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Bond Engine Rebuild


Algy

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25 minutes ago, Anglefire said:

Blimey, 2thou tolerance is tight! I think the spitfire was 6-14thou - I got mine down to 8 I think as that was the available trust washers. Any closer to 6 would have meant custom washers!

But is an amazing amount of detail to go - I'm very impressed!

2thou! If we are talking the distributor drive 0.003” to 0.007” is 4 thou in my maths. Thankfully my one needed to be packed to get the clearance.

I don’t see why it needs to be that close as the distributor is driven in one direction only by the cam, so I can’t see any problem with your Spitfire.

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5 minutes ago, Algy said:

2thou! If we are talking the distributor drive 0.003” to 0.007” is 4 thou in my maths. Thankfully my one needed to be packed to get the clearance.

 

I don’t see why it needs to be that close as the distributor is driven in one direction only by the cam, so I can’t see any problem with your Spitfire.

 

4 hours ago, Algy said:

Hi Paul,

 

I thank you and the others for your interest in my little project.

 

I have edited the post to include the information for others but have also included it here for you.

 

I used 0.005” oversized thrust bearing to get a end float figure of 0.006” which is the low end of the acceptable limit of 0.006” to 0.008”.

 

Regards Algy

 

I was referring to this Algy! The thrust bearing!

 

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There's worse off than you Algy!

I had a re-bore and re-grind, thanks to a massive 1/4" end float when I bought the car. And a re-bore and replacement crank thanks to my ex not noticing the oil warning light. :angry:

But, massive fun putting it all back together, all over too quickly.

Doug

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So, time to get timing.

P1 Checking the clearance on the Cam retainer as this will determine the camshaft end float. I had 0.004” the limits given are 0.004” to 0.008”

P2 The camshaft is fitted after having a drink of assembly oil (I use Millers competition engine assembly oil). As you can see from the crankshaft sprocket the engine is being built with a duplex timing chain, it was modified to this some time in its history so all I am doing is replacing it like for like, I assume the original was out of a 2.5 but it makes sense with the higher lift cam. I was going to use a Mk2 cam but opted to use this one, which matches the original fitted (and came with the car).

P3 I checked the alignment of the sprockets, no shimming needed.

P4 In go the cam followers, after a quick swim in lub.

P5 From the information on an oil soaked piece of paper, I found out that the max lift for the inlet and exhaust is at 107Deg either side of TDC. So first off was to determine the max lift points and mark the can wheel. To do this I used an old cam follower upside down and a DTI and the bracketing system (for both inlet and exhaust) the same way as I determined TDC.

P6 So I use the flywheel ring gear as a protractor, it has 117 teeth so each tooth is 3.08Deg so nearly 35 teeth each side.

P7 Having set up the cam for the exhaust max lift and the crank at 107 BTDC, I turn the crank through to 107 ATDC and check the inlet is at the max lift point and as I divided the cam wheel marks, I could check at the TDC point as well. The photo was taken after torqueing the bolts (24lb/ft to 26lb/ft) and locking the bolts with the tab washer, the actual result showed an error at the crank so small that I could not see it, having said that I had to wipe the marks off the cam wheel and go through the process a second time to get the bolt holes to line up. Note this is not the method for the standard cam, as I don't have the figures for those, I can not say if this method would work for them!

P8 & 9 Getting some of the ancillaries on, the fuel pump first, which I had refurbished and has new diaphragm and valves fitted, was fitted and torqued (12lb/ft to 14lb/ft).

P10 & 11 The crank case breather plate with blanking plate, obviously a mod carried out when a later inlet manifold was fitted but keeping the breather to be able to revert back, so I have fitted it as it was (inoperative), of course torqued on fit (12lb/ft to 14lb/ft).

P12 Setting up the distributor drive is a bit of a pain as you need it to finish up in this position but it urns as it goes in and you have to also set the oil pump drive to line up. My method was to first get the drive to engage with the cam to finish in the right place, with the oil pump drive about lined up with were the slot on the drive would end up, and tried it out but when it didn’t engage with the oil pump, so I lifted it slightly and turned the crankshaft to turn the drive and kept on trying to engage it to the pump until I was successful.

P13 The fitted the pedestal with 6 Thou of gasket and torqued it down (12lb/ft to 14lb/ft).

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A little more work done.

P1 Note the studs have a grove in the end that screws into the block, I used new studs. Part of my prep, was to fill the stud holes with brake cleaner and sock it up with tissue and repeat until the tissue comes out clean, with no signs of oil.

P2 I use the two-nut method for fitting studs and “Studlock A70”, tighten the nuts together and then fit the stud by spannering it down with the top nut then use two spanners to slacken the nut from each other and unscrew them by hand.

P3 Fit the studs, you do not need to tighten them to much about half the nut torque is the general guide (making sure they are fully seated), unless using self-locking nuts; as the stud tension / hold is carried out by the top nut, if you over tighten then you can throw up a ring around the base which can interfere with the fit of components, unless the is a recess bored for this (which there is not on my engine).

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So a bit more engine building!

P1 Using Loctite 574 on the timing cover gasket, again used very little.

P2 The timing cover went on easily and no need to any tool to hold the tensioner out of the way as described in the manual. Bolted on and torqued, do note the two different torque settings: for the bolts going into the plate only 8-10 lb/ft and for the ones going into the block 12-14lb/ft (as normal I set the torque wrench to 9 and 13lb/ft respectively and carried out a retorque about 1/4hr later to allow the gasket and sealant to settle).

P3 A drop of oil smeared around the spacer. Note the orientation, when I stripped the engine it was the other way around.

P4 I checked the pulley timing mark and it was spot on, so there is hope that this is not a loose one!

P5 I have reconditioned the water pump housing and fitted a new pump. I did not want to use the old one as the chances of a degraded gland seal was extremely high. The housing had been ultrasonically cleaned and electro zinc plated before paint.

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  • 1 month later...

Well I have my cylinder head back and I have done some more work.

P1) Washers which I reduced in external diameter and then hardened and tempered, quenched in oil, for the cylinder head nuts (heavy duty of course).

P2) The before and after for the washers.

P3, 4 & 5) The cylinder head, with hardened seats ported and skimmed, to give a CR or 9.75:1

P6) The head bolts after torqueing down in stages with 30mins between each round, I started with 15lbft then 25lbft, 40lbft, 44lbft then left over night and retorqued to 44lbft.

P7) Rocker shaft studs fitted, using the locked nut method.

P8) Push rods and rocker shaft fitted and then the gaps set to 0.010” using rule of 13.

P9) Rocker cover fitted. I know it is not the same as the original, which was a alloy one so distorted and corroded that it was not usable but it is close enough.

P10) the water pump gasket got some sealant.

P11) The water pump fitted; the upper bolt is a shorter bolt than the final fit as it will be changed out, once I have got the dynamo adjuster made up or bought and fitted.

There will be a delay again as I am working on other parts of the restoration but I will keep you posted on the engine as I progress.

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  • 3 weeks later...

So, I have done some more work on the engine. I stripped the old distributor and found that I needed to make up bushes for the main shaft as it was extremely worn as are the bob weight pivots;  as I was intending to convert to electronic ignition, I decided it was not worth doing the work and bought a full kit. See photo with the HT leads made up and coil fitted.

Next up was the inlet manifold that I have had vapour blasted.

Last two photos. So, I decided to trial fit the manifolds and all was not well, the stainless coolant pipe did not fit around the exhaust manifold, it sort of wanted to go through the rear branch. I will need to make up a new pipe, 1” lower, bent down by the pump and with a 90deg bend inline with the rear vertical, to take the pipe between the manifold and block. So glade I did a trial fit!

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I should have taken the clue from the original bits that was bent down from the pump, I thought it was damaged when removed from the car by previous owner but thinking about it, it would have kinked. I will try to make one from stainless (less rust).

The restrictor is in the union on entering the back of the manifold, or rather I should say it will be when I have made it, but I did find the diameter from a multi branch union. Thanks for reminding me about that.

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Right so I fabricated the union to go onto the end of the manifold out of brass stock. It took a couple of hours a lot of which was me thinking about the method, whether I should turn it out of a single piece or as I opted to use two.

A flat was filed onto the main body to receive the spigot.

The inlet spigot has a restriction hole 1/8” diameter the same as the multi branch union has. Thanks to Pete Lewis for reminding me.

I threaded the two parts a 5/16 UNF and filed a flat down the thread so the solder would run through the joint from inside to the outside, making it strong and sealed.  The reason for the fairly small thread size is to produce a good shoulder for the solder bond.

The spigot was hard soldered (a low temp silver solder) and then set up in a four-jaw chuck and the excess turned off the inside of the union.

A good clean and a pit of a buff and it looks okay.

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