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Search found 646 matches

by Circlotron
Thu Feb 20, 2020 7:50 am
Forum: Engine Tech
Topic: Running a Diesel with no load and no water
Replies: 5
Views: 329

Running a Diesel with no load and no water

I note that modern spark ignition engines have the facility that if they overheat they cut the fuel to one or more cylinders (probably walk through a pattern) to make you open the throttle further so that the dead cylinders ingest more air in an attempt to cool the engine and save it from catastroph...
by Circlotron
Mon Jan 27, 2020 6:55 am
Forum: Engine Tech
Topic: can Oil be TOO slippery ?
Replies: 39
Views: 1797

Re: can Oil be TOO slippery ?

I once knew a guy who put some magic oil additive (PTFE based?) in a Peugeot 504 manual gearbox and it was slippery enough that the synchros refused to work.
by Circlotron
Sat Jan 11, 2020 11:00 pm
Forum: Engine Tech
Topic: 1400 hp Big Chevy combinations
Replies: 91
Views: 2948

Re: 1400 hp Big Chevy combinations

How long is it required to run at the 1400hp level?
by Circlotron
Mon Dec 16, 2019 7:06 am
Forum: Engine Tech
Topic: spark plug gap vs lean mixtures
Replies: 74
Views: 3341

Re: spark plug gap vs lean mixtures

As we close the mixture gap the required firing voltage diminishes...up to a point. When the gap becomes less than the quenching distance, the spark will still jump the gap and ignite the flame kernel. But the kernel size will be too small to sustain the heat loss to the disc electrodes and the fla...
by Circlotron
Wed Dec 11, 2019 11:51 pm
Forum: Engine Tech
Topic: spark plug gap vs lean mixtures
Replies: 74
Views: 3341

Re: spark plug gap vs lean mixtures

Many years ago I experienced the flip side of large plug gaps. During a hasty midnight valve job on a Morris Mini Minor we left the spark plugs in. Back in 1980 I also had the misfortune of owning one of those things, a '63 850cc one. Opened up the plug gaps from the standard 0.025 to 0.050 and put...
by Circlotron
Tue Dec 10, 2019 7:05 am
Forum: Engine Tech
Topic: spark plug gap vs lean mixtures
Replies: 74
Views: 3341

Re: spark plug gap vs lean mixtures

For me with 9.3:1 and lean propane, 60 thou made a nice improvement, 80 thou no obvious further improvement, and 100 thou okay when driving along but slightly uneven idle after idling for more than 20-30 seconds presumably because the plug cooled off a little and so it was easier to arc down the sur...
by Circlotron
Mon Dec 02, 2019 7:12 am
Forum: Engine Tech
Topic: Rod strength
Replies: 35
Views: 1493

Re: Rod strength

It says "1500 pounds" not 1500 psi. That 1500 pounds may be concentrated on an area way smaller than a square inch.
by Circlotron
Thu Nov 28, 2019 3:04 am
Forum: Engine Tech
Topic: Cam break in via electric motor?
Replies: 22
Views: 1089

Re: Cam break in via electric motor?

Maybe special lifters to break-in the cam and swap out to a different set afterwards. Does need to be In the actual block, because the lifter location and angle and cam thrust of most production blocks are not exact. The way I understand it, you are making two different surfaces become suited to ea...
by Circlotron
Wed Nov 20, 2019 7:18 am
Forum: Engine Tech
Topic: when are 3/4 grooved main bearings needed for bbc ?
Replies: 275
Views: 9295

Re: when are 3/4 grooved main bearings needed for bbc ?

A groove might feed oil to the drilling in the journal for more degrees of rotation but it reduces the load bearing capacity of a bearing considerably. Think of how a bald tyre so easily loses contact with a wet road, then you put grooves in it and it cuts through the water and makes contact with th...
by Circlotron
Thu Nov 14, 2019 9:56 pm
Forum: Engine Tech
Topic: "Hedifolds" the good, bad, and ugly?
Replies: 13
Views: 729

Re: "Hedifolds" the good, bad, and ugly?

I can't stop wondering how much extra heat must be dumped into the coolant by having the exhaust manifold effectively surrounded by water. Kinda like Ford flatheads with the exhaust port going across the full width of the bank.
by Circlotron
Mon Nov 11, 2019 1:35 am
Forum: Engine Tech
Topic: What happened to propane and CNG
Replies: 16
Views: 874

Re: What happened to propane and CNG

What type of fleet vehicles are these? We had/have some public transport busses running CNG here. Far better than the diesel versions regarding fumes in the city run busses. Trash trucks.... Even better if you can get the NG from the rotting trash. Many municipal rubbish dumps are starting to use t...
by Circlotron
Thu Nov 07, 2019 1:22 am
Forum: Engine Tech
Topic: Straightened crankshaft revisited
Replies: 15
Views: 964

Re: Straightened crankshaft revisited

modok wrote:
Wed Nov 06, 2019 11:04 pm
Strightened it with a press, cold....hmmm
I'm glad it worked for you, usually it does not.
Would you be more likely to have success using a press on a forged crank rather than a cast one?
by Circlotron
Thu Oct 24, 2019 2:36 am
Forum: Engine Tech
Topic: "symmetrical" head description?
Replies: 10
Views: 781

Re: "symmetrical" head description?

Why are heads with the valve layout IEIEIEIE called symmetrical? That word is for something that is mirror image about a centre line. The only heads I can think of that would qualify for that description are early Holden 253 / 308 CID that are IEIEEIEI. For me examples of Mirror would be EIIEEIIE o...
by Circlotron
Wed Oct 23, 2019 9:41 pm
Forum: Engine Tech
Topic: "symmetrical" head description?
Replies: 10
Views: 781

"symmetrical" head description?

Why are heads with the valve layout IEIEIEIE called symmetrical? That word is for something that is mirror image about a centre line. The only heads I can think of that would qualify for that description are early Holden 253 / 308 CID that are IEIEEIEI.
by Circlotron
Tue Oct 22, 2019 7:47 am
Forum: Engine Tech
Topic: Bore, Stroke, and block strength
Replies: 42
Views: 1497

Re: Bore, Stroke, and block strength

Example: imagine trying to torque a bolt with a swivel socket and extension on your ratchet. Can you do this properly without supporting the ratchet head with your other hand? (Hint: NO.) Does the requires support vary with the applied torque? (Yes) Does it diminish if the torque remains the same, ...