Build progress and pushrod question

[Adam76]

  Hey guys,  I'm installing the pushrods and have a question about TDCC - I seem to be having a little trouble with whether I'm on the compression cycle or not with my TDC...

Rotating the rear wheel until I feel the puff of air out of the spark plug hole tells me the front piston is/ has risen to the top of the cylinder, but that happens twice for one full cycle, right?
I'm getting the puff of air each time the piston rises, so how do I know which compression cycle to stop at to make the pushrod adjustments for that (front) cylinder?

In other words, theoretically where would the rear piston be sitting in the rear cylinder when the front cylinder is at TDCC stroke? Closer to the top of the cylinder or further down the hole?

Also, if the front cyl lifters look like they're sitting on the base circle of the cam,  and the rear ones are not, then is that TDCC for the front?

Thanks for any help, I hope that made sense 

[capn]

Watch your intake lifter.When it goes up your piston is dropping on intake stroke.Next the lifter will go down.When it is down your piston is rising on the compression stroke.Dont turn it too far but if you do you have to go around again.Dont turn the crank backwards.

[turboprop]

  Hey guys,  I'm installing the pushrods and have a question about TDCC - I seem to be having a little trouble with whether I'm on the compression cycle or not with my TDC...

Doesn't make a difference as long as the lifter is on the base of the cam when the pushrod is being adjusted.

[kd]

The fail proof way is when one valve is open on each cylinder (pushrod in the up position) the other will be on the base circle and can be adjusted.  For example the rear exhaust in your pic is ready to be adjusted.  Just pay attention or make a note or score card of which ones are adjusted as you go so as to not miss any or don't install the pushrod until it looks like the rear exhaust comparison I point out.  With solids it was always a quick and easy way to do it but with hydraulic you still have to wait for bleed down before rotating the engine to the next candidate.

[Pete_Vit]

  Hey guys,  I'm installing the pushrods and have a question about TDCC - I seem to be having a little trouble with whether I'm on the compression cycle or not with my TDC...

Rotating the rear wheel until I feel the puff of air out of the spark plug hole tells me the front piston is/ has risen to the top of the cylinder, but that happens twice for one full cycle, right?
I'm getting the puff of air each time the piston rises, so how do I know which compression cycle to stop at to make the pushrod adjustments for that (front) cylinder?

In other words, theoretically where would the rear piston be sitting in the rear cylinder when the front cylinder is at TDCC stroke? Closer to the top of the cylinder or further down the hole?

Also, if the front cyl lifters look like they're sitting on the base circle of the cam,  and the rear ones are not, then is that TDCC for the front?

Thanks for any help, I hope that made sense 

The fail proof way is when one valve is open on each cylinder (pushrod in the up position) the other will be on the base circle and can be adjusted.  For example the rear exhaust in your pic is ready to be adjusted.  Just pay attention or make a note or score card of which ones are adjusted as you go so as to not miss any or don't install the pushrod until it looks like the rear exhaust comparison I point out.  with solids it was always a quick and easy way to do it but with hydraulic you still have to wait for bleed down before rotating the engine to the next candidate.

that's what I did, well the Old Crow did when fixing what a Indy messed up and so far 

[Hossamania]

I rotate it until both lifters for one cylinder are at the bottom

[Burnout]

On one cylinder when the exhaust just starts to open, set the intake, and when the intake just closes, set the exhaust.

[Ohio HD]

My three cents worth....


https://www.sscycle.com/tech-info/pushrod-adjustment

[kd]

My three cents worth....


https://www.sscycle.com/tech-info/pushrod-adjustment

Those are good instructions.  One caution that I think needs to be stated is in step 3 (and step 4 & 5 for limiters) turning the pushrod before the jam nut is locked must be done with care.  The internal resistance makes it possible for the adjuster screw to back off or load tighter.  I like to lightly snug the jam nut first to prevent that from happening.

As a side comment, when using limiters being set to one flat of bottom, even more care is suggested. Be sure the engine is cold to the core so the cylinder head and barrel stack height is not expanded from heat. Remember that when the jamb nut is tightened, it pulls the internal threads "outward" effectively making the pushrod slightly longer.  For that reason I choose up to almost 2 flats. That way with a cold engine (non expanded cylinders) the valve won't be held off it's seat. This condition can effect starting compression.

[Adam76]

I rotate it until both lifters for one cylinder are at the bottom

Thanks Hoss, this is where I'm at with the front cylinder,  both lifters sitting on the case circle of the cam.  So I'll adjust these and then move onto the rear.
I guess I'm over thinking it. 

[Adam76]

  Hey guys,  I'm installing the pushrods and have a question about TDCC - I seem to be having a little trouble with whether I'm on the compression cycle or not with my TDC...

Doesn't make a difference as long as the lifter is on the base of the cam when the pushrod is being adjusted.

Thanks turbo. This is what I thought. I guess I was over thinking the whole process. 😁

[Adam76]

My three cents worth....


https://www.sscycle.com/tech-info/pushrod-adjustment

Thanks Ohio, I'll go through this again carefully.
Cheers. 👍

[Adam76]

On one cylinder when the exhaust just starts to open, set the intake, and when the intake just closes, set the exhaust.

Thanks burnout, that method sounds good, but without being able to actually see the valves and whether they are opening or closing I don't trust myself with this method. Unless there is a trick I'm missing. My intake manifold has already been re- installed so it blocks the ability to see into the heads.

[turboprop]

You are making this harder than it needs to be. With the pushrod tubes raised, simply rotate the engine until the pushrod you want to adjust starts to go up. Then rotate the engine in the reverse direction until that pushrods starts to go up. Now rotate the engine in the opposite direction and stop about half way between the two points. This does not have to be exact. Just make sure the lifter is on the base of the cam. Lots of room here. Adjust that pushrod and then do another until all four are done. You could have adjusted a pushrod in the amount of time it took to type this response.

[Adam76]

You are making this harder than it needs to be. With the pushrod tubes raised, simply rotate the engine until the pushrod you want to adjust starts to go up. Then rotate the engine in the reverse direction until that pushrods starts to go up. Now rotate the engine in the opposite direction and stop about half way between the two points. This does not have to be exact. Just make sure the lifter is on the base of the cam. Lots of room here. Adjust that pushrod and then do another until all four are done. You could have adjusted a pushrod in the amount of time it took to type this response.

Rodger that.  😁

[Adam76]

Thanks guys, all adjusted and buttoned up. 

Do you guys recommend the slight drilling of the rocker box oil drain hole - drilling it one size drill bit up from the stock size,  for higher than stock compression builds?  It's mentioned in the 101 performance projects book.... Thought I'd ask before I finish installing the rocker boxes.
Cheers. 

[kd]

Drilling that hole out (.125") requires the rocker stands to be removed.  Re-drilling (and chamfering the top of the new hole) is definitely a recommended practice and now is your chance to get it done. Speaking of practice, it looks like you'll be getting some reinstalling and adjusting pushrods. 

[FSG]

did you drill out the top of those upper PR tubes?

did you fit any rocker lockers?

[Adam76]

Drilling that hole out (.125") requires the rocker stands to be removed.  Re-drilling (and chamfering the top of the new hole) is definitely a recommended practice and now is your chance to get it done. Speaking of practice, it looks like you'll be getting some reinstalling and adjusting pushrods. 

Thanks kd, book didn't mention anything about removing the rocker stands, I just have only the lower rocker box installed as per picture with the middle d- rings and top cover still on the bench.
Yes, I have had plenty of practice on adjusting PRs now 😁

[Adam76]

did you drill out the top of those upper PR tubes?

did you fit any rocker lockers?

Hey FSG, no I haven't drilled out the top of the PRs, and no I haven't got rocker lockers.
Are these a must do?
Thanks.

[FSG]

No NOT a must do BUT I'd sure bee opening up the tops of the RP Tubes, just so easy to do

[Adam76]

No NOT a must do BUT I'd sure bee opening up the tops of the RP Tubes, just so easy to do

Ok, thanks. 👍

[kd]

Drilling that hole out (.125") requires the rocker stands to be removed.  Re-drilling (and chamfering the top of the new hole) is definitely a recommended practice and now is your chance to get it done. Speaking of practice, it looks like you'll be getting some reinstalling and adjusting pushrods. 

Thanks kd, book didn't mention anything about removing the rocker stands, I just have only the lower rocker box installed as per picture with the middle d- rings and top cover still on the bench.
Yes, I have had plenty of practice on adjusting PRs now 😁

Even if you can drill them in place the risk of aluminum chips disappearing into the engine would be more than I would like.  When you remove them you can check the fasteners for marks from the type of rocker shaft contact that lockers are made to prevent.  No marks = no problemo.    When you reinstall them (with the pushrods in place) you can position them to best center the pushrods in the pushrod tubes and on the valve stem tips. 

[Adam76]

Drilling that hole out (.125") requires the rocker stands to be removed.  Re-drilling (and chamfering the top of the new hole) is definitely a recommended practice and now is your chance to get it done. Speaking of practice, it looks like you'll be getting some reinstalling and adjusting pushrods. 

Thanks kd, book didn't mention anything about removing the rocker stands, I just have only the lower rocker box installed as per picture with the middle d- rings and top cover still on the bench.
Yes, I have had plenty of practice on adjusting PRs now 😁

Even if you can drill them in place the risk of aluminum chips disappearing into the engine would be more than I would like.  When you remove them you can check the fasteners for marks from the type of rocker shaft contact that lockers are made to prevent.  No marks = no problemo.    When you reinstall them (with the pushrods in place) you can position them to best center the pushrods in the pushrod tubes and on the valve stem tips.

Thanks, the rocker arms and fasteners had no marks on them that I could see when I had removed them and reinstalled them. Even checking rocker am clearances - they were right on the perfect end of the tolerance listed in the FSM...
I think I'll give that whole thing oil breather modification a miss at this stage and just reinstall the middle and top rocker covers.  I'm pretty keen to get the top end all back together, the carb back on and get this motor running. So close now

[Adam76]

No NOT a must do BUT I'd sure bee opening up the tops of the RP Tubes, just so easy to do

I haven't done it,  but if you were to do it - what's the correct method?  How do you not get metal shavings down inside the top of the PR as you are enlarging the hole?