Jonny-Jimbo Posted January 18, 2018 Share Posted January 18, 2018 Last night when torquing up the crank nut on the Spitfire 1500 I have in for a bit of work I noticed that there is a gap between the engine backplate and the bellhouse. With the starter motor fitted and torqued up the gap didn't close. Using feeler gauges I found the gap to be 2.281mm.I'm wondering if this will effect the starting of the car, as with the backplate bent, the starter motor is sitting at a slight angle to normal. Should I see how it goes, or will the back plate need changing for definite, in which case it'll be better to get the gearbox out and get a new plate on ASAP. Quote Link to comment Share on other sites More sharing options...
thescrapman Posted January 18, 2018 Share Posted January 18, 2018 JonThere is a gap in the bellhousing by the starter usually I am sure, but maybe not that big,Any bend in the backplate will give a clutch life in months if not weeks if badly bent.Take the plate off and put a straight edge in it,CheersColin Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted January 18, 2018 Author Share Posted January 18, 2018 Hi Colin,Is that because with the backplate bent it means the bellhouse mounts up on the cock? I ask as all the other bellhouse bolts are pulled home tight and flush, it's only by the starter that it's got the gap, hence thinking it will effect starter engagement.I admit, I hadn't thought about the fact the clutch itself could be effected too! Quote Link to comment Share on other sites More sharing options...
thescrapman Posted January 18, 2018 Share Posted January 18, 2018 I just remember the problems the guy at Yarmouth had (Jason?) with a backplate that did not look bent, but was very slightly.He got through 3 clutches before I gave him a spare backplate to try.All problems disappeared.Cheers Quote Link to comment Share on other sites More sharing options...
rlubikey Posted January 19, 2018 Share Posted January 19, 2018 If it is pringle-shaped you can fix it with sheet metal rollers. My experience was that the clutch will judder as you feed in drive. However, my clutch did last 4 years until I eventually stripped the engine down (for a different problem). On discovering the offending pringle-like article (the gorilla at the main dealer without a clutch alignment tool) I found that back plates were NLA new! (This was 1993) So I gave it to my friend in our company model shop who put it through the rollers, turning it over and around by 90' each time, and slightly reducing the bend (increasing the roller distance) until the back plate was dead flat. Voilà! - it's a bit like demagnetising something.Cheers, Richard Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted January 19, 2018 Author Share Posted January 19, 2018 A couple of friends have rollers etc, and one has access to a very large press, so might be able to squeeze back flat if needs be... however, I also have a few spare plates myself, or could get an aluminium plate from Canleys. Quote Link to comment Share on other sites More sharing options...
glang Posted January 19, 2018 Share Posted January 19, 2018 I reckon the ally ones must have to be treated very gently! Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted January 19, 2018 Share Posted January 19, 2018 Perfectly ok if made from the right aluminium - though many are not!Anyway, it's bad practice to use the bell housing bolts to drag the input shaft through a slightly mis-aligned clutch - but if you must, use the top three studs that go through to the block and push down on the back of the box when it starts to tip.......Nick Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted January 19, 2018 Author Share Posted January 19, 2018 I didn't do it Nick, the owner assembled it all all, I just noticed the back plate was bent by the starter, but the gearbox is pulled home. Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted January 19, 2018 Share Posted January 19, 2018 Was only a general comment JJ, not an accusation 🙂As Colin said earlier, they do quite often have that look around the starter area, maybe even because the BH has more material removed from the face in that area (don't have a loose one to examine at present), so what you are seeing may well be normal - though I can see why you find it a bit worrying.Nick Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted January 20, 2018 Author Share Posted January 20, 2018 Alex Chandler sent me a photo earlier of his 1500 and it has the same gap, so actually it might be okay in the end... Quote Link to comment Share on other sites More sharing options...
piman Posted January 21, 2018 Share Posted January 21, 2018 Hello Jonny, the extent of the bend is the important thing, if the starter motor face is flat on the inside then I suggets it is not a problem, i.e. the bend is only outboard of the starter axis? The fact that the gap did not close up when tightening the starter motor bolts is a good sign.It may be possible to rectify, if it is only a limited length of bend, in situ with a hydraulic bottle jack and some wood packing?Alec Quote Link to comment Share on other sites More sharing options...
efp Posted January 21, 2018 Share Posted January 21, 2018 I’m having a little trouble understanding this. Surely the backplate is bolted tight to the (flat) block end all around the circumference of the clutch? And the bell housing flange bolts will be pulling it flat the other way? I can’t see how, short of dropping the combined engine and box from a height the main part of the plate can be bent? If the starter motor part is a bit bent off that plane I can see it giving ring/ starter engagement problems but don’t see how it can affect the clutch. Am I missing something? Quote Link to comment Share on other sites More sharing options...
Alex Posted January 22, 2018 Share Posted January 22, 2018 If you look at the picture the backplate is straight the gap is between the bell housing and the backplate. This is shaped into the bell housing, both my spitfires are exactly the same.....Now as to why it’s shaped like that I don’t know..... Quote Link to comment Share on other sites More sharing options...
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