Revell Visible V8 Engine Rebuild / Upgrade

[dr_gn]

Apologies if this is in the wrong forum, but this one seems the most appropriate. This is a model I started to build a very long time ago (probably Christmas ‘78 or ‘79). It was quite complicated for an 8 year old, and I never finished it. I managed to assemble the crankshaft, pistons and cylinder heads, but the main issue was the camshaft was badly warped, and I couldn’t straighten it. Looking back, it never really had a chance of fitting, never mind working. Despite this, I was fascinated by the model, and I never threw it out. I re-discovered it a while back during a major clear out. I found another partially built 1970's one on EBay, which I got for £12.80 (unbuilt kits go for £70+), plus I also got an unbuilt more current version (which go for much less), but aren’t motorised and don’t have the spark plug lights. This was the end result of combining the tree kits, with a few refinements to make it look better, and run more smoothly:

 

 

 

 

 

 

 

 

I can upload a video to YouTube if anyone is intrested to see it running.

 

This was what remained of mine:

 

 

The plan was to make one good one out of the three, using my original parts wherever I could. I stripped mine and washed all the lubricant (Vaseline, which hadn't affected the parts at all from what I could see) off the moving parts. Luckily, after 40+ years the glue had gone brittle, meaning that it was easy to disassemble without much damage. Some of the transparent parts were ok, but the majority were scrap:

 

 

On arrival, the EBay engine had got a bit mashed in the post, but all the missing bits on mine were there, apart from one distributor rivet:

 

 

The camshaft was there - not warped, but the end with the gear was snapped where the previous owner tried to glue it after a breakage:

 

 

The clear plastic was brittle (as it usually is even in modern kits), but I thought I could make one good block out of the best bits from all three kits:

 

 

Was also nice to find the original instructions in the box:

 

 

The original 8 bulbs worked too:

 

 

I cleaned up the best bits from all blocks and re-assembled. This time I used canopy glue because:

 

a) It dries clear

 

and

 

b) If it all goes wrong I could dunk it in some warm water and it would revert to kit form with no further damage:

 

 

Got some small metric M2 fasteners from EBay:

 

 

The standard kit has you assembling the crankshaft webs and pins with the eight one-piece con-rods, and eight pistons, and then building the cylinder block parts around it (there isn’t enough clearance for any other way). It means aligning and glueing many different parts simultaneously, which isn’t easy. I therefore decided to split the con-rod bearings using a razor saw. As well as looking a bit more realistic, it means I could assemble the crankshaft into the block and get it running smoothly without the pistons. I 3D printed a simple jig to speed up the whole process:

 

 

Here are the finished connecting rods and pistons:

 

 

I machined some new cam followers out of PVC to get rid of the slop from the originals, and to stop them snapping over the cam and making a knocking noise. Also machined aluminium pushrods. I put threaded adjusters in the rockers so that I can take any free-play out of the system:

 

 

I made some clear plastic inserts for the cam followers. These were a better fit on the newly turned followers, and more importantly, gave a longer sliding contact area. This reduced the jamming effect of the originals. I machined them to a top-hat section, and they’re PVA’d in place:

 

 

 

I wanted to use tappet adjusters on the rockers, like on a real pushrod engine, but the alignmemts were too far off. I still needed some way of taking up the rattly free-play in the system though, so opted to drill the aluminium pushrods and install domed head screws. I did put some dummy adjusters on the rockers, just for effect. I used some knitting needles off EBay for the rocker shafts. They’re anodised and give a nice smooth action for the rockers without lubrication. The ends were drilled and tapped for retaining screws and washers:

 

 

I also found the two original cylinder head retaining screws per side weren’t enough. The heads would tilt under the action of the valves. I added three more by drilling the heads to the inside of the V:

 

 

Like all other simulated bolt heads, I replaced the sump fasteners with real screws, and made a brass sump plug:

 

 

The weakest point of the model is the distributor bevel gear drive. I modified the gear mesh method by using a lightly sprung-loaded distributor gear:

 

 

This is the main assembly, with the modifications:

 

 

 

 

 

Filling and painting the red bits…the moulds were nearly 20 years old even back in 1978, and the parts pretty much only fitted where they touched…Lucky that the Ford paint I got was an almost perfect match for the original plastic:

 

 

 

 

Made some paper oil and air filters:

 

 

 

 

And a rubber hose for the thermostat housing outlet:

 

 

Also filled the huge gaps in the transmission housing:

 

 

I gathered parts for the battery box. I found a geared micro 12v motor, which I run at 9v. I made a step-down adapter for the original pinion. Also got a voltage reducer so I could use the 9v battery at 3v to power the spark plug lights. The original kit used two plastic push-buttons for the starter and ignition. I’ve got some single pole toggle switches which fit into the original button holes. I drilled out the buttons and glued them onto the switch stalks to keep it looking authentic:

 

 

The later version of the starter motor housing was just about the right size to fit over the new motor:

 

 

The original carburettor was a bit of a lump:

 

 

So I added a few fasteners, and an inlet pipe. All probably incorrect, but at least it looks a bit more carburettor like now:

 

 

Also masked up the battery top and painted it to look more like a real one:

 

 

And that was it!

 

 

[Flintstone]

Excellent build. I had one of those kits back in the 70s and whilst it worked it was not a smooth runner!

[dr_gn]

1 hour ago, Flintstone said:

Excellent build. I had one of those kits back in the 70s and whilst it worked it was not a smooth runner!

 

Thanks.

 

After all that effort, it does run pretty smoothly considering it's plastic, but it's still pretty noisy!

 

Half way through the build, I started on true model engineering, and built a Stuart 10V steam engine, and I'm now on with a twin cylinder mill engine. Totally different modelling types, and I must admit I lost interest in trying to polish the V8 turd half way through. Still, I couldn't not finish it, and to be honest it's still a favourite - an itch that needed scratching for many years!

[binks15]

I built one back in the 60s with my dad, we wrapped the crank and rod journels with teflon fitting tape and it ran smooth and quiet Your build brings back some fond memories.Your work is top notch!

[Bozothenutter]

Very cool!

[Neddy]

Beautiful job!  Like others I built a "visible" engine back in the '60s, a four cylinder OHC one, and that gave me enough headaches.  It ran after a fashion but its deficiencies took a lot of the pleasure out of it.  You've done a remarkable job re-engineering it and it was a pleasure reading about the restomod process.

[desert falcon]

Great piece of engineering, good you managed to finish it !!