Hi

I've worked on cars since the early 60's but will be the first to admit that my knowledge of the intricacies of the Discovery's engine were zero when I have started on it but I have learnt a lot since, mostly from posts here.

That said, I noticed, when dismantling this engine, numerous bolts and nuts were missing including some quite crucial ones. I had noticed, when I first purchased the car, that the engine note was slightly odd though I couldn't put my finger on it...

Move forward many months with me reassembling the engine and I noticed that I had only removed 15 manifold bolts so when it came to refitting the manifold I discovered why... the right side front lower manifold hole has a damaged thread and the cowboy that worked on the engine before didn't bother to try and fix it. He just left the bolt off....

I knew I had a fairly comprehensive metric tap and die set at my electronic workshop and whereas a 10mm 1.6 pitch die fitted the new manifold bolt perfectly, I did not have a matching tap in the set... only a 1.5 pitch 10mm tap.

A trip to Home Depot only located another 1.5mm and Autozone had nothing.

I am hoping that running a tap into hole will restore the thread enough for the bolt to engage as the next step... that I would like to avoid... would be a helicoil insert. I might have to pull the head off again to do that....

What are expert thoughts on this and where can I get a 10mm x 1.6 here in the USA? Having done a Goggle search I can't even locate one and am beginning to doubt 1.6 except the die fits it perfect whereas the 1.5 die didn't.



AGH!!!!!! I just checked the Rover North site and it's a 3/8" UNC thread... the UK has been metric since 1976 who would have guessed the @#$% thing was UNC?


Postscript:- My local hardware store had a 3/8" taper tap and a gentle tap with a 4lb hammer persuaded it into the hole over the problem entry threads. Rather laborious turning the tap 45 degrees at a time but once driven all the way in and extracted, the manifold bolt started easily in the thread.

A P.I.A morning but at least I had more gumption than the "mechanic" that chose to leave it minus bolt!

 

And just to complete my misery with the reassembly task...

I had been ultra careful to lay out the parts removed on a long bench and discovered, to my horror, with the hindsight that new found knowledge brings, that the @#$% that last worked on the engine had not fitted any of the secondary air vacuum hoses. The car would still run as normal and I recall hearing the compressor run, but without the vacuum there would be no valves sending the air to the exhaust valves.

Another sorte at Rover North it seems....