Team-BHP - View Single Post

71Convertible · 28th January 2008, 19:17

Engine Overhaul – Part 1

The engine on this car has tended to run hot for the past 20+ years now. Typically the mechanic says it needs a rebuild and I think the most recent has been a few years ago. I want to determine what the problem is and fix it properly. I've checked & corrected valve clearances, carb settings, and timing. Then next thing on my list to check is the oil cooler. Since oil plays an important role in cooling this engine, the oil cooler is critical. Getting to the oil cooler requires removing the entire upper half of the engine including the engine deck lid and it's mounting brackets. I also took the opportunity to replace the manifold gaskets.

So, I removed the following:
Decklid & mounting
Carb & Distributor
Fanhousing, belt, and generator
intake manifolds
Oil cooler & cooler mount flange

Here's a pic of the engine bay after removing all the above (except the last two)

There was some oil, but not a lot and most looked old. I removed the oil cooler. There was gasket sealant underneath the seals partially blocking the passages and the seals were hard and old. (though this was probably not a big cause of the overheating). More importantly, the foam that's supposed to be there around the oil cooler (you can see the adhesive marks on the cooler) was missing. Also missing was a small but critical piece of metal which attaches to the bottom of the cooler called the “hoover bit”

Without the foam and the hoover bit the air sent by the fan towards the oil cooler goes around the cooler in the gaps between the cooler and the engine tin and not thru the fins of the cooler itself. This is one of the major causes of overheating (but not the only).

So I cleaned up the engine and cooler. Installed fresh seals. Torqued it down to spec. Then installed some foam around the cooler and some more where the hoover bit would sit (I do need to get a replacement). While I had access I check the torque on the engine nuts only to find that none were to the correct specs. So, I corrected all those I had access to.

Pic of cooler with new seals.

Pic of cleaned engine without manifold and cooler.

I then installed the cooler and then the manifold along with new gaskets at the manifold/head interface and new rubber connecting seals connecting the 2 parts of the manifold.

Pic with cooler and manifold reinstalled.

Then proceeded with reinstalling the other bits and finally the engine lid. The lid gave me the most problems – took me a couple of days before I finally learnt the right way – then it took me only all of 10minutes (Aargh!!)

Anyway, drove the car to work today and the oil light did not come on and the engine was noticeably cooler. Return journey in the afternoon would be the better test and it passed that as well. Typically the light begins to come on at lower rpms by the time I hit Marathahalli bridge, but is stayed off all the way home. So far so good. Want to see if this holds up. I am concerned a little about the durability of the foam I've used. But, if it lasts a couple of months, then I will replace it when I remove the engine in March or April. This exercise also got me much more comfortable with the idea of dropping the engine myself.

28th January 2008, 19:17	#29 (permalink)
71Convertible BHPian Join Date: Oct 2007 Location: Bangalore Posts: 113	Engine Overhaul – Part 1 The engine on this car has tended to run hot for the past 20+ years now. Typically the mechanic says it needs a rebuild and I think the most recent has been a few years ago. I want to determine what the problem is and fix it properly. I've checked & corrected valve clearances, carb settings, and timing. Then next thing on my list to check is the oil cooler. Since oil plays an important role in cooling this engine, the oil cooler is critical. Getting to the oil cooler requires removing the entire upper half of the engine including the engine deck lid and it's mounting brackets. I also took the opportunity to replace the manifold gaskets. So, I removed the following: Decklid & mounting Carb & Distributor Fanhousing, belt, and generator intake manifolds Oil cooler & cooler mount flange Here's a pic of the engine bay after removing all the above (except the last two) There was some oil, but not a lot and most looked old. I removed the oil cooler. There was gasket sealant underneath the seals partially blocking the passages and the seals were hard and old. (though this was probably not a big cause of the overheating). More importantly, the foam that's supposed to be there around the oil cooler (you can see the adhesive marks on the cooler) was missing. Also missing was a small but critical piece of metal which attaches to the bottom of the cooler called the “hoover bit” Without the foam and the hoover bit the air sent by the fan towards the oil cooler goes around the cooler in the gaps between the cooler and the engine tin and not thru the fins of the cooler itself. This is one of the major causes of overheating (but not the only). So I cleaned up the engine and cooler. Installed fresh seals. Torqued it down to spec. Then installed some foam around the cooler and some more where the hoover bit would sit (I do need to get a replacement). While I had access I check the torque on the engine nuts only to find that none were to the correct specs. So, I corrected all those I had access to. Pic of cooler with new seals. Pic of cleaned engine without manifold and cooler. I then installed the cooler and then the manifold along with new gaskets at the manifold/head interface and new rubber connecting seals connecting the 2 parts of the manifold. Pic with cooler and manifold reinstalled. Then proceeded with reinstalling the other bits and finally the engine lid. The lid gave me the most problems – took me a couple of days before I finally learnt the right way – then it took me only all of 10minutes (Aargh!!) Anyway, drove the car to work today and the oil light did not come on and the engine was noticeably cooler. Return journey in the afternoon would be the better test and it passed that as well. Typically the light begins to come on at lower rpms by the time I hit Marathahalli bridge, but is stayed off all the way home. So far so good. Want to see if this holds up. I am concerned a little about the durability of the foam I've used. But, if it lasts a couple of months, then I will replace it when I remove the engine in March or April. This exercise also got me much more comfortable with the idea of dropping the engine myself.