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+--- Thread: Speedy engine big end bolts (/showthread.php?tid=896)
RE: Speedy engine big end bolts - Colin Wilks - 03-02-2019
Cheers Steve, that is a really useful tip which makes practical sense. I had no idea that the original bolts were fatter than normal.
Colin
RE: Speedy engine big end bolts - Chris KC - 03-02-2019
Colin,
If I could find no replacements I would re-use what I had, unless they have seen very hard use. I would first inspect the bolts under a magnifying glass for any signs of wear and tear.
The rods on my car (n.b. these are not Austin rods) have been modified by inserting helicoils in the 'rod' half so a bolt can be screwed in from below. This solves the problem of clearance to the camshaft. If done properly a helicoil is very strong. I've never tried this on an Austin Seven rod, and the first thing would be to check there is enough clearance on the big end bore. My car has run like this for decades, using plain shanked 5/16" bolts.
I'm not advocating this and certainly wouldn't to be held repsonsible for the outcome! Just offering it up as a possibility.
RE: Speedy engine big end bolts - Jeff Taylor - 03-02-2019
Colin,
Might be worth contacting Sports and Vintage Motors of Shrewsbury, I believe they supply 5/16" BSF High Tensile Racing Quality Big End Bolts and Nuts for the MG M, D, J, F1, F2, F3 and PA Types - whether they're of the correct length and head type / shape to fit your Speedy / Nippy rods and crankcase I can't say - but no harm in asking.
http://www.sportsandvintage.co.uk/news.htm
1935 to 1948 Morris Eight Big End Bolts are M8 x 1.0 mmp but probably too long at 44mm - they have a chamfered all round head with a locating flat, but no pin - torque is 25 lb ft.
RE: Speedy engine big end bolts - Bill Sheehan - 05-02-2019
(09-03-2018, 05:13 PM)Steve Berg Wrote:Purely by chance I happen to glance back onto this subject and found that an item I submitted some time back did for some reason not appear. So here's another go. Roughly what I said was that most people wouldn't be aware that Speedy starter dogs are different from the standard ones. If you measure from the front to the face of the circular bit, a Speedy is 1 5/8" against a standard dog 1 3/8". The nut is 5/16" thick whereas the standard one is 1/4", consequently the nut to the end of the thread is 1 1/16' as against the standard 1 1/8". Sadly These measurements were taken when I had a baby dinosaur as a pet, and I failed to measure the location of the holes and their diam. so can't remember much about them. But at least people, including those who've found out the hard way, will know now that the dogs are definitely different,. As to the relation with the Phoenix, I'd imagine this is of not much help. Cheers, Bill in Oz(04-03-2018, 08:42 PM)Ian Williams Wrote: I found no problems or surprises other than the starter dog, my car uses the original 3/8" lift cam and everything cleared when assembled. The issues were the that oil ways within the dog were too small for my liking and the cross drilling was in the wrong place, the dog is hardened so a drill bit with tungsten carbide tip is required to open the holes out. Probably with hindsight, had I been aware of this when I ordered Phoenix could have made the starter dog to suit my engine. I believe the issue stems from the fact most pressure fed cranks are built into non original engines using a completely different oil bottle and seal arrangement at the front of the engine.
Ian, I have been in touch with Marc Taylor of Phoenix Crankshafts and he very kindly sent me a drawing of the starter dog that they make based on a 30 year old design they received from an A7 owner, Brian King (are you out there anywhere Brian?). On this drawing the cross hole for crankshaft lubrication is positioned 13/16" from the external face of the 1 1/2" AF nut whereas on my starter dog the cross hole is 1 1/8" from the face of the nut. I guess this is the same problem that you faced. The diameter of the hole is 3/16" as on the drawing.
Marc says it would be possible to relocate the cross hole to fit.