TuftyTR Posted October 31, 2008 Report Share Posted October 31, 2008 Hi All, First of all, managed to post this in the wrong category initially (buy/sell/trade) idiot!! But it may well be of use to all TR owners, here goes anyway!! Just thought I would report a positive experience! I am currently restoring a '69 ex american car (although it never left good old England!! - US Forces) and the original USA engine needed a bit of work (!!) I won't go into the details here but suffice to say I felt the need to get the crank looked over and balanced. The crank was in generally good nick but I considered it prudent whilst the engine was spread all over the garage floor to get it checked by those who know. Enter Newark Engines of er, Newark! (Nottinghamshire England for our friends across the atlantic!). A quick 'phone call, took the crank and flywheel down to the workshop and the Guys there did a top job. Initially checking the crank, they picked up that some of the bearing faces were out a couple of thou' here and there - reground the iffy ones and polished them all - sorted. On to the balance, the crank showed 176 units of imbalance at the back of the crank and 143 at the front (ounces/inch I think!) both readings at 4000 rpm "you need that below 30!" was the call from those who know Duly, after some fettling I now have 15 at the back an 13 at the front, at 8,000rpm!!! Of course you are welcome, as a Customer, to witness this operation (health and safety to the fore obviously). Well, the cost of this, including a set of new big end bearings (-10s) came to £117:50 (vat inc.) Friendly, no nonsense service, easy to find and get to (just off the A1) the only prerequisite, give them a call prior to arriving with your crank under you arm!! They also carry out the full range of engine work, unleaded head conversions for example, so definitely worth a call IMHO. ( am I allowed to post contact details???!!) Incidentally, I have no personal interest or connection to the Guys at Newark Engines, just wanted to let everybody know and hopefully avail themselves of some excellent service! Hope this is useful! Dave G Quote Link to post Share on other sites
Richard Crawley Posted October 31, 2008 Report Share Posted October 31, 2008 Not only did I have the crank balanced but the complete rotational assembly; crank, front pulley, flywheel & clutch cover which came back with alignment marks for final assembly. Don’t know who did the actual balancing work as it was through a 3rd party but it’s really worth getting the whole rotational mass as much “in balance” as possible. Quote Link to post Share on other sites
Guest ntc Posted October 31, 2008 Report Share Posted October 31, 2008 Hi Dave As Richard said balancing the crankshaft without the rest attached is a total waste of time. I would check the manufacture of the main bearings prior to fitting. Funny figure that £100 + vat! I had 2 CP short engines rebuilt by the same company and both were rejected due to bad workmanship. You are obviously local to me, pm me with a phone number and we'll have a chat about it if you wish. Regards, Neil Quote Link to post Share on other sites
Alec Pringle Posted October 31, 2008 Report Share Posted October 31, 2008 Come on Neil, let's not get too carried away A reasonably balanced crankshaft is always going to be an improvement over a significantly unbalanced crankshaft . . . but it's certainly of limited benefit in comparison to a proper job of balancing the overall rotating assembly. As for Newark, my only experience is of being fortunate enough to source some proper old-fashioned nos bearings from them, and at a very reasonable price too and promptly despatched. I haven't had any work done though, not exactly local to Wiltshire !! Cheers, Alec Quote Link to post Share on other sites
john.r.davies Posted October 31, 2008 Report Share Posted October 31, 2008 Balancing a crankshaft, with the bits and pieces that rotate with it, I understand. And balancing pistons is just making sure they weigh the same. But how do you balance conrods? Is it weighing each end and making sure they weigh the same when the other end is supported? John (I'm engine building this winter, and never balanced con rods on previous engines, but this one will be a screamer) Quote Link to post Share on other sites
Alec Pringle Posted October 31, 2008 Report Share Posted October 31, 2008 Hi John, try googling for 'balancing con rods' and you'll find all you need to know . . . in a nutshell, you're trying to achieve 4 rods of the same weight apiece, and with 4 matching small ends and 4 matching big ends. Not as easy to achieve as it is to write !! Con rods have balance pads, which can have material removed for balancing purposes, although often enough it's necessary to machine outside the pads themselves. In an ideal world, you have a big box full of new rods and patiently work through until you have 4 that are pretty close, and then fine-tune them to an average. Be warned, bolts are a more common fail point than the rods themselves. You may not be able to afford the best rods, but you can't afford to skimp on the best bolts (and nuts) . . . If your rods aren't purpose made race units, you'll need to clean up and shotpeen them. the link below shows a similar jig to the one we used 30 years ago with Pinto engines, although back then it was scale pans and not digital . . . http://www.angelfire.com/ca4/CorvAIRCRAFT/RodBalance.html Cheers, Alec Quote Link to post Share on other sites
Richard Crawley Posted October 31, 2008 Report Share Posted October 31, 2008 (edited) But how do you balance conrods?Is it weighing each end and making sure they weigh the same when the other end is supported? The aim is not only to get each end to weigh the same (as you say) when supported at right angles from the other end but to get the total weight of each conrod the same; no mean feat which requires experience, some fairly delicate weighing equipment & an awful lot of patience! IMO it would be unnecessary on even the fastest of road cars & only of benefit if you intend putting out some really serious power at frighteningly high revs; & I wouldn't expect to be using standard rods either! Edit Alec beat me to it! Edited October 31, 2008 by Richard Crawley Quote Link to post Share on other sites
TuftyTR Posted October 31, 2008 Author Report Share Posted October 31, 2008 Blimey! I was only trying to let people know about what I considered to be some decent service and at a reasonable price!! I did omit to mention by the way that I did have the crank and flywheel balanced as one, does that at least wipe some of the egg from my face ?! I do agree obviously, that a full balance of the all of the major rotational components is the absolute but then my wallet is only so big and, as Alec says, it has to be a lot better than it would have been??!! Quote Link to post Share on other sites
Alec Pringle Posted October 31, 2008 Report Share Posted October 31, 2008 Hi Richard, No problem ! But John did say 'screamer' . . . a term which dates back to the old 1 litre F3 (and latterly F4) days. Which was my old stamping ground. The revs were indeed frightening, what was basically a Ford Anglia engine in origin being pushed to five figure rpm. Five figures was the definition of a 'screamer', more or less. One F4 championship we won, 1977 I think, the last round down to the wire - and the driver came in with 11,800 on the tacho telltale. Holbay built good engines. Need I add that the lump had passed its sell-by date a few yards after the chequered flag Cheers, Alec Quote Link to post Share on other sites
88V8 Posted October 31, 2008 Report Share Posted October 31, 2008 Blimey! I was only trying to let people know about what I considered to be some decent service and at a reasonable price!! I did omit to mention by the way that I did have the crank and flywheel balanced as one, does that at least wipe some of the egg from my face ?! I do agree obviously, that a full balance of the all of the major rotational components is the absolute but then my wallet is only so big and, as Alec says, it has to be a lot better than it would have been??!! And thankyou for taking the trouble to let us know. Balancing is never a waste of time, although to half do it seems a shame, on the other hand not half as much of a shame as not doing it at all. I spent £109 with Real Steel having a brake disc balanced. A handbrake disc. A disc of a mechanical disc handbrake for my V8 Landrover which will hang on the back of the (auto) box and rotate at engine speed. The cost included making a mandrel on which to mount the disc on the balance machine. My wallet is not bottomless, but where balancing is concerned, no amount of money is too much, IMHO. One day I might actually get back to rebuilding the Landrover.... Ivor Quote Link to post Share on other sites
john.r.davies Posted October 31, 2008 Report Share Posted October 31, 2008 Thnaks to Alec and Richard, and apologies to tufty for hijacking his thread. "Screamer" may be relative, but when Spitfires can go to 7.5/8K with relative ease, sticking to 6K on a 2.5 Triumph six is a bit limiting. I allowed myself 7K for my last stint at the Birkett, and it was a whole new world. New engine will be 2 litres, so 7 regularly will I hope be possible. Defo, crack test, lighten and shot peen the Triumph con rods - Carillo would be nice, but........ John Quote Link to post Share on other sites
Wilfried Posted November 1, 2008 Report Share Posted November 1, 2008 Hi John, try googling for 'balancing con rods' and you'll find all you need to know . . . in a nutshell, you're trying to achieve 4 rods of the same weight apiece, and with 4 matching small ends and 4 matching big ends. Not as easy to achieve as it is to write !! Hi Alec, As we are here in the TR6 Forum, it would be better to balance all 6 rods...... Wilfried Quote Link to post Share on other sites
Richard Crawley Posted November 1, 2008 Report Share Posted November 1, 2008 Hi Alec,As we are here in the TR6 Forum, it would be better to balance all 6 rods...... Wilfried Quote Link to post Share on other sites
trfella Posted November 1, 2008 Report Share Posted November 1, 2008 I also believe that the rev limit (according to the tacho) was originally set because of some crankshaft resonance at 6k, and not for any other reason. So balancing your unit was not a waste of time IMO. Quote Link to post Share on other sites
Guest ntc Posted November 1, 2008 Report Share Posted November 1, 2008 I also believe that the rev limit (according to the tacho) was originally set because of some crankshaft resonance at 6k, and not for any other reason. So balancing your unit was not a waste of time IMO. Well the next time you take your car for a wheel balance take the tyre off first then you will see Quote Link to post Share on other sites
trfella Posted November 1, 2008 Report Share Posted November 1, 2008 Well the next time you take your car for a wheel balance take the tyre off first then you will see No comment! Quote Link to post Share on other sites
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