macca 0 Posted August 29, 2003 Hi What mileage for a VR6 Head rebuild? Is it worth doing the bottom end as well? Mine has covered 122K, with a full service history, I noticed a slight loss in water and may be thinking head gasket, no oil in water (that i can tell) no mayo, runs well. Can you get the water tested to see if its contaminated with combustion gas, if so how much and who is likely to do it or can you buy a test kit? And any Ideas on parts prices, head gasket set, new bolts? will new tappets be needed, timming chains, etc. If it needs doing will do it myself. While the head is of is there any porting and flowing to be done? All assuming that it is the head gasket. Cheers Guy Quote Share this post Link to post Share on other sites
Mike Edwards 0 Posted August 29, 2003 In answer to the question: "What mileage for a VR6 head rebuild?" the anwer is - "When it breaks". The head gasket on the VSR-equipped VR6 has done 160k miles and seems to be fine, The one on the other VR6 needed to be replaced after 120k miles. Both have spent their lives on the motorway. Coolant loss may be due to the thermostat housing leaking (does it run at about 110 degrees on the motorway?) Quote Share this post Link to post Share on other sites
macca 0 Posted August 29, 2003 Usually just above 1/2 and peaking at 3/4 on the temp gauge before fan cuts in. Oil is about 102 at normall to 110 when pushed. I know what you mean, dont fix it untill it breaks. Just read else where VR6s H/G are a bit weak and thought I might be in for a bit of DIY. Once rebuilt a Porsche engine, (snapped head bolts), thought I would do the bottom end while i was on, when it was stripped there was no signs of wear at all, spent a few more £ and a lot of time for no reason. How strong are the VRs bottom ends?? are piston rings a problem? Am going to monitor it closely and see what happens, if its loseing water will start with the easy bits first. Cheers guy. Quote Share this post Link to post Share on other sites
Bruno 4 Posted August 30, 2003 Is it worth doing the bottom end as well... will new tappets be needed, timming chains, etc. ...porting and flowing to be done? Guy, the bottom end shells are really strong and dont have a problem. Bearings are good, I'd be surprised. However even if those cylinders look brill, get someone with eyes like a hawk to measure them up and make sure that they all come up to the same spec, then re-ring. As for the head, the yanks reckon its not a big issue, except for making sure that your valves are air-tight, that the airways are clean, your cam is dead true, and that the lifters and spacers are dead right. Apparantly ECS in the US does a head mod with port and airways mods that help considerably with t/s'charged engines. A few people on the west coast swear by them. Make sure that the engine is clinically clean when you rebuild it. Otherwise you will wonder why at 200 miles you have to open her up again. Dont ask why I know - and no it wasnt my fault - it was down to the VAG "master engineer"....(my hat!). The cam chain is a pain, make sure the tensioner shoe is replaced. Dont forget to replace everything with G12+ when you put it all together. There are some decent threads on this elsewhere - or was it you that wrote them.....? Quote Share this post Link to post Share on other sites
macca 0 Posted August 30, 2003 Bruno At the moment I’m getting clued up on the worst case Scenario , and hope I don’t need a new H/G, (would enjoy the challenge though). Read in one of your other posts about "heat stress" if the water is exploding from the header tank, now this is what has happened to mine in the past, what would be the result of heat stress and the cure?? So the piston rings would need replacing, engine out job then? New cam followers? Thats Cleveland NE UK if you were woundering. Cheers Guy. Quote Share this post Link to post Share on other sites
Mike Edwards 0 Posted August 30, 2003 Sorry, should have made the last post clearer. The head gaskets do tend to go as do the rings on cylinders 1 and 6. In extreme cases the bores wear oval as well meaning that the block is scrap. There is no set mileage fo any of this though as it depends more on how the engine has been used and looked after. Hence, if it isn't bust leave it alone. If you're losing coolant check for leaks before assuming it's the head gasket. Get the coolant checked for traces of exhaust gases if there are no leaks (or they're only around the expansion tank). Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted August 30, 2003 If the 2.9 block ovalises, your choices are a brand new short engine from VAG at £3,600 + VAT or a 2.8 overbore. You can't get over sized pistons for the 2.9. You have to bore the 2.8 out to 2861cc and use stock 2.9 pistons. The 2.9 is notoriously fickle. Some last forever, some die at 130K. The earliest full rebuild I'm aware of is 88K. Maybe some were built better at the factory than others, who knows. I've seen a few engines with the Conrods fitted back-to-front. There really is no guarantee on longevity, regardless of care and attention. My advice is to just check the spark plugs. All 6 should be uniform in colour. If 1 and 6 or either or are oil fouled (on the tips, not the threads) then get your wallet out. Tappets only need doing when noisy, 80K is an average replacement age. Using thin oil kills them off quicker. When in need of replacment, they'll be noisy at 2K and on start-up. Heat stress....the only tips I can give you here are a jammed thermostat or an air lock. Never refill a VR6, or any engine for that matter, from the expansion tank. Fill from the radiator top hose as this forces air out of the galleries from the bottom up. Kev Quote Share this post Link to post Share on other sites
