For those about to do an engine build consider using a Torque Boaring Plate. Pic shows one for both VG30DETT and VQ30-35DETT motors. When torqued up this puts the block under tension the same as when the heads are bolted on, for more accurate and true bore. This slightly reduces friction and eliminates uneven piston and piston ring wear.
Boring! Boring! Anyone contemplating this procedure should be aware that it has the potential to become a real PIG of a job.:rofl::sorry:
Would using one of these be as accurate as using 1 per bank? Also, do the VG's suffer for 'core shift' during casting, and if so, does this torque plate allow for rectification of this if it is present?
VG'S do have terrible core shift from factory boring .. one side of the bore can be as thin as 100thou while the other side can be 300thou Using a torque plate doesnt rectify it .. torque plate simulates the stress/distortion that the heads would ..allowing for a true round bore under tension .. (in theory)
Hmmm... that seems to be a amount of core shift. From what I've read in the past, you can offset bore a core-shifted cylinder to maintain bore alignment along the bank. The stuff I've been reading is mostly in regards to Iron block V8's, but same principles apply. If core shift in these blocks is so prevalent, and the figures are representative of tolerances, a big 'blueprinted' build would not be able to be corrected thru boring- you'd have to find the right block from the start of the build. But then again, most people won't worry about it.
Depends on how much you are overboreing. Can't correct 300thou out with a 40 thou overbore Just get a few blocks and find a good one to work from. They are pretty cheap these days, not like we're talking about a N1 RB26 here.
Core shift doesn't seem to be as big a problem as casting slag in the water passages. In all those "I blew my engine" post has anyone ever seen a knackered bore caused by bore shift ???
i dont buy too much into the benfits of torque plate boring, firstly the torque plate is of an entirely different construction to a cylinder head so i dont accept that the block is distorted in the same way when the torque plate is fitted. Secondly , the boring is done when the motor is cold, heat obviously has a dramatic effect on a motor, so its quite likely that the motor will not be the same hot as when it is cold. Ive heard of some far out boring and honing procedures for high output and endurance engines where a head is fitted, torqued down and hot fluid is pumped through the oil and water galleries, final honing is done with the motor upside down. But i wouldnt bother doing that and i wont be using a torque plate any time soon
a tq plate is only used for honing purposes. when you bore a block out the bores are out of round. The boring bar has a self centering head on it to appropriately bore square to the deck. This allows for true concentricity. The tq plate is then outfitted onto the block when honing. You MUST tq down the mains as well. You have to stress both the tops and bottoms of the cylinders to ensure true alignment when honing. Whether cold or hot the bore is going to remain straight once honed under tension. Of course the bores move slightly in pattern but if done correctly (machining) the blocks can be as true as you can get them. When I bore/hone blocks this is the way I do them and they come out perfect (for me and my practices with my tolerances) everytime. Everyone hones differently but I can assure you that using a TQ is VERY VITAL in ensuring the bores are square up and down through the entire stroke process of the piston/rod assembly. if you have any out of round/shape issues it will affect compression, oiling, friction value...the list goes on and on.
How does this honing process simulate the ammount of flex in the block during operation? It may give you a warm fuzzy feeling when you dial up zero's on the bore gauge but in reality it is not even close to how it is in actual use. I have my blocks done with head bolts tensioned and main girdle fitted and tensioned, they are the only things you can simulate on a bare block accurately with out going to huge expense in doing it other ways. Do some reading of both for and against and make an informed descision for yourselves.
This is a cheap shot joke, and I'm going to hell for it... But Niall used to work with leaky-old Jaguars which used more oil than fuel. Torque plate schmork plate :rofl: I'm joking. I love every single one of you :zlove: I'm still not sure if I'm going to do a backyard stock NA build with a bottle-brush hone job and see how it lasts, or just chuck another engine in and rack up the Km with minimal cost. This is for the daily hack...
lol, ive seen a few of those, 7 thou wear in the bores, 1 litre of oil with every tank of fuel. There is nothing particularly dodgy about honing a block yourself. i did my first vg with a drill and it made alot of power and didnt burn oil(it did leak a bit though) lol Im with Eric, this is another one of those things, like run in procedures where there is alot of info for and against, most of it is opinions or info from manufacturers which can be biased to say the least. Tech at EPR you are obviously knowledgeable and articulate your posts well but yours is just an opinion at the end of the day, same as mine, I dont use torque plates and my builds make good power and dont burn oil
didnt mean it like that, sorry dude always respect your opinions!! Im pressing page up/page down playing with a fuel map lol shows my competency
I would love a engine built to the most minute of tolerances, but for a daily driver (and a NA at that), doing it on the cheap is the most economically rational way. And I'm a cheapskate. The pro's and con's are all on the table. Some will aim to extract every drop of horsepower from this 3L engine, while others will cut their losses as the law of diminishing returns plateaus out (dollars spent vs power unleashed). For a cheap build, DIY surely sill be a learning experience, and if proper care is taken should be a good outcome. Hell, if they can rebuild mine trucks in the middle of a dusty open cut coal mine, then building an engine in your backyard shed should be no dramas. Nissan can keep their hermetic chambers
Do it Mitch I have already got parts coming for build number 2 and haven't even finished build number 1. This one includes a HKS 'style' T04z and a stainless top mount manifold courtesy of Shanghai China.
yes but whats the highest power VG you have built ? 300rwkw is good power not big power and I wouldnt use a torque plate either for that.
