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Pi fouling


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After a long stayaway covid  during wich I had the time to  tackle some long due jobs I now have a similar issue with my Pi, and today spend more than a hour fine tuning the butterflies and still fouling, see picture attach!

check list:

  • Late february, car runs ok, allways with some fouling but accepted as a normal pi issue
  • Tackle jobs none related to engine or fuel system during lockdown
  • Starts at first turn after 3 months, but after short run plugs fouling (all similar oily)
  • Ok, renew points and condenser from Dr, change coil from sports coil to backup normal coil non ballast (its a 1971 model year cp car)
  • same fouling, allways NGK 6eps wich as I have several sets, clean, set gap, and replace 
  • Tried ngk 5r, same results
  • MI working fine, recently refurbished and fine tuned form KMI, fuel filter and lucas pump
  • All fuel system related issues test wright, prv, pressure, return and injectors
  • Set flow at all pairs with very slight difference, with a proper flow meter
  • No leaks on the air induction, engine stalls when valve closed
  • What the gauges say: 800 rpm, 11º advance, oil pressure 70's cold, 20's hot very low at idle < 10's, amp good readings, checked electrics following lucas manual, everything tested ok

I'm looking for either a electrical problem, too weak spark overall, alternator?, or time to rebuild meddle engine, pistons rings, because head and bottom recently refurbished

Before i tackle engine where should I look?

Thank you TR oracle wise men :rolleyes:

20201018_120342.jpg

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If its old fuel, that could be the culprit. If so, drain it and replace with fresh fuel, then take ik out for a longer 1 hr drive.

Cheers,
Not so wise and definitely not an oracle man, Waldi

 

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1 hour ago, Mike C said:

+1 for old fuel, used to happen to me each winter before I started adding Stabil. And check the enrichment lever on the side of the MU isn't stuck.

+1

Not wishing to be the bearer of bad tidings but the oil pressure is low. 20s hot and <10 at idle is a clear sign that the bearings are letting too much oil pass. Mine is 60-70 above 2000rpm and 25-30 at idle after a long high speed run on a hot day. It is never below 25. My sidescreen TRs the same.

It may be related to the plugs fouling in that if the rings are as worn they are letting a lot of oil into the combustion chamber. Is the fouling petrol or oil. It looks like it could be oil as it isn't evaporating before the photo.

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9 hours ago, John McCormack said:

+1

Not wishing to be the bearer of bad tidings but the oil pressure is low. 20s hot and <10 at idle is a clear sign that the bearings are letting too much oil pass. Mine is 60-70 above 2000rpm and 25-30 at idle after a long high speed run on a hot day. It is never below 25. My sidescreen TRs the same.

It may be related to the plugs fouling in that if the rings are as worn they are letting a lot of oil into the combustion chamber. Is the fouling petrol or oil. It looks like it could be oil as it isn't evaporating before the photo.

Following up on what John says! I would do a compression check on all cylinders when hot and then do the oil test on compression? You are looking for blow by the piston rings! To see what the difference is? On a good condition engine it is usually only 5 & 6 that gives the problem? Which can be cured by using hotter plugs. But your plugs look beyond that! What is the oil consumption?

Bruce.

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  • 2 months later...
3 hours ago, tr6tuga said:

Just a update, it was the return spring on the mu...not on top end return, and then, 6 litle pigs foulling:rolleyes:

Fear of Covid related stress  sindrome

Problem solved

Always good to have the simple fix work.

What about the oil pressure?

 

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On 10/18/2020 at 11:52 PM, John McCormack said:

+1

Not wishing to be the bearer of bad tidings but the oil pressure is low. 20s hot and <10 at idle is a clear sign that the bearings are letting too much oil pass. Mine is 60-70 above 2000rpm and 25-30 at idle after a long high speed run on a hot day. It is never below 25. My sidescreen TRs the same.

It may be related to the plugs fouling in that if the rings are as worn they are letting a lot of oil into the combustion chamber. Is the fouling petrol or oil. It looks like it could be oil as it isn't evaporating before the photo.

I have to agree with John! Have you done a compression check? Your oil pressure is way too low and as John says I would also suspect that the rings are letting too much oil past them. What is the mileage of your engine, mined died through glazed bores and age! My current oil pressure is even above John's after a rebuild 3 years ago!

Bruce.

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On 10/18/2020 at 11:52 PM, John McCormack said:

+1

Not wishing to be the bearer of bad tidings but the oil pressure is low. 20s hot and <10 at idle is a clear sign that the bearings are letting too much oil pass. Mine is 60-70 above 2000rpm and 25-30 at idle after a long high speed run on a hot day. It is never below 25. My sidescreen TRs the same.

It may be related to the plugs fouling in that if the rings are as worn they are letting a lot of oil into the combustion chamber. Is the fouling petrol or oil. It looks like it could be oil as it isn't evaporating before the photo.

Dont worry about these oil pressure readings. My 6 has been reading 10/15psi at tick over for years and its still going. Oil pressure gauges were the bane of the industry back in the 60s. Anything below quoted pressures customers panicked and took their cars in for checks. I have a 1600 cc Land Rover that was reading 5psi at tick over, I swapped the pressure gauge and it cured my low reading, they do not give 100% accurate reading. If you do not intend to race it or do a constant high speed/revs for long periods, use a good oil and it should be ok for years. If it doesnt rattle when you fire it up cold leave it till it does.

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14 minutes ago, Phil Read said:

Dont worry about these oil pressure readings. My 6 has been reading 10/15psi at tick over for years and its still going. Oil pressure gauges were the bane of the industry back in the 60s. Anything below quoted pressures customers panicked and took their cars in for checks. I have a 1600 cc Land Rover that was reading 5psi at tick over, I swapped the pressure gauge and it cured my low reading, they do not give 100% accurate reading. If you do not intend to race it or do a constant high speed/revs for long periods, use a good oil and it should be ok for years. If it doesnt rattle when you fire it up cold leave it till it does.

Unfortunately that is not my experience! The longer you leave it the more they have to grind off the journals  to bring it back to a round size? By going from standard to -0.020" in one go. For some that has shorten the life of the crank unless you know a company that can spray Stellite  and regrind it, to bring it back to standard size.

Bruce.

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Every one has there own individual experiences. I was an apprentice for a Triumph main dealer in the 60s and worked for them until 1979, varied oil pressure was common on all cars of the period. Low oil pressure is not a problem under normal use, particularly at tick over. I have a TR6, TR4A and a 3A, all show 70psi  plus on start up, once warm they all tend to run at just above 50psi plus at 2000rpm  to @60psi at high revs as stated the 6 drops down to 10/15psi at tick over the other two slightly higher, that is what I would expect, they are not new engines. I do not see the point of removing and stripping down an engine, and incurring costs if it is not neccesary

Why would you want to bring a crank back to standard? Grinding cranks undersize is common practice and does not create a problem in normal use. If you are racing fair enough, you are putting extra stess on the crank.

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4 hours ago, Phil Read said:

Every one has there own individual experiences. I was an apprentice for a Triumph main dealer in the 60s and worked for them until 1979, varied oil pressure was common on all cars of the period. Low oil pressure is not a problem under normal use, particularly at tick over. I have a TR6, TR4A and a 3A, all show 70psi  plus on start up, once warm they all tend to run at just above 50psi plus at 2000rpm  to @60psi at high revs as stated the 6 drops down to 10/15psi at tick over the other two slightly higher, that is what I would expect, they are not new engines. I do not see the point of removing and stripping down an engine, and incurring costs if it is not neccesary

Why would you want to bring a crank back to standard? Grinding cranks undersize is common practice and does not create a problem in normal use. If you are racing fair enough, you are putting extra stess on the crank.

It is but not when you get to -0.060"? The scrap bin awaits that crank!

Bruce.

 

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2 minutes ago, astontr6 said:

It is but not when you get to -0.060"? The scrap bin awaits that crank!

Bruce.

 

I won the 1988 TR Register championship on a 4 cylinder crank with -20 thou mains and -60 thou big ends (Massey Ferguson Tractor) which were offset ground to increase the stroke. At the end of the season after 240 racing laps (about 500 miles) the car was used for the British Heart Foundation event at Snetterton where it did another 186 laps at race speed (about another 370 racing miles) before I broke it...the mainshaft on the gearbox.

After the season I stripped and rebuilt the engine with new shells (nothing else necessary) and sold the car to my sponsor who ran it again the next season and again the car won the Championship performing in a similar manner over about the same sort of laps.

You know... I think these cranks are more robust than you think. :ph34r:

Mick Richards  

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2 hours ago, Motorsport Mickey said:

I won the 1988 TR Register championship on a 4 cylinder crank with -20 thou mains and -60 thou big ends (Massey Ferguson Tractor) which were offset ground to increase the stroke. At the end of the season after 240 racing laps (about 500 miles) the car was used for the British Heart Foundation event at Snetterton where it did another 186 laps at race speed (about another 370 racing miles) before I broke it...the mainshaft on the gearbox.

After the season I stripped and rebuilt the engine with new shells (nothing else necessary) and sold the car to my sponsor who ran it again the next season and again the car won the Championship performing in a similar manner over about the same sort of laps.

You know... I think these cranks are more robust than you think. :ph34r:

Mick Richards  

A but of thread drift here but regarding the offset crank grind, I have only heard of it recently from a friend and it took a little to get my head around it. I am not super technically savvy. My friend is looking to get 2.9 liters from a 2.5 motor with a bore and offset crank grind. I have read about most modifications but this was a new one to me but has obviously been around for a while but perhaps not that common?

Simon

 

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It's a fairly common modification Simon. For example, offset grind on a Triumph "Small Car" 1500 engine with 1300 con rods and a cheap set of TR5 pistons (one had been damaged in a failed engine build) gets you an approx. 1650 motor. The increased stroke means it's less revvy but more torque.

P3060334.JPG

DSCF7432.JPG

Cheers, Richard

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Just another update

Went for a decent 100k blast in a lovely cold sunny weather, what a joy,smoth and vigorous driving, no issues,  now back to curfew :ph34r:

Phill , oil pressure in the 20s at 15k 40s in the 30k and consumption 1,5 every 2k so not bad, if another lockdown a new set of pistons is on the bucket list, any advice for a standard set supplier is welcome.

Steve 

Still saiiling but with masks... not a great idea but as soon away is free

Keep in touch

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