Hello guys, Recently I have had various problems with my engine, from low oil pressure buzzer and bottom end of the engine sounding faintly like a tractor. I initially replaced the oil pump and 1.8bar oil pressure sensors, which had cured the oil pressure buzzer going off, but the bottom end of the engine still didnt sound right. I have just dropped the sump again, and checked the big end bearings (piston 1 so far only). I replaced the big end bearings on piston 1 (with standard Kolbenschmidt bearings), however I can feel theres movement of these bearings when fitted (I did smear some new oil on the bearings). Or is this normal and I am worrying about nothing? I havent measured the tolerances yet, which i will do, but what would my next steps be? Old bearings are here, the left one is the bottom one, the right one is the top (piston end) one. Many thanks,
A cheapo digital Vernier is one of those tools that once you have had it and measured 10 things, you will wonder how you ever did without one. Drop the sump, pull the BE off and measure the crank. You will get a rough and ready go/no go answer. try and measure in different 'plains' if that makes any sense.. (across bearing journal, side to side, end-end) Haynes will give you the tolerances. Take the oil pumpout and to bits, look for wear, scoring etc. Jon
Cheers mate, I'm collecting a digital Vernier tomorrow to measure the crank. The oil pump is new, and only covered 10 odd miles, but I will check this. Am I correct in thiinking the crankshaft connecting rods diameter from Haynes is 47.80mm?
Looks like the right number. VW have been very kind to us engine builders with compatibility, over the years. Basically the BE size hasn't really changed over a range of engines. (yes, I know...) Jon
Thanks Jon, So I've managed to measure two of my big end journals for pistons 1 & 4 (as these were both the lowest) Piston 1: 47.35mm Piston 4: 47.36mm Assuming pistons 1 & 3 are similar, do I just need 0.45 - 0.50mm undersized bearings like these: https://www.heritagepartscentre.com/uk/034105713-big-end-bearing-set-1-6-1-8-0-5mm-undersize.html
I would look at the shells, inside edge. They will be marked STD, or 0.25 (undersize) etc. VW etc quote undersizes, so once your crank gets worn, you takeiot to a machinist who grinds it 1/4mm undersize, to recover the journal shape. Then you use undersized (oversized) shells. Sorry, if all this is obvious. So, if your crank is STD shell size, and you are outside OEM minimum tolerance, that's why you haver poor pressure. Its then a crank out job, off to the machine shop (engine rebuild) Your machine shop will grind off the amount needed to get std undersize, and you buys shells to match So, first, see what size shells are fitted (engine may have been rebuilt) If it has a new set of shells (at the correct size) may get the job away. At this stage you can get a crushable plasticine material to measure the gap, well worth doing, as its cheap (plastiguage) Othe wise its an engine out rebuild Jon
Thanks Jon, Nothing is obvious, I am new at this and all useful information, but just want my golf working again, hehe I totally forgot to check the shells. The outside edge of the shells are VW marked with also 0.5. Could I get away with 0.5mm undersized shells? I dont believe the engine has been rebuilt at all (my uncle brought the golf at 2 years old, then gave it to me in 2005) FIngers crossed its not a crank out job, engine is still in the car, hehe.
So its been ground 0.5 undersize. Take the original measurement and tolerance and subtract 0.5. This gives you the number to compare with you Vernier measurement(s). VW cranks are rock hard, the best of production stuff I have played with. For it to have had a 0.5 grind in the past tells a story Hope it goes ok. If it were me in your position, I would also pull the rocker cover off and check a few cam bearings, for piece of mind. Jon
Could this have been done in the factory during production? The shells do have VW Audi stamped too, so look original. I did the headgasket 2 odd years ago, so have had the rocker off, but do have some new tappets to fit (as i had rebuilt my orginal tappets). Although the cam bearings isnt something I checked but will do. The standard diameter is 47.80mm, so with 0.5mm off is 47.30mm. Ive measured 47.35mm & 47.36mm with a Vernier on two jornals. When I had the Standard shells in, I could feel it loose, so it looks like I need 0.5mm undersized ones?
0.5mm clearance is massive, so, yes you need shells to match. Unlikely (IMHO) VW supplied new under sized cranks Jon
This could explain why I could feel the conrod moving when I fitted standard shells. Seems strange, but my shells look orignal and definately VW... Seacrhing for 026 713 for the 026 713 part number on google doesnt come up with bearing shells. From the VW Hertiage website (https://www.heritagepartscentre.com/uk/034105713-big-end-bearing-set-1-6-1-8-0-5mm-undersize.html) Ive found the oem part number is 034-105-713, which there are some Kolbenschmidt bearings around with the part number 87 200 620: https://www.ebay.co.uk/itm/BIG-END-BEARINGS-KOLBENSCHMIDT-87-200-620-/253212514202
size looks right, main obvious difference I have found on BE bearings is whether they have the little end oil feed hole, or not. Second, look at the shape size of the location tang. This must be 'right' Jon Sounds like you are now on the right track. Make sure everything mega clean, buy and use some plastiguage if you have the time/inclination. Its really good stuff, and relatively cheap
Thanks Jon, Seems strange this may have been like this from factory, or work possible carried out within 2 years by VW, god knows. Its funny, the current bearings in the car doesnt have the oil feed holes, where are the new standard ones I purchased do. Hopefully the new 0.5mm undersized ones will too. The location tang looked okay on the new standard ones, and I will check the he new 0.5mm undersized ones when I get them. Two old bearings on the left & middle (with no oil hole), and the new standard one on the right:
the hole is the oil feed to the little ends, most of the early stuff didn't have a rifle drilled rod. important its there if you need it, if your rods aren't drill I woulnt worry about it Jon
Thanks Jon, So after waiting for the big ends bearings delivery, I was finally able to fit them all, together with the oil pump, sump and new oil. I measured up the new bearings compared to my old ones, and they were spot on. Unfortunately after my engine still doesn't sound right (essentially sounds like the same as before the big end bearings change). Here is a link of the engine running, however I suspect it might have been the crackshaft main bearings all along. How realistic is crackshaft main bearings replacement with the gearbox and engine in situ? Or failing that, a cost to have these replaced? Thank s in advance,
If you believe its a 'mains' problem (unlikely, in my experience) Then the procedure is the same as the big ends. Pull the centre main bearing, in situ and examine. Obviously, this is 'open' heart surgery, so take care (ie keep it mega clean). The thrusts bearings will come with it. Reinstall, torque up, bit locktight. Again, caps only go on one way. Oil pump off is 2 bolts, tang engages into dizzy on re-assembly (note angle) Once off remove the M6 bolts and examine inside the pump for wear. Do one main bearing at a time. New sump gasket, don't overtighten Jon
Bugger, I thought mains replacement was an engine out job, not something I want to do I am assuming it is mains as it sounds like bottom end, and I've just done the big ends. Ive had the oil pump just replaced too. Thanks Jon, I looking at the eBay oil pressure gauge kits, do you have any links of some inexpensive ones? Do you have any ideas what it could be, or better to see results of the oil pressure? Im loosing the will with this car
So I have been tinkering with the golf over the weekend and tried to eliminate the bearing noise I am hearing. I removed the aux belt (which also drives my alternator and water pump). The engine seemed a lot better and noticeably quieter. On checking the water pump pulley, it seems like the water pump bearings are gone. Looks like I have found my issue, and may have been the noise all along (although replacing the big end bearings needed replacing judging by looking at the old ones). Current water pump was fitted under 40,000 miles, 8 years ago.
