Fallon Posted July 12, 2022 Share Posted July 12, 2022 Hello Fellow 7 owners1st time posting and a bit new to 7 motoring and engine mechanics so please forgive me if this is a daft question.I suffered a blown head Gasket on my 25 yr old Supersport and had a local mechanic replace it with the new uprated laminated replacement, new bolts, water pump etc etc. When he had finished he noticed the tick over was a bit "bobbly" so he went back in and checked all the timing which was all correct.I now have a couple of differences in performance:-Sometimes when dipping the clutch, say approaching a junction, as the revs drop and the engine stopsThe engine feels down on power as to how it was before and top speed is downThe Mechanic says as the new gasket is thicker it may have altered the compression ratio so I am now looking into booking it into an Engine tuning specialist.I thought it worth asking if this is the right course of action before I fork out a load of cash on this.Thanks for any adviceDave Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 12, 2022 Member Share Posted July 12, 2022 Welcome, Dave.Please could you tell us a bit more about which engine this is.And where you are.ThanksJonathan Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted July 12, 2022 Area Representative Share Posted July 12, 2022 Hi FallonNear Coventry you should have a number of people who know their way around the K Series (of all specifications). I think the key question after the blown head gasket is whether the head is still true. Was it linished before refitting? Link to comment Share on other sites More sharing options...
revilla Posted July 12, 2022 Share Posted July 12, 2022 I've never known the small difference in the head gasket thickness between an MLS and elastomer gasket make a noticeable difference. It certainly shouldn't lead to stalling and a noticeably lower performance. My guess would be - and it is a guess without seeing the car - that the person who changed the gasket has got the cam timing wrong on reassembly (despite apparently checking it). The other possibility that I can think of is that he's disturbed something electrical, maybe not got a sensor connector back on correctly or something. Certainly something sounds wrong, the change to an MLS gasket should not make that kind of difference to the running of the engine.Where abouts are you based? Link to comment Share on other sites More sharing options...
revilla Posted July 12, 2022 Share Posted July 12, 2022 PM sent. Link to comment Share on other sites More sharing options...
SM25T Posted July 13, 2022 Share Posted July 13, 2022 Andrew is The Man when it comes to timing k-series engines Link to comment Share on other sites More sharing options...
Area Representative Nick Bassett Posted July 13, 2022 Area Representative Share Posted July 13, 2022 My old 1.4 SS had exactly the same trait that you describe - sometimes the revs would dip and the engine would stall. When I took it to DVA for some work, he said the cams were all over the place! Once set up properly it never happened again and the awful shunting I used to have at low revs, light throttle disappeared completely too.My money is on the cam timing. Link to comment Share on other sites More sharing options...
TomB Posted July 13, 2022 Share Posted July 13, 2022 Could be Throttle Position Sensor related - check connections here, and perhaps reset it. The ECU might not be detecting properly the closing of the throttle and its stalling. I had this on my old 1.4SS - however, I never fully got to the bottom of it as i swopped to TB with a new TPS - but it went away afterwards! Link to comment Share on other sites More sharing options...
Fallon Posted July 13, 2022 Author Share Posted July 13, 2022 It was sent of to be skimmed and crack tested, ne liners etc Link to comment Share on other sites More sharing options...
Fallon Posted July 13, 2022 Author Share Posted July 13, 2022 Hi, All I know is its a K Series EngineI live in the Coventry areaDave Link to comment Share on other sites More sharing options...
Fallon Posted July 13, 2022 Author Share Posted July 13, 2022 Thank you for the advice! Link to comment Share on other sites More sharing options...
SM25T Posted July 13, 2022 Share Posted July 13, 2022 Andrew is your man ! Link to comment Share on other sites More sharing options...
Area Representative paul richards Posted July 13, 2022 Area Representative Share Posted July 13, 2022 I would also suspect the valve timing. Link to comment Share on other sites More sharing options...
oilyhands Posted July 13, 2022 Share Posted July 13, 2022 Cam timing disrupting MAP signal.Oily Link to comment Share on other sites More sharing options...
revilla Posted July 13, 2022 Share Posted July 13, 2022 See you on Saturday Link to comment Share on other sites More sharing options...
revilla Posted July 16, 2022 Share Posted July 16, 2022 Dave brought the car over to see me this morning. As soon as I heard his car turning into my driveway I knew the cam timing was wrong.With the crank timing mark aligned, one cam pulley was three teeth up and the other one three teeth down! So basically three teeth or 45° out at the crank. No wonder it wasn't happy.We realigned the pulleys and did a hot leak down test just to make sure it hadn't bent any valves - everything checked out fine.The car now idles normally, has its mojo back, and is on its way back to Coventry. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 16, 2022 Member Share Posted July 16, 2022 Thanks for adding the solution.We're lucky to have you.Jonathan Link to comment Share on other sites More sharing options...
ScottR400D Posted July 16, 2022 Share Posted July 16, 2022 #16 Well done, JK is right!! Link to comment Share on other sites More sharing options...
John Vine Posted July 16, 2022 Share Posted July 16, 2022 Delighted to hear it's fixed (and full points, Andrew).Do you plan to have a "chat" with your local mechanic?JV Link to comment Share on other sites More sharing options...
Fallon Posted July 16, 2022 Author Share Posted July 16, 2022 1st of all, Andrew such a pleasure to meet you and the family. A real gentleman and clearly an expert on K series engines.My 7 was like her old self on the trip back, Power back up, Tops peed there again and the noise from what was a very "angry" sounding engine back to a much more acceptable level and tone. So pleased with the result!My local mechanic will get some feedback but he was such a nice guy to deal with and clearly a decent chap it will be an entirely civil conversation, we're all human after all. Again Thank You Andrew, really appreciate your help with this matter! Link to comment Share on other sites More sharing options...
ECR Posted July 16, 2022 Share Posted July 16, 2022 So kind of you Andrew. Top marks! Link to comment Share on other sites More sharing options...
SM25T Posted July 16, 2022 Share Posted July 16, 2022 Great result. Lucky no contact damage occurred ! Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted July 16, 2022 Area Representative Share Posted July 16, 2022 Well done Andrew. Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 16, 2022 Share Posted July 16, 2022 Another example why this is such a great club. Well done Andrew! Link to comment Share on other sites More sharing options...
DanRo Posted July 16, 2022 Share Posted July 16, 2022 For those of us with K series cars, Andrew, Dave Andrews and others have offered so much free advice in my short time in the club. It's been invaluable and very reassuring to have available. Link to comment Share on other sites More sharing options...
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