Premix question
Sohn adapter is a basically a sandwich plate that seals off the source of oil from the crank case and allows you to gravity feed another (typically 2-stroke) oil from a separate reservoir. It sits between the OMP and the engine. Rotary Aviaton sells them brand new, but I think they're named after the guy who made them first (Richard Sohn). Here's a link:
Sohn adapters source
Sohn adapters source
Isn't it a bit adventurous to replace a pressurized lube supply with a gravity fed one?
No because the OMP is a positive displacement pump. Within reasonable limits, it will deliver however much volume it is commanded to deliver regardless of pressure on input or output sides.
As an anecdote, I go through well over a quart of oil through the Sohn in a 6x20 minute session trackday.
As an anecdote, I go through well over a quart of oil through the Sohn in a 6x20 minute session trackday.
Last edited by NotAPreppie; Mar 27, 2018 at 06:43 PM.
I don't see why gravity feed would be any different from pressurized feed. You're not using engine oil pressure to push oil through the oil injectors. As long as there is no chance of an air bubble getting into the feed, the flow of oil is continuous and correctly metered by the omp.
See this log showing a full throttle power run follow by foot right off the throttle , FPW is low ...but it is still putting some in :
Last edited by Brettus; Mar 27, 2018 at 10:12 PM.
Its like asking if you have more faith in an umbrella made of metal versus one made of polyethylene. Metal sounds like it would be better, but it super doesn't matter if all you want is to keep the rain off you.
I don't see that faith is required. Either way there is no chance of air getting into the OMP if the oil is not empty. Beyond the OMP orifice nothing that happens before the OMP has any bearing.
Its like asking if you have more faith in an umbrella made of metal versus one made of polyethylene. Metal sounds like it would be better, but it super doesn't matter if all you want is to keep the rain off you.
Its like asking if you have more faith in an umbrella made of metal versus one made of polyethylene. Metal sounds like it would be better, but it super doesn't matter if all you want is to keep the rain off you.
. The lines (post pump) were back to full within a couple drive cycles. I premixed in the meantime. It was a little worrying but they seem to be flowing correctly again.
One more question that I have regarding premix.
I have heard that premixing lowers the octane in the gasoline and that you need to use 95+ octane. Where I live, highest I have seen is 93. Is this going to be an issue?
I have heard that premixing lowers the octane in the gasoline and that you need to use 95+ octane. Where I live, highest I have seen is 93. Is this going to be an issue?
Lack of lubrication, yes. I have a 186000 mile DD original 2007 engine taken apart in my garage currently. The PO kept it well, and used GTX 5-20 exclusively, which seems to me based on this engine to be a better oil than I thought it was. The bearings look great, the innards are very clean, but what killed it was lack of lubrication to the apex seals in my opinion. The side seals all had large clearances to the corner seals (.018- .022"), but minimal wear on their faces, and minimal wear on the front irons. The engine ate an apex seal on the rear rotor ultimately, but prior to that compression on both rotors was low, the engine would barely start with a 13t starter, hot or cold. I believe from the wear I see that the apex seal fatigued from excessive "fretting" type wear against the rotor groove and/or the side piece, and then cracked.
The undamaged but worn front rotor housing had evidence of metal to metal contact (very shiny mirror finish in many areas) from the apex seals. No chrome flaking on this engine. The apex seals themselves appear to be the primary wear item as engineered originally, as they are much softer material than what they ride in and against in the engine. They were worn in the middle portion more than the sides, which others have posted, likely from heat related "banana" deforming. Unfortunately, from that fretting wear I described, it looks like the seals are basically kept "dry" in the grooves, with very little in the way of lubrication at that point with the stock injection amounts.
It looks like the stock oil amount and "aiming" was adequate to keep the side seals/irons from wearing excessively, but the apex seals suffered. Again when the forum rules allow me to post the engine pics, I will do so. I think they will be interesting given the mileage of the engine.
The undamaged but worn front rotor housing had evidence of metal to metal contact (very shiny mirror finish in many areas) from the apex seals. No chrome flaking on this engine. The apex seals themselves appear to be the primary wear item as engineered originally, as they are much softer material than what they ride in and against in the engine. They were worn in the middle portion more than the sides, which others have posted, likely from heat related "banana" deforming. Unfortunately, from that fretting wear I described, it looks like the seals are basically kept "dry" in the grooves, with very little in the way of lubrication at that point with the stock injection amounts.
It looks like the stock oil amount and "aiming" was adequate to keep the side seals/irons from wearing excessively, but the apex seals suffered. Again when the forum rules allow me to post the engine pics, I will do so. I think they will be interesting given the mileage of the engine.
Not significantly if you stick to 1:200 to 1:250 ratio.
9k-
PO bought car at about 11k miles from dealership. He was owner since then, and told me it was. His motivation to be untruthful during negotiations would in my opinion
would be to say something otherwise.
Also:
When he experienced the initial failure he had it towed to a Mazda dealership for repair. When he found out the bad news he decided to list it on ebay. long and short, I picked the car up off of that dealership's lot, but before the deal was done, I had the service writer check the service records for various things, one of which was engine replacement. No record of it.
No sign on the "block" of reman tags or overheat telltale stamps.
Has an engine number stamped on front housing.
That engine#, 517806- would correspond well with being the original install in a 2007 s1.
Plus, I have no signs at all that it is not the original engine, no wrench marks on specific bolts, no scrapes from the ac compressor, no sign on hoses that the clamps were ever moved, no sign at all in the engine compartment that it was ever removed. But now there are, unfortunately, lots of those signs.
Therefore, I believe the PO when he told me it was the original.
PO bought car at about 11k miles from dealership. He was owner since then, and told me it was. His motivation to be untruthful during negotiations would in my opinion
would be to say something otherwise.
Also:
When he experienced the initial failure he had it towed to a Mazda dealership for repair. When he found out the bad news he decided to list it on ebay. long and short, I picked the car up off of that dealership's lot, but before the deal was done, I had the service writer check the service records for various things, one of which was engine replacement. No record of it.
No sign on the "block" of reman tags or overheat telltale stamps.
Has an engine number stamped on front housing.
That engine#, 517806- would correspond well with being the original install in a 2007 s1.
Plus, I have no signs at all that it is not the original engine, no wrench marks on specific bolts, no scrapes from the ac compressor, no sign on hoses that the clamps were ever moved, no sign at all in the engine compartment that it was ever removed. But now there are, unfortunately, lots of those signs.
Therefore, I believe the PO when he told me it was the original.
Huh, a 186k mile engine is definitely an outlier but I suppose it's not impossible. Your description seems very unlikely but that doesn't mean impossible.
Any chance you took photos of the various components?
Any chance you took photos of the various components?
With the rate we go through engines and the rate at which these cars are losing value, there's no amount of ????? steps that get you back to the profit step.


