Shimming a 200Tdi governor

[RRC200Tdi]

Shimming the governor in a Bosch VE FIP is a common practice in the VW world which use the same type of governor as the 200/300Tdi. The problem is these folks are running in excess of 6000 RPM with their adjustments and I have no interest in going anywhere near that high. My goal is to alter the fueling curve slightly to keep fueling up for another 200 RPM before it starts to taper off. I estimate that my fueling starts tapering around 2500 RPM, give or take, and I want to elevate that to around 2700 - 2800 RPM. I am not exactly sure when the governor springs begin to act on fueling. I pulled my governor out to study its operation and what I found is that the fuel arm uses a link-rod to pull on a lever that controls fuel delivery. There are three springs on this rod that act as part of the fuel governor mechanism. There is an idle spring, a mid-range spring and a high-range spring. The governor uses the spring tension of both the mid-range and high-range springs to push on the fuel delivery lever. There is also a rotating assembly with fly weights that use centripetal force to oppose the the spring tension, which all combined regulate fuel supply throughout the RPM range. The spring tension and fly weights operate in a balance, at lower RPM the spring tension exceeds the force of the fly weights, but as RPM increases the force of the fly weights exceed, first, the spring tension in the mid-range spring, then, when RPM get high, the spring tension in the high-range spring. In doing so, beyond a preset threshold, the fuel delivery is restricted.

VW folks shim these springs to increase the spring preload thereby increasing the RPM at which fueling begins to become reduced. In some cases they eliminate the high-range spring altogether and replace it with washers or short spacers. Some people shim the mid-range spring with as much as 5 or 6 mm of spacers, but of course they are chasing HP which we are not. I was able to determine which was the high and which was the medium by measuring the spring constant of each spring and I found the shorter spring (4903 N/m) was the high-range spring and the longer spring (1962 N/m) was the medium-range spring. These were crude measurements and the values were very small, so I could be wrong.

Unfortunately, from here I can't really calculate the relationship of the thickness of shim and RPM as the math becomes difficult because I don't know the force that the governor pin places on the fuel delivery lever at different RPM. I could add the shims and measure the delta of RPM when the power begins to taper, but I really can't quantify at which RPM that actually begins without a datalogger accurately measuring RPM versus, perhaps, turbo boost pressure. 

Has anyone attempted this before? If so do you have an idea about the relationship between thickness of shims for each spring and their effect on the fueling curve? If not, I will start with 1mm for each spring and try to estimate the delta and report back. 

[reb78]

I am pretty sure fourby sell the spacer for this. Might be worth a look? Might be a good place to start?

Edited February 5, 2021 by reb78

[reb78]

Here - https://fourby.co.uk/epages/950004277.mobile/en_GB/?ObjectPath=/Shops/950004277/Products/DTS01&Locale=en_GB

[RedLineMike]

43 minutes ago, reb78 said:

Here - https://fourby.co.uk/epages/950004277.mobile/en_GB/?ObjectPath=/Shops/950004277/Products/DTS01&Locale=en_GB

i believe @NRS91nick steggel was selling them before fourby, https://stegs4x4.co.uk/product/dynamic-timing-advance-spacer-kit/

 

 

However i believe they are a timing spacer rather than a governer speed spacer like the OP is trying to do,

 

 

 

[reb78]

Ah. Sorry. My mistake. 

[NRS91]

3 hours ago, RedLineMike said:

i believe @NRS91nick steggel was selling them before fourby, https://stegs4x4.co.uk/product/dynamic-timing-advance-spacer-kit/

However i believe they are a timing spacer rather than a governer speed spacer like the OP is trying to do,

Thanks for the tag.

Yea the OP is talking about the engine speed governor which lives in the top of the bottom half of the pump (just below the AFC housing which contains the boost pin).

The VW and Land Rover pumps use a "cage" style governor set up to resist the movement of the governor weights whereas Cummins uses a pull type spring. 
Joseph Buswell shimmed the governor cage in Drew Wrights challenge truck and it went really well!

[RRC200Tdi]

Thanks everyone for your input. I just placed an order for 6 mm x 11 mm shims for the longer spring and 8 mm x 10 mm for the shorter spring. I was not able to find shims in these sizes through normal channels, but found them quite easily from RC car sellers, FYI. I will update when I get them in a week, unless I find some shims or appropriate washers somewhere in my collection later today.

10 hours ago, reb78 said:

Here - https://fourby.co.uk/epages/950004277.mobile/en_GB/?ObjectPath=/Shops/950004277/Products/DTS01&Locale=en_GB

 

9 hours ago, RedLineMike said:

i believe @NRS91nick steggel was selling them before fourby, https://stegs4x4.co.uk/product/dynamic-timing-advance-spacer-kit/

 

 

However i believe they are a timing spacer rather than a governer speed spacer like the OP is trying to do,

 

 

 

Thank you for this. I actually have one on order as I was hoping to advance the timing a bit since my fueling has been turned up and I would like to shorten the injection event. I ordered one for  a cummins, since shipping is much cheaper and they are commonly available in the US. It should be here on Tuesday. I am hoping it is identical to the part offered by Nick (except for the Bosch O-rings, which I have a set of). If not I will have to order from Stegs and pay the overseas shipping charges and exchange rate 😞  

I will try to resist installing the governor shims and the timing shim/spacer at the same time so as not to confound the results, but it is going to mighty difficult since the timing shim is arriving first!

  

[RRC200Tdi]

5 hours ago, NRS91 said:

Joseph Buswell shimmed the governor cage in Drew Wrights challenge truck and it went really well!

Also, thank you Nick @NRS91, this really encouraged me to move forward with the shims!

[NRS91]

11 minutes ago, RRC200Tdi said:

Thank you for this. I actually have one on order as I was hoping to advance the timing a bit since my fueling has been turned up and I would like to shorten the injection event. I ordered one for  a cummins, since shipping is much cheaper and they are commonly available in the US. It should be here on Tuesday. I am hoping it is identical to the part offered by Nick (except for the Bosch O-rings, which I have a set of). If not I will have to order from Stegs and pay the overseas shipping charges and exchange rate 😞  

I will try to resist installing the governor shims and the timing shim/spacer at the same time so as not to confound the results, but it is going to mighty difficult since the timing shim is arriving first!

  

As yours is a 200TDi it might be ok, 300TDis and later UK Cummins VE cant run the American DTAS kit. Mine will fit them all. 

[NRS91]

1 minute ago, RRC200Tdi said:

Also, thank you Nick @NRS91, this really encouraged me to move forward with the shims!

Ive sent him a link to this topic so hopefully he can guide you a little.

[RRC200Tdi]

44 minutes ago, NRS91 said:

Ive sent him a link to this topic so hopefully he can guide you a little.

Thank you, Nick!

 

45 minutes ago, NRS91 said:

As yours is a 200TDi it might be ok, 300TDis and later UK Cummins VE cant run the American DTAS kit. Mine will fit them all. 

This is really good to know, for me and for others that are interested in this upgrade. I will definitely post whether or not my Cummins part will work. During my online research for the timing upgrade, I found that your's was the most recommended and highly regarded, many mentions and links to your site. Some others don't provide the spring-tension shim, which I am not sure how that affects the advance but I would steer clear of those.

[NRS91]

42 minutes ago, RRC200Tdi said:

This is really good to know, for me and for others that are interested in this upgrade. I will definitely post whether or not my Cummins part will work. During my online research for the timing upgrade, I found that your's was the most recommended and highly regarded, many mentions and links to your site. Some others don't provide the spring-tension shim, which I am not sure how that affects the advance but I would steer clear of those.

I'm honoured to be so well spoken of, I always try to use the best components possible and back it up with speedy customer service for those that need support, it is nice to see it paying off  

The shim provides the preload and controls the rate of timing advance, without it the timing would advance quickly and your vehicle would respond like you had moved the static pump timing which negates the benefit of using the timing spacer in the first place.
The shim I provide is custom CNC machined to a specific thickness that allows the maximum preload while allowing the full range of timing advance travel. Too thick and it will become coil bound first, too thin and the timing advances quickly. 

Hope this helps.

[reb78]

9 minutes ago, NRS91 said:

I'm honoured to be so well spoken of, I always try to use the best components possible and back it up with speedy customer service for those that need support, it is nice to see it paying off  

The shim provides the preload and controls the rate of timing advance, without it the timing would advance quickly and your vehicle would respond like you had moved the static pump timing which negates the benefit of using the timing spacer in the first place.
The shim I provide is custom CNC machined to a specific thickness that allows the maximum preload while allowing the full range of timing advance travel. Too thick and it will become coil bound first, too thin and the timing advances quickly. 

Hope this helps.

So a specific question on my pump. I think dieselbob advanced the timing slightly when he reconditioned my FIP. Can I still fit and benefit from one of these spacers?

[NRS91]

3 hours ago, reb78 said:

So a specific question on my pump. I think dieselbob advanced the timing slightly when he reconditioned my FIP. Can I still fit and benefit from one of these spacers?

Yes the spacer will still work as intended if its a standard spec pump besides the timing being set a little advanced.
Only thing to watch is if the the overall timing advance then becomes a little too much for the engine, it will rattle and diesel knock a bit and would just need the static timing retarding a little but its highly unlikely it would go this far as often they a little retarded to start with.

[reb78]

17 minutes ago, NRS91 said:

Yes the spacer will still work as intended if its a standard spec pump besides the timing being set a little advanced.
Only thing to watch is if the the overall timing advance then becomes a little too much for the engine, it will rattle and diesel knock a bit and would just need the static timing retarding a little but its highly unlikely it would go this far as often they a little retarded to start with.

Perfect. Thanks. When the pump was refurbed Bob said a slight timing advance would help as I run on SVO fairly often. Thats as much as I know about how far he advanced it! Otherwise, the pump is standard. I spend a lot of time on the motorway between 2300 and 2800 ish rpm (the overdrive helps keep the revs down) and others seem to suggest there are benefits around these engine speeds. I will give it a go I think. 

[NRS91]

4 minutes ago, reb78 said:

Perfect. Thanks. When the pump was refurbed Bob said a slight timing advance would help as I run on SVO fairly often. Thats as much as I know about how far he advanced it! Otherwise, the pump is standard. I spend a lot of time on the motorway between 2300 and 2800 ish rpm (the overdrive helps keep the revs down) and others seem to suggest there are benefits around these engine speeds. I will give it a go I think. 

Yes it will help make the engine feel more "eager" at those speeds and help maintain cruise.

[reb78]

Great. Looking back at my emails I am sure I discussed a slight timing advance but this is what dieselbob told me he did (in the context of SVO use and better performance):

'the use of stronger seals & a nice (but not silly) improvement to fuel delivery, this has been done without the need to change the boost pin.'

I will purchase a spacer from your site Nick and give it a go. 

[Snagger]

Bob did the same to my 200 pump, for the same reason.  I don’t need a performance improvement - I’m very content with the performance of that I give in my 109 and don’t want to add to any transmission stress, but would the spacer and shim bring smoothness or economy benefits?  

[NRS91]

11 hours ago, reb78 said:

Great. Looking back at my emails I am sure I discussed a slight timing advance but this is what dieselbob told me he did (in the context of SVO use and better performance):

'the use of stronger seals & a nice (but not silly) improvement to fuel delivery, this has been done without the need to change the boost pin.'

I will purchase a spacer from your site Nick and give it a go. 

Cheers!

5 minutes ago, Snagger said:

Bob did the same to my 200 pump, for the same reason.  I don’t need a performance improvement - I’m very content with the performance of that I give in my 109 and don’t want to add to any transmission stress, but would the spacer and shim bring smoothness or economy benefits?  

It may help the economy but the main improvements are that it will run cleaner, cooler and feel more responsive in the mid to high rpm range.

[Snagger]

I’ll do that, then, for that car and my 300 powered RRC.  Thanks.

[reb78]

9 minutes ago, NRS91 said:

Cheers!

It may help the economy but the main improvements are that it will run cleaner, cooler and feel more responsive in the mid to high rpm range.

It seems like a no brainer to do this really?!

[RRC200Tdi]

Now I am really looking forward to doing the timing advance 🙂

 

I reassembled my governor cage assembly to have a better look to see which spring compresses first and confirmed that I was wrong with my spring rate measurements. The weight I used was too small to properly measure the changes in length. Also, the method of just pulling the rod in the cage assembly, simulating what the fly weights would do at higher RPM, was a much more sensible way to identify which spring was the mid-range and which was high range. 

 

 

As the rod is pulled away from the throttle shaft, the mid-range first compresses until the two spring collars contact, then the high-range spring takes over, requiring more force to compress. I am not certain, but what I think is happening is that both the mid-range and idle springs are acting as a buffer to smooth out throttle response and not really govern anything. The mid-range spring will work with the fly weights to maintain a more constant rate of fuel flow when the driver is intending to drive at a consistent speed. This would keep minor fluctuations in throttle input by the driver from causing the speed to change, or when there are small inclines or declines on the roadway. Only when you apply enough throttle to fully compress the mid-range spring and  the RPM are high enough does the high-range spring become engaged. I think shimming the mid-range spring will improve throttle response and degrade driveability. Shimming the high-range spring will increase preload, requiring more force generated by the rotation of the fly weights, which means higher RPM. 

I am not sure how I feel about shimming the mid-range spring. On the one hand, more throttle response would benefit offroad driving, but on the other hand I am concerned that the RPM will wander at speed. However, another problem I suspect is that changing the amount of force that is required to engage the high-range spring, might make the mid-range spring too soft by comparison and there may need to be a slight increase in preload in the mid-range spring to offset this.  I wonder if not increasing the preload in the mid-range spring might make acceleration feel more binary--nothing and then suddenly full throttle acceleration--unless some shimming is used to smooth the transition from one spring to the other. These are things to consider before reassembly. Under other circumstances I would enjoy experimenting with different settings, but opening the FIP is messy and fiddly and I don't want to do it more than necessary.

Of course all of this might be rubbish and I have completely misunderstood how the governor system in the FIP works 🤣

[vulcan bomber]

I've not read all this, but the idle spring as you've labelled it is the start spring, that spring is what's responsible for the puff of smoke at start up and when the engine is running has no further effect on the running of the engine unless you try to stall the engine. 

[RRC200Tdi]

Thank you @vulcan bomber for this very helpful correction. Then perhaps the 'mid-range' spring alone acts as a throttle buffer to maintain speed under changing conditions, i.e., hills and inconsistent pedal pressure.