AarhusTr6 Posted January 1, 2023 Report Share Posted January 1, 2023 Hi all It’s not totally clear to me if I have got the piston caps the right way round, can you please have a look at a picture and let me know? Quote Link to post Share on other sites
Phil Read Posted January 1, 2023 Report Share Posted January 1, 2023 I think the 'tags' that locate the big end shells should both be at the same end. Quote Link to post Share on other sites
AarhusTr6 Posted January 1, 2023 Author Report Share Posted January 1, 2023 Just now, Phil Read said: I think the 'tags' that locate the big end shells should both be at the same end. Exactly - it looks like that in the book but it’s a bit unclear Richard Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 1, 2023 Report Share Posted January 1, 2023 (edited) Yes tabs both at same side. Your picture shews the cap incorrectly assembled to the rod oops I did not enlarge the photo sufficiently Next answer. Split side of rod on the camshaft side of the engine Edited January 1, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
John L Posted January 1, 2023 Report Share Posted January 1, 2023 Make sure the off set ends of the rods are fitted correctly, then make sure the pistons are on the correct way round, with the arrow pointing to the front. If the pistons havent been off the rods just make sure the arrow points to the front as the gudgen pin is not in the centre of the piston thats why you have to get correct. If you look closely at the ends of the rods they should be marked with vibrating pen or even a stamp mark to match them together. All this stuff is in the Manual why don't you get one? John Quote Link to post Share on other sites
AarhusTr6 Posted January 1, 2023 Author Report Share Posted January 1, 2023 Hi So looking in the manual, I am correct? Quote Link to post Share on other sites
BlueTR3A-5EKT Posted January 1, 2023 Report Share Posted January 1, 2023 (edited) 9 minutes ago, AarhusTr6 said: Hi So looking in the manual, I am correct? Yes Sorry I was wrong as I had not enlarged your photo sufficiently. Correction made above. The line drawing you have posted is correct. As stated above. Get the correct caps on their matching rods. Check for an etch or stamp on the rod adjacent to the cap which is the same number, letter symbol as stamped on the cap. Mix em up and you may shorten the engine’s life. Edited January 1, 2023 by BlueTR3A-5EKT Quote Link to post Share on other sites
AarhusTr6 Posted January 1, 2023 Author Report Share Posted January 1, 2023 (edited) 4 minutes ago, BlueTR3A-5EKT said: Yes I was wrong as I had not enlarged your photo sufficiently. the line drawing you have posted is correct. As stated above. Get the correct caps on their matching rods. Check for an etch or stamp on the rod adjacent to the cap which is the same number, letter symbol as stamped on the cap. Mix em up and you may shorten the engine’s life. Thank Peter I have matched the numbers on the caps to the rods, some of the numbers on the caps are very hard to see, but my main concern, which I post on another question is the PO seemed to have 3&4 rod & piston wrong way round in engine. Out of curiosity, why the big issue on the cap numbering? Is it because the rod and cap are cast together? Richard Edited January 1, 2023 by AarhusTr6 Quote Link to post Share on other sites
Waldi Posted January 1, 2023 Report Share Posted January 1, 2023 They are machined together. Quote Link to post Share on other sites
Andy Moltu Posted January 1, 2023 Report Share Posted January 1, 2023 There's usually a tell tale mark on the opposing faces of the rod and cap. Quote Link to post Share on other sites
Motorsport Mickey Posted January 1, 2023 Report Share Posted January 1, 2023 It's tempting to think that if the big ends are machined together...then the hole has to be round and why should it matter if the cap is fitted the wrong way around. However (there's always a "however") the caps stress up differently if clamped up the wrong way around, which can change the shape of the clamped big end from round to oval, and screw up your bearings and then the crank journal. Mick Richards Quote Link to post Share on other sites
TonyC Posted January 11, 2023 Report Share Posted January 11, 2023 Elin Yokov explains the big end cap matching on the con rod in this video. Essentially piston is marked with an arrow or the word ‘FRONT’ indicating that this must face the front of the engine (ie the timing chest end.) insert piston into the bore with offset of the con rod facing towards the camshaft side of the engine, and big end caps have different profile shapes which must match with the same shape on the con rod itself. Caps and rods are numbered 1 through 6 and must stay together. Hope it helps. TonyC Quote Link to post Share on other sites
Motorsport Mickey Posted January 11, 2023 Report Share Posted January 11, 2023 Good basic stuff, I review his bodyworking and admire his welding but I'm not a fan of his mechanicing. Fitting piston rings without using a piston ring expander is risky. The parts supply shops have ring sets brought back all the time, where the owner claims there was a ring broken when he opened the set, often caused by clumsy ring fitting by hand (yes I've done it, AND broken the ring, but no I paid for a replacement). Live and learn. Also he should be measuring the turning torque of the engine as the piston and rod sets are added. The turning torque should increase incrementally cylinder by cylinder so you can check the fit of the piston conrod and bearing assemblies. If you get a wayward reading say 5 lb ft more on one cylinder there's a problem, stop strip and inspect. Mick Richards Quote Link to post Share on other sites
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