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-   -   Crank install, what else (http://forums.tdiclub.com/showthread.php?t=480004)

TDI-T July 27th, 2017 21:37

Crank install, what else
 
Need to put in a new crank. Sadly mine only had 168,000, but I lost the rear bolt holes due do a faulty flexplate.
I found a crank with low miles (supposedly 84,000). I've read that replacing main bearings can actually cause more wear to a crank on these?
Say I don't replace the main bearings, just the main bolts (with 12.9's) , but get some Rosten rods and arps, new KS rod bearings, and some new rings (since I'll have to pull the pistons anyway.
Thoughts on this?
I'd like to leave the top half of the engine together and avoid any line honing.
Engine ran great before, but rings are cheap and if I have to pull the pistons anyway... just not sure on cylinder wall ridge and new rings.
Cheers!

smelly621 July 27th, 2017 21:44

What motor is this on, and what performance modifications do you have or are planning on?

Are you proposing not removing the head?

HamBam July 27th, 2017 23:31

If you replace the crank, you should also replace the bearings. You should also check the radial clearance of the crank!

Which engine Code do you have?

oilhammer July 28th, 2017 04:16

It says AHU, but all those were manuals here (so no 'flexplate').

So is this a different engine OR did you mean to say 'flywheel'?

In either case, assuming it is some 4 cyl VAG TDI sold here, you do not need to remove the engine from the car, you can do it all from below. You will of course need to remove the transmission.

Up to you if you want to replace the bearings or not. Mains hardly wear at all. Rod bearings will wear more, but you can tell easily how much they are worn by looking at them once you get it apart. Chances are you'll want to at least replace the rod bearings, just because you'll have them out anyway. And depending on which engine we are talking about, new rod bolts or nuts, too.

All Stock July 28th, 2017 06:57

Pistons come out top side. That means yanking the head. Supposing you could remove the oil squirters and get at them from the bottom... have fun getting the rings compressed properly and all things inserted without breaking one!

As for a re-ring using cast iron rings there's SAE papers about installing without honing that makes a lot of sense. However you still have to set the end gap and that's not going to be fun from underneath either.
All you want to do is doable in car, but you should pull the head off. At this point you will have the trans out...or you already do anyway so its not much more to just yank it.

jmodge July 28th, 2017 07:03

Not quite enough info to give you exact advice. I have done in car bearings on Chevy's before without removing heads. One issue is clearance can't be accurately checked due to compression, weight of rods and pistons putting force against the gap you are checking. So it is some guess work there, if your issue is just one bad main.
I am assuming mains come in oversized combo's?

If you are pulling a piston from it's bore, I recommend rings and honing, at minimum.

So, are you dealing with one bad bearing, or is your crank damaged and pulling and replacing it. If the crank is coming out, then my choice would be to pull the head, hone and ring, check rod trueness(rods can deform during trauma). Pulling a crank and fighting rods hanging in your way when you put it back in is a miserable task.

So, exactly what are you dealing with? One bad main bearing, crank ok? Bad rod bearing, crank ok? Damage to crank that needs replacing?

jmodge July 28th, 2017 07:14

Agree with an above post, if the crank has to come out, pull the engine. Put it on a stand, go through it and do it right. Depending on the severity of the "injury", a lot of things should be checked, at least.
Cranks can also get deformed, rods can twist slightly, rod bores can "squish". I am assuming the motor Knocked?

TDI-T July 28th, 2017 07:15

Thanks for all the responses. I'm running a conversion, so no VW trans. I had it on an automatic Aisin trans. Flexplate bolts didn't hold and they ruined the bolt holes on the crank. Otherwise the engine ran super strong. That's all I think is wrong. No knocking, oil burning, etc.

I'm running a 1Z or AHU with a 4BT pump and with a Garrett 2052 turbo. I wanted to add some stoutness to the bottom end. That's why I wanted to add the Rosten rods. I'm not sure I want to do a whole rebuild when the engines is well below 200,000 miles.

I can pull the engine, but I'm not keen on pulling the head even if I do. I have a new timing belt, water pump, and my injection pump timing was great.

It sounds like pulling pistons is not going to work. I was just hoping to get by for less than $1000 with a stronger bottom end and not a whole lot more work. Can I put the Rosten rods in without pulling the pistons? I'm guessing not.

It is really hard to know where to start and stop. I suppose I could just go stock on some rod bearings with new stock bolts all around and call it good. I just wanted some stronger rods in case I play with boost a bit.

Really appreciate the opinions.

oilhammer July 28th, 2017 07:38

Not sure what the upper limit of the AHU's bottom end is and still be reliable. Up to you if you want to update it, but as I said above, if all you want/need to do is replace the crank, that can all be done from below, unless your conversion in some way prohibits doing so. You just unbolt the rods and leave them hang by the pistons in the block from above.

http://pics.tdiclub.com/data/500/med...0141013-00.jpg

http://pics.tdiclub.com/data/500/med..._crank_001.jpg

A couple pictures of cars I put crankshafts in. Engines never left the car.

I took your original post as "Well since I have to take the pistons and rods out to replace the crank..." when you actually do not have to do that.

TDI-T July 28th, 2017 08:53

Quote:

Originally Posted by oilhammer (Post 5309521)
A couple pictures of cars I put crankshafts in. Engines never left the car.

Just putting in a crank is tempting. Did you add any new bearings and bolts?

My challenge is I have a third member in the way (this is in a 4x4). So, it's either pull the engine or the front axle assembly. With the trans out the engine pull is looking like the route to go.

oilhammer July 28th, 2017 09:07

The top one is an AEG 2.0L gas engine, and it was a used crank install, so I used the used mains that were with the crank and put new rod bearings in, with new rod cap nuts, and new main cap bolts.

The bottom pic is a BHW after the chain drive was allowed to blow apart and starved the engine for oil. It got a NEW crank, new main and rod bearings, new rod and main cap bolts.

Main bearings really do not wear much at all so long as the engine is not run out of oil. I have torn some VAG engines down (like my old ME 1.6L) with over 400k miles, and the mains looked great. The outer babbitt not even worn through. The stout deep skirt design helps keep the crank from flexing, and the crank themselves are very sturdy chunky little things.

smelly621 July 28th, 2017 09:35

Thing is - if you're replacing the crank you're going to have to remove the timing belt, and deal with replacing front and rear main seals. Also think about maybe throwing in a new oil pump chain and tensioner?

I would plasti-gauge the main and rod bearing clearances.

If you're not getting paid (or paying) by the hour to do this - take the extra couple and pull the motor- it will be much more pleasant.

To install new rods the current ones must come out the top. If you go that far - might be worth your while to install some pistons with better oil cooling channels - I think that's one of the most important upgrades on a motor that's been swapped into a significantly heavier vehicle. Also think about a larger oil/coolant heat exchanger while you're at it.

Never heard of it around here - but would some sort of time-sert / thread-sert be an option on the flywheel bolt holes?

oilhammer July 28th, 2017 09:52

Quote:

Originally Posted by smelly621 (Post 5309573)
Thing is - if you're replacing the crank you're going to have to remove the timing belt, and deal with replacing front and rear main seals. Also think about maybe throwing in a new oil pump chain and tensioner?
I would plasti-gauge the main and rod bearing clearances.
If you're not getting paid (or paying) by the hour to do this - take the extra couple and pull the motor- it will be much more pleasant.
To install new rods the current ones must come out the top. If you go that far - might be worth your while to install some pistons with better oil cooling channels - I think that's one of the most important upgrades on a motor that's been swapped into a significantly heavier vehicle. Also think about a larger oil/coolant heat exchanger while you're at it.
Never heard of it around here - but would some sort of time-sert / thread-sert be an option on the flywheel bolt holes?

The AHU has no chain. :p

turbovan+tdi July 28th, 2017 10:40

What is this remove the head to replace a crankshaft bs? I'd pull the engine, I've done the in car crank method and its not fun.

As for bearings, what oilhammer said, I inspect and only replace if necessary. IF the crush is a little weak, just gently spread them out.

GTiTDi July 28th, 2017 11:33

What's with leaving out the details about what this is swapped into?


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