Possible to bend a valve if rockers are real loose??

OX1 · Jul 3, 2008

ARGHH, never had this kind of a problem slapping a motor back together. Most of the rockers were very loose. (before I knew that, tried running it and it sounded worse than any other motor I have ever heard (massive backfiring out intake and loud metal to metal sounds). I only ran it for maybe 3 minutes, trying to mess with timing.

I guess it's possible I forgot to tighten all of them (too worried about making those bling bling tall valve covers fit%)), but several were tight???

Viperwolf1 · Jul 3, 2008

I don't think too loose will bend valves, could damage rocker arms though. Did you go through the adjustment process and adjust one at a time while on the base circle?

oleguy74 · Jul 3, 2008

if they were real loose better check push-rods.

OX1 · Jul 3, 2008

Viperwolf1 said:
I don't think too loose will bend valves, could damage rocker arms though. Did you go through the adjustment process and adjust one at a time while on the base circle?

Adjustment??, I thought ford's stock rockers just get cranked down and that was it?? Only thing I've adjusted on all my M-blocks (I understand, this is not an M-block) was lifter preload with small shims. Otherwsie, they get cranked down until tight.

OX1 · Jul 3, 2008

oleguy74 said:
if they were real loose better check push-rods.

Yes, ordered another set, should be here tomorrow. 1 was bent and others had malled ends.......

bax · Jul 3, 2008

Do you have bent valves or just wondering if you could have bent valves? A pushrod that comes out of the seat on a rocker can ruin a rocker and /or a pushrod. I have also seen a pushrod come out of a lifter and sit on the edge/ body of the lifter. This caused the spring to bind bending the pushrod and pulling the press in rocker stud in the head about 1/4'' out. Do you see any other visible damage. Check the Keepers on the valve retailers. A rocker that is loose can come off the stem of the valve and push on the side of the retainer. This can unseat the keepers and cause a real problem.

Viperwolf1 · Jul 3, 2008

OX1 said:
Adjustment??, I thought ford's stock rockers just get cranked down and that was it?? Only thing I've adjusted on all my M-blocks (I understand, this is not an M-block) was lifter preload with small shims. Otherwsie, they get cranked down until tight.

You're right. I was thinking of older motors.

OX1 · Jul 4, 2008

bax said:
Do you have bent valves or just wondering if you could have bent valves? A pushrod that comes out of the seat on a rocker can ruin a rocker and /or a pushrod. I have also seen a pushrod come out of a lifter and sit on the edge/ body of the lifter. This caused the spring to bind bending the pushrod and pulling the press in rocker stud in the head about 1/4'' out. Do you see any other visible damage. Check the Keepers on the valve retailers. A rocker that is loose can come off the stem of the valve and push on the side of the retainer. This can unseat the keepers and cause a real problem.

I don't know. I don't believe it had bent valves before I took it apart. It ran great, except an intermittent exh backfire (only when engine was warm), but that was due (was 99% sure) from this timing chain that was SHOT!!

http://luxjo.supermotors.net/70 EB SPORT/ENGINE/TIMING CHAIN/DCP03804.JPG

After running engine for about 3 minutes messing with timing, but before I realized rockers were loose, I videod this.

http://luxjo.supermotors.net/70 EB SPORT/ENGINE/REGASKET_ PAINT/MOV01976.MPG

I've never tried to crank (or run) and engine with the rockers loose as heck. They could not have been that loose as the engine did finally start and run (like total crap of course). Worse case is it's like a really wiped cam, right.
The popping had me concerned that an intake valve is bent somehow. When I had the motor apart, I redid valve seals and inspected every single valve, nothing unusual on a motor from 1970 (dirty, deposits, etc...). I did clean off all the deposits from the face of the valves and comb chambers (get rid of possible "hot spots").

This is what the passenger side looked like before/after I removed rockers/pushrods.

http://luxjo.supermotors.net/70 EB SPORT/ENGINE/REGASKET_ PAINT/MOV01977.MPG

None the the pushrods came out and retainers seem fine (on the one rocker that moved itself off it's valve). The drivers side was mostly tight, cept a couple on the exh side?

bax · Jul 4, 2008

Bring it up to TDC on #1 and check your timing mark. I am wondering if you got the chain lined back up properly. That labored cranking and popping back makes me think your valve timing is not correct. If the cam was wiped it still would not pop back thru the intake. The pushrod problem is due to the loose rockers. Check for damage to the rocker and pushrod and you should be good there.
Thats what I am thinking anyway.

Good luck
Bax

OX1 · Jul 4, 2008

bax said:
Bring it up to TDC on #1 and check your timing mark. I am wondering if you got the chain lined back up properly. That labored cranking and popping back makes me think your valve timing is not correct. If the cam was wiped it still would not pop back thru the intake. The pushrod problem is due to the loose rockers. Check for damage to the rocker and pushrod and you should be good there.
Thats what I am thinking anyway.

Good luck
Bax

The timing mark and TDC on #1 won't tell me much (cept balancer is on right

).

I don't think cam is wiped, was just saying that real loose rockers could emulate a cam being wiped. I've had wiped cams and it still did not make it pop through intake, hence I don't think popping was due to the loose rockers unless I bent a valve. The only other reason I could think of the popping was maybe the exh stroke built up compression since exh valve was not opening (totally loose rocker) and then if intake valve opened it would just release the pressure??

I'm going to stuff in new pushrods and move each cyl to TDC, making sure both valves are completely closed at each cyl. If that looks good, I'll try cranking again with all the rockers tight (ign disconneted and carb off intake again). If it still pops, then yes I agree, I probably put the new chain in wrong

.

I know a 302 is not an interference motor (I believe), but I always wondered if cam timing was totally off (and I mean totally off), would valves hit pistons?? If it can never happen, there would be no reason to ever "clay" P/V clearance.

bax · Jul 4, 2008

OX1 said:

The timing mark and TDC on #1 won't tell me much (cept balancer is on right ).

Click to expand...

OX1 said:
I don't think cam is wiped, was just saying that real loose rockers could emulate a cam being wiped. I've had wiped cams and it still did not make it pop through intake, hence I don't think popping was due to the loose rockers unless I bent a valve. The only other reason I could think of the popping was maybe the exh stroke built up compression since exh valve was not opening (totally loose rocker) and then if intake valve opened it would just release the pressure??

I'm going to stuff in new pushrods and move each cyl to TDC, making sure both valves are completely closed at each cyl. If that looks good, I'll try cranking again with all the rockers tight (ign disconneted and carb off intake again). If it still pops, then yes I agree, I probably put the new chain in wrong .

I know a 302 is not an interference motor (I believe), but I always wondered if cam timing was totally off (and I mean totally off), would valves hit pistons?? If it can never happen, there would be no reason to ever "clay" P/V clearance.

Yeah I should of elaborated more on that. You already had the valve covers off and I just assumed you would check the valve timing in relation to the piston. Loose rockers have nothing to do with that popping.

Sure you can bend valves if the cam timing is way off. The pistons make a good hammer. When you miss with a chain you usually only miss by a tooth and in these motors that should not bend valves. yes you can get a motor to run if the cam is off one tooth. I have seen it done%)

OX1 · Jul 4, 2008

bax said:
Yeah I should of elaborated more on that. You already had the valve covers off and I just assumed you would check the valve timing in relation to the piston. Loose rockers have nothing to do with that popping.

Sure you can bend valves if the cam timing is way off. The pistons make a good hammer. When you miss with a chain you usually only miss by a tooth and in these motors that should not bend valves. yes you can get a motor to run if the cam is off one tooth. I have seen it done%)

It's back together. Cam timing seems perfect. #1 TDC is dead on with both valves closed, right after intake valve closes. Each TDC follows the previous according to the firing order.

Each cyl builds compression right after the intake closes. All valves seem the same height (@ their respective TDC). Each pushrod has about the same minor "looseness" at it's respective TDC and rockers have about the same loosness that I'm used to. All the valves seem to open close the same amount and at the right time.

I cranked it with no carb on and ign off, no popping and it sounds much more like what I'm used to of an engine that just isn't starting. I'm afraid to fire it up............, so I decided to take a break and eat some cookies........

bax · Jul 4, 2008

Your good. finish the cookies and go bolt that carb on. I bet it runs.

OX1 · Jul 4, 2008

bax said:
Your good. finish the cookies and go bolt that carb on. I bet it runs.

Yup......... ;D

http://luxjo.supermotors.net/70 EB SPORT/ENGINE/REGASKET_ PAINT/MOV01978.MPG

bax · Jul 4, 2008

You the man!

Possible to bend a valve if rockers are real loose??

OX1

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