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We are building a tv8 engine . Im no expert but my mechanic is doing it . Thankfully .
The machine shop is saying we might need to go +30 on the rebore . Is this ok . ??
Hi Richard what will you use for the main bearings? King? I am having my engine rebuild currently and my mechanic tells me they are basically s**t. He is in the process of having some prototypes made with vandervell, clevite 77, cosworth YB/BDA as a quality standard. They will go into my engine before a decision is made to market them. I would like your opinion if you would do the same.
Hans
Hi Richard what will you use for the main bearings? King? I am having my engine rebuild currently and my mechanic tells me they are basically s**t. He is in the process of having some prototypes made with vandervell, clevite 77, cosworth YB/BDA as a quality standard. They will go into my engine before a decision is made to market them. I would like your opinion if you would do the same.
Hans
I approached Mahle classic (who now have the vandervell rights)
they kindly provided us with low volume quotes for tri metal bearing shells in all sizes.
the total minimum order value needed was over £30,000. (2019 iirc)
the individual engine bearing sets were in the region of £750+
the member who asked for tri-metal vandervell bearings, (cost no object) didn’t actually want to ‘shell - out’ for them when it came down to it.
i did seek member feedback regarding poor performance from king bearings / county.
apart from hearsay I received no evidence of poor performance…. Only really stories about issues likley to have been out of spec mating parts & or dirty builds.
one very prolific (&respected) stag engine builder mentioned that they’d never had any issues with using king bearings.
so, some owners are using expletives to describe what they reckon about available bearings…. But there’s almost no evidence being provided to substantiate.
interesting to hear what happens with hans jochims engine build / sourcing of ‘higher quality’ bearings.
also Interesting…. Aluminium based shell bearing marketing says they are very good for debris embedment / accommodation…. Tri metal based bearing marketing claims to be very good for debris embedment too.
Whilst debris cannot be entirely eliminated, the best route is to ensure laboratory levels of cleaning during the build….
Post crank grinding and hardening inspection / measure report is helpful…. If only for peace of mind. (Some cranks will need resizing and or straightening, post grinding and hardening)
Finding shops that can still do that is a bigger issue than bearings imho.
Thoroughly checked / re manufacturing of conrods is often overlooked with stag engine rebuilds …. Having taken a few apart after early issues after rebuild.
correct chain tensioning is often not achieved.
correct torque to turn is often not achieved with respect to crankshaft (aim for max 45 Nm imho, 25-30 is better) and also water pump (aim for max. 1.2 Nm imho)
I believe my mechanic took care of all the other stuff as well.
Block, pistons, clutch have been refurbed at South Cerney Engineering.
Crankschafts and gearbox at Techniques Surfaces UK Ltd.
Springs at Coil Springs Ltd.
Camshafts at Kent Performance Cams Ltd
Fingers crossed it comes all together in the summer after 4 years waiting
correct torque to turn is often not achieved with respect to crankshaft (aim for max 45 Nm imho, 25-30 is better) and also water pump (aim for max. 1.2 Nm imho)
Julian I was interested to read the ‘max torque’ you quoted. What condition is the engine when this is measured ?
Are we talking just short engine, no chains or jackshaft or full engine (no plugs).
Recently built up a spare engine, rebore with new pistons, crank grind with new mains and big ends. Checked for smooth turning of each component at every step but was surprised by the amount of effort required to turn it when fully assembled. I can measure the torque just to begin turning but are we talking about the torque required to keep turning after the initial ‘stickion’ is overcome?
-Alan
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