Assessing an unknown engine

[impmad2000]

https://www.pelicanparts.com/More_Info/ ... e%20guides
And measured at 13.08mm. No problem if you don’t want them, I’ll use them one day

[RobFrost]

Re: Cleaning Magnesium, Soda Blasting works very well. Gets all the much off without damaging the mag.

Thanks Ollie. The ferric chloride was great at softening and dissolving the salts which had grown on my stacks, but I wouldn't recomment it because you have to be quick at getting it off and it will eat in quickly if left on. I was meticulous, and washed within minutes. But even in the bucket of water I had on hand for cleaning and rinsing, the magnesium was fizzing due to the residue in the water and I had to re-rinse repeatedly. Current plan is media blasting at a firm down the road which specialises in alloy wheels, followed by Iridite #15 treatment and powder coating. Do you think the media blasting will be too harsh?

[Ollie]

Re: Cleaning Magnesium, Soda Blasting works very well. Gets all the much off without damaging the mag.

Thanks Ollie. The ferric chloride was great at softening and dissolving the salts which had grown on my stacks, but I wouldn't recomment it because you have to be quick at getting it off and it will eat in quickly if left on. I was meticulous, and washed within minutes. But even in the bucket of water I had on hand for cleaning and rinsing, the magnesium was fizzing due to the residue in the water and I had to re-rinse repeatedly. Current plan is media blasting at a firm down the road which specialises in alloy wheels, followed by Iridite #15 treatment and powder coating. Do you think the media blasting will be too harsh?

The advice I've received is that soda or walnut shells for blasting is best for magnesium, anything more is considered too harsh. I had my original Mahle Gas Burners soda blasted with great success.

[RobFrost]

I've spent a bit of time flowing the intakes. I bored out the bottoms of the MFI stacks to exactly match the throttle bodies.




...eliminating the step that was there between them and making sure they all line up nicely.



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[RobFrost]

I took the intake ports from the 32mm that's standard on an E, out to 34mm, which I hope will increase top end power with the mod solex cam grind I currently intend using. Taking care to not touch the little aerofoil which guides flow around the valve stem and guide.



I'm hoping to lose no bottom end torque or possibly even gain, due to the oversize pistons and higher compression I plan on using.

I took the cylinder head side of the throttle bodies out to 34mm too.






...and again made sure everything lined up nicely with no steps or kinks.



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[RobFrost]

Removing the throttle flap screws was a tricky job requiring very carefully drilling and I had to re-cut one of the slots on the top using a multitool after the brass sheared away. But I wanted to refurb the bodies properly so it was worth it.



Tim's valve guides turned out to be standard spec., not oversize, so I ordered new.

These arrived from Germany - first oversize. I was advised to measure them all and all were within a hundredth of a millimetre over the 13.26mm spec., and even all round with no taper. Inside diameter was around a hundredth narrower than the 9mm spec., but that will probably come in further once they're installed. There was a little taper on them, less than 0.01mm, which may be deliberate due to valve stems being hotter at the cylinder end and therefore expanding more.



Since two of the pistons had been oil-starved, I'm being careful with the oil system. I noticed a couple of holes in the crank weren't plugged. This one goes right through all the way past the distributor gear. It could be for draining oil from the chain case but I thought I'd check anyway.



A Pelican user had a crank to check and he confirmed both that one and this one are normal.






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[RobFrost]

The crank journals are all within standard size spec, and they look entirely shiny and smooth. But with the right lighting it's possible to highlight any imperfections in a photo.


Journal polishing by engineers who seem to know what they're doing on YouTube starts with 300 grit wet and dry paper, lubricated with fine oil, but I didn't think that kind of approach was appropriate here.

I started with 3,000 grit paper which had already been smoothed down somewhat by polishing a woodworking plane blade.

The technique is to wrap the hem of an old t-shirt around the journal, with the sandpaper wrapped around it.



20 wasn't quite enough so I gave each 40 strokes, moving the crank through a range of positions as I went to ensure an even action all round.



After all the big end journals were done, I bolted it to the flywheel, stood it up and did the main bearings. That's enough of that for now. I may return with something finer.

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[RobFrost]

Pulling studs seems like unnecessary work, to me, the layman, but I have to trust the experience of those having been through this a hundred times before. There being five studs around the ims drive gear, which should be replaced even though all looks to be in order.



Lacking the necessary drill press I set about making a jig to keep the holes on the mark and perpendicular.



Important to keep the metal surface polished and deburred, so as not to risk marring the case.



These were reamed out to 8.5mm to provide a guide for the drill. Then I slid them over the existing studs, spaced with a paper wrapper around the studs so as to keep the studs perfectly central within the tube.



Did somebody say magnesium was flammable, and burns strongly in both water and CO2?



I had a wetted newspaper separating the jig from the case, to tack the jig together. While water won't smother a magnesium fire, it will cool it, so the plan was to prevent temperatures reaching combustion level during the welding, and prevent any temps which might heat damage the mating surfaces of the case.

The magnesium drilled nicely and I disposed of the hazardous shavings. I kept the jig bolted down on the remaining studs and there wasn't any play. The holes seem good and square but I'll see when the studs go in. The effect we're aiming for is more Naomi Scott than Ramesh Ranganathan.



Four out of five holes drilled. I'm not cutting the threads until I have the case savers in hand. On paper it's all correct but I want to make sure the case savers, studs and thread cutters all match in the flesh so to speak, before committing.



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[911hillclimber]

Over the last few years I've drilled heavy holes in magnesium Dymag wheels for the Lola, no probs at all.

Have to say, never replaced any studs at all on my rebuilds, but a slow and considered approach is well worth it!
All the studs need to be very perpendicular.

[RobFrost]

Fortune favours the brave, or so they say.



An engine builder on Pelican claims he does the oil bypass mod by hand with no jig, drill press or engineering mill and it takes about twenty minutes.

I started out with a small end mill, with a view to creating a flat surface which would take a drill bit. But even having taken one of the case studs out, the small bits weren't long enough to get the job done before the chuck was interfering with something.

So I ended up with a longer 10mm end mill. It took a while to work out the best way to get it to stay still and cut nicely, was on high speed, touching the case only very gently, and with plenty of oil. It did skid from side to side initially, scratching the inside of the oil tube.

Soon, however, it stabilised and was cutting beautifully and clean shavings dropping on the bench below. When it stopped, it became apparent there is a non-cutting centre to the bit, so I had to reach in and break off the centre nib of magnesium with a screwdriver.




The instructions from Pelican were to start with a small drill bit and work out. So once I had a nice flat surface, I domed the centre with a 10mm bit before continuing with a smaller one, say 3.5 or 4mm.



After a surprisingly long while drilling, I was starting to worry I had missed my mark. In theory (and according to the experienced hands on Pelican), and looking at the job, it's next to impossible to get it wrong. It looks like you're aiming for this oil galley, which you can see plugged at the end of the case.



In theory the spec is i think 28 degrees from vertical and it was hard to imagine I had missed it, but the drill was going ever deeper...

And then I saw this:



Shavings appearing in the vent to the case, exactly what I was hoping for!

I gradually stepped up the drill bits until the hole was 10mm. I may go a little wider later. The spec may be 12mm I think, but I'll check carefully.



Twenty minutes (for somebody who knows what they're doing) includes tapping and blocking off the hole which drains into the case, too. I spent about an hour in all doing this half of the job, going slowly. I think 10 minutes for somebody knowing what they're doing is reasonable.

Saved myself the £200+ I was quoted for doing this job. I don't think that's an unreasonable price, though, for twenty minutes work. You would be paying for expertise, skill, and taking responsibility if they screw it up. On this occasion, no mishaps. But I guess a job like this can easily grow into a day's work. And they'd need to measure, check specs, get the right tap, plug and loctite etc.

Next part of this job requires a 1/4" tapered BSP pipe plug. I couldn't find an aluminium one, which I'd have preferred for galvanic corrosion reasons, so I have brass on order as well as the tap and I'll wait until I have the loctite open for another purpose before doing that.


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[RobFrost]

There are some who say, when cracking a 2.2 case, it will definitely be out of alignment and need a line bore. Others say it's usually okay and yet others say measure and see.

The advice I received which I trusted most, said torque up the case and see how the crank rotates.

This engine wasn't turning, remember, before I opened it, as the oil pump was seized, so i had no clue whether the case was straight. And I've peened a couple of hundredths of runout out of the crank, and gently polished the journals. With all that in mind, I was hoping I could torque up the case and get a good result.

I oiled the journals and assembled everything. Not every last bolt, and not all exactly to torque, but close enough. And surprisingly, the tighter it got, the better it turned, as if tightening the bolts pulled it together straight around the crank.

https://photos.app.goo.gl/5d4gqj2tvD1a2J1U9

All in all a satisfying result. Based upon this, I won't skim and line bore the case.

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[911hillclimber]

Very good result to my mind Rob.
Fresh shells will close things a bit but all will be well.

Tons of cleaning now i think?

[RobFrost]

Very good result to my mind Rob.
Fresh shells will close things a bit but all will be well.

Tons of cleaning now i think?

Seems like I'm cleaning the case daily at the moment. Still more to do. All the mating faces I've done with a razor blade, bearings are clean. All the grease and oil is gone. Most of the corrosion is gone from the outside. There's still some white powder adhered to surfaces of the case in places needs scraping away. Most of the components have been through the parts washer. I'm separating them out into steel for blasting and plating, and aluminium / magnesium for something else. I've a tumbler coming for the nuts, bolts and small parts.

[RobFrost]

I threaded four of the five case studs for inserts tonight. Going slow and taking meticulous care to keep them vertical was the name of the game.



The tap wrench wouldn't pass one of the longer studs nearby so it was time-consuming to keep taking it off, but it meant I could keep checking for perpendicular.

I'll put all the inserts in at once when I have the loctite open.



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[hashman]

Great work Rob, really enjoying this thread.

Karl