, then *lightly* oil the threads of the rear cam bolt and between its head and the washer. Then torque it to 30-40 ft-lbs. Will be more than enough to hold it in place, and will make it easy to get it loose again next time. The rear cam sprocket is not the crucial one, since if it does come loose there will be no lasting damage, the engine will just quit running until it is re-set. That's why it is just a flat fit, whereas the critical front sprocket is a taper fit and requires much more care. If that one comes loose, it means the end of the engine's life.

Timing it by moving the rear cam sprocket on the cam is the way to go -- avoids disturbing the position of the hard fuel delivery lines, and it is also much easier, faster, and more accurate than trying to move the whole pump.

HOWEVER: DO NOT BREAK THE BOLT LOOSE WITHOUT HAVING A WAY TO COUNTER-HOLD THE SPROCKET. If you try to break the rear bolt loose (or re-tighten it) with the cam only being held in position by the front timing belt, you will damage the front belt, and if that belt breaks, the engine is done. Many thousands $$$$ to fix it, if a fix is even possible, after a broken belt. YOU NEED MORE THAN JUST A WRENCH TO REMOVE THE REAR BOLT. You have to have a substantial tool designed expressly for the purpose of counterholding the sprocket and absorbing the torque, as well. Otherwise you can cause instantaneous engine destruction when you go to start it back up.

Sorry to word this so strongly, but unfortunately with a high-performance diesel engine like the D24, there is so little margin for error that you really can't afford to make even a little mistake when it comes to belts and engine timing. They are very unforgiving of errors and inexperience, and if you blow it up, finding parts to fix it will be difficult and very expensive. It's easy to do the job right, but you have to be prepared, and have the right tools and knowledge.

Might also want to have a look at your front belt and see if it looks like it's in OK shape.

It sounds like your car runs fine, so I would just not mess with it unless you have reason to suspect that the timing is not set right (smoke, hard starting, etc?). If you want to get the right tools and check it to see where it is, that would not be a bad idea, but don't try to start playing around with calibrations if you don't have the tools and haven't done your homework to make sure you know what you are doing. With a non-turbocharged engine, monkeying with timing and fueling will only gain you 2 or 3 HP, no more..... and if you don't know what you are doing it's more likely you will make the engine run worse, or potentially even do long-term damage to it.

That's a good-looking car. Don't see too many that color. :cool:

v8volvo
05-05-2010, 12:51 PM
You do not need to grind the fuel pin. Your pump is already capable of injecting way more fuel than the engine could ever need. If you turn the fuel up more than necessary, and the fuel-to-air ratio exceeds stoichiometric, you will not make any more power, just more soot and smoke, and that is bad for the engine, for your MPG, and for the environment.

You may want to read up on your diesel theory a bit. Diesels *always* run lean. At idle the fuel-air ratio is close to 1:100. If you add more air by installing a turbo, you do not need to be concerned about it "running too lean" under boost. Diesels are OPPOSITE from gassers. With a gas engine, detonation, high temps, and other problems result from running too lean. In a diesel, the leaner the better.... High boost and low fuel (aka a very "lean" mix at WOT) will give you nice cool EGTs and plenty of power, whereas too much fuel and not enough air will give you massive EGTs... yes, even if you DON'T have a turbo at all. In a diesel, the thing to avoid is OVERFUELING, not underfueling. There is no danger in not running enough fuel, only in running too much.

If you are going to add a turbo, start by getting it installed, working properly, and all dialed in......... THEN worry about adding more fuel.;)

Jason
05-06-2010, 05:43 AM
There is a sticky in the performance section on getting more power from your D24t that I wrote, that has lots of info on pump mods and settings. You have no fuel pin to grind, but that doens't matter, the non turbo pump has the same fueling capability as the TD pump. The AFC housing and fuel pin/cone is a fuel limiter designed to reduce no boost/low rpm smoke. You will have to do that with your foot rather than the pump doing it for you. More timing will add some mileage, and if its retarded pretty far getting it up to spec will probably add some power, but not much. I would at least check it before you go and try to add more fuel to the mix!

Jason

hvguy
05-06-2010, 01:16 PM
thanks v8 and jason!

It does look like I need some diesel knowledge... although now thinking about it... since diesels are always "WOT" as far as intake air goes... and it only controls the fuel...

Ill see if I can get some time off and fab up a manifold for it..


any tips on sourcing some oil pressure for the turbo? I usually T-off of the oil pressure sensor... or.. atleast thats what I did with my 5e starlet...:D

Jason
05-06-2010, 06:18 PM
I would save yourself the time and just buy a stock TD manifold. I would bet you can find one cheap, it keeps the turbo tight to the engine, wont crack or have stress like a homemade one probably will, and its already a standard T-3 flange so turbo options are endless.

Jason

hvguy
05-06-2010, 09:16 PM
I would save yourself the time and just buy a stock TD manifold. I would bet you can find one cheap, it keeps the turbo tight to the engine, wont crack or have stress like a homemade one probably will, and its already a standard T-3 flange so turbo options are endless.

Jason

i would buy one but diesels around here are few and far between...

I posted up on the wanted section but no takers yet.

If it comes down to it ill duct-tape one together if I have to... but if I can find an oem ill use it.