S16 Spun A Big End Shell

[jonand 0]

I have been unlucky enough to suffer the dreaded big end knock at high revs in my racer. The engine was shut down almost immediately and there was no prior warning of low pressure (have a 25psi warning light), although the oil and dipstick were extremely hot. I have removed the sump and found that No 3 shell had lightly welded itself to the crank, and there were tell tale signs of molten alluminium in the sump. After prising the shells off the crank, they had worn through approx 50% on the outside of the shell - with the molten alluminium at the edges (presumably the escape path). There is also an idication of some of the bearing material adhereing to a part of the crank journal.

 

After searching through this forum, I am still left with a few questions:

1) I am not aware of any surge issue with my form of racing (clockwise oval racing on the loose) - particularly as this is the S16 engine (full baffles etc) - the oil level was to the full mark with fresh semi-synthetic oil - therefore what caused this ?

2) Under the above conditions - is it likely that the rod is damaged? (remembering that the aluminium bearing had not worn through completely - but was wearing from the outside as it was attached to the crank)

3) Should I stick to the later (S16) aluminium bearings, or would lead/copper be more appropriate?

 

I am considering re-building the bottom end with a 1.9 diesel (Mi16) crank as detailed in this forum - does this come from the n/a or turbo engine or are they the same ? Any advice would be appreciated

 

Thanks

Jon

[deejay391 0]

s16 is prone to the big ends going, mine went a few months ago, and i also had no oil pressure drop that i noticed

 

Possibly due to a blockage in the oil pump id advise a change of that as for the other bits im not really in a position to comment but sure someone else will be along soon

Edited October 1, 2006 by deejay391

[Miles 331 1 Cars]

You might be lucky you might not, is there any sign of heat build up on the rod?

It's also common for the crank to bend so get that checked out.

lead/copper beraings are hard to find and only available (AFAIK) in std size.

The S16 baffles are pretty usless from what I've found.

[jonand 0]

You might be lucky you might not, is there any sign of heat build up on the rod?

It's also common for the crank to bend so get that checked out.

lead/copper beraings are hard to find and only available (AFAIK) in std size.

The S16 baffles are pretty usless from what I've found.

 

Thanks for the replies guys.

 

There is no noticable discolouring of any component. My theory so far is that the failure was probably caused by the oil breaking down (note it was extremely hot - no oil temp gauge but dipstick burned my fingers )I shall be fitting a mocal oil cooler and upgrading to a higher resistence oil in future - Does this sound feasable ?

 

Jon

[deejay391 0]

is there not a oil cooler fitted already? mine has one not sure on how benificial and i did enquire into a mocal jobby from Demon thieves and was only £140 from them so might be worth the purchase.

[dazEmad 0]

I reckon its essential to have an oil cooler fitted to a mi16 engine on track days. The constant high rev's hitting 7000 rpm certainly cooks the oil and makes it very thin. I noticed this around curborough in august where 3 laps (30 secs) stuck mostly in 2nd gear resulted in high oil temps (light was no where near on) and the engine did sound a little tappety when i fired back up after a few mins rest. Also it had consumed quite a bit of oil as well which is again down to high oil temps and the oil getting that thin, something i was quite suprised considering it is a brand new engine. I am planning on getting a 13 row oil cooler after seeing many people with big end shells spinning when there has not been an oil cooler used.

[boombang 2]

i did enquire into a mocal jobby from Demon thieves and was only £140

 

Check rally design www.raldes.co.uk for their prices before buying at DT.

 

stat + hoses OC11828T - £55 + vat = 64.63

Stainless hoses - £75 + vat = 88.00

13 row thin cooler 13/115 - £38.30 + vat = 45.00

13 row thick cooler 13/235 - £50 + vat = 58.75

 

 

I use rally design purely down to their customer service. I ordered the basic above kit, they called to say it was out of stock and offered the stainless kit for £5 extra, which I of course accepted. Every order with them so far has been handled well and some of their prices are unbeatable.

[deejay391 0]

Result i though £140 wasn't a bad sum to pay

[jonand 0]

I reckon its essential to have an oil cooler fitted to a mi16 engine on track days. The constant high rev's hitting 7000 rpm certainly cooks the oil and makes it very thin. I noticed this around curborough in august where 3 laps (30 secs) stuck mostly in 2nd gear resulted in high oil temps (light was no where near on) and the engine did sound a little tappety when i fired back up after a few mins rest. Also it had consumed quite a bit of oil as well which is again down to high oil temps and the oil getting that thin, something i was quite suprised considering it is a brand new engine. I am planning on getting a 13 row oil cooler after seeing many people with big end shells spinning when there has not been an oil cooler used.

 

 

Thinking about this in the light of the responses, could it be that the dreaded (and much discussed on this forum) oil surge related bearing failures have as much to do with the temperature and quality of oils used. This would explain the apparent lack of consistency i.e. why some people suffer from bearing failures and others dont - when subjected to similar operating conditions. In my case I am convinced that surge was not the issue - my car is not subjected to the lateral forces experienced by track cars on slicks (with a good driver) - but it is subjected to constant high revs.

 

It would be interesting to hear from anyone out there who has experienced big end failure in mi16 / s16 motors, what grade of oil and type of oil coolers were used .

(I was using 10 - 40 semi-synthetic with standard S16 water cooled oil cooler)

 

thanks

Jon

[dazEmad 0]

(I was using 10 - 40 semi-synthetic with standard S16 water cooled oil cooler)

 

thanks

Jon

 

Oil i was using was mobil super syn 15w-50 (very expensive) with no oil cooler, my m8 had the standard oil cooler on his mi (alloy block) and suffered exactly the same.

[deejay391 0]

It would be interesting to hear from anyone out there who has experienced big end failure in mi16 / s16 motors, what grade of oil and type of oil coolers were used .

(I was using 10 - 40 semi-synthetic with standard S16 water cooled oil cooler)

 

I was using Castrol 10-40 semi-synthetic with standard s16 water cooled oil cooler as well

 

No drop in oil pressure that was noticed and i do keep an eye on it, broke at high revs no cornering force, so didnt indicated a surge issue.

[jonand 0]

I was using Castrol 10-40 semi-synthetic with standard s16 water cooled oil cooler as well

 

No drop in oil pressure that was noticed and i do keep an eye on it, broke at high revs no cornering force, so didnt indicated a surge issue.

 

 

Pattern emerging here ??

[deejay391 0]

Pattern emerging here ??

 

well be interesting to see what everyone elses experience is but it was alarming reading your post

something else that might be interesting, my s16 runs extremely high temp, after a very short time of driving engine will be very hot and heaters feel very uncomfotable after a while. Thermostat was ok and fan kicks in after a while and temp not reading anything alarming.

 

What sort of temps are other s16's running?

Edited October 3, 2006 by deejay391

[Butler 0]

I would have thought 10w60 oil would be better for a race car.

 

Oil surge would spin an end shell 1 or 4 not 2 or 3.

[jonand 0]

well be interesting to see what everyone elses experience is but it was alarming reading your post

something else that might be interesting, my s16 runs extremely high temp, after a very short time of driving engine will be very hot and heaters feel very uncomfotable after a while. Thermostat was ok and fan kicks in after a while and temp not reading anything alarming.

 

What sort of temps are other s16's running?

 

I have aftermarket water temp and oil pressure gauges fitted, and did not record excessisvely high water temps at the time of faiure - approx 90 degrees from memory, and only ever needed to turn on the fans on the run down lap and cooling off period.

 

Wish I had fitted an oil temp gauge though.

[jonand 0]

I would have thought 10w60 oil would be better for a race car.

 

Oil surge would spin an end shell 1 or 4 not 2 or 3.

 

Yes - I have just bought some Millers 10 - 60 fully synthetic (£32 ish for 5 litres from Rally Design) as I was in there buying a cooler kit (approx £120 all in with braided hoses and 13 row cooler).

 

I'm afraid I dont understand your comment re: shells 1 or 4 under surge conditions -- is this because they are furthest from the pump and would dry out first under conditions of starvation ?

 

Thanks

Jon

[C_W 3 1 Cars]

I'm not saying it caused it but I would say constant oval racing is just as bad if not worse than regular ciruits although I suppose you will have problems in the first lap or not at all as the oil will settle to one side of the engine/sump. But I read somewhere that there were concerns of oil surge for a certain race series (can't remember which) running at Rockingham as it had very long banked corners.

[Miles 331 1 Cars]

As I've posted often, 76 racing oils are the best i've found to date, I wouldn;t use synthetic oils in any race engine now

[jonand 0]

As I've posted often, 76 racing oils are the best i've found to date, I wouldn;t use synthetic oils in any race engine now

 

Thanks Miles,

 

I've done a search for '76 racing oils' and not found anything - excuse my ignorance but is this a makers name or a type of oil. Am a little concerned with your statement regarding sythetic oil -- can you elaborate.

 

Cheers

Jon

[Miles 331 1 Cars]

the web site is here, www.aaoil.co.uk I've known all types of oil to be used in the Race engines and found this the only oil not to wear the bucket tappet's due to a very high lift cam

Give them a call s there very helpful and know what's what

[jonand 0]

the web site is here, www.aaoil.co.uk I've known all types of oil to be used in the Race engines and found this the only oil not to wear the bucket tappet's due to a very high lift cam

Give them a call s there very helpful and know what's what

 

Thanks Miles - useful site.