Re-Rebuilding the 440-493 in a 1970 Charger

[Geoff 2]

Kern,
Two comments:-
-I always get a chuckle when I see people going to the nth degree [ pardon the pun ] to degree their cam. "So #1 is exactly at 4* adv where I want it". What about the other 7 cyls [ if it is a 8 cyl ]??
- if you are pretty sure you have plenty of V to P clearance, but just want to check to make sure, you can do this. Assemble the heads & bolt in place with head gasket, but bolts not torqued, just nipped up. Pick which valve, I or E, you want to check. Use a solid lifter or a bottomed out hyd lifter & take up the lash. Rotate the crank until you are at overlap, TDC. Valve will be open slightly. Next step is easier if you have a helper. Measure from the spring pad to the retainer. Using a pair of multi-grips or similar, lever on the prod side of the rocker to push the valve into the piston; while holding in this position, measure spring pad to retainer again. The difference between the two measurements is the V to P clearance. If you have 0.150" or more, job done, head bolts can be torqued. If less, then the procedure should be repeated @ 10* BTDC for the exh valve & 10* ATDC for the intake. This is because with some fast acting cams, combined with some rod/stroke ratios, the valves are closer to the piston than at TDC. Good luck.

 

[Wietse]

-I always get a chuckle when I see people going to the nth degree [ pardon the pun ] to degree their cam. "So #1 is exactly at 4* adv where I want it". What about the other 7 cyls [ if it is a 8 cyl ]??

If you check 1 cylinder and find it within the safety margin you are done, the others will be similar.
Whats your suggestion? Twist the cam to adjust?

And as per what you wrote, you expect the V-P clearance to be tightest at TDC?
If you want to know the closest V-P clearance you can find that position and exactly how much as i described before, having a certain clearance at TDC doesn't mean anything.

 

[Geoff 2]

Wietse, you should read what I said more carefully.

[1] Maybe you missed my point about cam degreeing. Anything man-made can be faulty.....including cams. 99% of people just check #1 cyl & some sweat if the ICL comes in 2* out from what the card says [ which is only a suggestion, because no way of knowing without testing what ICL is best for a particular combo ]. So they get #1 correct, but the others could all be 'out'. Without checking them, you would not know. What I am saying/said: one cyl is correct, the others are assumed to be correct. If all cyls were checked & there is a difference, there are two choices: split the difference or get a new cam.
[2] V to P clearance. If you have 0.150" clearance at TDC, you have more than enough clearance & IF the the clearance tightens before/after TDC it is by just a few thousandths & can be accommodated within the 0.150". The most common V to P recommended clearance is 0.120 exh 0.100 int; I have seen tighter, 080.060. So with 150 @ TDC there is no need to check further, you have enough clearance.

 

[RemCharger]

I used light springs and adjust the crank by 10 deg increments. With a dial gauge on the spring retainer (set properly in-line with the valve stem) you can push down till the valve contacts the piston. The range you find it closest you can redo per degree of crank rotation and by the same procedure you will find the exact position where the valve to piston clearance is closest and by how much.

If you check 1 cylinder and find it within the safety margin you are done, the others will be similar.
Whats your suggestion? Twist the cam to adjust?

And as per what you wrote, you expect the V-P clearance to be tightest at TDC?
If you want to know the closest V-P clearance you can find that position and exactly how much as i described before, having a certain clearance at TDC doesn't mean anything.

Well stated Wietse.

 

[Kern Dog]

In 2014 when I ran this Lunati cam before, I used the checking springs and just pushed down on the valve at TDC, There was close to 1/4" of movement before the valve hit the piston. That is .250". This was with different pistons...

I'll check but I strongly suspect that I have equal to or greater clearance now.

 

[Wietse]

one cyl is correct, the others are assumed to be correct.

With a CNC machined camshaft i would not worry now days, if you find the .120" on cyl #1 it would be bad news for the manufacturer to find any other cylinder has, say .060".
The point is since you are using a camshaft, crankshaft and timing set from various manufacturers as a combined set where 1 wrong part can cause disaster.
That is the part to confirm, if you building something exotic which requires clearance that makes you piss your pants i would check all, yes.
And making sure your cam is set on the advance intended by manufacturer or any other number you are aiming for.

 

[Kern Dog]

The timing set did come in on Friday but I didn't have the time to do anything. I had a busy weekend too.
Oddly, the box only had a tech sheet for small block and big block Chevy and small block Ford. Nothing for BB Chrysler.
I set the #1 piston to TDC and aimed the crank sprocket to the 4 degree advance setting...

This put the "A4" mark at the 12:00 position.
The cam sprocket was put at the 12:00 spot as well. This should put the cam at the #1 firing position.

I will degree the cam to be sure.

I swapped the lightweight checking springs on cylinder #1.

Then set the head gasket on and placed the LH head on the block with the bolts ran down but not tight.

There is a BUNCH of piston to valve clearance at TDC as well as 10 degrees before and after TDC. The deep dish really helped.

 

[RemCharger]

There is a BUNCH of piston to valve clearance at TDC as well as 10 degrees before and after TDC. The deep dish really helped.





View attachment 1348868

I'm sure you know, you have to finish putting everything together in as run, condition and check. Head torqued, rockers lashed etc

 

[RemCharger]

I took a pic of this and realized... my checking spring might be fudging my numbers lol. Lost my good ones.

 

[Kern Dog]

The Fel Pro gasket is .039 compressed but with the head just resting on the block, it can't be that much thicker.
I don't see how having rocker arms and pushrods in place are going to eat up the 3/8"-1/2" clearance that I have now. If I am missing something, I'd need to have it explained where I am not seeing the issue.
I sure don't know everything. When I installed this cam in this engine with the flat top pistons, (Calculated to 10.98 to 1) I had over 1/4" of free movement of the valve when I was compressing the checking springs. I later switched to thicker head gaskets and had even more. These pistons are like zero deck flat tops on the quench side and dished on the valve side. My last combination was approximately 10.1 to 1 using .075 Cometic head gaskets and the pistons .012 in the hole.

 

[Kern Dog]

I took a pic of this and realized... my checking spring might be fudging my numbers lol. Lost my good ones.View attachment 1348881

That looks a bit more than mine compressed but not by much. That sure seems well within the safety margin.
Yours looks like the coils are stacked, You might have more clearance that you think.

 

[RemCharger]

The pic I showed is how far down the exh is at min clearance, ( this is a roller, different) and its close for comfort,.075 thou.
Your results will vary, as your mileage. Tread carefully, don't hurry now.

 

[Geoff 2]

Is post #469 meant to be showing both valves open at or near TDC on overlap. If so, there is much to worry about.......

 

[Wietse]

Is that timing kit from Howards?

 

[Kern Dog]

Yes, it is a Howards timing set. The last set I used was also a Howards but a 3 bolt style. It was still tight after thousands of miles as compared to the Edelbrock sets I've used before.
This isn't an exact depiction....


It was hard to hold the phone for the picture, take the picture and push the valve.

 

[PRHeads]

I'm sure you know, you have to finish putting everything together in as run, condition and check. Head torqued, rockers lashed etc

Correct.
V/P clearance is checked with the valvetrain assembled and lash set, on the overlap period....... not the firing stroke.

What’s being depicted in the post above is total available valve drop......... which would remain unchanged regardless on which cam is being used, or where it’s installed.

 

[Kern Dog]

Correct.
V/P clearance is checked with the valvetrain assembled and lash set, on the overlap period....... not the firing stroke.

What’s being depicted in the post above is total available valve drop......... which would remain unchanged regardless on which cam is being used, or where it’s installed.

I had a feeling yesterday that I was missing something. I don't do enough high performance stuff to automatically know each step. I understand now that both valves will be partially open before, at and after TDC. It is from there that the "range" of clearance starts.
I've only degreed a cam twice and it was THIS cam when I had it in this engine.
I emailed Howards regarding the lack of a tech sheet for the timing set. They have not responded.

 

[Ray70Chrg]

Kern, You are using a lunati cam that you used previously and now advancing it 4* as you did earlier. I'm assuming that the cam did not come with any advance built into it. I'm asking only for my own information because my lunati cam came with 4* built in and I also had to check for a 106* centerline and have considered if I would be able to advance another 4* without any problem. Just wondering if your cam has any advance built in or not. Thanks

 

[Kern Dog]

Yes it does.

 

[cdr]

Thats a bigger cam duration wise minus the amount loss for lash than I run in my junker , pretty big for a street car, I forget what cylinder heads you are running ?