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Author Topic: TLC for my GTD (rebuild), IT RUNS!  (Read 12964 times)

Reply #15November 20, 2011, 09:06:56 am

BlueMule

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Re: TLC for my GTD (rebuild)
« Reply #15 on: November 20, 2011, 09:06:56 am »
Wil, I know you said that the machine shop said the Aux bearings were OK, was that before or after the block cleaning? I was just wondering whether a heated detergent solution was used or was it a heated caustic solution. If it was a caustic solution your aux drive bearings are most likely trash and need to be replaced. In any case look them over really good before assembly just in case. I don't know the standard procedure in UK or the Enviro rules, thats why I ask.


BlueMule
BlueMule
A.S.E. Master Since 1986
Nissan Master Since 1995
Auto Tech Since 1975
Totally Ignorant When It Comes To MY
'86 Golf TD

Reply #16November 28, 2011, 10:55:50 am

wil892

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Re: TLC for my GTD (rebuild)
« Reply #16 on: November 28, 2011, 10:55:50 am »
Hi

Ok so its engine build weekend coming up but I’ve got a few questions to make sure this thing goes together well! So if anyone can answer any individual question, please do! This is my first engine build so I’m going to be confident, but that continual voice telling me how much money this engine has cost will certainly be lingering!

1)   Main bearing caps, I know the Bentley says which way the numbers go, but is it correct. Will it be obvious which orientation to install them?
2)   Thrust bearings: I have the separate thrust bearings on recommendation from numerous sources all over the internet, but is there a recommended way to install them. I have read the crank may need striking with a rubber mallet at each end to properly align the crank with the thrust bearings, any truth to this?
3)   Con rods: which way round are they installed, or does it matter?
4)   Main and con rod bolts: are they oiled prior to torquing or should I torque them dry? If I need oil should it be mineral or synthetic?
5)   Shaft seals! What is the best way to install these? Load them into the carrier and fit them with the carrier. Or fit the carrier and press the seals in? Are they difficult to get right? I have a complete Elring bottom end and top end gasket kit so they are good quality
6)   Assembly lube? For bearings I was thinking of using some Mobil 1 15w50 oil I have sitting around? Or should I use assembly lube like graphogen (recommended by machine shop). The rings and bores will be lubed with some 10w40 semi synthetic oil

I’ll be taking pics at each step, for reference and also to potentially produce a basic pictured walkthrough which the Bentley doesn’t really provide.
Thanks for the help so far!
Bluemule, I checked with the machine shop, the wash was with detergeant not caustic solution, so int bearings are looking good to go.
1991 Golf MK2 GTD

Reply #17November 28, 2011, 12:43:54 pm

Mark(The Miser)UK

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Re: TLC for my GTD (rebuild)
« Reply #17 on: November 28, 2011, 12:43:54 pm »
I could be wrong, but AFAIK you don't want synthetic oils anywhere near this engine whilst breaking it in, and super slippery stuff not on those bolts in case of over torqueing
Mark-The-Miser-UK

"There's nothing like driving past a bonfire and then realising; its my car on fire!"

I'm not here to help... I'm here to Pro-Volke"

Be like meeee: drive a Quantum TD
 ...The best work-horse after the cart...

Reply #18November 29, 2011, 07:00:57 am

wil892

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Re: TLC for my GTD (rebuild)
« Reply #18 on: November 29, 2011, 07:00:57 am »
Good point, I've got a bottle of pretty old 15w40 mineral oil I will use for the con rod bolts and mains then. I guess I will use it for installing the pistons as well
1991 Golf MK2 GTD

Reply #19November 29, 2011, 09:13:43 am

Mark(The Miser)UK

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Re: TLC for my GTD (rebuild)
« Reply #19 on: November 29, 2011, 09:13:43 am »
Good point, I've got a bottle of pretty old 15w40 mineral oil I will use for the con rod bolts and mains then. I guess I will use it for installing the pistons as well
Don't forget you want a gallon of multigrade for ring break in, else you'll end up 'French Polishing' the bores, and have to live with eternal oil burning
Mark-The-Miser-UK

"There's nothing like driving past a bonfire and then realising; its my car on fire!"

I'm not here to help... I'm here to Pro-Volke"

Be like meeee: drive a Quantum TD
 ...The best work-horse after the cart...

Reply #20December 02, 2011, 05:49:32 pm

wil892

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Re: TLC for my GTD (rebuild)
« Reply #20 on: December 02, 2011, 05:49:32 pm »
I didnt have the wrist pin bushings replaced in the con rods, and now wondering if I should have done. There doesn't seem to a any spec in the Bentley. The machine shop said they had never seen VW bushings need replacing. Do they generally need replacing? Do these pictures tell anything?



Also I just noticed one of the con rod caps has succumbed to some rust is this a problem? The rods were resized by the shop, and they obviously didnt think it was a problem.

1991 Golf MK2 GTD

Reply #21December 02, 2011, 11:23:21 pm

kevinm

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Re: TLC for my GTD (rebuild)
« Reply #21 on: December 02, 2011, 11:23:21 pm »
As for the wrist pins i went and ordered new ks bearings and had a shop press them in and hone them to about .001 slide fit maybe a few tenths more... The machinist looked at me like a bit of a nut for asking for new bushings as the pins from my new ks pistons fit just fine in the old wrist pin bushings, im guessing .001 clearance (no wiggle up down, just slide fit).  When i picked them up after being pressed in and honed i noticed the same fit, by feel anyways.  The only benefit you might gain by doing this is oil retention due to new hone marks?  If you have any lobe pattern worn into the brass bushing due to wear then replacement might be a good idea.  Save your money if your new piston pins fit with no up down play...  another thing, the pin bushing currently in the rod has been honed nuts on concentric by vw,  something a machine shop could screw up if you go get new ones pressed in and honed.. Save your money... 

As for the big end of the rod, buy some scotch brite, and by hand just wipe it over the rusty areas on the surface where the bearing shell sits. Go easy on the scoth brite, just take the rust off.

Reply #22December 03, 2011, 03:41:58 am

Toby

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« Reply #22 on: December 03, 2011, 03:41:58 am »
I am not a proponent of "fixing" things that are not broken. You almost certainly went backward with the wrist pin bushings. They were just fine. You have no way to judge the quality of aftermarket crap. Almost none of it is as good as a used factory part. Almost all of it is made in china.

As far as the big ends go: If you did not have a spun bearing you definitely went backwards. The finish on the big ends is ***. WAY courser than stock stuff with no guarantee of concentricity, taper, center to center length, nor whether the bore center lines are parallel. Sad to say most, so called, "automotive machine shops" are incapable of doing acceptable work and all should be viewed as incompetent until proved otherwise. This comes from 30 years in the automotive trades.

Jason's Rule #2: NEVER fix, repair, or rebuild a part that is not out of spec. It will almost always be worse when you get it back than when you dropped it off.

Reply #23December 03, 2011, 12:14:27 pm

wil892

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Re: TLC for my GTD (rebuild)
« Reply #23 on: December 03, 2011, 12:14:27 pm »
Ok I have decided to use the original con rods I took out of the engine, which I will check for out of round after I press in the new bolts. The ones you see in the picture I am just not happy with. I think the caps may be mismatched.

BUT!!! I'm in the process of installing the crank, but it is binding when no4 cap is tightened. I have torqued all the others up and the crank spins lovely, but as soon as no4 is tightned it binds. I then removed all caps, took out the no4 upper bearing and put a used (good condition) one in. Placed the crank and only installed no4 cap with an old (good condition) bearing. I then torqued the bolts and the crank bound again!!
What is going on?
The crank was polished.
1991 Golf MK2 GTD

Reply #24December 03, 2011, 12:40:51 pm

Mark(The Miser)UK

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Re: TLC for my GTD (rebuild)
« Reply #24 on: December 03, 2011, 12:40:51 pm »
Ok I have decided to use the original con rods I took out of the engine, which I will check for out of round after I press in the new bolts. The ones you see in the picture I am just not happy with. I think the caps may be mismatched.

BUT!!! I'm in the process of installing the crank, but it is binding when no4 cap is tightened. I have torqued all the others up and the crank spins lovely, but as soon as no4 is tightned it binds. I then removed all caps, took out the no4 upper bearing and put a used (good condition) one in. Placed the crank and only installed no4 cap with an old (good condition) bearing. I then torqued the bolts and the crank bound again!!
What is going on?
The crank was polished.
Maybe the  old but good bearing is off a crank that is undersized. Ie that bearing is oversized. Remove crank and measure each bearing surface to see if#4 is different If not then try cap off #3. Or shell.
You have marked the caps with a punch, haven't you?
Mark-The-Miser-UK

"There's nothing like driving past a bonfire and then realising; its my car on fire!"

I'm not here to help... I'm here to Pro-Volke"

Be like meeee: drive a Quantum TD
 ...The best work-horse after the cart...

Reply #25December 03, 2011, 01:06:50 pm

wil892

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Re: TLC for my GTD (rebuild)
« Reply #25 on: December 03, 2011, 01:06:50 pm »
Old bearing is STD size as are new ones. Crank is binding when all upper bearings are installed but only the no4 cap is put in and torqued. It binds both with the new std size bearing and the old std sized bearing. Don't understand it.
1991 Golf MK2 GTD

Reply #26December 03, 2011, 01:26:45 pm

Toby

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Re: TLC for my GTD (rebuild)
« Reply #26 on: December 03, 2011, 01:26:45 pm »
Make sure the cap is on the correct way around, first. Second make sure that it is the cap off of that block. They can not be interchanged. Then platigauge the main bearings to see the actual clearance on #4. Pull the crank and bearings and instal the #4 cap and inspect the parting line. It should have .000" of overhang/mismatch and should be smooth and not catch a finger nail run across the parting line. Remember that  the grooves for the bearing tangs are on the same side, no matter what the number on the cap says.

Reply #27December 03, 2011, 02:34:24 pm

wil892

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Re: TLC for my GTD (rebuild)
« Reply #27 on: December 03, 2011, 02:34:24 pm »
Ok. The I just checked, and the cap is definately on the right way round. I can see the tang marks from its original position. The cap is the only main no4 bearing cap I have so unless the machine shop somehow mixed them up with another block.
Unfortunately I haven't got a plastigauge kit (yes stupid) I can try and find one here in the uk.
I pulled the crank and all bearings and fitted the no4 cap, it seems to fit in a number of positions. I can see the original position of the cap, shown here



It seems that when the cap is torqued down it pushes the crank down on to all the upper bearings.
1991 Golf MK2 GTD

Reply #28December 03, 2011, 03:41:05 pm

theman53

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Re: TLC for my GTD (rebuild)
« Reply #28 on: December 03, 2011, 03:41:05 pm »
I cannot see the assembly lube and how are you trying to turn it? IIRC mine turned but turned very hard with all new stuff and very tight tolerances. Without the lube I wouldn't want to turn it too much anyway. The lube should make it easier to rotate.

Reply #29December 03, 2011, 04:34:43 pm

wil892

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Re: TLC for my GTD (rebuild)
« Reply #29 on: December 03, 2011, 04:34:43 pm »
I'm using 10w40 engine oil to lube it all (lots of it). Basically with all caps torqued the crank spins on the oil film really nicely. But as soon as the number 4 is torqued down the crank becomes very very hard to turn, so much so it feels like the bearings would be damaged if I continued to turn it. The upper bearings are showing some equal marks from the crank already from this and the lower no4 bearing is showing that the cam is pushing down on one side.


1991 Golf MK2 GTD

 

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