Fuel injection rebuild

Give details and pictures of your ACVW projects here.
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

So after what feels like 50 open-close cycles, the cam is spinning freely in the thrust bearings. It was definitely riding up on the edges as you can see on the photo.
I know I broke the rule that says don't use abrasives on the bearing surface, but there was no other way. I basically used a well worn flapper sander and 3 grades of scotch brite pads to sand and polish. I will still give it another polish with the final clean to try get out any small abrasives that might be bedded in the surface.


On to the centre bearing... Wish me luck...

Image


User avatar
fourier
Oil Cooler
Posts: 342
Joined: Fri Sep 26, 2008 1:21 pm
What model do you have?: '59 Ghia, '77 Beetle
Location: Melkbosstrand, Cape Town
Has thanked: 31 times
Been thanked: 37 times
South Africa

Re: Fuel injection rebuild

Post by fourier »

Had the same problem with the centre main on my current build. Case measures perfectly round on size, when it is torqued to spec. Put the bearing in, and you get the same result as what you have.

Don't know what made me look, but I shone a bright light from the back of the case, whilst looking in from the front. I saw the case was not closing above and below the centre main, with the case torqued to spec. This told me the centre main OD was too big. Measurements were taken with a dial bore gauge, so know the case was good.

Long story short, the case ate three sets of imported steel backed bearings, before oil clearances were in spec. All bearings had the same size on the box, but clearly not manufactured to the same size. Lesson! You simply can't trust sizes, you have to check.

Your case looks new, but have you measured it properly (not vernier) when torqued? You have to figure out where the problem lies. Is it the case, or the bearing? If it is the bearing, buy new ones...a few sets, until you find one that has the correct oil clearance.

An oval (smaller in horizontal plane) main bearing can also be "created". This is don by increasing the torque setting above spec. It may be a calibration issue with your torque wrench, but unlikely,as the other mains do not have the same problem. Your issue is either caused by a case ID that is too small, or my guess, a bearing OD that is too big.

You can possibly solve your problem by sanding the bearing ends that butt against each other. Just run it over a piece of 1200 wet/dry sandpaper, stuck to a piece of glass. Make a few passes, ensuring both ends touch the paper at the same time. Count the number of passes you do with each bearing half, in order to remove similar amounts from each half. Then bolt the case together, and see if things improve... Not ideal, but the bearing is toast anyway, so you might as well try to fix it.

Keep going!
(o= i =o) (o\ ! /o)
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

Thanks for the insight. I will certainly go and check it out with a torch when I torque it up again. Interestingly, on one of the assemblies yesterday, it actually didn't bind up completely like the first time. So there is definitely some human-bearing-seating error somewhere.... I will be investigating this week.

The case is new (it is one of those Autolinea ones from Brazil). I have checked it as best I can (fully torqued) using a set of snap gauges and the vernier. Unfortunately I don't have a dial bore gauge... thought I can see how much easier it would be if I did. What do you mean by "Not vernier"? Are you implying that a mic would be a better option? The small one I have is no more accurate than the vernier, but wouldn't measure the larger bores.

I still want to try understand the seating issue, but if it turns out that it is too ovalled/still binding, then I certainly will go find one. By the sounds of it, I can still use Mahle's and hope for the necessary variation in dimensions.
User avatar
Tony Z
Donor
Donor
Posts: 14992
Joined: Wed Sep 14, 2005 8:33 am
What model do you have?: 2.3L 69; 1302; P/Van
Location: Klipheuwel (near Durbanville), Cape Town or working at sea
Has thanked: 191 times
Been thanked: 487 times
South Africa

Re: Fuel injection rebuild

Post by Tony Z »

have you checked to ensure that your dowel pins arent actually too long?
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

Damnit Tony, I was hoping you were right on that! It would have explained it all! But no... there is ample headroom (roughly 0.7mm).

So the mystery persists! I plan on cleaning up the back side of the bearing and the case a little more so that I can be sure it's not a small burr somewhere. Will keep you lot informed.

And thanks a ton to every for being my product support team! It helps more than you know.
User avatar
fourier
Oil Cooler
Posts: 342
Joined: Fri Sep 26, 2008 1:21 pm
What model do you have?: '59 Ghia, '77 Beetle
Location: Melkbosstrand, Cape Town
Has thanked: 31 times
Been thanked: 37 times
South Africa

Re: Fuel injection rebuild

Post by fourier »

Simmy wrote: Mon Oct 22, 2018 7:47 am What do you mean by "Not vernier"? Are you implying that a mic would be a better option?
A vernier is not the tool to use for this measurement. Even snap gauges have issues with repeatedly.

Use either a tubular inside micrometer, or first prize, a dial bore gauge. A dial bore gauge is expensive if you don't use it often, but a good option would be to torque up the case, then take it to a automotive engineering shop to have it measured properly. They have the correct tools.
(o= i =o) (o\ ! /o)
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

Success! The problem does seem to lie with the installer of the split bearings, namely me :oops:

In trying to be more meticulous about fitting the bearing Halves, I found the right half would "wobble" slightly when pressed in like I usually do. It didn't move much at all, but it seems it is enough to obstruct the crank. After really trying to press and seat it fully, the crank now turns when fully torqued. I can feel the slightest bit of friction at one specific point in the rotation. Could it be the 0.01m runout I am feeling? I need to part the case again to inspect and check repeatability, but I am feeling pretty good about it at the moment regardless.

I don't feel that I have done any damage to bearing or crank since I pretty much stopped torquing when it bound up. However, I still plan to check it out, and I might take it past someone to double check my handiwork as well (thanks Fourier).
User avatar
Wentzel
Donor
Donor
Posts: 983
Joined: Thu Oct 11, 2007 12:10 pm
What model do you have?: T1 1977,76
Location: Witbank
Has thanked: 6 times
Been thanked: 13 times

Re: Fuel injection rebuild

Post by Wentzel »

Great news glad you found the problem.
Oxyboxer Project

Never Ending Beetle Project viewtopic.php?f=23&t=35724
Lolette Spyder Project http://www.aircooledvwsa.co.za/viewtopi ... 23&t=32175
User avatar
fourier
Oil Cooler
Posts: 342
Joined: Fri Sep 26, 2008 1:21 pm
What model do you have?: '59 Ghia, '77 Beetle
Location: Melkbosstrand, Cape Town
Has thanked: 31 times
Been thanked: 37 times
South Africa

Re: Fuel injection rebuild

Post by fourier »

Glad you found the issue.

There should be no point where you notice more friction. The crank should spin freely if the clearances are correct.

Do you have the cam drive gear installed onto the crank, and the cam into the case, when you find the friction? If so, it could be that the woodruff key is forcing the gear to be out of round ever so slightly. You can check by rotating the crank with the cam installed. If it binds when the crank woodruff key is aligned with the gear on the camshaft, the woodruff key is your problem.
(o= i =o) (o\ ! /o)
User avatar
Tony Z
Donor
Donor
Posts: 14992
Joined: Wed Sep 14, 2005 8:33 am
What model do you have?: 2.3L 69; 1302; P/Van
Location: Klipheuwel (near Durbanville), Cape Town or working at sea
Has thanked: 191 times
Been thanked: 487 times
South Africa

Re: Fuel injection rebuild

Post by Tony Z »

are you pushing the bearings in dry or dipping them in oil before installing?
They need to be dry as the oil takes up space and you could loose the clearance you need because of it
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

At this point I have just installed the crank. No gears, no cam. That's the next phase.

I have been using WD40 since is the thinnest lubricant I have. I was using a 10w40 oil, but found that it was far too thick. I will still still check it dry, now that I feel I have solved part of the issue.
User avatar
retrovan
Donor
Donor
Posts: 8709
Joined: Mon Feb 07, 2011 8:51 pm
What model do you have?: 52T1,68FB,72Bay,75FL
Location: Eich! no, in Jefferys Bay
Has thanked: 421 times
Been thanked: 539 times
Contact:
Netherlands

Re: Fuel injection rebuild

Post by retrovan »

Simmy wrote: Tue Oct 23, 2018 6:24 am .....I have been using WD40 since is the thinnest lubricant I have. I was using a 10w40 oil, but found that it was far too thick.....
:huh: :huh:

Hope you talking of the block side of the bearing, as you would have to assemble crank to bearing side with oil to turn test it after tightening.

If your tolerances are to tight with 10w40 then something is wrong big time.

How you going to get normal engine oil in between the bearings even before start up ??

Your oil will not get in and you will scrap the motor in the 1st 10 seconds of running. :wtf:

OMO

Herman
1952 Split Beetle 1835cc
1968 Fastback 2Lt.type4
1972 Low Light Bay Panel Van 2Lt type 4
1975 Fleetline Panel Van 1914cc
2020 MeFusco Beetle Truck 2Lt type 4
1972 FT Hahn SP 1776 cc
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

retrovan wrote: Tue Oct 23, 2018 6:54 pm Hope you talking of the block side of the bearing, as you would have to assemble crank to bearing side with oil to turn test it after tightening.

If your tolerances are to tight with 10w40 then something is wrong big time.

How you going to get normal engine oil in between the bearings even before start up ??

Your oil will not get in and you will scrap the motor in the 1st 10 seconds of running. :wtf:
I think I didn't explain myself properly. I used the motor oil initially as assembly lube, but found it a little too viscous to feel whether the crank and cam were spinning freely. I changed to the WD40 as a compromise to dry bearings (as Tony and other sites have suggested) because I just am uncomfortable with metal-on-metal even if just for the purpose of trial fitting it.

But point made, it's probably a good idea to give it a feel with normal motor oil, but I highly doubt it's going to bind up in the same way. I also like the idea of having a machine shop double check me, since there is quite a lot of money at stake here! :shock:
Simmy
Oil Pump
Posts: 220
Joined: Thu Mar 30, 2017 9:07 pm
What model do you have?: 1978 Beetle
Location: Johannesburg
Has thanked: 5 times
Been thanked: 5 times
South Africa

Re: Fuel injection rebuild

Post by Simmy »

Good news. The problem has been located. Bad news. It comes with school fees...

I don't know how or when I did it, but with all the parting of the case, I managed to misalign the dowel on the number 1 bearing.

Image

Digging further, I can also explain the slight tightness at one point of the rotation. It seems I bent the crank in the process. From an about 0.01mm runout, it's now out of spec at 0.035mm.
i really feel stupid for letting this happen... I thought I had truly been careful enough to torque and check as I went.

I am going to take a breather on this and get the machine shop to take a look as well. Let the irritation die off a bit.

Image

I assume I will need to have the crank ground again to get the journals straight one the crank itself is straightened? A new set of bearings are also in order, at least to replace the damaged one, if not to also deal with a regrind.
User avatar
fourier
Oil Cooler
Posts: 342
Joined: Fri Sep 26, 2008 1:21 pm
What model do you have?: '59 Ghia, '77 Beetle
Location: Melkbosstrand, Cape Town
Has thanked: 31 times
Been thanked: 37 times
South Africa

Re: Fuel injection rebuild

Post by fourier »

If it was that easy to bend, it should be easy to straightened, without grinding. Let a machine shop take a look... Get an answer, before you buy more bearings.
(o= i =o) (o\ ! /o)
Post Reply