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Insanity Too
 The winter rebuild 2014/2015

The Engine
 

An Engine Rebuild

As can be seen from the first page the engine in the car was completely destroyed. This was the result of running a tired engine to the limit (and beyond the limits) over an extended period of time.
The old engine had been giving the warning signs fro several events, knocking on hard acceleration and low oil pressure at idle, so it was no major surprise when running a lap in low box finished it off.

Below is the story of the rebuild of the replacement engine, the frustration, mistakes, some of the lessons learnt and the joy of finally getting it to run.

The Plan was to build the best possible engine, but keeping the costs within reasonable boundaries. I also wanted to improve on the power available without over stressing the engine and transmission, the idea being to get a strong powerful engine that should last some time without breaking the bank.

I already had a engine block from another donor vehicle. The basic engine is a Rover V8 3.9 EFI serpentine unit from a late Disco 1. These are generally good strong units with a proven history and parts that are reasonably easy to get, therefore a little cheaper than some of the more exotic options.

Although as it turned out later, getting hold of a good one is starting to get more difficult.

The first thing to do was get this stripped and checked out;

The engine was duly stripped and the block and crank was sent to the engineers to determine if it was within tolerances etc.

The feedback was very good;

The block just needed a basic re-bore and the crank had very little wear evident and only required a polish.
Once this was established (or so we thought) the procurement of parts started.

  • New piston, these are standard cast items +20 oversize with rings etc.
  • A set of cam bearings, Clevite
  • New cam, Viper Cyclone. a high lift camshaft, but not too extreme.

These parts were provided to the engineering company and they where instructed to do the work including replacing the cam bearings. They needed the pistons to ensure that all final fits where correct and the cam shaft to ensure correct alignment of the cam bearings, the cam must run freely in the new bearings.

 

The engine was re-board to +20 and the new cam bearings fitted (and matched to the new cam shaft). The crank proved to need no work other than a polish to clean it up.

At this point I also purchased several other parts ready to start building the engine back up when I got it back from the engineers.

  • Big end shells, Clevite
  • Main bearing shells, Clevite
  • Timing gears and chain, Cloyes “Street True-Roller” set
  • Main bearing stud kit, ARP. This was to subsequently cause a lot of problems

Once this was all done and we got all the parts and reworked block into the "Engine shed" the engine build could start in earnest.

The engine block in the back of the "Engine Shed" on the stand ready to stat the build.
As you may see its a very small (dark) space and not the perfect place for this nature of work.
Crank, pistons con-rods all in place.
Note the use of ARP studs in the main bearing caps and that in this engine the main bearing caps are the fully enclosed type. I could have "cross bolted" these but decided not to at this point as the use of studs should massively improve and reduce any risk of cap shimmy/chatter.

The cylinders where fitted "dry" using only silicon as a lubricant, recommended by some engine builders as it allegedly reduces the risk of "glazing" during the run in period. This was to be the first of several mistakes (read on......)
The main bearings where torqued up to 110 lbs. ft. as per the documentation received with the studs. Potential mistake number two (remember this as you read on).

Cam shaft fitted in place with plenty of cam lube, the followers would be next. 
Roller timing chain and sprockets in place the lower sprocket has three positions to enable the cam to be set up advanced or retarded. 
By changing the cam timing, enhancements to the camshaft characteristics can be achieved. For example, retarding the cam timing will increase high RPM horsepower, and advancing the cam timing will increase low-end torque.
I have set this engine up to to use high end power as the engine spends most of its time in full throttle conditions in the events I do.
   

At a later stage I also purchased parts to rebuild the cylinder heads;

  • Cylinder head stud kit
  • New inlet valves
  • New exhaust valves
  • Bullet valve guides

and finally all the other bits needed to assemble the engine;

  • Hydraulic cam followers
  • New push rods
  • New rockers
  • New rocker shafts
  • Rocker shim set
  • Top gasket set
  • Bottom gasket set
  • New oil pump gears (serpentine, crank driven) 
Before the heads were sent away for some more engineering work considerable time was spent gently  "Porting" and "matching" the inlet and exhaust ports.  I did not go overboard with this as I don't have the facilities to do proper gas flow analysis etc. however, just making all the ports a similar size and removing the obvious obstructions should make a difference.
Once again the cylinder heads are back from the engineering company having completed the following work;
The head faces skimmed, new "bulleted" valve guides fitted and the valve seats recut to suit the new valves.
The rebuild of the heads can start.
Fitting the new valves with new valve springs and seals. Most of the valves in place!
Cylinder heads going back into place.
It's just possible to make out the new head studs on the left hand side.


Cylinder heads bolted back on with new followers, push rods and rebuilt rocker gear all fitted.
The rocker pedestals have been shimmed to compensate for the skimmed heads and new high lift cam shaft.
All the front covers and distributor in place. The distributor was aligned with the rotor pointing to No1 whist the engine was at TDC.
All the ancillaries fitted ready to return the "mill" back to its home in the car.


The rebuilt engine back in place and almost ready to run!

Or so we thought!............

When we came to start the engine things started to go wrong!

Firstly before I even started the engine I had some concerns that the engine felt a bit "tight".
Every one I had spoken to up to this point had "agreed" that the main bearings should be torqued to the 110 lbs/Ft figure, however, I found various reports that this sometimes will not work. I found some details for the later 4.2 engine that listed different lower figures.

The sump was duly removed and the main bearing re-torqued to a new lower figure 90 lbs/ft. Things did feel a bit better.

The engine was re-filled with the oil and running-in lubricants. Initially the engine was turned over with no plugs etc. to get the oil primed and the pressure to a basic minimum, the engine felt like it was turning freely with no untoward noises etc.

The plugs where refitted and we tried to start the engine!!!

However;
It was not to be!

The engine turned and even once or twice "popped" and "banged", no matter what we did it would not run!
Many things and many different "fixes" where tried out. Including striping the front end from the engine to double check the cam timing, several compression checks where carried out, these where not perfect but well within acceptable ranges. We had an expert plug in diagnostic equipment, all to no avail.

Several people, many hours of head scratching later we where forced to give up as the first event was only two weeks away now!

The car was loaded onto the trailer and taken to its alternative home in the South West, in the vain hope something could be done mid week rather than just at the weekends. After several more attempts at the alternative workshop, the cylinders where primed with oil and left over night to soak.

The next day the plugs where refitted and the starter button pressed;

The car stared and ran.
Briefly!

Very quickly more problems started to present themselves, the engine ran hot, boiled and over heated, blowing most of the water out of the coolant circuit. It looked like a blown head gasket!

Engine Strip-build number 2

No signs of any damage at this point and everything looks clean.
All the bores are clean and dry and only slight signs of soot.

The top end was reassembled with new gaskets etc. The oil pressure primed and the start button pressed again;
It started, however, the engine started to run hot again (this time it did not boil) it quickly became evident that the cooling fan was not cutting in. This was investigated and diagnosed as the fan-motor being full of "gunk" from the last race at Walters Arena. The motor was stripped, cleaned, reassembled and tested.

Now with the fan cutting in and out the engine runs at a good temperature.

All well and good, so you would think:

Now the oil pressure light starts to come on and stubbornly will not go out again even at relatively high rev's, The engine is immediately stopped before any serious damage can occur. More head scratching and various tests etc. are performed.

Finally the sump was pulled off again and the bottom end stripped and investigated.

The main bearings where totally striped of any bearing face and on further investigation a mat of fibrous debris was found totally blocking the oil strainer, hence no oil pressure!

What appears to have happed is the main bearings have suffered what is technically referred to as "Wire Wooling".

I tried to replace the main bearings with the engine still in place. Although many people claim to be able to do this I could not, so the engine was removed again and inverted.

Engine strip and re-build number 3

On stripping things down with the engine inverted in the engine stand again,
        This is what I saw!

The picture is looking "up" through the engine with the crank shaft removed this shows the number one cam-shaft bearing that appears to have "walked" out of the Block.

So!

The engine block is completely stripped (only leaving the cam shaft in place) and returned to the engineers that originally replaced the bearings for investigation.

It was not possible to determine the true cause of why this has happened, and there is no damage to the cam etc. however, the cam bearings where replaced and refitted FOC.

I cannot help but keep asking myself did the loss of oil pressure contribute to the bearing moving out or did the bearing location cause the oil pressure drop? Look at a diagram of the oil paths around this engine and decide for yourself?

Now the next issue becomes apparent. During this rework the main journals are measured and deemed to be out of true. I was advised that this would require "line boring" of the main bearing journals, however, this engineering company could not do this work and finding an engineer that could proved very difficult.

The first company I took the block to for line-boring, deemed the block too far out of true (oval) to do successfully, effectively declaring the block scrap!

"Panic"

After pulling in some more favors, a new replacement engine was found, collected and stripped. Ready to start the entire process all over again!

The replacement engine on its cradle in the back of the car.
It looks like a good unit, and a good start to another build project. 
However it has suffered a blown head gasket
Not unrecoverable though as there is nothing wrong with the heads on the first build.

While this is going on I am still making phone calls, and find a company that is willing to look at the original engine.

So the original block and crank are shipped out to yet anther engineering company (That's number four by the way).

In very short order I have the engine back, line bored and assembled with a set of test bearings with a freely turning crank and some more advise on assembly techniques.

This time the crank main bearings are tightened to approximately 80 - 90 lbs/Ft. The technique however was very different. The bearings where tightened in sequence and stages as normal however once over 60 lbs/ft the crank was continually turned and the bearing tightened in smaller stages until the crank started to bind. I took note of the torques at this point. Next I slackened the entire assembly and re torqued to a figure just short of the bind point (still checking the crank rotates freely).

It should be noted that the thread that the nuts run on, on the studs is a finer pitch so the clamping force through the caps is significantly higher even if I had tightened the nuts to the standard LR figures.

The engine is back in the engine shed and rebuild starts again!

 
 
Crank in and turning freely, this time torqued to just short of where it tightens up approximately 80 lbs. ft. remembering this is using studs with a far higher clamping force anyway!  
The new big end bearing shell on the left, note the small notch in the "old" bearing on the right that allows oil to "squirt" from the side of the big end journal into the bottom of the cylinder.
I "cut" the new shells to include this.
The pistons all lined up on the bench assembled ready to go back in again.
Pistons back in, the crank pulley is just pushed in place to provide something to hold and turn the engine during assembly, even at this stage the engine can still be freely turned without significant effort.
Cylinder head studs in place.
More stud used on the cylinder heads to improve engine "strength" and reduce the damage to the threads in the block during assembly processes.
Heads in place.
And bolted down.
Rocker assemblies waiting to be installed.
Cam and followers in place, with plenty of Cam lube.
I had an issue with some of the new push rods provided as they where subtly different lengths, even a couple of thou, makes a difference!
On a later "service" of the engine I have refitted standard LR push rods.
Getting the shims sizes right is not easy. I ended up re doing this a couple of times before it was correct, makes a huge difference to engine performance when it is set up correctly.
The heads all built up.
Again even more Cam lube liberally applied.
   
   


The "Mill" returning to its home.
Hopefully for the final time!

 

Some of the detailing of having to "repackage" things around the new suspension etc. 

a pair of simple but load horns!
Air box secured inplace
Oh.....
A new radiator fan and cowling assembly, 

Every thing running Ok and we are off to race!
.......................................

Finally were racing again!

The car at the new venue for 2015, Hafren

As a final comment, after competing in the following event I was generally very pleased with the way everything worked and the engine behaved very well. It was observed that the "top end" was a little rattlely, so once we got home again the rocker shims where changed for shims one size down, early indications are that this small change will make a big difference to the performance of the engine. Watch the Facebook page  for news and and the website for ongoing updates.

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