jimh_1962

I really screwed up! During the initial startup the pistons hit the top of all of the exhaust valves. It kept bending push rods when it was cranking. Today, I took off the heads and saw the marks on the pistons. I think the pistons are fine since the marks are not that deep. The machine shop told me chances are the timing is off on the timing chain.

The intake valves look fine. Luckily the engine was not running at all. Now, I have to shore up the engine and start taking off motor mount, water pump, fan, fan shroud and whatever else so I can see the timing marks. I will make sure not to mess with it until I know it is the timing. The machine shop is taking the heads apart to see if the intake valves are okay.

The cam is the L-79 nostagia cam from comp camp. Same for the hydraulic lifters. Using 461x heads with 1.5 rockers. The push rods were standard length.

Pilot Dan

Who assembled the motor???? It's pretty hard to mess up the alignment of the timing marks. Nevertheless, it's still a bummer, at least the motor was not running. It's not too hard to pull the timing cover and get things squared away and buttoned up. Replace the bent parts on the heads and try again. I don't think you have to worry about the pistons. Pilot Dan

jimh_1962

Like I said "I think screwed up". Yeah, just frustrating is all.

Now, I have to get the rest of the front of the engine off and see what the timing marks look like. What fun!

Kerrmudgeon

It will be easier to yank it out to work on it. And once again, you can save a lot of crying and expense if you turn a new motor over by hand, plugs out on the stand, before lighting the fire.

jimh_1962

I do not want to take the motor out. Logistics make it easier for me this way.

midyearvette

......how do you build a motor without turning it over by hand??......

mikem350

How do you adjust the valves without turning it over?????

Maybe the exhaust valves were set way too tight???

Careful inspection (and reassembly) will shed light

vettefred

Did you measure piston to valve clearance upon assembly? I guess not if you have interference on cranking....Put a piece of clay on top of piston with head on and rotate assy. Then measure depth of valve into clay on top of piston. I don't know your specs on cam lift I assume it is a solid lifter cam. Maybe you have the wrong cam/wrong cam in box....rocker arm ratio?

I had wrong packaging which happen with my Olds. They gave me cam for 67 and earlier 400 and I have a 68. Very different. In your case it is
not as bad as it sounds....just labor. Could have been worse. Hopefully your valves are not bent. Go online and get procedure for indexing cam, check centerline, then check valve lift, then redo.
Here is YouTube link. www.youtube.com/watch?v=5AFyb4CAGxg

Good luck.....you will get it right.

Fred

jimh_1962

Yes, I did check it by putting two solid lifters during pre-assembly about three months ago. The exhaust valves are bent after trying to start it this week for the first time. I will check the indexing and centerline then check the valve lift once more. I know the intake has enough clearance. I will do the putty test once more if the timing marks were correct.

Yes, I did turn the motor by hand using a 5/8s on the harmonic balancer. I had the procedures to check the lash at TDC
Exhaust 1, #, #, #
Intake 1, #, #, #

rotate the motor 180
lash
Exhaust 2, #, #, #
Intake 3, #, #, #

Then rotate the motor once more back to TDC.

Also, at first I was using 1.6 rockers without rollers. That definitely caused a problem when two of them jumped off of the valve. I do have the assembly book and DVD from boxrwrench which shows what to do for the preassembly and assembly.

I bought it as a kit (lifters, cam and timing chain).

http://www.atlanticspeed.com/product...idcategory=133

Valve Setting
RPM
Range
Cam Grind
Number
Duration
Valve Lift @ 1.5:1
Lobe Sep.
Angle
Int.
Ext.
Adv.
@.050"
In.
Ex.
In.
Ex.
In.
Ex.
12-671-4
Hyd
Hyd
1800-6200
N+L79H
276
283
229
236
.468
.462
112

pullin-gs

Something slipped (or stuck?) after you spun it then.

jimh_1962

I think the first thing I need to check is the cam and crankshaft and see if the timing marks are off.

Mossy66

That is a bummer. I have seen someone who carelessly assembled a rocker arm with the pushrod not in the cup in the lifter. But not all of them. I wonder if it's something as simple as that?


Gerry

Mossy66

I would get one of those degree tapes that you put on the balancer, and throw on a head and pushrod. With a dial indicator you should be able to find at what degree the pushrod is at max lift, and compare that to what it should be. Then you know if you have to take the timing cover off.

Just a thought.


Gerry

INMYBLOOD

Truly sorry to hear, but it's still early, you will be out cursing before long. My guess is also timing chain incorrect but then again I don't see how you managed to turn it over?

00fxd

I did that once on a BB. I had an indexed crank sprocket with 3 keyways. I had set the timing mark @ the 0deg instead of the timing dot. The machine shop said that that is pretty common. He had done it himself in his younger years. I can't belive that the push rods bend before the valves...

00fxd

I did that once on a BB. I had an indexed crank sprocket with 3 keyways. I had set the timing mark using the 0deg mark instead of the timing dot. The machine shop said that that is pretty common. He had done it himself in his younger years. I can't belive that the push rods bend before the valves...

Mossy66

[QUOTE=INMYBLOOD;1577281924]you will be out cursing before long.


I'll bet he's done a lot of cursing already!

larrywalk

If the valves were adjusted properly, since only the exhaust valves contacted, this is a sure sign that the valve timing is retarded because the piston chases the exhaust valve closed.

You can leave the motor in the car, but you'll need to pull the water pump, pulleys, harmonic damper, loosen oil pan bolts to allow the front of the pan to drop down about 3/4", pull the timing cover and check the dot alignment. Further, you'll need to check for bent valves and pushrods. Pistons should be obvious with the heads off.

INMYBLOOD

[QUOTE=Mossy66;1577282382]

Spell check..

vettsplit 63

I agree, more often than not that is what the OP is looking at-- since the head gaskets are toast anyway, clay the exhaust valve lump on the pistons. No way he should be having anny kind of interference problems with a cam that small. One other thing comes to mind-- I had a cam one time that came in ground one tooth off. It was from a major manufacturer, the only way we were able to get the cam to spec out was to misalign the line up marks by one full tooth. Unusual maybe, but it does happen.