| Author |
Message |
Terry Springer (Tspringer)
Member
Username: Tspringer
Post Number: 793
Registered: 4-2002
| | Posted on Sunday, August 31, 2003 - 5:00 pm: | |
JRV..... Are you saying that if you have a rich running issue, the washing effect of oil from cylinder walls would cause smoke on startup? Is this because the oil from the cylinder walls is washed off and pools with some fuel on top of the piston waiting to be burned on startup? It seems the car would smoke black due to excess fuel on startup and not blue/grey?
In your experience, if the rich running issue is corrected, would the car cease to smoke on startup given that the problem was mixture and not valve seals? |
bob snow (Resnow)
New member
Username: Resnow
Post Number: 48
Registered: 5-2001
| | Posted on Monday, February 03, 2003 - 3:28 pm: | |
JRV,
You're probably right on the availability of the older style guides. I had my heads machined and the guides replaced in '84 and have had negligible startup smoke since. The old guides were readily available then but are certainly much rarer now.
Bob |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 791
Registered: 11-2002
| | Posted on Monday, February 03, 2003 - 1:07 pm: | |
>>>Did you have valve guides simply replaced with original-style bronze guides or did you have some machining of the valve guide posts done to enable the use of post-1966 guides of a more durable material (aluminum-silicon-bronze) using Perfect Circle Teflon seals? <<
That thought fleeted across my mind also, however I haven't heard of the original guides being availible in 10 or 15 yrs at least...maybe twenty.
Is it even possible to still get the original style ? |
bob snow (Resnow)
New member
Username: Resnow
Post Number: 46
Registered: 5-2001
| | Posted on Monday, February 03, 2003 - 11:56 am: | |
Ed,
Did you have valve guides simply replaced with original-style bronze guides or did you have some machining of the valve guide posts done to enable the use of post-1966 guides of a more durable material (aluminum-silicon-bronze) using Perfect Circle Teflon seals?
The tendency to smoke at startup indicates a possible/probable valve guide leak. On the GTE, there was a tendency for small pockets in the head to fill with oil during slow running then, under acceleration, the oil empties through the valve guides.
Bob |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 790
Registered: 11-2002
| | Posted on Monday, February 03, 2003 - 10:05 am: | |
Mr. G., sure reading the tailpipes is a good way to get read on cars without cats. but to get a read from tailpipes the car has to go some distance at temp. Race type & Performance engines are normally easier to read tail pipes because they have headers and short systems....on long systems it takes awhile to get the tips hot . But certianly when running on the track for example the tailpipes are something to look at and if they were off color a plug read would be in order. Like you mentioned CoCo Brown/Greyish is right on, White is Lean and Black is Rich. |
James Glickenhaus (Napolis)
Member
Username: Napolis
Post Number: 451
Registered: 10-2002
| | Posted on Monday, February 03, 2003 - 9:52 am: | |
Thanks!
Is tail pipe color a good guide? Grey vrs Black or white? |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 789
Registered: 11-2002
| | Posted on Monday, February 03, 2003 - 9:40 am: | |
Mr. G, by modern standards over 1%CO is rich..lol.
However, on the older motors 3%-4% is about right..although 2%-2.5% is better...anything over 4%CO warm is RICH...but the HC's are a very important # to watch and actually tells more about what's going on inside as far as potential 'wash' is concerned. HC's should never be over 600ppm on older engines with 400ppm a good number to see. What prevents 'wash down' is fully burning the fuel which is reflected in the HC's #. HC = HyroCarbons which really means UnBurned HydroCarbons or Raw Fuel exiting the Combustion Chamber and into the exhaust where it's read by the gas analyzer.
On a perfect late model engine (FI) I expect #'s of (pre-cat) 0.5% - 1.2% & 60 - 150ppm HC's,
On an older motor of any type 2.5%-4.5% CO & 200 - 450PPM HC's is acceptable. Anything over 600PPM HC's means ineffective burning of the fuel for some reason and 800-up is very poor.
The fattening up of the mixture for acceleration and power is the job of the accelerator pump circuits and the main jets...not the job of the idle or intermediate circuits.
Ideally an engine should run a touch on the lean side (crisp & clean) at idle or part throttle and recieve any rich running needs by additional injection when throttle is moved quickly. Both FI & Carbs have a specific circuit or method to achieve/meet the additional fuel needs of acceleration. |
James Glickenhaus (Napolis)
Member
Username: Napolis
Post Number: 450
Registered: 10-2002
| | Posted on Monday, February 03, 2003 - 8:42 am: | |
JRV
What are your thoughts Rich/Lean? On the street I find my race motors run better slightly Rich. ie. cooler, idle better, can be driven at lower RPM to get one to the open roads. How much should I worry about wash down? So far (10 years of street driving) MK-IV 427 seems ok. That one is a bit over carborated: 2 850 Holley's.
Best
Jim |
JRV (Jrvall)
Member
Username: Jrvall
Post Number: 788
Registered: 11-2002
| | Posted on Monday, February 03, 2003 - 7:07 am: | |
A recently ringed & valve guide renewed engine (old V-12 or new V-12) shouldn't smoke more than perhaps a trace. However a rich running (4%-9%CO) V-12 can and will smoke due to "washing" of the oil from the combustion chambers by excessive fuel.
A cylinder leakage test could narrow down the possible problems. Any engine (including old V-12's) should give readings of no more than 5% Leakage after a ring and valve job. A nicely done ring & valve job properlly sealing should produce results of 1%-3% leakage after breakin any more than 10% would be cause for concern..
You don't give any info on breaking in the new rings...this should have been done after refresh job, and takes between 100-1000 miles of mixed rpm running. Old V-12's that use fossil based oils and sit for extended periods of time have been known to be prone to sticking rings, causing excesive smoking when put back into service.
Not having any more info, I'd set carbs on a Gas Analyzer to 3% max (with the help of a Colortune)....then run engine moderately for 500 miles and check cylinder leakage. After 500-1000 miles the valves need to be adjusted & heads retorqued anyway, so while the covers are off the cylinder leakage test can be performed quite easily.
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Simon Campbell (Simonc)
Junior Member
Username: Simonc
Post Number: 70
Registered: 2-2002
| | Posted on Monday, February 03, 2003 - 6:34 am: | |
I have a 400 which smokes on starting and at tickover when hot. Fine when cold. This is valve guides or valve seals - I think it is the valve seals gone hard. My engine has done 58,000 miles.
Just about every 50,000 mile V12 Ferrari I have seen does exactly the same thing. I know they shouldn't but they do. Trouble is the rebuild costs far outweigh the increase in value that a rebuild would bring. Mike Sheehan did a piece on this and decided it was better to buy oil than to rebuild. He said that when you rebuild the heads then the bottom end will need doing soon after. See http://www.ferraris-online.com/Articles/SCM_9812.html and http://www.ferraris-online.com/Articles/SCM_0109.html
Simon
1977 400 Auto in London |
Henryk (Henryk)
Member
Username: Henryk
Post Number: 434
Registered: 8-2001
| | Posted on Sunday, February 02, 2003 - 9:59 pm: | |
Ed; I have seen where someone replaces the rings, and does not take time to properly hone the walls. This will produce blue smoke under acceleration. Proper clearances are important.
Also, one can have new rings, and properly honed walls, yet still burn blue smoke due to not properly "setting" the rings. This is very important when getting new rings. |
ed evangelista (Eve23)
New member
Username: Eve23
Post Number: 4
Registered: 2-2003
| | Posted on Sunday, February 02, 2003 - 9:44 pm: | |
thanks henryk....i'll check into it...they are supposed to be new.... |
Henryk (Henryk)
Member
Username: Henryk
Post Number: 432
Registered: 8-2001
| | Posted on Sunday, February 02, 2003 - 9:30 pm: | |
I believe blue smoke means oil burning, not excess gas.....this would produce black smoke.
I would suspect bad rings.
Too many ferrari owners buy their car, from a dealer, who states that the smoke is normal for these cars. I totally disagree!!!!! My 88 TR does not smoke, blue or black, at any time, even after sitting for months....it has 63,000 miles on it.
My 83 Boxer smokes blue after sitting for several days. I suspect valve guides. It has only 18,000 miles on it!!!!!!!
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ed evangelista (Eve23)
New member
Username: Eve23
Post Number: 3
Registered: 2-2003
| | Posted on Sunday, February 02, 2003 - 9:20 pm: | |
just had the car tuned and shes running perfect...
but after stopping at a light... she blows a lot of blue smoke when i start to go...i know these cars run rich but is this normal for a 45 yr old V12??
my guess is yes....just confirming....
new valve guides and rings 2 yrs ago. ..
brand new exhaust this week...
carbs adjusted barrel by barrel...
new oil and filters...(using ultra gas) near empty...
overall running very smooth and response is incredible...only put on 25 miles today since tune-up...
thanks
eddie |