JohnD Posted July 14, 2021 Report Share Posted July 14, 2021 I want camshaft bearings for my new 2.5L engine, so I turn to the Spitfire experts, although advice from anyone gratefully received. I've had this done before and the machinist did a good job, but he's snowed under right now and has referred me to a colleague in the next town. The new guy comes well recommended but has a different attitude so where the old one just got on with it, this one asks me, how tight do I want the cam bearings fitted? Interference fit, I said. Ah, but how tight, he replied, 1 or 2 thou undersize? Early Spitfires were fitted from the factory with cam bearings, and it's those that will be fitted, as production six cylinders had the cam running in the block, as later Spits did. So can anyone tell me? How tight should the cam shaft bore be? Thanks! JOhn Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 14, 2021 Report Share Posted July 14, 2021 maybe use a bearing fit loctite to make sure the bush wont rotate Pete Link to comment Share on other sites More sharing options...
JohnD Posted July 14, 2021 Author Report Share Posted July 14, 2021 Pete, maybe you would like to suggest that to a master craftsman? Who can do the work to that precision? I wouldn't dare! Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 14, 2021 Report Share Posted July 14, 2021 well it was used on production by many makers it is good stuff and no i dont have shares in the Co ha !! it can solve the Oh Too late its a loose fit Pete Link to comment Share on other sites More sharing options...
Nick Jones Posted July 14, 2021 Report Share Posted July 14, 2021 7 hours ago, Pete Lewis said: maybe use a bearing fit loctite to make sure the bush wont rotate Nooooo! I had a machinist who thought that would be an ok approach and two of the bearings came out while I was fitting the cam. I can tell you that on the 4 cylinder 1300 & 1500 engines, all camways are bored to the same size so you can fit shells or not to suit your cam. Only the Spit Mk3 and 1300TC FWD had them from the factory though. Nick Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 14, 2021 Report Share Posted July 14, 2021 that surprises me when ive used it it needs a Nuke to get it apart was it the right stuff ?? Pete Link to comment Share on other sites More sharing options...
PeteH Posted July 14, 2021 Report Share Posted July 14, 2021 Having no experience of the use of Triumph Camshaft shells, Are they White Metalled?, or Plain?. Pete Link to comment Share on other sites More sharing options...
thescrapman Posted July 14, 2021 Report Share Posted July 14, 2021 1 hour ago, PeteH said: Having no experience of the use of Triumph Camshaft shells, Are they White Metalled?, or Plain?. Pete Same material as the crank bearings 1 Link to comment Share on other sites More sharing options...
DanMi Posted July 14, 2021 Report Share Posted July 14, 2021 2 hours ago, Nick Jones said: Nooooo! I had a machinist who thought that would be an ok approach and two of the bearings came out while I was fitting the cam. I can tell you that on the 4 cylinder 1300 & 1500 engines, all camways are bored to the same size so you can fit shells or not to suit your cam. Only the Spit Mk3 and 1300TC FWD had them from the factory though. Nick and the spitfire mk2 at least the later ones and I believe the early mk4 Link to comment Share on other sites More sharing options...
Nick Jones Posted July 15, 2021 Report Share Posted July 15, 2021 May well be right about Spit Mk2, but I think the early MkIV thing is a myth. Nick Link to comment Share on other sites More sharing options...
rogerguzzi Posted July 15, 2021 Report Share Posted July 15, 2021 Hello All I fitted bearings to the new engine and as far as I know they are still ok (1500) But I did turn up a Go and No Go gauge to check the bores to make sure they would be ok! But 5k to 8k later they are still ok. But John you need a GOOD machine shop to bore them in line and to size Roger Link to comment Share on other sites More sharing options...
KevinR Posted July 15, 2021 Report Share Posted July 15, 2021 3 hours ago, Nick Jones said: May well be right about Spit Mk2, but I think the early MkIV thing is a myth. Nick Nick, the early MKIV has camshaft bearings as its camshaft is the same one as fitted to the MkIII engine. Link to comment Share on other sites More sharing options...
Nick Jones Posted July 16, 2021 Report Share Posted July 16, 2021 Ok. So is this actually an FD small-crank on the first few hundred, using up stocks, or something more widespread? Or is it a big crank FH with the Mk3 cam. I’ve never seen one (not surprising) and I don’t know anyone who has. As it happens, our earlyish MkIV does have a full FD engine. But only because we created it specially. The car came with a large crank FH. Didn’t measure the cam but it had no cam bearings. Nick Link to comment Share on other sites More sharing options...
JohnD Posted July 16, 2021 Author Report Share Posted July 16, 2021 I've found these specs in the GT6 Mk 1 WSM: Camshaft New Dimension Inches Clearances Inches Journal Diameter 1.8402 0.0026 1.8407 0.0046 Bore in block 1.8433 1.8448 Please ignore the heavy table lines - I didn't put them in! But what do these specs mean? Why two dimensions for the journal and bore widths? Were these the tolerance Triumph worked to? A journal width 1.8402 in a bore 1.8433 has a clearance of 31 thou. A journal 1.8407 in a bore 1.8448 has a clearance of 41 thou! Neither agrees with the stated clearances! Confusing! This doesn't answer the machinist's Q, what dimension to bore out to for bearings, but could inform the decison, if I had some illumination! John Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 16, 2021 Report Share Posted July 16, 2021 thats the way many triumph manuals show the tolerances of min /max sizes it pops up in a number of places they dont use a nominal with a + _ tolerance just the two sizes i find it bit odd Pete Link to comment Share on other sites More sharing options...
KevinR Posted July 16, 2021 Report Share Posted July 16, 2021 2 hours ago, Nick Jones said: Ok. So is this actually an FD small-crank on the first few hundred, using up stocks, or something more widespread? Or is it a big crank FH with the Mk3 cam. I’ve never seen one (not surprising) and I don’t know anyone who has. As it happens, our earlyish MkIV does have a full FD engine. But only because we created it specially. The car came with a large crank FH. Didn’t measure the cam but it had no cam bearings. Nick Nick, The early MKIV Spit engine (pre FH25000HE) has a large journal crank, but is fitted with the MK3 Spitfire Camshaft. I've got FH4HE in my stock of core engines, and FH6xxHE in my very early MKIV Spit. The engine is perkier than the later MKIV Spit engine, but not as high revving as the MK3 engine. Link to comment Share on other sites More sharing options...
rogerguzzi Posted July 16, 2021 Report Share Posted July 16, 2021 2 hours ago, JohnD said: I've found these specs in the GT6 Mk 1 WSM: Camshaft New Dimension Inches Clearances Inches Journal Diameter 1.8402 0.0026 1.8407 0.0046 Bore in block 1.8433 1.8448 Please ignore the heavy table lines - I didn't put them in! But what do these specs mean? Why two dimensions for the journal and bore widths? Were these the tolerance Triumph worked to? A journal width 1.8402 in a bore 1.8433 has a clearance of 31 thou. A journal 1.8407 in a bore 1.8448 has a clearance of 41 thou! Neither agrees with the stated clearances! Confusing! This doesn't answer the machinist's Q, what dimension to bore out to for bearings, but could inform the decison, if I had some illumination! John Hello John I think you will find it is 3.1 Thou and 4.1 Thou Roger Link to comment Share on other sites More sharing options...
thescrapman Posted July 16, 2021 Report Share Posted July 16, 2021 5 hours ago, KevinR said: Nick, The early MKIV Spit engine (pre FH25000HE) has a large journal crank, but is fitted with the MK3 Spitfire Camshaft. I've got FH4HE in my stock of core engines, and FH6xxHE in my very early MKIV Spit. The engine is perkier than the later MKIV Spit engine, but not as high revving as the MK3 engine. Is it a Mk3 bearing type camshaft, or a Mk3 grind on a non-bearing sized blank. And I think you have FH14HE. But I only used it and it was sha**ed. Never looked inside. Link to comment Share on other sites More sharing options...
DanMi Posted July 16, 2021 Report Share Posted July 16, 2021 It is the same camshaft part no 212164 shared by late mk2 from fc61023 mk3 and mk4 prior to FH25000 https://rimmerbros.com/Item--i-GRID005552 Link to comment Share on other sites More sharing options...
KevinR Posted July 16, 2021 Report Share Posted July 16, 2021 1 hour ago, thescrapman said: Is it a Mk3 bearing type camshaft, or a Mk3 grind on a non-bearing sized blank. And I think you have FH14HE. But I only used it and it was sha**ed. Never looked inside. Colin, it’s the MK3 camshaft with bearings in the block. Same camshaft part number as the MK3 engine Link to comment Share on other sites More sharing options...
JohnD Posted July 16, 2021 Author Report Share Posted July 16, 2021 9 hours ago, rogerguzzi said: Hello John I think you will find it is 3.1 Thou and 4.1 Thou Roger D'accord, Roger! Lost the decimal point, somehow. Link to comment Share on other sites More sharing options...
JohnD Posted July 16, 2021 Author Report Share Posted July 16, 2021 With respect, I'd like advice on fitting the bearing to a six, please, not a discussion of Spitfire fitments! Link to comment Share on other sites More sharing options...
rogerguzzi Posted July 16, 2021 Report Share Posted July 16, 2021 Hello John They are the same bearings just 2 less so the same! they only left them out to save money! Basically you have got to have the block bored to the same(Triumph saving money!) We love our cars but they were parts bin made sometimes! Just look how many parts fit so many different models? If you you look at large journal and small journal cams it is the shell difference in diameter!(cheap!!) and more than adequate for a road car!# Roger Link to comment Share on other sites More sharing options...
thescrapman Posted July 17, 2021 Report Share Posted July 17, 2021 I thought the bearings push fit into the block, and the journals on the cam are reduced in diameter to suit. So you just get the 6-cyl cam made with reduced journals. Link to comment Share on other sites More sharing options...
KevinR Posted July 17, 2021 Report Share Posted July 17, 2021 1 hour ago, thescrapman said: I thought the bearings push fit into the block, and the journals on the cam are reduced in diameter to suit. So you just get the 6-cyl cam made with reduced journals. My thoughts too Link to comment Share on other sites More sharing options...
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