20B Engine Rebuild

So around February 2017 it was decided with a basic map now sorted and engine seemingly run well it would be a good time to rebuild it before something let go and caused expensive damage. This had loosely been the plan all along as the true history of the engine was never known. So it was for peace of mind. If it was all still original low miles then the water seals would be getting tired if nothing else. It would also give me the chance to get a few other bits done while the engine was out such as change the gearbox for one that didn’t leak, same with the clutch cylinder and reface a couple of exhaust flange faces that had slight blows. Lots to get on with and not much time if I wanted to have the car on the road for the summer. Not to mention the fuel pressure issue I needed to get to the bottom of.

Whip and Strip

First on the agenda was of course whip the engine out.. I have done this a few times now so almost getting good! Started stripping bits off and draining everything of course.

I just got rid of most of the bulk to make it a bit lighter and easier to pull out.

Engine Out (4)Engine Out (5)

Feels such a shame to be doing this but better safe than sorry I say! I didn’t have a stand so I had a make shift engine trolley that would do the job for pulling it apart.

TearDown1 (1)TearDown1 (2)

After Stripping the remaining ancillaries off it was time to disassemble the main engine block. As I found out the 20B is kind of like two engine. It is built from front to centre and then rear to centre. So I started but pulling the front end off and working my way down.

Once you hit centre of the engine you need to split the E-shaft in half which is an interesting task in itself and the pull the engine of from the back side forward. The e-shaft is supposed to have an extravagant splitting tool but a block of wood, a lever bar and a dead blow hammer worked for me. Very carefully I might add! Then finally you are left with a garage full of bits!


I was glad to see the engine was in good shame really.. Expected levels of wear and tear but nothing sinister which was my main worry. I did notice a couple of the water seals looked like they were on the verge or blowing too so I was glad I hadn’t left it any longer. Plan was, I would replace all the usual bits, give it a good overhaul and get it back together as soon as I could. Just like that!

Freshen up.. Freshen up

First though the oil smelly mess needed a clean up before I could do anything with it!

Cleanup (1)Cleanup (2)

Various degreasers, some fetching marigolds and a good few days scrubbing and it all came up pretty good. Plenty of thorough cleaning of rotors and seal lands to be done that is not worth showing.. but it all takes time to get it right. A bit like painting a car in some ways. The key to a good rebuild is all in the prep. Or at least a solid foundation is!

Sleeve it out

First job for me was to whip out the restrictive 20B exhaust sleeves from the Rotor housings and change these for some 13B ones. Not an easy job. The sleeves are held in with steel roll pins and there is no easy way to extract them. Option one is get some very good drills and taps and try and tap a thread in the centre you can use to pull them out. Option 2 is  you drill a hole through the inside of the old sleeve and push them out that way. But that means the sleeves are for the bin. and Option 3 you try and weld a pin to the dowel and pull it out with that. Well I did a combination of 1 and 2 and eventually got there!

Once out I gave the housings a good clean around and then gave the 13B ones a little port out to smooth them over.


Then I sourced some new roll pins and they were back in.


Pondering Paint

After much deliberation about polishing bits or what colour to do this that and the other I decided to go for a bright silver paint on the parts that were currently exposed aluminium and give the irons a splash of colour to contrast the black. Candy red. I don’t usually like red but when it comes to Candy that is a whole different story! For the Candy you have to lay down a silver base coat anyway so first job was prep, prime and silver everything!

At this point the Rotor housing were basically done other than a quick once over with clear coat.

Rotor Paint (4)

Then it was on to the red for the irons.

I love it!! So much so I thought I would do my inlet plenums in it as well just to be different to the usual polished ones. Thought I would do it a bit different to above though. As I had been looking into Chrome powder coating for the inlet plenums I thought I would use this as a base for the candy and hopefully get more of a deep mirror finish in the red. it was a toss up but thought I would give it a try.. The cast finish on the manifolds is pretty heavy so I set about flatting this off and going partially through the grades with wet and dry so as not to leave big scratch marks!

I may as well have polished them!! Only thing stopping me is it does take a lot more to get a good mirror polish and you are forever cleaning it to keep it that way!

So next it was off to powder coat and to be fair they came back looking pretty sweet!

There was a bit of texture on the Lower manifold but it was almost tempting to leave them like that.. But I started with a goal in mind so onward I continued!

The result was pretty much as I had hoped.. The process of painting over the chrome does tend to kill the chrome effect a touch but you could still see the extra depth in the colour. Finally it was time to get very brave to give the UIM it’s finishing touch. Please don’t slip!

Candyred (2)

Well I for one was very pleased! There was still one more final touch to come in the way of a carbon plaque where the ‘sequential turbo’ one once sat. Still got to make that though!

A bit of Buff

So the last bits for the engine that needed a tart up were the inlet elbow and the throttle body. I decided I would polish these to break up the red and go with the remaining pipework better. The throttle body was a fiddle but workable.. as ever just time and elbow grease!

it did the job.. Not quite as bright as I would like on the throttle body but good enough. (not a phrase you will hear me say often!)

Ready to rebuild

I will just let the pictures do the talking.. You have to take a lot of care sizing all the side seals for the rotors and fitting them all out. That is where the bulk of the time is. Then you carefully stack it all together. Not quite that simple but you get the idea…

After torquing up all the main bolts it was time to start fitting all the ancillary parts. Topped with my shiny red UIM!

That was it.. Engine ready to go back in to it’s rightful home!

Final bits of plumbing and we are done! Oh and Thanks to a friend I treated my baby to a new Turbo Smart Fuel Pressure Regulator and Sytec Inline filter after my previous fuel flow issues. I did some testing while the engine was out on the fuel flow and found the small billet filter I had put in was no where near man enough for the job and hugely restricting fuel flow. Like 75% drop in flow at free flow! After the new Sytec filter was fitted there was n visible drop at all.. Even when loaded up. Hopefully that puts that issue to bed now!

Filter and FPREngine in6Engine in4

Engine rebuild complete now time for run in.. The story on continues on the main build page!

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