Hi Everyone,

Can anyone tell me what size thread is used for the crankshaft sludge plugs on a Series 1 XJ6? My best guess from measuring the plug itself is 5/8-14 BSPP. Can anyone confirm? I need to chase the threads before re-installing the sludge plugs and don't wanna spend $40 on the wrong size

Thanks!

~Rustfreemike
72 XJ6 (x2)
73 XJ6
85 XJ6
84 XJS

 

Hey Rustfree! That's the size, but not sure about whether the plug itself should be tapered (BSPT) or straight (BSPP). Check out the recent thread in the E-type section of Jag-Lovers.

 

Hi Bob! Always good to hear from you. Thanks for the info. That was me who started the thread on Jag-Lovers

It's weird because it seems like it should be tapered for sealing purposes and some people say it is but I can't measure any real taper using a caliper on the plug and the tapped hole is so shallow it's very hard to tell even with a locking telescoping gauge.

I'm wondering if it was tapped parallel and the plug just seals against those first few threads at the bottom. Thinking I may get a parallel tap cause it's cheaper and maybe modify if if necessary - it's only for chasing threads after all....

 

I sure do not know.


But, one or both of tap and thread boxes has a "thread guage". But, as far as I can tell USA sizes not Brit. Is there a Brit equivalent? Probably, but where to find it??? Any taper is likely to be very slight, and thusly hard to measure. Can you do a better measure over the removed male counterparts?


Examples of each in good shape to gently try?


Carl

 

I thought there was a lip at the bottom that the plug butted-up to, but maybe it is a taper. It's so long since I replaced these plugs on an XK engine, (circa 1989), I can't remember. The only thing I do remember is the sludge in the cavity was amazing, almost blocking the passageway, and the fact that the plugs have to be staked in position using a punch on the crankshaft by the edge of the plug. As for getting them out teh friendly man who sold me an uncracked block got them out for me.

 

Fraser, you reminded me that I am still looking for a 4.2 uncracked block!

 

At one time used 4.2 XJ6 engines were 10 a penny, but most have now gone for scrap. There used to be a Jaguar breaker near Wrexham in a place called Rhosllanerchrugog and he advertised in the JEC mag, but I don't see the ads any more. There is a chap advertising engines in the mag, incl an XJ Series 2 4.2 engine. Try 07856 314711 Gloucester
Here's a 1984 engine so it'll have the slotted block, no cracking ! However its in Lanark. These engines are very heavy and hard to move around as I'm sure you're aware. The guy may take an offer.

https://www.ebay.co.uk/itm/Jaguar-4-...QAAOSwlUhZ5QoD

Most engines on eBay are either for the earlier cars or E-types and hence expensive. Plenty of stuff for the later aluminium block engines and the V8s of course.

 

I do not wish to hijack this thread. Forgive me! I am in touch with both the Gloucester and Lanark! Negotiations on the go. I missed one engine in Maidenhead. As for Dave Kelly from the Wrexham area, he was my prime source at one time. However, he is no longer in business and the yard is closed - more is the pity, I used to enjoy scouring his treasures.