Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

Replaced all three coolant hoses under the header tank with new clamps.

In the process of vacuum leak check on the cooling system.
Left it over 40min to confirm that there was no leakage at all.

All of the hoses will be squashed more or less and especially the big ones will be squashed to this level during the leak check.

Started filling the system with Honda Type2 coolant.

Although I have oiled all of the internal mechanical parts around the cam shafts and also rotated the engine by hand for many times, I still prefer cranking the engine several times without spark or fuel before firing it up for the first time so disconnected the INJ and IG coils.

Fired up and warmed up the engine.




Engine was running smoothly but I noticed low frequency exhaust sound which was not there before start of the service so there is a crack somewhere around the pipe.

After cooled down the engine, fired up the engine again and put my hand around the exhaust pipes and found that it was leaking from the front down pipe just before the front CAT but hidden by the heat shield and the meshed screen around the flex joint.


As OEM exhaust pipe has twin tube structure, it is difficult to spot the sign of leakage and looking at the heavy corrosion around the area, it was already on the way to go and I killed it.

The problem is, all of the nuts at the front CAT were completely corroded and rounded.

This was the very reason why I decided to take the entire exhaust system out of the way in order to take the engine out.


Obviously, it’s my mistake so phoned the owner and apologised for it with the possibility of delay in the service.


I have my spare front down pipe that is no longer in use after the installation of KSP Engineering header so if I can remove these heavily corroded three nuts at the forward section of front CAT, I can still meet the target delivery date.



Bit frustrated and disappointed in myself but things can happen when dealing with the classic cars so decided to stop for the day and start from fresh tomorrow to finish rest of the services such as compression check, bleeding the brake, torqueing the suspension related bolts, etc before attempting to remove these nuts.


In the meantime, started soaking the CAT nuts with the mixture of ATF/acetone and going to leave them overnight.
It's not easy to press in the nut extractor and operate the impact gun around the exhaust pipe due to the limited space......

Will also try the propane torch to cook them until they change into red if above mixture doesn't work.

In the worst case scenario, I can cut off all these stud bolts on this CAT, and replace it with my CAT which can be easily removed as all six nuts are still fresh but that is the final option.

Challenge continues.....

Kaz