Embarking on an engine rebuild journey - some advice needed

[RGH0]

Just an FYI for anyone rebuilding a VW engine - VW has used torque-to-yield connecting rod (and in many cases cylinder head), bolts for decades. By tightening them to the specified angle they are placed in the plastic deformation range of the metal - which is why they require replacement every time the engine is disassembled. If you reuse these "stretch bolts" they will not hold the proper torque when actually in service because the metal has already yielded once.

With ARP of similar high performance aftermarket con rod bolts as noted measuring the bolt stretch places the bolt in it's optimal tension but does not permanently stretch the bolt as happens with a torque-to-yield bolt. Replacement OEM style aftermarket bolts unless specified differently are also one-time use torque-to-yield bolts like the factory bolts. The aftermarket high performance bolts are typically a requirement for higher than stock engine RPM because the OEM or aftermarket "stretch" bolts were never designed to handle the significant increase in jerk moment load at TDC that occurs with increased RPM.

Not all bolts with a specified tightening angle or bolts that are recommended not to reuse are actually Torque to Yield bolts. Depending on the length of the bolt and the material and the thread pitch which is probably 1.0 mm, a 90 degree turn is a stretch of 0.25mm / 10 thou which may not get the bolt into the yield region. Rod bolts will stretch in use which is why TTY bolts are not normally used and replacement of non TTY bolts is normally recommended. Using a 90 degree turn after seating the bolt with 30 Nm ensure a specified stretch and clamping force is achieved much more accurately than just specifying a torque value. I would need to know the detailed material specification and dimensions of the VW rod bolt assembly to determine if its truly TTY or just specified for a specific stretch in the elastic region

 

[siLc]

Put in a bolt in the end of the cam shaft or grip the cam between the lobes with a set of big multigrips and you should be able to rotate the cams OK. At least I can on engines i build

EA111 camshaft module is closed-top, so when it's installed, the camshafts lobes are not visible. Only threading in a bolt remains.

 

[RGH0]

Are there slots on the back of the cam where the alignment tool fits ? a suitable blade should enable the cams to be turned using this ?

Edit

I looked up what the alignment tool looks like and if i have the right one then the cams have a hole for a pin in the tool to fit into, not a slot. If you fit just one end of the tool into the cam carrier back end and into the hole and leave the other free you should be able to turn the cam using the tool to get it into the alignment position ?

 

[siLc]

The camshaft module is aluminum and the cylinder head seems to be iron.

Cylinder head is also aluminum. I'm using Elring EL-Liq 73. I've so far not heard anyone using an activator with that.

I will give it a try to install the camshaft module on my own using the oriental tool. If timing doesn't line up, I'll take it to the shop. To help with that, I enlisted a friend to laser cut me holders for the T10171 which doesn't have any provisions of it's own to fix it to the camshaft module. Behold



As preparation for camshaft module install, I went over all the hydraulic lifters. They were sitting in a cardboard holder for two months after removal. Most of them were "loose" ie. they didn't hold tension apart from the spring inside them. A few of them I loosened up by depressing the valve in them with a thin HEX key. I poured 5W30 in a clean spray bottle cap and dunked each lifter in that one by one, trying to pump them up to rigidity. A few of them became completly rigid but most of them did not, retaining some springiness. What should I be looking for here?

 

[BlueR32]

Not all bolts with a specified tightening angle or bolts that are recommended not to reuse are actually Torque to Yield bolts.

Correct

Depending on the length of the bolt and the material and the thread pitch which is probably 1.0 mm, a 90 degree turn is a stretch of 0.25mm / 10 thou which may not get the bolt into the yield region. Rod bolts will stretch in use which is why TTY bolts are not normally used and replacement of non TTY bolts is normally recommended.

Rod bolts that stretch during use will lead to immediate bearing/engine failure. No rod bolt should be stretching in use as it would allow the cap to separate from the rod body. Stronger high performance bolts are used for higher RPM specifically to prevent this issue.

Using a 90 degree turn after seating the bolt with 30 Nm ensure a specified stretch and clamping force is achieved much more accurately than just specifying a torque value. I would need to know the detailed material specification and dimensions of the VW rod bolt assembly to determine if its truly TTY or just specified for a specific stretch in the elastic region

While torque-to-angle seems like a more reliable tightening method than to a specified torque number, in practice this is not always the case. At VW's engine factory in Salzgitter, Germany I have personally observed the torque-to-angle clamp force of the head bolts and the "clamp force scatter" is scary. It's not "suppose" to be that way but in practice it is.

The bottom line is to use quality bolts and good installation practices to prevent engine failure.

 

[RGH0]

Blue52 a few clarifications on my comments and your responses

All bolts subject to high and fluctuating loads such as rod bolts will suffer from permanent creep to some degree overtime even if is operating in the elastic stress / strain range. How long it takes and how much creep depends on many factors. As long as the creep is small compared to the elastic stetch initially set in the bolt to clamp the joint, the joint clamping force is maintained. ARP for example recommend their bolts length be measured initially and if you are reusing them measure them again and replace if they have stretch by more than 1 thou. The normal ARP installation elastic stetch is 6 thou.

Failure of the joint only occurs if the creep in bolt length reduces the clamping load for the join sufficiently for the bolt to begin fatiguing.

Bolts that have been initially yielded by a TTY tighten method will suffer faster creep when they return to the elastic range after yielding which is why they are not usually used as Rod bolts.

Torque to angle is more accurate at establishing a specified bolt tensile load and stretch than tighten to a specified torque but that is not saying much as tightening to a specified torque is about +/- 50% on establishing the correct tensile stretch and load. Thread distortion and bolt twist all affect the tighten to angle bolt stretch as you observed. Directly measuring rod bolt stretch where that is possible in better and more accurate and normally recommended for rod bolts.

I fully endorse you final statement of use good quality bolts and good installation practices

 

[siLc]

Speaking of bolts, an unexpectedly high percentage of costs are new genuine one-time-use bolts. Generally they're at least 2€/piece, can be twice as much and there's tens and tens of them.

I will get the oil pump chain kit on Monday. Before that, I want to get the camshaft module installed. Before I can do that, how can I ascertain that the lifters are good? Before disassembly, there were no issues with lifter tick, but still I'd like to make sure.

 

[siLc]

As for the oil pump chain kit, the kit turned out to be incorrect and I was able to return it. A well-known local VAG repair shop has great local availability of genuine spare parts, so I took my old oil pump chain and sprocket with me. Bought some other parts and asked for comparison. Draped my "old" chain and new genuine chain on a pen - there was no difference in length! Also no difference between brand new and old sprocket, so a 100€ saved there So just bought a new genuine chain tensioner and reused the chain and sprocket.

Since the lifters are quite cheap at 2,7€/piece I just opted to replace them all. Installed the camshaft module and Febi Bilstein updated chain kit. To make absolutely bang-on sure the first cylinder is at TDC, bought an indicator dial gauge and carried out installation of the chain kit, using Chinese T10171 and T10340 tools. I wasn't very sure about these tools as I got to compare them to genuine tools, but they worked a treat. I quadruple checked the timing between all work steps, so it better be good

Essentially the engine is now 99% put back together. I only need to fit the sump and gearbox and then it's only a matter of putting it back into the car

 

[siLc]

I put the engine back in, filled up with Castrol Edge 5W30 and G12+ and...it runs!

The exhaust flex which runs under the sump came apart, so it's running "a bit" noisily at the moment. Must weld in a new flex joint before I can drive it to have it's yearly inspection done.

I started putting the front end back together and the plastic holder for the ambient temperature sensor snapped when reinserting the sensor...great! A 5€ piece of plastic but I can't put the bumper back on until it's replaced. It's already on order from the dealership. And no, I won't be using any zipties etc

 

[Dr Sheldon]

 

[Uwe]

it runs!

-Uwe-

 

[siLc]

And now for the conclusion.

The engine is buttery smooth now in the lower end. I buttoned everything up, took my regular winter wheels from my replacement vehicle and went to have the already expired annual inspection done...and I failed. Not because of emissions - emissions figures were perfect, like a brand new engine. I failed because I forgot to check whether the headlight washers work. As my vehicle has factory xenon headlights, which needs to have working headlight washers. By Estonian law, now I have a month of grace period to remedy this issue and have the vehicle re-inspected for that single thing (cost 5€) before I have to have the vehicle fully re-inspected for full cost of 45€. I can drive the vehicle freely in the meantime. It's MUCH better than driving on an expired inspection, which when caught, will incur a fine.

I think I didn't plug the headlight washer hose sufficiently tight to the washer pump. Luckily it's quite easily reachable by removing the right front wheel well liner.

So the vehicle is now back on the road after three and a half months, with a caveat

 

[siLc]

OK, now to really wrap things up. It turned out that the headlight washer pump had died. Probably because the bumper was off for three and a half months, the washer tank was drained and thus the pump sat there...dry. Though the windscreen/rear screen pump also sat dry (but with it's hose connected) and it continued it's service successfully. 24€ new pump and gasket and inspection passed!