Bond Engine Rebuild

[Algy]

Thanks Colin,

Only about 25 hours, 15 on the steering wheel, filling, sanding, painting and polishing.

[Algy]

The lower column had been bodged some time ago, so I had to do something to make it straight and better looking.

I cut the ends off and turned them and inserted them into 2.5mm wall (seamless aircraft grade steel) tube, then brazed them in.

[Algy]

The conrods have been balanced both in weight and end to end as have the pistons. Note I had already checked the small and big end alignment and replaced and reamed the small end bushes (details of how to do this is in the manual).

In the first photo you can see how the rods are balanced.

The second photo shows all ready for assembly, you can see the piston weight marked on top.

The third shows the rods fitted, do make sure the circlips are correctly seated as there is nothing worse than having one try to go AWOL and score your nice bore. You should always check the pin fit in the small end and piston before and after assembly.

 

[Algy]

My next step is to check the piston rings.

The first picture shows how my new rings came packaged, which had them sorted into sets and the position on the piston.

The second picture shows that the rings are marked top, so you know which way up to fit them.

The third photo, shows how I check the ring fit so I can measure the end gap. My engine has had a re-bore so I can do this near the top but normally I would have the ring about an 1/4 inch down the bore. I use the piston to ensure the ring is level. The manual gives compression ring clearances different to the figures given with my pistons as they overlapped I adjusted them to conform to both (0.0025"), using a fin diamond dressing file (driven in from the outer side of the ring inwards so any bur in by the piston and can be cleaned off) and the rings are then cleaned before fitting to the piston. (The gap looks bigger in the photo because I moved the ring from level to be able to show it better)

[Pete Lewis]

circlips.  remind me of  1963 yoof,  hair , no money on aprentice pay,   had to re ring the minx flyer, and yes out popped a circlip and keyhole slotted the bore, wrecked a brilliant engine for the sake of making sure.  got the learning curve early years Tee shirt on that one 

Pete

[Anglefire]

I had a Beetle (My first car 1200) and it too lost a circlip - not I hasten to add due to my rebuilding skills! - and scored the bore - I can't remember now how I found out - I think I did a oil change (every 3000miles with mono oil from memory) Just a gauze filter - anyway out popped a twisted circlip.

So in true Beetle style, dropped the engine and did a rebuild - which wa easy as you simply bought new cylinders, bearings gaskets and threw it back together. No water to worry about, just 4 bolts to hold it on the gearbox, throttle cable and fuel. Optionally reconnect the flexible heater hoses 

[Algy]

Some more photo’s!

P1-  The piston with the rings fitted getting a drink of engine oil. I don’t use build oil on the pistons do the viscosity being too high and causing extra wear on start up. I will set up the ring gaps so that the compression rings are 180 degs apart and the gap aligned with the crankshaft, as the oil control is a multi-ring type I set these up with the gaps about 5 deg either side of the butt joint on the centre ring and on the left side of the engine.

P2-  Me trying out a cheap ring compressor (a friend has borrowed my nice ones) and it worked okay, just make sure they are bedded down on the top of the block before putting the piston down (yes, I push them down, not the normal hammer handle tapping system that can stop you feeling the ring catch).

P3-  The pistons in and ready to turn the block. It would be easier on an engine stand but my one will not fit on this engine and also has a XK140 engine on it in my main workshop.

P4-  Shells being fitted to caps. Make sure the joint between shells and cap is clean and degreased, this helps ensure no hydraulic action during build, which can lead if no check torque carried out to bearing spin.

P5-  The same goes for the shells going into the block and rods.

[Algy]

More pictures and explanation!

P1 Build oil applied to shells.

P2 Checking the crankshaft end float. Additional note 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”.

P3 I smear build oil on the big end caps and loosely fit the bolts so I can turn the engine over. Also at the same time I prime the crank shaft oil ways with engine oil.

P4 Next I fit the Main Bearing caps, again having smeared build oil on the shells first and lightly tighten. Then I torque them to the lower torque figure 55lbs/ft from the front to the rear, leave for 15mins and turn the crankshaft over then repeat at a mid-torque figure of 57.5lbs/ft on my digital torque wrench this allows for torque tolerance.

P5 Next it is the big ends turn and I remove the bolts apply a drip of thread lock and torque them to 38lbs/ft then 40lbs/ft, turning the engine over after each pair have been torqued.

P6 Applied Loctite 574 to the rear seal gasket spread it so I have a thin film on both sides.

P7 Give the rear of the crank a little drink of oil before the seal goes over it, as you can destroy the oil seal on first start if the seal is dry!

P8 Sorry for the photo but you try and take a photo at the same time as doing the work! I lightly fit the bolts then make sure the joint is alighted with the block. The torque it up to 17lbs/ft.

P9 Trim off the gasket that is above the joint.

P10 Onto the other end. I fettle the wood blocks to fit the block and reduced the chamfer they came with.

P11 I have test fitted the block as it was new (the original was missing), to make sure it was flat to the block and had to dress one end. When I was happy, I used some more Loctite and then fitted the block loosely.

P12 A drip of thread lock and then fit the wood blocks with the chamfer facing into the sealing block and the gap and wood prepared with Loctite 574, then tapped them in with a wooden mallet.

P13 Trim off the excess and then it is on to checking the alignment P14 & 15

P16 Finish of by torqueing the screws to 13lbs/ft then retrim the wood and gasket and recheck alignment.

Do let me know if I am going into too much detail.

[Anglefire]

Too much detail? Can you have too much detail? I think its great - keep it up!

[Colin Lindsay]

A great set of reference photos - many thanks.

[Algy]

Thanks for the feedback. I did not want to bore people.

[Gully]

Not something to bore anyone on here I would have thought - I've been enjoying the updates!

Thanks,

Gully

[dougbgt6]

Algy,

Fantastic photos! Those wooden shims, why did they do that?  This is the best bit of the rebuild, but, it goes so quick. Is the bridge Ali or a modern steel one?

Doug

[Algy]

Hi Doug,

It is an aluminium alloy one. These should not cause any problems as long as they are fitted correctly, most of the distortion is due to over tightening the sump with the bridge incorrectly aligned with the block and not supported by the front plate.

But I do agree with you why make it with wood seals at each end, but there are other engines I have seen with some strange joints on crankshaft ends.

[Algy]

Some more photo’s then. ?

This is how I prepare a sump.

P1 Without the oil pump fitted and with the crankshaft turned to reduce any big ends sticking up too far. I cover the lower surface of the block with cling film.

P2 Then The gasket is placed on top which has already had a smear of high temperature gasket sealant spread on the top only.

P3 I use masking tape around the outer edge, then I apply sealant to the sump face to fill the flutes and all around the inner edge.

P4 Then the sump is placed on top ensuring all the holes line up and then I use weights to press it down, this expels the excess sealant inwards and out.

P5 Once happy the sealant has been forced out, I remove the tape, while the sealant is still uncured. I then leave the sump like this for at least 24hrs, for the sealant to cure.

The reason for doing it like this, is to ensure the gasket line conforms to the lower face of the block.

[Pete Lewis]

You prefer a hi temp silicone to 574  we dumped all paper gaskets and used 574 on everything, this was back in the 90s but this stuff 

Solved many historic leaks that could develop on trucks  , guess things have moved on more these days but it gets a 10 from me 

Use it everywhere

Good series of pics  well done 

Pete

[Algy]

No Pete, I don’t prefer high temp silicon to 574 but I use it on sumps (and only sumps and then only partly), you will see what I do in the near future and I will explain why then. ?

[Algy]

So back to work!

P1 I cut away the excess high temp sealant and cleaned it out of the holes.

P2 Loctite 574 applied to both sides of the front plate gasket, you need the gasket as this affects how far forward the camshaft is.

P3 The front plate fitted with temporary bolts fitted in place of the timing cover, to ensure the plate is seated, all torqued up.

P4 The rear plate fitted dry (no sealants) and torqued up.

P5 The oil pump seat with a very thin film of Hylomar sealant.

P6 The oil pump fitted and torqued. Those in the know will note it is a Mk2 oil pump but this is what was fitted, in the past as it has a higher flow rate than a Mk1 oil pump. All too often people fit increase pressure by over shimming the pressure relief valve but that doesn’t address the problem of flow rate and can actually wear an engine faster.

P7 Now I lay down a thin line of Loctite 574 in the area that will be covered by the inner half of the sump gasket.

P8 Then I fit the sump and tighten the bolts working from the centre bolts on the long sides out in a similar manor to the way you would torque down a cylinder head; I do it in three stages, up to the final torque.

Why high temp sealant and then Loctite 574? Well Loctite will not air dry and is not a good gap filler, so will not fill the flutes in the sump flange, the silicone sealant air dried, filling the voids and ensuring the gasket was flat on the block. I use the 574 on the block side as it bonds the gasket and produces a good seal also if penetrates the gasket paper.

[Algy]

Sorry did not put the main reason for the sealant combination.

By using the combination of sealants and a paper gasket, it allows you to take the sump off should you ever need to without distorting the flange. This is also why a reason I use the gaskets as some would go for a straight 574 joint but this leaves little space to get anything in to cut the joint and allow removal of the component at a latter date.

It makes an excellent seal, especially on CNC machined engines, hence the use on a lot of modern engines as they have a long service life and more often then not if they have a component failure it is masked by the ECU until it becomes catastrophic.

[dougbgt6]

Algy,

That's a work of art! I wouldn't want to put the sump on, just have it on a stand in the lounge inviting appreciative comments.

Doug

[Bordfunker]

Agreed! That looks far to good to hide away!

Makes me want to rebuild my engine now!

Karl

[Paul H]

Following your post with interest . I noticed you measured the end float - what results did you get and what is an acceptable range 

Paul 

[Algy]

1 hour ago, Paul H said:

Following your post with interest . I noticed you measured the end float - what results did you get and what is an acceptable range 

Paul 

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

[Algy]

Okay so, I continue with the engine build, getting it ready to take the camshaft.

P1 I only use a drip of thread lock, there is no need for any more.

P2 The flywheel in bolted on and torqued up, I bolt a bar to the flywheel to stop it turning (sorry no picture of it).

P3 With the flywheel on I checked the runout. This is done with a DTI as in the photo (within the area that the friction plate acts), then I apply pressure on the front of the crankshaft (so the crankshaft end float id taken out), as I turn it through two full turns. The reading I got was <0.001” the maximum permissible is 0.003”.

P4 I Then carried out a TDC check, with a DTI on piston 6 and used the bracket method to confirm the mark on the flywheel matched the plate. What is the bracket method, did I here someone say? Well I turn the crank and mark the flywheel when the DTI gets to a measurement that I record (it is not important what it is) and then I carry on turning the crank until I have gone past TDC and the DTI drops down to the measurement recorded earlier and mark the flywheel again. I repeat with a different measurement, and then find the point between the first marks and check it is centre between the second set and that is the true TDC point. My flywheel was accurately marked.

P5 I wanted to get the over piston volume so that the combustion chamber volume can be set to give the correct compression ratio. It was done with a piece of Perspex with a small hole and filled with a pipette. I got a volume of 4.4ml so this along with the gasket volume of 7ml I have to subtract 11.4ml from the clearance volume to give the head chamber volume.

P6 Next up before fitting the cam was to check the distributor drive clearance so I checked the thickness of a ½” washer (0.060”).

P7 Then with it on the drive gear, held in place with light oil.

P8 The with the gear in the block and the housing on top, I measured the gap and got a figure of 0.061”, so will use 0.006” of gasket to get a clearance of 0.005”. The tolerance in the manual is 0.003” to 0.007” but show calculations for 0.005”.

[Anglefire]

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!