Rebuilt 318 Refuses to Start

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you could check every one, but I was thinking if you checked all four corners, and all the valve stem tips are at exactly the same height, then that should be sufficient. You check them by putting a STRAIGHT straight-edge on the top of the valve stems, after you removed the rocker shafts assemblies.
 
95dakotadude said:
nm9, I didn't replace the chain because it's almost new. It only had maybe 1/4 of play on the slack side.

GTS, how did you go about measuring your pushrods then? I had previously broken all of my pushrods before I spun the bearing because I guess they were too long? So, I remeasured them by getting one of those extendable pushrods and put it on the #1 rocker arm while the lifter was at the base lobe of the cam and then tightened it were it should, and extended it just a half turn more for lifter preload. My new measurement was only .1 shorter. Granted, my engine is far from stock. Is there anyway to tell if I got it right this time? Before, when I had the valve cover off looking at the valves I tried twisting the exhaust pushrod while at TDC because you're supposed to be able to do so, I could. Is that a good enough insurance? I'm pretty sure I measured them right, but your comment puts a seed of doubt in my mind. Does it matter if I checked them on #1 or #6?
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OK, good on the chain, even a new one will have a smidgen of slack on the passenger side. Sounds like you're OK.

BTW, 1/2 on the checking pushrod turn probably means you have around .020" preload: the threading on the checking pushrods that I have seen are 24 TPI, which means around .040" length change per turn.

Twisting the push rod is not always good enough as the pushrod could be too loose (too short), or even too long if the lifter happened to leak down some since the engine stopped. You can find waaay too loose (obvious slack) or waaay too long (pushrod bound up) with the pushrod check. But you can be very close to one end of the piston range in the lifter and still spin the pushrod, and then when things heat up, something expands and things go out of the piston movement range.

The way I like to do it is look at the lifter tops closely when the rocker shafts are all assembled and torqued in place. When a lifter is on the base of the cam, then the piston inside the hydraulic lifter should be down from the retainer by approximately by the amount of the preload. This means you have to rotate the engine over and look at each lifter pair when it is for sure on the base of the cam lobe (at TDC of the compression stroke). To see this gap accurately between retainer and lifter piston, you need to have the intake off. (You can even insert thin wire gages into the retainer-lifter piston gap to get an accurate measurement.) It is a check to do just prior to putting on the intake.

Unfortunately, measuring the pushrod length on just one valve/rocker position could lead to issues as that one particular valve.rocker set could be off from the rest. Which I suspect is why you want to check....
 
rustycowll69 said:
you could check every one, but I was thinking if you checked all four corners, and all the valve stem tips are at exactly the same height, then that should be sufficient. You check them by putting a STRAIGHT straight-edge on the top of the valve stems, after you removed the rocker shafts assemblies.
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That technique assumes all the rockers are identical and ride the same way on the shafts. That may be questionable with used stock rockers.....!
 
95dakotadude said:
nm9, I didn't replace the chain because it's almost new. It only had maybe 1/4 of play on the slack side.

GTS, how did you go about measuring your pushrods then? I had previously broken all of my pushrods before I spun the bearing because I guess they were too long? So, I remeasured them by getting one of those extendable pushrods and put it on the #1 rocker arm while the lifter was at the base lobe of the cam and then tightened it were it should, and extended it just a half turn more for lifter preload. My new measurement was only .1 shorter. Granted, my engine is far from stock. Is there anyway to tell if I got it right this time? Before, when I had the valve cover off looking at the valves I tried twisting the exhaust pushrod while at TDC because you're supposed to be able to do so, I could. Is that a good enough insurance? I'm pretty sure I measured them right, but your comment puts a seed of doubt in my mind. Does it matter if I checked them on #1 or #6?
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.1 shorter?? that's .100 or 100 thousandths...that's quite a bit...unless u made a typo...
 
Yes, as i remember it was .02 preload. I can't say for absolute certainty, but I'm pretty sure the new ones were .1 shorter from stock. Keep in mind I've had the heads slightly milled and the block slightly decked coupled with (what I think are) slightly thinner than usual head gaskets.
 
I measured push rods just like you did, only I run a solid cam, I don't have to worry about preload.
 
oldkimmer said:
I slide the p/r up and down to check/ set preload Kim
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One the engine has been run, any hydraulic lifter with a good tight check valve will make it difficult to impossible to check in this way. OP, I can't think of any reliable way to check preload with stock type rockers other than to look at the plunger movement directly.... which means pulling the intake. Maybe someone else has a good trick up their sleeves....
 
95dakotadude said:
I have recently rebuilt my 318 after it spun a bearing. It is a highly modified engine meant for street/strip use.

It will not start. We have spark, compression and fuel to the carburetor. It cranks and cranks but no start. Once in a while it will cough, but it's intermittent. I have put the long mark on the harmonic balancer to TDC and verified that the piston is actually at TDC on this point with a screwdriver and with the valve-cover off looking at the rocker arms. I've tried starting it from TDC with no luck. I've tried starting it ~8degrees advanced and retarded to no luck. We've always rotated the distributor all the way during these times to no avail. I am running a full MSD ignition system with a Holley 650 double pumper carb with 5.5lbs of fuel pressure to the rail.

We are unsure if gas is actually getting into the cylinders though. It's going through the carburetor because I can see the gas squirting in it, but when I pull the plugs, they're dry. However, when I pull the carburetor which is sometimes full of gas from pumping it, the intake will have a little bit of gas in it. Sidenote: The carburetor is a newly rebuilt piece with less than 600miles on it.

It still refuses to start and I've been working on it for like 3 days just on this stupid timing aspect. Does anybody have any ideas?
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Pull the distru
95dakotadude said:
I have recently rebuilt my 318 after it spun a bearing. It is a highly modified engine meant for street/strip use.

It will not start. We have spark, compression and fuel to the carburetor. It cranks and cranks but no start. Once in a while it will cough, but it's intermittent. I have put the long mark on the harmonic balancer to TDC and verified that the piston is actually at TDC on this point with a screwdriver and with the valve-cover off looking at the rocker arms. I've tried starting it from TDC with no luck. I've tried starting it ~8degrees advanced and retarded to no luck. We've always rotated the distributor all the way during these times to no avail. I am running a full MSD ignition system with a Holley 650 double pumper carb with 5.5lbs of fuel pressure to the rail.

We are unsure if gas is actually getting into the cylinders though. It's going through the carburetor because I can see the gas squirting in it, but when I pull the plugs, they're dry. However, when I pull the carburetor which is sometimes full of gas from pumping it, the intake will have a little bit of gas in it. Sidenote: The carburetor is a newly rebuilt piece with less than 600miles on it.

It still refuses to start and I've been working on it for like 3 days just on this stupid timing aspect. Does anybody have any ideas?
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pull the dizy turn it 180° and you may need to look at your cam card to see if you need to advance the crank at all i did that on my la318 i rebuilt and it fired right up
 
^^HEH^^ This was back in April.................

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