I re-newed the big engs on my mk3 1.8 today (same as 1.8 mk2 block), it's done nearly 250 k and they came out like this, from 1 to 4 Left to right: progressively worse from no1 to no 4, the con rod half was much worse than the cap half on all cylinders. Here's the worst on no4: Any opinions? Mark
What state were the main bearings at no4 end in - if play developed the crank would start to whip. Also is No4 rod farthest from the oil feed into the crank? I guess the reason the conrod half is more worn is it takes the pressure from the power stroke, the cap half has a lot easier life. Still not bad for 250K. barkstar
any damage on the crank, or the big end journals?? if you have access to vernier calipers you can measure the diameter of the crank, top to bottom & left to right to check for the roundness if its scored of out round ness, try to post the figures up and someone on here can give you some advice options include - same sized bearing (should have a part number on back) as a replacement (minus the wear on the bearings) or what I've just done on my TDI was to have the crank reground to get the trueness back, and fit undersized bearings to allow for the metal took off thats the better option for long term reliability & safe power
The cap half takes the power stroke in the suck-squeeze-bang-blow cycle? And No. 4 is furthest from the oil pump, which is what puzzled me (saw the pics earlier).
It's all back together now. I couldn't see any damage, i measured one jourmal to see if it had been ground, it was spot on original size and round as far as i could tell, but that was no1. I didn't look at the mains. The story goes: i put some VW quantum sinta gold oil in a few months back and it started knocking (which my limited experience and lots of deliberation with TSC led me to believe was b/e knock) at startup, for 2 - 5 secs, even tho the oil pressure light goes straight out. I then quickly changed the oil for 20w50 and it knocked less, so i decided to fit new b/e bearings. Maybe it always knocked lightly, but i didn't notice it till the oil change At 15 quid for OE KS bearings i thought it was worth a throw, although it was really an inspection to see if i need to get another block lined up, hence my question. I was just trying to get an idea about the likely condition of the crank from the photo's really. If there's damage on no4 and it wrecks the bearing straight off, i'll hear it soon enough. I could hear whats picured here quite well. The pistons were quite stiff in the bores, even with the plugs out, so i'm assumung there's not too much amiss with the rings. It would be handy if i could nurse another couple of years out of it, i only rev it to 4k, but i do 135 motorway miles a day...
In principle yes, but not according to the mk3 haynes... Also a wise man told me that *i* could get away without new bolts, and also that changing the bolts is not that simple and can lead to other problems...
I've just ripped the new no4 bearing (the worst one) out to see how it's wearing. This is what it looks like: It's done 6000 motorway miles, and has started knocking for the first 5 - 10 secs on cold mornings again Is this normal bedding in? or is damage on the crank causing this polishing? And what oil should i put in it? 20w50? The oil pressure light goes out instantly, but it's as if there's a bit too much clearance somewhere for the first few seconds causing the knocking. In the past (b4 the bearings were changed) quantum gold has made the knocking a lot worse, and 20w50 sorted it out... car's done 250k BTW
I'd go to 20/50 without a doubt.... or an anything/60 even, if you can find a cheap one. I'd guess that about 1/3 of that polishing is due to bedding in, and the rest due to simple wear due to the mileage and probably worn crank. It's a sin to say it, but I have put in bearings for the first oversize on an unground crank and let the crank do the grinding, when a cheap fella doesn't want to pay for anything and has been told by his pub expert that it just needs new bearings. A bit of VERY careful running in while stationary on thin oil (once you get it to turn over!), then nip up the studs to full tightness and do the same again..... a complete and utter bodge, but he came back to me 8k later for a new water pump, still on the same bearings and running fine. That engine was on about 340k I think. Take from that what you will......
I wouldn't advise it, but it worked...... if you do try it, kerosene(paraffin) depending on what they call it in Hollandish, thins the oil out nicely. Would only reccomend it as a "final try", though........
I'll chuck the comma 20w50 i've got in in the morning and see how it goes. I was thinking of building a cuttout switch to cut the ignition for the first 5 secs of cranking, to let the 20w50 get round b4 it fires, worth it?
Well it's done 10k in 7 months and it's only polished the white-metal... It's not actually worn the whole white-metal top surface away yet, and there seems to be about 0.5mm of white metal to play with before i start damaging the crank again. So on that basis, (i realise the wear process will speed up as the clearance due to (bearing) wear increases) i recon new shells every 2 years will see it through.... The cuttout switch won't help cos it won't stop the knocking in the 1st 10 secs of running, which i assume is what's causing this... An engine pre-heater would appear to be the only thing that will have any effect on the wear, by stopping the initial knocking. BTW, thank's for giving me permission to use the Lords machine shop, which it appears has no machines in it...
Hmmmm... Just inspected the old bearings, it looks like the white metal layer is less than 0.5 mm thick Anybody know the thickness?
sorry to but in but im going to change my big end bearing and main and oil pump on my 8v at the weekend. and was wondering if you can do it in situe. i.e sump off. also i looked up ordering big end bearings but the part number says con-rod bearing set standard with oil hole is this correct? maany thanks
you can do the oil pump and big ends with the sump off, BE bearings have the oil hole.. gsf has them... they're quite universal for your car, 15 quid or so.
many thanks mark is it a ok job to do? ive got my brother whos a vauxhall technican to help me so im hopeing its ok? so the ones listed in gsf con rod bearing set std 14.50 are the ones? thanks again
