joed
Active Member
- Joined
- Mar 6, 2002
fresh stock pump, lifter preload is about a heavy 1/2 turn from zero, so .025-.030" give or take.
Engine guys please help!
- Thread starter joed
- Start date
- Joined
- May 28, 2001
Your second set of pics looks better. You mentioned alky. I would start by backing off the boost down to about 8 psi and see what it does from there. If the alky is not set right you could be pig rich in boost with that just as well.
Go back to 8 psi and start from there. Find a baseline and work off of that.
I take it you have no way data log what the car is doing?
Go back to 8 psi and start from there. Find a baseline and work off of that.
I take it you have no way data log what the car is doing?
The plugs are not uniform.
Not even close
When everything is inform at 10.1 afr they all will be rich.
joed
Active Member
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- Mar 6, 2002
power logger includes WBAFR
joed
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- Mar 6, 2002
Chuck said same thing. I feel good about cam sensor, rebuilt and set myself with caspers tool, will recheck however. If I pull front cover, how do I know what I'm looking at with cam alignment and timing set? Do i need to rent a degree wheel? Or just check centerline on #1 TDC?
- Joined
- May 28, 2001
You can set it 180 out with that tool, too.
- Joined
- May 28, 2001
Those are extended tip plugs.
joed
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- Mar 6, 2002
OK I pulled the cap off the cam sensor and rotated the motor to make sure I was on number one compression then moved to my 1-15/32 aka 25 degree after timing zero and the window in the cam sensor wheel is facing the power steering gearbox so that should confirm cam sensor.
The old plugs are NGK UR4(not a good choice?) I have and will install a fresh set of AC cr43ts. Will swap to spare set of wires and ohm out both sets. Will try to grab a quick PL and post before I take off for NATS and we can pick this up next week something when everyone back home. Thank you!
Anyone please stop by the NY tent along the river. Will have Bill Brooks GN (REALKWIK) and Sam Chinelli’s WH1 Designer (BOOSTIN). Hope to see you!
Not a good choice
Get off the projectile plug and go to a non projectile plug
TIMINATOR
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- Joined
- Jan 26, 2020
Cam sensor, alky, changes in programming, and plugs have nothing to do with cranking compression. Although changing from a projected nose, to a standard plug nose can change the actual head effective CC by a few hundredths.
ACTUAL compression ratio to "advertised, factory spec" is usually one half point to a full point lower.
Unless you have CC'd YOUR heads, measured the ACTUAL compression height, know the head gaskets actual cc volume, crevice volume , and pistons actual dish volume, you are only guessing what the compression ratio might be. Every time a valve job is done, the valves sit deeper in the chamber, and that adds to the chambers CC volume, as does valve/seat wear. New head gasket to old headgasket thickness may have changed with a different brand, type, or even the new gaskets bore size.
Rather than fixate on cranking compression, try and isolate what any possible differences are between when the car ran well and now. Including what could have changed when the engine was remachined/repaired and reassembled.
A larger cam or differences in degreeing, or if the cam is one tooth retarded, will affect cranking compression, but not leak down.
JMHO TIMINATOR
ACTUAL compression ratio to "advertised, factory spec" is usually one half point to a full point lower.
Unless you have CC'd YOUR heads, measured the ACTUAL compression height, know the head gaskets actual cc volume, crevice volume , and pistons actual dish volume, you are only guessing what the compression ratio might be. Every time a valve job is done, the valves sit deeper in the chamber, and that adds to the chambers CC volume, as does valve/seat wear. New head gasket to old headgasket thickness may have changed with a different brand, type, or even the new gaskets bore size.
Rather than fixate on cranking compression, try and isolate what any possible differences are between when the car ran well and now. Including what could have changed when the engine was remachined/repaired and reassembled.
A larger cam or differences in degreeing, or if the cam is one tooth retarded, will affect cranking compression, but not leak down.
JMHO TIMINATOR
joed
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- Mar 6, 2002
Thanks Timinator. I agree. Heads are essentially brand new champions (maybe 20 hours street driving) and part of last setup. Everything is same as last time when it ran well so I agree cam setting could be suspect to me. I wanted to just put some data up before I go after front cover removal next week after NATS.
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TIMINATOR
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- Jan 26, 2020
Harbor freight has a video monitor with a 30" snout about 7/16" diameter. Color screen too. Ya might be able to pull the cam sensor and look down the hole at the dots on the cam sprockets top to top or top to bottom on alternate revolutions. It has a mirror attachment too. Tape it on there if u use it! One tooth off is about 20 degrees!
TIMINATOR
TIMINATOR
hensleyt
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- Feb 20, 2008
First I don't think it would run one tooth retorted or advanced. if you have the cam card you can slack the intake valve and it should open 5-10 degrees after TDC. Is it perfect no but it will tell you your darn close.and the exhaust should be closing just before TDC your cam sensor should be pointing 9 o'clock ( I THINK ) problem wrong Its been a long time sense I've been under the hood of my car.
spark plug is a touchy subject, 43 should be a good choice Im not a real fan of one heat rang colder and projectile plug. Enjoy the NATS
spark plug is a touchy subject, 43 should be a good choice Im not a real fan of one heat rang colder and projectile plug. Enjoy the NATS
TIMINATOR
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- Jan 26, 2020
HENSLEYT, I assure you engines will run even two teeth retarded.
The Comp 260 flat tappet V-6 cam closes the intake valve at 58 degrees after bottom dead center(@.006 advertised duration). That's the next size bigger than his cam.
The Comp hyd rlr cam 294 closes the intake valve at 73 degrees after bottom dead center (@.006 advertised duration), and it is a street roller and not that big, (242 degrees at .050.)
That's 15 degrees later, and one tooth on a Buick V-6 is 18 degrees. You get into more spirited hot street cams and the intake closing is at around 80+ degrees after bdc! That equals 2 teeth or more.
I personally have had two old engines jump 2 teeth, and they both drove me home. The first was my 1969 GTO (400 engine) that I was street racing, (but I'll deny it,) and the second was a 1973 Dodge 360 in a 4wd pickup truck that I had just bought to put in a fresh built 440, and I was running the crap out of it all the way home. It jumped two teeth also, and I drove it home the last two miles also. Both engines had the stock nylon upper gear. They both also ran like poop, and barely idled, but they got me home.
The 276 @ .050 roller in my boat closes the intake at 88 degrees @ .050!!!! After bdc! That's over 100 degrees abdc at .006, and considering there is only 180 degrees between BDC and TDC the intake valve closes past the pistons half way up position on the compression stroke! Many cam companies sell race cams that are over 290 degrees at .050 and they run.
A cam retarded one tooth will have less trapped compression, due to the later intake valve closing, but will usually smooth out at around 3000 rpm or so.
TIMINATOR
The Comp 260 flat tappet V-6 cam closes the intake valve at 58 degrees after bottom dead center(@.006 advertised duration). That's the next size bigger than his cam.
The Comp hyd rlr cam 294 closes the intake valve at 73 degrees after bottom dead center (@.006 advertised duration), and it is a street roller and not that big, (242 degrees at .050.)
That's 15 degrees later, and one tooth on a Buick V-6 is 18 degrees. You get into more spirited hot street cams and the intake closing is at around 80+ degrees after bdc! That equals 2 teeth or more.
I personally have had two old engines jump 2 teeth, and they both drove me home. The first was my 1969 GTO (400 engine) that I was street racing, (but I'll deny it,) and the second was a 1973 Dodge 360 in a 4wd pickup truck that I had just bought to put in a fresh built 440, and I was running the crap out of it all the way home. It jumped two teeth also, and I drove it home the last two miles also. Both engines had the stock nylon upper gear. They both also ran like poop, and barely idled, but they got me home.
The 276 @ .050 roller in my boat closes the intake at 88 degrees @ .050!!!! After bdc! That's over 100 degrees abdc at .006, and considering there is only 180 degrees between BDC and TDC the intake valve closes past the pistons half way up position on the compression stroke! Many cam companies sell race cams that are over 290 degrees at .050 and they run.
A cam retarded one tooth will have less trapped compression, due to the later intake valve closing, but will usually smooth out at around 3000 rpm or so.
TIMINATOR
TIMINATOR
Well-Known Member
- Joined
- Jan 26, 2020
The above post is made solely for informational purposes to educate all to the fact that cranking compression is affected by cam size, which controls when the intake valve closes on the compression stroke, and that if the cam timing is off by improper installation it too will affect cranking compression.
Bottom line: You can't state that X compression ratio always results in Y cranking compression.
Changing cam degreeing within a degree or two, will not change cranking compression enough to see.
A partially or fully charged battery, or a hi torque starter will affect cranking compression more.
No offense is intended to Hensleyt, or anyone else. But, I have been drag racing for 55 years, and owning a Hi Perf. Machine shop for almost 50 years, so perhaps I have seen a few things that others haven't.
TIMINATOR
Bottom line: You can't state that X compression ratio always results in Y cranking compression.
Changing cam degreeing within a degree or two, will not change cranking compression enough to see.
A partially or fully charged battery, or a hi torque starter will affect cranking compression more.
No offense is intended to Hensleyt, or anyone else. But, I have been drag racing for 55 years, and owning a Hi Perf. Machine shop for almost 50 years, so perhaps I have seen a few things that others haven't.
TIMINATOR
TIMINATOR
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- Joined
- Jan 26, 2020
Contemplate this!!!
The stops adjust the start point, and end point, the spring adjusts the rate of cam retard.
The range is TWENTY SIX DEGREES!
These units appeared in the late 1960s!
It allows the cam to be advanced for more low end torque, then as the RPMs climb it retards the cam timing for more top end power!
Problems:
Adjustment stops and spring rate stops loosened with use. No Loctite at that time!
As the cam retarded for top end power, the timing retarded too! That killed the cams power gains! No crank triggers then either!
The units sold for about $40.00.
Some new flat tappet cams sold for less!
Great idea!
Ahead of its time!
Lousy/ incomplete instructions!
They were only made for small block Chevies.
Some of us figured out how to make them work, we kept quiet. They went out of business anyway....
I haven't figured out how to make one for my Turbo Coupe. Yet....
But I will prolly whip one up for one of my BBC street projects only for use with a double roller chain and crank trigger ignition or Thunderbolt IV box.
TIMINATOR
The stops adjust the start point, and end point, the spring adjusts the rate of cam retard.
The range is TWENTY SIX DEGREES!
These units appeared in the late 1960s!
It allows the cam to be advanced for more low end torque, then as the RPMs climb it retards the cam timing for more top end power!
Problems:
Adjustment stops and spring rate stops loosened with use. No Loctite at that time!
As the cam retarded for top end power, the timing retarded too! That killed the cams power gains! No crank triggers then either!
The units sold for about $40.00.
Some new flat tappet cams sold for less!
Great idea!
Ahead of its time!
Lousy/ incomplete instructions!
They were only made for small block Chevies.
Some of us figured out how to make them work, we kept quiet. They went out of business anyway....
I haven't figured out how to make one for my Turbo Coupe. Yet....
But I will prolly whip one up for one of my BBC street projects only for use with a double roller chain and crank trigger ignition or Thunderbolt IV box.
TIMINATOR
