Don Terrill’s Speed-Talk

Many years ago I had a third-hand Morgan Plus Four sports car with a 2.0 litre twin-carb Triumph engine. It had no air cleaners when I got it and it was hard to imagine how they would even fit, with the cowl less than 2" from the front carb mouth. I tried not to follow anyone on dusty roads and would even shut it off and coast through dust clouds. Decades later I saw a perfectly restored example at a show and asked the owner about the air cleaners. Ha he said, these cars were built without them!

My call would be with others here. Much to much dirt ingestion! What air filtration is there if any? I don't see detonation on those pistons. Another question, was any blasting done on any components, especially pistons or heads? Abrasive media blasting on heads or pistons requires some careful choice of blasting media and after blast cleaning and removal. Colors are not indicative of real problems here in my opinion.

That's dirt, not galling. I've had the unfortunate task of dealing with too many local dirt track engines whose owners believe air filters are evil.

I don't know about blue fuel, but back years ago some of the synthetic oils were dyed bright colors. As far as I know it was for marketing purposes. I remember at least one of them was blue. I'm used to seeing gum or oil glaze at the top of overheating cylinders; just as a wild thought, is he running some kind of designer oil?

I just checked and he uses a paper panel filter, so air filtration should be ok.
Maybe the cylinders were not cleaned enough during assembly?

I don't see any detonation on the cleaned pistons




even if there are some strange marks in a perfect circle on piston #1




Is the wear on the 1st and 2nd rings ok?




Anyway I noticed that on all pistons/cylinders the wear is deeper on the anti-thrust side

Another owner in denial?


It happens all the time with japper turbo engines.

Tuned wrong.




You haven't answered any of the above questions about it?




Oh but it was tuned by the best tuner around.



No it wasn't.

It looks like the dirt came from below more than above.

I have assembled quite a few engines in what I'd say is a dirty environment, dust from abrasive wheels all over ect
You don't need a clean room to do a good job, but you do need to clean the parts if they need it, you do need to keep them clean until they are assembled, and you do need to assemble it minimizing airborne contamination. This can be as simple as
Clean parts at the carwash and dry with compressed air, dishwasher.... whatever. Heat, water, and detergent is the key.
Cover all parts in trash bags when not working on it.
Blasting the parts and yourself with brake-clean is not going to work, unless the parts were never exposed to any harmful dust in the first place.....then is fine. Don't have to clean what isn't dirty so think ahead. Solvent does poorly at removing dust/grit because it's too light, you need water and detergent.
And just like painting a car......sweep and possibly wet the floor -before- taking off the trash bags, and don't blow air around or work in wind.
I use a propylene glycol mist to reduce static, and glue the dust down. Funny story how I discovered that. Once I did some part time mechanic work for a friend. He was working out of a warehouse, his brother was a carpet installer so he got all the scraps and put them down in his shop. Unfortunately, they all got soaked in anti-freeze. Crawling around in the slime carpet was.....memorable , but I noticed there wasn't a spec of dust on anything in there.
Dust really varies far as what's actually in it, might be harmless biological material or might be highly abrasive silica dust....you don't know, but sometimes you find out the hard way.

How is the crankcase ventilation system filtered? Does it use a non-recirculating bypass valve that is open to atmosphere (pulls unfiltered air at part throttle)?

The level of wear on the rings appears OK.

joe 90 wrote:Another owner in denial?


It happens all the time with japper turbo engines.

Tuned wrong.

This.

Every jap engine tuner is the best - just ask them! Ask them to touch a V8 or carbureted motor "noooo, dont have time for that" LOL

There is no damage to other parts, like rod mains?

When i've seen motors ingest dirt - there is a hell of a lot more damage been done than just scored bores.

joe 90 wrote: It happens all the time with japper turbo engines.

Tuned wrong.

You haven't answered any of the above questions about it?

As I said, unfortunately I don't have all the answers to your questions, anyway what are you seeing to say it was tuned wrong?
Thanks

modok wrote: Unfortunately, they all got soaked in anti-freeze. Crawling around in the slime carpet was.....memorable , but I noticed there wasn't a spec of dust on anything in there.
Dust really varies far as what's actually in it, might be harmless biological material or might be highly abrasive silica dust....you don't know, but sometimes you find out the hard way.

Very good hint, will definitely try it

peejay wrote:How is the crankcase ventilation system filtered? Does it use a non-recirculating bypass valve that is open to atmosphere (pulls unfiltered air at part throttle)?

It's unfiltered to atmospehere, but through an oil vapours catch tank and a very long tube under the car

modok wrote:The level of wear on the rings appears OK.

Ok thanks

carmakerevive wrote:

joe 90 wrote:Another owner in denial?

There is no damage to other parts, like rod mains?

When i've seen motors ingest dirt - there is a hell of a lot more damage been done than just scored bores.

Yes, there are also some strange marks on the bearings:

rods


mains

Bearings seems fine, main bearing line hone is not perfect but nothing to worry about.

Cylinder bores look like a classic fuel wash. Non-oiled parts of cylinder wall then have melted bit of ring material to cylinder.

Matt80 wrote: As I said, unfortunately I don't have all the answers to your questions, anyway what are you seeing to say it was tuned wrong?

If you listen to him, nobody in the world knows how to tune an engine. Also, there's never a mechanical reason why anything fails, it's all because of a bad tuneup. I guess you can make 5000hp from a 1.6l four if you just tune it right, or something.

A few large chunks in the bearings but otherwise good.
I figure whatever scratched the cylinders must be in the oil filter or still in the skirts.
One time I scrubbed pistons with scotchbrite wet, to get the chunks out, and I dipped and worked over a bowl of water. When I was done there was a amount of stuff in the bottom of the bowl. I used a magnet to collect the dust off the bottom of the bowl, must be iron! That was an eye-opener. Did it come from the cam? the cylinders themselves? never will know, but it came from somewhere. That scoring is especially common with very soft forged pistons, some of that scratching often is considered acceptable, but you get everything just right and they hardly do it at all even with no coating.
Your pistons "looked" more like a hyper, so should not be prone to it, but I could be wrong.

The pistons got too hot, too big, too tight.
Aluminium pistons +too much heat = aluminium oxide.
It's abrasive.

You see this exact same damage very often with diesels which have leaking injectors.
Caused by pre ignition.


If you measure the diameter of the skirt(s) you might find that it's shrunk.
That's compared to the specs you had when it was built.


One of the most common mistakes made by the ricer crowd is to fit the biggest fuel pump they can get, fit a low quality FPR and then either refuse to measure the fuel pressure......OR.......if they do measure it, they've got no idea what they're looking at on the gauge.
That's a universal problem with ricers and turbos.


Then when they pull the plugs, they're sooty around the outside and white in the middle.




Oh but it must work...........everyone else does the exact same mods?

So aren't the mains a bit short on clearance?

And what about this wear? Nothing to worry about?



About the fuel wash/map issue, I read somewhere that rpm limiter with ignition cut only could have caused that wear on pistons/cylinders: do you agree? Thanks