Thread: Go to start the rebuilt 3.9 and ARRGH - core plugs leak!

I should have trusted my instincts...

When I had the block on the stand fitting the new core plugs, I thought - gees they went in easy. At the time I put it down to the freezing effect of the solvent in the Hylomar spray I was using (the core plugs went extremely cold after being coated). However they have come back to haunt me...

Just finish 4 long days, ripping the old 3.5 out, swapping bits onto the fresh 3.9 short motor and reinstalling. Last job... fill with water prior to starting and cam run-in session. Then I hear drip, drip, drip. It's just a loose hose somewhere I thought until I saw all 3 core plugs on the starter motor side leaking. I felt pretty bad.

So, I just removed the starter, manifold, engine mount and pulled the leaking plugs in-situ. I get my vernier and measure the diameter right on the lip (largest diameter). They are all around 37.95mm. So perhaps they were only 38mm to start with and the supplier has given me the wrong size , as they should be 1.5" (38.1mm), although according to RPI engineering (eBay.com.my: Range Land Rover V8 Engine KitCar Morgan TVR P6 SD1 (item 190306730801 end time May 16, 2009 02:56:09 MYT)) they should be 38.32mm diameter. So is the 1.5" the hole diameter and not the plug diameter?

I will order some more generic 1.5" plugs from a different supplier (previous supplier was a rover specialist) and see what size they measure too.

And whilst the 3 on the other bank were not leaking, I guess they should be replaced as well. And whilst I could probably get to them by removing the engine mount, what about the two at the rear of the block behind the flywheel :-( Looks like I have to pull the donk out again... arrgh

Originally Posted by Taz

I should have trusted my instincts...

When I had the block on the stand fitting the new core plugs, I thought - gees they went in easy. At the time I put it down to the freezing effect of the solvent in the Hylomar spray I was using (the core plugs went extremely cold after being coated). However they have come back to haunt me...

Just finish 4 long days, ripping the old 3.5 out, swapping bits onto the fresh 3.9 short motor and reinstalling. Last job... fill with water prior to starting and cam run-in session. Then I hear drip, drip, drip. It's just a loose hose somewhere I thought until I saw all 3 core plugs on the starter motor side leaking. I felt pretty bad.

So, I just removed the starter, manifold, engine mount and pulled the leaking plugs in-situ. I get my vernier and measure the diameter right on the lip (largest diameter). They are all around 37.95mm. So perhaps they were only 38mm to start with and the supplier has given me the wrong size , as they should be 1.5" (38.1mm), although according to RPI engineering (eBay.com.my: Range Land Rover V8 Engine KitCar Morgan TVR P6 SD1 (item 190306730801 end time May 16, 2009 02:56:09 MYT)) they should be 38.32mm diameter. So is the 1.5" the hole diameter and not the plug diameter?

I will order some more generic 1.5" plugs from a different supplier (previous supplier was a rover specialist) and see what size they measure too.

And whilst the 3 on the other bank were not leaking, I guess they should be replaced as well. And whilst I could probably get to them by removing the engine mount, what about the two at the rear of the block behind the flywheel :-( Looks like I have to pull the donk out again... arrgh

the last engine i did had steel plugs in it probably zinc coated, i thought oh maby ill pull one out to have a look at it, fine on the outside and rotted nearly through on the inside. would never have known. when i put the new ones in i had to bash the *&^* out of it ! they were rily nice to use tho, i got them from super cheep auto, made of brass. bound never to rust, i would not use any thing elts. ( eg zinc coated ) brass is the go i reccon. they were cheep too. if you do go for brass be carful some are brass coated !! lol check by making sure they arent magnetic.

i have not pulled my plugs out of the 3.9 yet. i have 2 expensive boxes of parts, no plugs yet, what size did you say they were ? was it 6 of 1.5 " ?

thanks, jeff.

ps i reccon your right to pull the other side too, wile its in your drive way rather than on the road some ware, or off road !

cheers.