Saturday 13 January 2018

Engine Rebuild (Part 7) - Studs and Inlet Manifold

With the head in place I went round and put in new studs for the inlet and exhaust manifolds, plus two replacements for the water pump housing. When the time comes, I've got new copper nuts for the exhaust manifold and locking nuts for the water heater pipe.

The cylinder head is odd in that some stud holes are 'blind' i.e have an end to them, whereas others are drilled right through into the water way. Ideally I would have used some kind of thread lock to prevent the studs from working loose, but with some stud holes open to the water way, it was more important that they were sealed again leaks. In the end I used Hylomar Blue on all the studs. 
Exhaust Manifold Studs Fitted.....
My thoughts turned to the inlet manifold.The inlet manifold had looked a mess.....
Mount Point for Clutch Re-engagenment Control 
When I'd first got the car going back in November 2014, I'd found a water leak under the manifold. It was impossible to get down there and find out why and where - especially in the gloom of the barn. I assumed it was a burst hose - maybe frost damaged. When the cylinder head was pulled in October 2015 I was able to look more closely and found the problem was actually a rusted-out core plug.
Silted Up Coolant Nozzle and Rusted Core Plug - 27 October 2015


I initially tinkered with the manifold earlier in 2017 and found that the little metal breather inlet (that takes a pipe off the sump breather tube) was completely blocked. I took advice and was assured that it was meant to be hollow. I eventually cleared out all the impacted silt with a small twist drill.Whatever it was meant to do - it hadn't been doing it for some time.
Cleaning the Breather Tube - 15 July 2017
I turned my attention to the core plug. Using a socket that fitted neatly within it, I tapped the rusted core plug into the manifold. I couldn't find a reference for it in the parts books, but It seemed to be coming up as 30mm diameter. I ordered a replacement from Ebay - for just a few pence. It wasn't quite as heavy duty as the original, but it was the best I could find.
Dead Core Plug
Having discovered the joys of vapour blasting in summer 2017, I put the inlet manifold through the process. It came out looking fantastic. 
Nice and Clean Inside - Excess Petrol Drain Hole
I fitted the new core plug. I smeared a little Hylomar Blue around the circumference and gently tapped it into place using a socket inside the cup of the plug. It seemed to fit quite nicely so I was happy with my choice of 30mm. Just to be sure, and using a screwdriver as a chisel, I bent over the three tangs that stop the plug popping out too readily.

The three gaskets for the inlet manifold are part of the engine gasket set and I soon had the manifold fitted and torqued-up. I'd ordered a new hose that runs between the water pump housing and the manifold and did a test fit.
Inlet Manifold Fitted
New Core Plug Fitted
Core Plug, Water Hose and Petrol Drain Nozzle

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