Low speed surging - updated

[BellCityDubber]

well, I'm not sure about the pump internals being suspect. I mean, I trust giles' work.  But I digress I didn't come here to give praise...

What was a big tip-off to me was that the oil dipstick support was cracked.  it's not flimsy tin, it's a tad bit thicker, but it's cracked and leaving the dipstick hanging and just wobbling about.

I'm totally stealing the pictures, but this is what I think I see


in this picture is the injection pump bracket (duh)
I THINK I'm missing one of the rear bolts.  when the pump gets to a certain point it resonates and causes all kinds of hell.

the reason why I didn't pick up on it right away - as it got worse and worse would maybe the bolt have walked out, and the dipstick "picked up the slack" as to hold the pump from shaking, and once it broke - all hell broke loose?

it's really hard to get a set of eyes, or a picture of what I see behind my pump but I'll do my best to get a picture..

[stewardc]

My theory is that the low speed surging happens due to an improper transition from the idle spring to the main spring.  Under the right circumstances, the governor will keep bouncing back and forth.  Adjusting the residual pressure and idle screws should cure that if a cure is possible. 

This could very possibly be the truth, although this only started after I got 10,000km on it. I'll dig out a pump diagram and try to find that screw.

[BellCityDubber]

yup... so it's confirmed...



I do not have those two bolts that attach the bracket to the engine block behind/below the pump.

I know they're M8 bolts, and etka says they're 18mm long (I have 20s)... does anyone know the thread pitch?

I'm certain that this is the cause of my surging at cruising speed

[theman53]

M8-1.25

[BellCityDubber]

Thank you good sir!
I did NOT want to strip or crossthread the holes in the block!
Thank you for verifying this for me!

Etka says: M8x18 + wave washer
but no thread pitch??... that's strange.
my local hardware store had M8x20, but didn't specify what thread pitch either!


I also found out my rear transmission mount bolt wasn't quite torqued down as far as it should be... (with all the talk about mounts and such contributing to the problem)

once I get this fixed I'll report back.

Anyone in Southern Ontario Region have timing tools and can time my diesel for a price??

[Rabbit79]

If it's any comfort to you I had the exact same problem quite a few years back. One of my IP bracket bolts had fallen out and the other had broken off. Replaced them with a couple grade 10.9s and cured the surging. I can't remember what thread pitch they are but my local hardware store had them so they aren't anything out of the ordinary.

[BellCityDubber]

And to follow up...

I replaced the two bolts underneath and behind the pump. (thanks to a friend who had much smaller and more dexterous hands than mine)
well.. HE did it coz I couldn't manage to do it.

it cured my surging...
now I probably need to re-time it....

does anyone recall a thread on using a simple bolt style timing tool? it was a bolt with a like... gauge on it?

[ORCoaster]

I remember a thread that used a plain M8 bolt with a certain type of thread same one as the bolt in the center of the 4 outlet jets.  The smaller bolt in the center of that big hub.  You thread in the bolt and back up the cam in the pump and because each 1/6th of the bolt equals a given number of degrees you can convert the number of degrees you turn the bolt in or out to MM of length on the bolt.  I have done it and it seems kind of difficult to do with one person as you are always under the car then back up, under the car turning the front crank bolt then up to the IP to adjust the bolt again. 

Get a real gauge and keep it handy.  A little adjustment goes a long way.

[BellCityDubber]

Yeah, it was an m8 bolt with a thread pitch of 1 thread per mm... or something like that.

I'd really REALLY like to get my own set of timing tools but I'm really brokeass at the moment

[theman53]

No. The only metric fine thread I have found on these cars is the rear axle stub and pressure plate bolts. There are probably more but I haven't had the entire car apart yet.

The bolt is M8-1.25 which is the common or coarse metric thread pitch. If you get the 20mm you will be fine, it won't be too long.

[Thezorn]

No. The only metric fine thread I have found on these cars is the rear axle stub and pressure plate bolts. There are probably more but I haven't had the entire car apart yet.

The bolt is M8-1.25 which is the common or coarse metric thread pitch. If you get the 20mm you will be fine, it won't be too long.

The banjo bolt for the turbo oil feed like that comes off the oil filter house/cooler is a M12-1.5, Took me days to find a bolt that size..Living in a small town doesnt help either though

[theman53]

Yeah I forgot about that one. The feed fitting is the same.

Also, I think the injection pump hole for the dial indicator is M8-1.0 but that is a special bolt anyway.

[ORCoaster]

that is the one I'm referring to.  I actually took the bolt out of the injection pump and took it to our local Ace Hardware.  The stock a killer amount of metric for some reason. Everything form the common black to stainless.  They also have all three pitches in sections.  So I just figured to get the correct bolt take it in.  I had to search every M8 place till I found the right one.  It cost me a whopping 1.36 or something like that.  Surely you can afford that!   The exact number of degrees per X mm are on this thread somewhere.  Or is it in the Hillbilly tuner section on another forum.  Moderator would know as he is on both. 

[fatmobile]

I've had those bolts come loose before,.. I always blue locktite them now.

[R.O.R-2.0]

that is the one I'm referring to.  I actually took the bolt out of the injection pump and took it to our local Ace Hardware.  The stock a killer amount of metric for some reason. Everything form the common black to stainless.  They also have all three pitches in sections.  So I just figured to get the correct bolt take it in.  I had to search every M8 place till I found the right one.  It cost me a whopping 1.36 or something like that.  Surely you can afford that!   The exact number of degrees per X mm are on this thread somewhere.  Or is it in the Hillbilly tuner section on another forum.  Moderator would know as he is on both. 

1 turn on the bolt is 1mm travel.. cause its a M8x1.0mm

theres 360 degrees in a circle, that would be a full milimeter.. its easy enough to figure out, but i would never rely on that bolt being perfectly exact. i would just use a dial indicator.. because its almost impossible to figure out your timing with a bolt unless you have that magnetic stick on degree wheel that the guy made with the bolt..