Escort Sigma 1600 Race Car

[Roadsport]

Re: Escort Sigma 1600 Race Car

Is the furutre 3rd member axle like the US Ford 9" where the pinion is in separate housing which can be removed to change shims and adjust the pinion debth? I like the best of both worlds ! Can you make it the best of all the worlds: strong, light and cheap ? That would be the bestest



p.s

Still tempted to try the alli 3rd member. And I propably will If I don't come across enough truple as it it. that would make the whole package 51kg's and the aforementioned solid discs would do too. I bet that would put it well under 50kg's

[Roadsport]

Re: Escort Sigma 1600 Race Car

Nice work mate, fingers crossed that all your hard work pays dividends this year

Lets hope so. The last years front springs and ARB mods made the car unbelievably drieable but I could not enjoy it due to these gearbox issues. I hope I get a chance to enjoy it all this summer with no DNF's

[Roadsport]

Re: Escort Sigma 1600 Race Car

Took the gearbox back to the car for late rinstallation and brought the engine back with me for little freshing up. Its now done two seasons with hte same rings and bearings so due time for a check up. Those two seasons were pretty broken though. I did change the oil grade for the last season so Interresting to see if theres any evidence of wear in the internals.

For such a featherweight engine it weights like F**k to lift in and out of me van.

[Roadsport]

Re: Escort Sigma 1600 Race Car

Took the gearbox back to the car for late rinstallation and brought the engine back with me for little freshing up. Its now done two seasons with hte same rings and bearings so due time for a check up. Those two seasons were pretty broken though. I did change the oil grade for the last season so Interresting to see if theres any evidence of wear in the internals.

For such a featherweight engine it weights like F**k to lift in and out of me van.

[Roadsport]

Re: Escort Sigma 1600 Race Car

looks like I could do with new piston rings. 3rd cylinder has burned a bit of oil




Not visible on the pistons though so I'm guessing it hasn't burned oil all that much. If there would have been actual oil burning on the piston it should have a destinctive clear parle ring on it. These have nice colouring except the 4th but thats only cause that piston was cahnged due to the engine failure a while back.

[RWD fords rule]

Re: Escort Sigma 1600 Race Car

Pistons and chambers are quite black, I would have expected a nice light brown colour across at least some of the pistons and chamber, sure it wasn't running a little rich or burning a small amount of oil? not saying it looks bad, just not what I would expect to see with full engine management, I would also expect the exhaust valves to be a light grey colour rather than light brown, definitely some room for improvement with mixture quality imho

[Roadsport]

Re: Escort Sigma 1600 Race Car

I really have not paid attention to the AFR. And it has not been on the rollers lately. It may just as be that rings are worn out. They've been there for two (broken) seasons. Usually I change them annually. Too bad I cant do a blow by test anymore but I could pour some liquid in down the cylinder to see if they leak. I think I need to visit the rollers once the engine is back together.

[Roadsport]

Re: Escort Sigma 1600 Race Car

Took the bottom end a part today. Nothing alarming was to be seen that has not been there before.
The fourth cylinder has some scoring and a dimp due to the failure two years back. But the fourth is not the issue the third was the one that had burned a bit of oil. Did'nt have a feeler gauge at hand but the piston ring gap is over 0,4 mm's perhaps a 0,6. Will maesure later on.

The only bit with some wear was the fourth big end bearing and the fifth main. Well the main wasn't bad but more worn than the others. The big end on the other hand was propper worn. The bearing fell out as soon as I got the cap in hand and refused to sit on the con or the cap on their own. Luckily the crank is unharmed.





Now, I do not know the reason for this. The fact that they have done two seasons or that I changed oil grade between the two seasons.

I think I'll fit all new bearings and rings and have it dyno'd with the thinner oil. If theres any gain that can be measured I have a good reason to wait till fall to see if it is actually the oil that Is causing the wear. I doubt it though I never noticed any severe drop in oil pressure. The thinner had lower pressure after serious track time when idling. And even that could be due to the worn out bearing.

[Tristan]

Re: Escort Sigma 1600 Race Car

Jeez it's a good thing you dropped out the bearings!

[Roadsport]

Re: Escort Sigma 1600 Race Car

Tristan, you can say that again. The fact that the bearings dropped out on their own is a tell tale sign that there has been some slack/knocking in the bearing causing it to deform. Thinking back if the gearbox had not failed propably the engine would have.

Propably going back to the TWS 10W60 oil.

[Tristan]

Re: Escort Sigma 1600 Race Car

Tws?

[Roadsport]

Re: Escort Sigma 1600 Race Car

Castrol TWS Motorsport 10W60 or perhaps try out a Millers equalent nano oil 10w60

[RWD fords rule]

Re: Escort Sigma 1600 Race Car

What sort of fully hot idle oil pressure were you getting? would be worth running a little extra big end clearance if the pressure side rotor is large enough to support it and still have good idle oil pressure, the more oil leakage the less the idle oil pressure will be, as a reference 20psi hot idle pressure is ok but I would not go any lower than that just to sure as the bearings wear there is still some volume left to spare, it does look like the big end clearances are a bit too tight tbh for best reliability, but I know some dry sump pumps have pressure side rotors that are barely large enough, if it were me I would design them with a slightly deeper or larger rotor and run 40psi hot idle pressure, that way you could run whatever clearances you like or feed oil to a turbo or whatever you like and still have plenty of volume to compensate, worth the few bhp you would likely loose due to the extra volume but maximum reliability

[Roadsport]

Re: Escort Sigma 1600 Race Car

No I'm not all that certain but on the hottest races I got momenterally under 20 psi readings at hot hot hot idle. With the thicker stuff I can't remember ever going under 20psi. I wasn't all that alarmed though I seem to remember a rule of thumb that one would need 10psi per every 1000RPM's

[RWD fords rule]

Re: Escort Sigma 1600 Race Car

Yes 7 to 10psi hot oil pressure per 1000rpm is generally a good rule, you only really need 10psi or less at idle but I personally don't like less than 20psi and 30psi is all the better