DonDP Posted September 28, 2019 Share Posted September 28, 2019 Hello,I have a vibration at high RPM over 7k which is definitely engine related. You can’t really notice it until flat out in 4th gear. I assume it’s because it spends more time getting to the shift point that makes it more noticeable.It is however, always there, you can simulate in 3rd holding it at high rpm and equally there is some vibration in neutral both with clutch engaged and when released.I am trying to work out if this is just a trait of sigma engine, possibly the 310 with the different cams?Does anyone else have this? Is this a case of TADTS? Link to comment Share on other sites More sharing options...
colindavies56 Posted September 29, 2019 Share Posted September 29, 2019 I thought they cut out at 6800rpm. Link to comment Share on other sites More sharing options...
DonDP Posted September 29, 2019 Author Share Posted September 29, 2019 310r limit is 7500rpm. My rev counter does over read slightly so vibration is probably within the last 800-1000 rpm Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 29, 2019 Member Share Posted September 29, 2019 Can you make it happen in the garage?All exposed belts and pulleys and alternator OK? Jonathan Link to comment Share on other sites More sharing options...
DonDP Posted September 29, 2019 Author Share Posted September 29, 2019 I haven’t done in the garage as yet, mainly due to noise and neighbours... might have to annoy them today...I have removed the exposed belt and checked all pulleys, alternator by hand and all seem smooth. Link to comment Share on other sites More sharing options...
DonDP Posted September 29, 2019 Author Share Posted September 29, 2019 So I made some noise this morning....first of all I noticed that the crank shaft pulley is not quite straight - not sure if this is normal? I took a slow motion video here: Once it was nice and warm I revved the engine right up to 7k-ish in the garage. There is more vibration coming from the front of the engine than the back (relative ro car). Again not sure if the amount is normal or not since all the belts and ancillaries are at the front? Link to comment Share on other sites More sharing options...
SM25T Posted September 29, 2019 Share Posted September 29, 2019 Have a link Link to comment Share on other sites More sharing options...
Tom_Arundel Posted September 29, 2019 Share Posted September 29, 2019 Is the vibration felt through the gear lever or elsewhere? Link to comment Share on other sites More sharing options...
DonDP Posted September 30, 2019 Author Share Posted September 30, 2019 The vibration is through the chassis, but can obviously be felt through the gear lever too. I have checked all engine mounts and and gearbox mounts.Clearance between the gearbox and chassis is very tight, roughly 0.5mm at its closest (lower left longitudinal). I removed the rivets under the gearbox mount (for the floor) as these seemed unnecessary considering the mount bolts over them. This has given a marginal improvement in clearance. Still need to test. Link to comment Share on other sites More sharing options...
Matthew Willoughby Posted September 2, 2020 Share Posted September 2, 2020 Did you ever solve this? I have a very similar issue and would be interested to know if you found a cause. Link to comment Share on other sites More sharing options...
Tom_Arundel Posted September 2, 2020 Share Posted September 2, 2020 I suspect its TADTS as mine does as well. Could be the way the engine is mounted, road cars tend to have a third top link I don`t go to max rpm. the power curve drops quite rapidly above 7k `Short shifting` at 6800 gets you there quicker. Stress goes up as the square of rpm., 6800 to 7500 is about 23% more stress. The engine may have the Ford flywheel and be balanced to production tolerances which don`t anticipate 7500rpm And then there`s.........!!! Let us know what you find, if anything Link to comment Share on other sites More sharing options...
Matthew Willoughby Posted September 3, 2020 Share Posted September 3, 2020 It isn't a case of TADTS. Mine started doing it two thirds of the way through my last race. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now