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Author Topic: VW ALH : Extreme smoke... on new rebuild  (Read 751 times)

March 11, 2019, 03:35:07 pm

Faztco

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VW ALH : Extreme smoke... on new rebuild
« on: March 11, 2019, 03:35:07 pm »
Hello again: heres my second big problem( besides Glow Plug system): 2001 ALH, full modified rebuild , Bored .5mm , new everything. When start the engine - to me, it smokes far too much for a fresh rebuild. I mean it clouds out the car.. kinda bluish white. The Turbo is fresh and is not internally leaking, engine is not using coolant. I only have about 100 KM driving time, and after engine is intermittantly loaded up on the highway, it doesnt seem to smoke anymore. Yet the next morning I start the engine and again tons of smoke. Am I just not allowing enough Break in time?, I have heard it takes up to 1000 K to Break in these motors. Reason I am alittle worried is because years ago I helped my brother rebuild a 1.6 TD in his Jetta. We fitted the oversize pistons in the newly bored block and they were VERY tight... I mean a thou or two clearance. Fast forward to my rebuild:IGet the block back with overbore and too me the pistons went in with too much clearance... thus the smoke problems I see now. I bet you there was 4-5 Thou on this 1.9 ALH. when the engine is running, it sounds good and there is lots of power on the Highway at 25 Lbs boost. Somebody tell me I`m freaking out for no reason. Car is off the road till the weather gets warmer, and I have a spare Block incase the worst senario - The machine shop Bored the cylinders too large.



Reply #1March 11, 2019, 04:55:38 pm

libbydiesel

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #1 on: March 11, 2019, 04:55:38 pm »
The spec is 0.001" piston to bore clearance.  You say you got the block bored for your oversize pistons, did you measure the bores afterward?  If there was any doubt about the clearance, that was the time to do it. 

Do you have clear fuel lines before and after the injection pump?  Any air getting into the fuel?  Air in the fuel will cause the exact symptoms you describe and is a lot easier to solve than incorrect bore.  I assume you timed the injection pump using vag-com correct? 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #2March 11, 2019, 05:35:18 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #2 on: March 11, 2019, 05:35:18 pm »
Yes Sir ; I timed with my Vagcom... towards the upper end of the advance scale on the graph . When I brought the Block + box of pistons to the machine shop, unfortunately I didnt check bore size because I trusted the machinest.... after he said that he had to make a call to check Bore. I am SURE that the pistons had far more than .001 Clearance. I guess that I will start stripping down my spare block soon and prepare to have it overbored. Thank you for your help.

Reply #3March 11, 2019, 05:43:47 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #3 on: March 11, 2019, 05:43:47 pm »
...Also: GOOD idea about the Clear Fuel lines, I just ordered some, will post results.... Thank you Sir.

Reply #4March 11, 2019, 07:20:05 pm

libbydiesel

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #4 on: March 11, 2019, 07:20:05 pm »
I can understand wanting to trust a machinist, but I don't understand installing the pistons, noticing that the clearance is larger than your prior VW diesel rebuild experience, and then simply continuing to finish the build.  I misspoke before - spec for ALH piston to bore clearance is 0.0015.
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #5March 11, 2019, 07:32:16 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #5 on: March 11, 2019, 07:32:16 pm »
Sir; at the time of engine assembly, I assumed the clearance the machinest bored the block to was correct- so unfortunately I didnt recheck . I am primarily a Gasser engine builder, in which the piston clearances I am now experiencing would be normal, thats why it never occurred to me at that time. I put the engine together over 2 years ago and have since moved from Vancouver area to the Okanagan. I am going to use the advice of a fellow member and first replace the Fuel In/Out lines off the IP with clear ones and see if there is air bubbles. I changed the Fuel filter from the stock one to a Raycor unit with water drain and bypassed the return line by joining both ends ( off the filter). who knows...perhaps I am drawing in air from somewhere causing the excessive smoke. Car sure runs good on the Hiway tho - under power

Reply #6March 11, 2019, 07:47:09 pm

libbydiesel

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #6 on: March 11, 2019, 07:47:09 pm »
I can understand wanting to trust that a machinist did the job correctly, but that often doesn't work out very well.  Parts new out of the box are sometimes wrong.  I've gotten 3 different sets of German bearings that had a wrong bearing in them.  Those occurrences are rare, but blindly assembling the engine with the assumption that everything is automatically correct without checking and confirming can waste a lot of time later.  You didn't bother to check the ring end gaps either?  That would have also shown the issue if the piston to bore spec was too large.  I don't usually check all the rings as there is a risk of breaking them when removing and reinstalling them on new pistons but I always check at least one set and in a couple of the bores at top and bottom, along with a good visual inspection of the other three sets of rings. 
« Last Edit: March 11, 2019, 07:50:52 pm by libbydiesel »
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #7March 11, 2019, 10:24:50 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #7 on: March 11, 2019, 10:24:50 pm »
Over the next couple days I am pulling the head... to see how much clearance I can get with a feeler gauge. If there is too much.. like I suspect - I guess I learned a valuable lesson. Luckily I have all the parts I will need on hand to remedy this. The overbore Clearance will be conveyed to the machinest as .0015 and I will mark and give him the Pistons and have the final measurements proven to me upon Pick up of Block.
Funny thing: At the time of my blocks machining...probably 2 years ago , I researched what the Bore clearance should be and never found the answer on the net. Perhaps when the Block was at the machine shop and they said they would phone someone to see what the clearance should be...they never found the answer either...or the job got passed to another machinest who bored my block to Gasser specs. I will let you all know what I find over the next couple days. 

Reply #8March 11, 2019, 10:51:30 pm

ORCoaster

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #8 on: March 11, 2019, 10:51:30 pm »
Don't you just LOVE finding the right answer at the wrong time?   At least you can redo, most can not. 
Turbo and Exhaust finally on, Time for tuning!

Reply #9March 12, 2019, 02:40:28 am

libbydiesel

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #9 on: March 12, 2019, 02:40:28 am »
Before pulling things apart I'd make sure you're not getting air infiltration in the fuel.  Also, the pistons are smaller at the crown than at the skirt so that when they get hot, the crown (which is hotter) expands to a similar dimension as the skirt.  The difference in diameter for the crown vs. skirt is large, like 20 thousandths.  If you're going to try to use a feeler gauge to measure the piston to bore clearance, pull the pan (which is easier and less expensive) and measure at the skirt although I don't envy trying to get a decent measurement around the crank. 
« Last Edit: March 13, 2019, 12:13:10 pm by libbydiesel »
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #10March 15, 2019, 09:13:58 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #10 on: March 15, 2019, 09:13:58 pm »
OK ...Today I pulled the head, and at first glance the pistons look tight in the bore. I measured each cylinder and they all measure exactly 79.86mm = 3.144". I took out a brand new set of .5mm OS rings and put the Top compression ring in a bore ( remember - only 60 miles on this build) and I got .018" = .457mm gap with a feeler gauge.... which seems good. Tomorrow I`ll be pulling all the pistons , measuring and if it checks out : changing the rings on spec. Stay tuned folks ... 

Reply #11March 15, 2019, 11:04:02 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #11 on: March 15, 2019, 11:04:02 pm »
HUMM!...something funny going on: I measured the cylinder bores : My Mitytoyo vernier says 79.86mm consistantly acoss all four ( pistons still in) , the tops of the .5mm OS  pistons say 79.95mm. How can this be?. changed the battery and same thing. am I losing my marbles??

Reply #12March 16, 2019, 07:19:25 pm

libbydiesel

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #12 on: March 16, 2019, 07:19:25 pm »
Did you even read my last post?  As I said in my last post, the gap between the piston crown and the bore is completely irrelevant.   The piston crown diameter is ~0.020 (0.5mm) smaller than the skirt and it is the gap between the piston skirt and the bore that you would need to measure.  Pulling the head was just a waste of time and money.   

Vernier calipers are decent for comparative readings but usually skew when you get very far.  The inside to inside reading is also often off from the outer to outer.  For any hope of an accurate bore reading with vernier calipers you would need to zero the verniers at a close standard and then measure from there.  I still doubt you would get good accuracy.  You should really be using a bore gauge or snap gauge with micrometer. 

Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #13March 19, 2019, 06:58:26 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #13 on: March 19, 2019, 06:58:26 pm »
OK...so I remeasured the cylinder bores with a bore gauge and it measures 80.00mm exactly. So if the pistons are 79.95mm , the Clearance is correct. I took out the four pistons, cleaned the carbon, reringed ( Yes- checked gaps in the bore first) and installed pistons again. The windage tray seemed kinda flimsy - hanging on by one bolt so I took a fellows advice and placed a spring in the built in pocket of the tray, drilled a few small holes and lock wired the spring in place. upon install of the oil pan now the spring pushes up on the tray and keeps it where its supposed to be. Head is now installed and today I finished  up the timing belt and may have come across the cause of my problems with Excessive smoke. If I do the timing procedure and use the Flywheel timing mark - it does not Jive with the two Harmonic Balancer TDC marks. The harmonic balancer marks are probably 10 - 15 degrees retarded. A few posts ago I said that I converted from a Auto trans to a 6 speed DRW Code trans. I bought a Billet aftermarket clutch setup , and went with the TDC marking on the flywheel.... which I think may be my problem. I took a second balancer to verify that the TDC notch hasnt slipped due to the rubber ring moving internally. Both balancers I have show the same position for TDC. Now installed and everything verified correct. Friday I will start engine and report findings. 

Reply #14March 23, 2019, 10:55:23 pm

Faztco

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Re: VW ALH : Extreme smoke... on new rebuild
« Reply #14 on: March 23, 2019, 10:55:23 pm »
OK...WE got the answer, HOLD ON!....this is really dumb.. on my part: Guess who put a 2.0 harmonic Balancer on his ALH ?, and YES... the timing marks are not positioned the same, YUP - ME. With a brand new Billet Clutch that has no TDC markings and a wrong Balancer... no wonder I couldnt get a true TDC to time IP and cam to. All is corrected now and engine runs good!. Timing set to 60 - 62 , with IQ at 5.0 ; very minimal smoke... to be expected with new rings and no miles. I also put the clear fuel lines on and fuel flow is clear ( no bubbles ). wiring is all in for the Intank pump mod coming real soon. Life is GOOD!. Take care All.

 

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