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Search found 229 matches

by naukkis79
Fri Oct 23, 2020 12:11 pm
Forum: Engine Tech
Topic: Ignition advance at cruise rpm?
Replies: 44
Views: 1795

Re: Ignition advance at cruise rpm?

YOU’RE DOING IT WRONG. Thanks, captain obvious. Work on your reading comprehension. Calculating dynamic compression to compare part-throttle ignition maps is good starting point, but valve timing isn't part of that calculation, engine load is. So if your engine 100% VE is 500mg/stroke and compressi...
by naukkis79
Thu Oct 22, 2020 1:07 pm
Forum: Engine Tech
Topic: Ignition advance at cruise rpm?
Replies: 44
Views: 1795

Re: Ignition advance at cruise rpm?

I've never measured it for this engine. It's got a relatively small cam, four valve head, etc. I've got a cruise ignition map from the factor for an engine that has about 8:1 "effective" compression ratio computed from the engine geometry and valve events. This engine has a 6.7:1 "effective" compre...
by naukkis79
Wed Oct 21, 2020 11:36 am
Forum: Engine Tech
Topic: Is a regrind cam as powerful as a billet cam
Replies: 12
Views: 991

Re: Is a regrind cam as powerful as a billet cam

You will struggle shimming anything with a much smaller base circle also. I've used 2mm lash caps on occasion, but shaft also becomes too thin for strength. With Fiat TC you could shave cam trays instead of lash caps and save weight. With bucket follower regrinds there's usually no strength effect ...
by naukkis79
Mon Oct 19, 2020 2:20 pm
Forum: Engine Tech
Topic: Is a regrind cam as powerful as a billet cam
Replies: 12
Views: 991

Re: Is a regrind cam as powerful as a billet cam

If these are for a bucket type follower, there will be no difference between the two. If this is for a finger follower, or rocker follower type system, then a change in base circle will effect the lift curve at the valve. Only if geometry is left as it is, finger and rocker arm geometry could be co...
by naukkis79
Mon Oct 19, 2020 2:13 pm
Forum: Engine Tech
Topic: Is a regrind cam as powerful as a billet cam
Replies: 12
Views: 991

Re: Is a regrind cam as powerful as a billet cam

panic wrote: Mon Oct 19, 2020 8:51 am Regrinding is limited to within 2-3 degrees of the original LSA.
Beauty of DOHC-engines is that timing for intake and exhaust cams can be set separately - so LSA isn't tied to cam profile at all.
by naukkis79
Sat Sep 12, 2020 1:15 am
Forum: Engine Tech
Topic: Exhaust flames - running lean or just high temp?
Replies: 13
Views: 893

Re: Exhaust flames - running lean or just high temp?

If the limiter cuts sparks, which is likely, it would load the exhaust with an ideal air fuel mix. Retarded timing would drive up EGT, promoting light-off. He also might be using a spark plug in each collector for the purpose: https://www.thevehiclelab.com/exhaust-flames/#:~:text=In%20essence%2C%20...
by naukkis79
Fri Sep 11, 2020 8:44 am
Forum: Engine Tech
Topic: Exhaust flames - running lean or just high temp?
Replies: 13
Views: 893

Re: Exhaust flames - running lean or just high temp?

Exhaust is red hot indicating late ignition timing. Probably due to too much boost and trying to prevent detonation. Combine that with too rich a mixture to equally prevent detonation and that is what you get. They are burning rubber - so retard ignition timing is from soft rpm limiter. Without sof...
by naukkis79
Sun Sep 06, 2020 1:47 am
Forum: Engine Tech
Topic: Watered gas.
Replies: 17
Views: 666

Re: Watered gas.

Just use it, little bit of water in gas only matter if there's freezing temperature and fuel pickup freeze. And to prevent that you just add alcohol to gas to solve that water into gas instead of it freezing in tank bottom.
by naukkis79
Thu Aug 20, 2020 12:09 pm
Forum: Engine Tech
Topic: Dual spark plugs or squish?
Replies: 68
Views: 1896

Re: Dual spark plugs or squish?

Prior to TDC, squish motion is inward toward the spark plug. After TDC, the squish motion is reversed and moves outward toward the perimeter. Naturally if squish area is in edge and spark plug in center of cylinder. But squish motion can be aimed to different location, aiming towards spark plug wil...
by naukkis79
Thu Aug 20, 2020 4:19 am
Forum: Engine Tech
Topic: Dual spark plugs or squish?
Replies: 68
Views: 1896

Re: Dual spark plugs or squish?

It shows to me like squish in this engine is directed towards combustion chamber roof. Squish should be directed to piston top instead, target is to make charge motion to where combustion takes too long time - gases stuck to piston and traveling downwards are main priority so targeting squish to tha...
by naukkis79
Thu Aug 13, 2020 11:52 am
Forum: Engine Tech
Topic: Non-EP, GL-1 gear oil - brass, synchros
Replies: 21
Views: 582

Re: Non-EP, GL-1 gear oil - brass, synchros

The GL ratings is a gear pressure rating, has nothing to do with if it works makes syncros work better or worse. EP additives are specially meant for lubricating sliding gear contact like hypoid gears. Syncromesh is also sliding contact which works better if oil don't have additives to lubricate sl...
by naukkis79
Wed Aug 12, 2020 1:22 pm
Forum: Engine Tech
Topic: Non-EP, GL-1 gear oil - brass, synchros
Replies: 21
Views: 582

Re: Non-EP, GL-1 gear oil - brass, synchros

I do use synthetic ATF in manual gearboxes - it usually works much better than GL-4 grade oils. Redline MTL is one excellent product that have both GL4 and ATF grades but it's expensive, any thin synth ATF works usually also well.
by naukkis79
Wed Aug 05, 2020 2:55 pm
Forum: Engine Tech
Topic: Crankcase Evacuation System on Stock Engine
Replies: 54
Views: 2176

Re: Crankcase Evacuation System on Stock Engine

What if a PCV system could be equipped with a 5 psi (~10 inHg) check valve on the inlet, filtered side going in the engine with the PCV to manifold side left alone. When vacuum exceeds 10", the valve opens and regulates fresh air into the crankcase at that depression. Late 90's up BMW has this kind...
by naukkis79
Tue Aug 04, 2020 2:45 pm
Forum: Vintage/Classic/Historical Engine Tech
Topic: Lead used to lube valve stems?
Replies: 16
Views: 870

Re: Lead used to lube valve stems?

Te lead did work to lubricate valve stems. Today's head rebuilds of older engines require additional stem-to-guide clearance to avoid hanging a valve on startup. The old guys had to learn new tricks when unleaded and now ethanol became the standard. Lead increases heat transfer between seat and val...
by naukkis79
Tue Aug 04, 2020 1:37 pm
Forum: Vintage/Classic/Historical Engine Tech
Topic: Lead used to lube valve stems?
Replies: 16
Views: 870

Re: Lead used to lube valve stems?

Main protection from lead is for exhaust valve/valve seat contact. Lead plating in those surfaces prevented material welding together and so reduced wear greatly. But lead stuck everywhere, sticking into hot valve stems was harmful side-effect not desired. Lead also stuck to other parts of valve fac...