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It is fun to learn of the wide range of backgrounds of everyone! Specifically, I wanted to say 'hi' to a fellow scientist!
Obviously a common theme here is that many of us enjoy figuring things out and understanding how things work. A good friend from grad school worked as an auto mechanic out of HS for many years before going to college and eventually getting his PhD in physics where I met him.
My favorite advice he gave me when I was having a problem with a car repair was "just hit it harder." LOL
Well, hi back to you!! I thought it was "Just hit it with a BFH"!!
I'm not so much of a true Scientist as I am a Chromatographer. Analytical Chemistry is only applied science. Business people in the offices up front think we are only technical help and they are the professionals (put the sample into the box and turn the crank - out pops the answer - anyone can easily do it - kind of like using a scanner for OBD2) - but as Quality Control we can stop production of anything in a heartbeat and we are more educated/make more money than most of them. Only time we get noticed is when we do something they don't like!
Maybe you can see why I chose to put "Professional Redneck" in my signature. I also drag race, shoot guns competitively, and have a vegetable garden/fruit trees as hobbies - and I am known to curse up a storm when working on cars!
Well Marc, see what you started!!! We can stop if you like! I realize it's your build thread! But wait - I guess I'm the one that asked about you first!!! I'm so bad!!
I'm definitively not going to stop this - way too much fun!
I think it does not really matter where you end up. Looks like all of us are doing something they like and put all their effort, knowledge and skills into. Add a little passion for what you do and you will probably succeed in any field life throws you into.
Les, I enjoy a little sideline from time to time. And I'm definitively looking forward to your drag racing build and the videos as well.
Christine, I like your definitions of nerd and geek, not being an English language native sometimes I have just a feel about a word and how it is defined. So, that means I also qualify as nerd and geek.
Billy1820
Should be this CompCams camshaft: Magnum 206/206 Hydraulic Roller Cam for Chevrolet 262/4.3L V6
When I bought it it was advertised as "works with stock computer".
Billy1820
Should be this CompCams camshaft: Magnum 206/206 Hydraulic Roller Cam for Chevrolet 262/4.3L V6
When I bought it it was advertised as "works with stock computer".
That looks like a decent cam. I went with a factory 92-95 CPI cam, it’s 208/208 dur@.050 with .432/.440 lift with stock 1.5 rockers on a 118lsa. It’s the hottest factory cam GM made for our engines, and a good selling point is less overlap. Duration is higher than the comp cam, and more lift can easily be attained with 1.6 rockers.
For my build, I wanted to keep things as stock as possible since it was a low mileage truck and I didn’t feel the need to pull the heads. I kept the stock net lash valvetrain but upgraded to LS2 beehive springs. IMO tuning is a must for any cam change and I did mine with HP Tuners.
That's the plan. At this time the stock EPROM has been removed from the ECU and the next time a friend is back in town we'll read the EPROM and see what we can do.
A bit of tinkering with EPROM socket should give us the ability to work through an emulator and with the laptop connected tune it directly.
With the engine swap I plan to fix some rust on the firewall, the cab supports and fit the Megasquirt ECU and cabling in addition to the stock ECU. This will keep things stock and running including the digital dash but give me all the data logging needed for a good tune.
Good luck with the tuning, I’m glad to hear you’ve got a plan.
My 2001 was a little easier, since it has the 411 PCM which is supported by HP Tuners. I’ll admit it was definitely a learning curve to do it right, but I invested in a tuning school course and took my time after doing weeks of research. In the end, the results were great and I became very confident in all aspects of tuning Gen III GMs.
IMO though, the one key factor in tuning to eliminate any guessing is installing a wideband and making all changes as per AFR.
I plan to use the Megasquirt for data logging. As it is "fully" programmable it can also serve as a data logger.
In the meantime I can develop the intake and by the time that is ready I have the VE of the engine figured out and a good basic tune for sequential fuel.
Waaaaay in the future. First getting that other project car on the road.
Head work. Finally got a couple of hours into the "missing link", the pushrods. Block with one head placed with spacers (feeler gauge). The rocker screw-in studs needed quite a bit of chamfering as the radius below the shoulder of the stud into the 3/8" thread is very pronounced. Should have gotten the angle of the bosses when it was on the mill, then used a cylindric milling bit to cut down along the thread. Should be ok. for this low power, low rpm application. Machinists dye to get the geometry right and finally get the pushrod length. The pushrods used are checking rods. After dinner going to re-assemble a second time and get all the same measurements again just to make sure.
Perfect witness marks. Starting inboard of the valve tip center and running the same amount to the outboard side. Minimum side loading of the valves.
The lift is a near exact 12.5mm which is 0.500". So the hydraulic lifters spring is much stiffer than the check springs I use to mark out the valvetrain.
I wish we had such things in high-school. Well, we had woodworking classes and blueprint drawing and such, which have served me well over the years.
Just having dinner, afterwards back to the shop. Turns out 7.250" pushrods are what I need. I measured 183 mm, add 1 mm for the hydraulic lifters and 184 mm / 25.4 = 7.244" (close enough).
The next step is addressing that bugger of a problem with the timing gear. As these engines have a balance shaft you need a specific timing gear. Unfortunately CompCams does not make them with an adjustable sprocket. When I had the head and valves on last week we found out that the cam is too far ahead by 6°.
That means boring the cam pin hole over. cutting out the bolt holes on a radius and inserting an excentric fitting to get it to the proper timing.
As usual with these R&D problems, you solve one - you get another one!
On the plus side - my Alfa Romeo comes along nicely due to COVID. As work is down by a fair bit I get more days to put into that project.
At 6 degrees off I suspect you are making an error in the measurement.
Usually the best method is to set the dial indicator right on the edge of an intake lifter with the head and lifter retainer off. Assume you are using a real degree wheel zeroed with a piston stop and a dial indicator.
LSA on this camshaft is 110 degrees. Camshaft has 4 degrees advance ground into it. So install on a 106 degree intake centerline by finding exact center of lobe. This is exactly halfway between 0.050 movement shown by turning engine from one side of the lobe to the other. Rotation should be normal engine rotation when running and you should turn the engine over with the flywheel (not disturbing the degree wheel or crank snout bolt). This is called the "Intake Centerline Method" for degreeing a camshaft.
Here is how I set things up to measure cam timing. I did have one piston in at the time with no rings to find TDC. Jegs provides a plate with a piston stop that bolts onto the head surface across the bore (not visible). Hope this helps.
When I did mine, I used a Mellings timing set with a Mellings tensioner P/N 3-8MMSRH72SB but not sure it will work on your block (1994 with a roller cam and balance shaft). I do know you have to use a specific plastic timing cover with the tensioner. In any case, a new stock replacement camshaft installed dead nuts on target.
10-01-2020, 12:51 PM
