Measuring Piston to Valve Clearance on my SBF
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- Опубліковано 3 лис 2023
- In this video, I demonstrate the two primary methods for checking piston to valve clearance - clay impression and modelling clay. The flat tappet cam that I had been running previously had similar maximum lift to the hydraulic roller cam currently installed, but the old pistons had much smaller valve reliefs than the Mahle pistons and there was no clearance issue with that arrangement, so I wasn't surprised that there isn't a clearance problem with this arrangement.
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Thank you for this video. First time engine builder and just ordered my heads for a 347 Stroker. Trying to learn all the checks and balances so I don't blow up my engine. This really helps explain.
Awesome, I'm glad to help. Thanks for watching, and good luck on your build!
Thank you for sharing your knowledge with us bill
My pleasure, thanks for watching!
Where did you get the bolts with safety wire holes for the lifter spider?
I get most of my specialty fasteners (including those) from McMaster-Carr. Thanks for watching!
Great video a lot of people should be thanking this guy he’s a great teacher explaining this process
Thank you so much!
The reason is no measurement with clay method is because you need to do it with a solid roller lifter or take apart your hydraulic lifter and add washers in it to make it solid
No need to do that when using checking springs - they're designed specifically for this, and aren't strong enough to collapse the lifters. The reason for no contact with the clay was that the actual clearance (as measured with the dial indicator) was more than the thickness of the clay.
Hope that you used solid lifters for the clay measurement
Not necessary when using checking springs, they can't cause a lifter to collapse.
Thats a good free education .. let me tell you how i do it … i bolt the head on finger tight with no clay on the pistons .. when i put my rocker arm on i put a hundred thousands thickness of a feeler gauge between the rocker tip and the tip of the valve .. .. then ill turn the oil pump to pump oil thru the lifters so they don’t begin to collapse once thats done i rotate the motor and if nothing hits then i remove the feeler gauge and simply just pit the rest of my head bolts or nuts on and torque it down and im finished .
I haven't heard of that technique before, but it sounds reasonable if you're not interested in the specific measurements but just want to know whether you've got a minimum amount of clearance. Thanks for your comments!
@@billsgarage i may have came up with it myself .. i never heard of it before til i thought it up .. im only interested in knowing i got enough room and thats it so it works for me .. its also good for installing a bigger cam in a already assembled motor while doing upgrades to add horsepower …
My idea is to give the ppl different options on how to do something .. btw thanks for showing how to check ptv clearence with the guage i had forgot all about that technique
So does that mean you could run a bigger ratio rocker atm 🤔
Great question. Physically, I could probably run a larger rocker ratio (say 1.72 instead of the stock 1.6) without worrying about the valves hitting the pistons. However, often this type of change will result in lower horsepower unless you also change the camshaft because the rocker ratio is just one part of the valvetrain geometry and needs to be matched to the cam profile in order to make the best power. My cam is a hyd roller designed to work with 1.6 rockers, and changing to 1.72 would give more lift, but would not add duration. This could be problematic for gasses flowing into and out of the cylinder considering roller cams already have a steep ramp. It would be less of a problem for a flat tappet cam, but still would be a crap shoot on whether it would make more or less power. Given the amount of clearance in my engine, I could safely run a cam ground for more lift and stick with my 1.6 rockers, or use a cam ground for use with 1.72 rockers, and may do so in the future, but I'm content for now.
@@billsgarage good points. Didn't think about that 🤔
Dial indicator, weak springs, measure clearance starting at 30°before, and every5°till 30°after btdc, zero indicator every time ,record you numbers.
Thanks for your comment. Your method is definitely more thorough than mine, but you can never measure too many times as far as I'm concerned.