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#60
by
53 willys
on 30 Aug, 2008 11:10
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Some more info:
"So do you take the taper out of the shaft? What about the lobe that is on the shaft, near the gear end, that drives the vacume pump? Do you take that off as well?"
Reply:
"I take the taper out of the intermediate shaft as well as the bump."
From doing a bit of reading, it appears that the IM shaft is pretty rough, and I suspect, not very balanced.
:idea: I am going to put forth the hypothesis that the IM shaft being out of balance is one of the leading causes of the dreaded IM shaft bearing failure / flaking.
I would further suggest that balancing the shaft will reduce or eliminate many of these failures. :idea:
Interesting!!! Then how do you run the vacuum pump, once you've installed the new lightened/balanced/bumpless IM shaft?
J.R.
there is a gear on the end of the shaft for the vac pump...that part stays stock
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#61
by
53 willys
on 30 Aug, 2008 11:15
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that gear on the right drives the vac pump
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#62
by
subsonic
on 30 Aug, 2008 11:32
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Man I got my IM shaft just sitting here...I think I may throw it in the lathe today and turn mine down.
so did they take the tapper completely out of the shaft??
this should be a real easy job...I will weight mine before and after too.
Correct, taper was removed. After the old gasser lobe was removed, it is just a matter of removing the taper with a few passes until you have the same dia at each ends. You can also turn behind the gear a bit if you want. I would not turn it too much. Finish up with emory cloth. If you have the equipment or access to the equipment go for it.
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#63
by
53 willys
on 30 Aug, 2008 11:36
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Man I got my IM shaft just sitting here...I think I may throw it in the lathe today and turn mine down.
so did they take the tapper completely out of the shaft??
this should be a real easy job...I will weight mine before and after too.
Correct, taper was removed. After the old gasser lobe was removed, it is just a matter of removing the taper with a few passes until you have the same dia at each ends. You can also turn behind the gear a bit if you want. I would not turn it too much. Finish up with emory cloth. If you have the equipment or access to the equipment go for it.
Sweet thanks for the info...I just weighted it and mine was 3.0 lbs even on a digital postal scale.....
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#64
by
53 willys
on 31 Aug, 2008 13:37
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well I did it...it was real easy too.(since my work has a lathe)
MAN i can not believe the wobble this thing had in the lathe!!!! it was WAAAAY out of balance..now it is smooth as silk
here are my before and after pics...
before 3.0lbs
After 2.75lbs
so I lost about 4oz's.... I weighed it on a different scale and it says I lost 5oz's
the scale I used does not break it down lower so the numbers may be +/- 1oz
I would think this mod would be worth the balancing alone..the weight loss can just be a bonus...lol
Sorry for the crappy pics...iphone is a cool little phone but it sucks as a camera.
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#65
by
Mark(The Miser)UK
on 31 Aug, 2008 16:54
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Worthwhile is subjective. The part needed to be replaced, and he all ready had it at the machine shop. Turning the shft is a very simpy job. Cost should have been low. There is no question that the part is improved. Balance has been improved and weight reduced, both good things. Is it the same as a flywheel turned down to 10 pounds? No.
Does it help with engine performance / longevity? Yes.
Would I pull the IM shaft just to turn it? No way. If I had it out during an engine rebuild, and had the opportunity to improve it at a low cost, would I? I sure would. Lots of small improvments add up to a better engine, cost goes up, but you still end up with a better product.
A few thoughts...
The shaft certainly looks better. I didn't realise it was so heavy. So you took off about 5 oz's, probably not significant momentum wise. I wonder why it was tapered in the first place?.
How common is the diaphragm type of vaccuum pump compared to the rotor type? My thoughts are on the amount of 'work done' by the shaft and whether its pulsed. Additionally because the oil drive is taken off tangentially, I wonder if it causes a degree of bowing, which would increase with your machining? Would this be detrimental to the bearings?
I have yet to take one of these shafts out. Sourcing bearings in UK is not possible AFAIK! Which bearing usually goes first? Neither?
I wonder if loading of the 2 pumps is insignificant compared with pulsed and continuous leverage from the timing belt; correctly tensioned, let alone over tightened :?:
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#66
by
subsonic
on 31 Aug, 2008 17:23
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I just checked the dia on mine. It is still .70". I did not measure the length of the turned shaft but it is not very long. You would have to have some pretty good force on it to get flex.
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#67
by
gigaz2
on 31 Aug, 2008 17:53
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I never heard of a diaphragm vacuum pump, the lobe is there for a diaphragm fuel pump in the gasser applications.
I remember seeing a pic of it being used on a diesel, but on a early stage of development of the 1.5D.
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#68
by
monomer
on 31 Aug, 2008 18:09
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I never heard of a diaphragm vacuum pump, the lobe is there for a diaphragm fuel pump in the gasser applications.
I remember seeing a pic of it being used on a diesel, but on a early stage of development of the 1.5D.
it installs where the distributer would be driven on a gasser.
i've only even seen a diaphragm in use.
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#69
by
Duster 5.9
on 01 Sep, 2008 18:34
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dodge used this engine as a gasser. i think it had a mechanical pump which would be where the lobe was. not 100% certain though
question i have is how are the harmonics of this new engine? does it idle smoother?
i've made thousands of those shafts for other diesels, and unless someone overgrinds one they should all weigh the same.
my thinking for the taper is, the shaft was smaller going to the lobe, where extra material was added (for the lobe). then making it more balanced in gerneral but not very perfect.
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#70
by
Mark(The Miser)UK
on 01 Sep, 2008 19:29
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dodge used this engine as a gasser. i think it had a mechanical pump which would be where the lobe was. not 100% certain though
question i have is how are the harmonics of this new engine? does it idle smoother?
i've made thousands of those shafts for other diesels, and unless someone overgrinds one they should all weigh the same.
my thinking for the taper is, the shaft was smaller going to the lobe, where extra material was added (for the lobe). then making it more balanced in gerneral but not very perfect.
Maybe the mismatch of the lobe was counteracted by the sprung lever of the gasser pump. Is there a possibility of creating a lift pump for the diesel when it gets old... perhaps a gasser pump would do it?
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#71
by
Duster 5.9
on 01 Sep, 2008 19:41
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perhaps, but i would have to look at a dodge gasser to find out if i'm right on thefuel pump. would be a late 70's eily 80's before the 2.2 came out. also would the ve pump benifit a lift pump? i know dodge/cummins guys do it w/ ve pumps and p pumps when looking for power.
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#72
by
RabbitJockey
on 02 Sep, 2008 17:41
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a lot of vw people even put a lift pump in, like daves nearly 200hp jetta td. it'd nice to use something so oem like a carbureted rabbits fuel pump
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#73
by
RabbitJockey
on 02 Sep, 2008 17:43
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#74
by
Duster 5.9
on 02 Sep, 2008 20:00
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you guy's are right on top of it. so who is willing to try it?