About to throw in the towel
#31
#32
I had an engine once where the rubber on the harmonic balancer seperated from the steel underneath. It looked fine to the eye but had rotated enough to put the timing marks almost 40 degrees out causing a massive compression loss. Does the engine have a harmonic balancer? If it is NOS it could be the issue.
#33
#34
Ilya, did the rebuilder give any warrenty? It just seems to me that he should have you tow it over to his shop and deal with it, or at least work with you to solve the problem. Its hard to watch as someone we all care about go thru this frustration. Just know it will run, and run nice, dont give up.
#35
Ilya, you may want to pull the timing cover and check the timing marks. These sixes (and Y blocks) have the marks offset from each other by 12 pins in the timing chain. If your builder assembled it "straight up" , (dot to dot) it will never fire. Easy mistake to make...
An old Motors repair manual has the diagram for correct alignment...
An old Motors repair manual has the diagram for correct alignment...
#36
Ok. Here's an update.
Just spent some time going over a few things. We performed a leak down test that resulted in the cylinders holding pressure. We then simulated a valve leak by cracking the valve open slightly. After the valve was released, the cylinders still held pressure.
Performed what "tractormanbill" suggested. With the valve cover off, set the #1 cylinder at TDC per the timing mark on the dampener. Valves were closed and had lash. The distributor rotor was pointing at #1, which confirmed the cam timing was correct. We then manually rotated the crankshaft 360 degrees back to TDC. Exhaust valve was open, so cam timing appears to be accurate. Rechecked the compression and it dropped down to 10-15psi versus the ~30psi we had a few days ago after oil was squirted into the cylinders.
Checking with a thumb placed against the spark plug hole, for compression stroke, there was heavy amount of suction on the intake stroke and minimal pressure on the compression stroke. So the motor has a lot more vacuum than air discharge.
Since we have fuel, spark and air, I don't understand why it wouldn't have compression. What if the timing chain is off by a tooth or two, would this create a no compression issue? If the cam was installed incorrectly first and then the valves were set to the incorrect cam timing, would this create no compression?
I'm ready to take a dynamite stick to rectify the situation!
Just spent some time going over a few things. We performed a leak down test that resulted in the cylinders holding pressure. We then simulated a valve leak by cracking the valve open slightly. After the valve was released, the cylinders still held pressure.
Performed what "tractormanbill" suggested. With the valve cover off, set the #1 cylinder at TDC per the timing mark on the dampener. Valves were closed and had lash. The distributor rotor was pointing at #1, which confirmed the cam timing was correct. We then manually rotated the crankshaft 360 degrees back to TDC. Exhaust valve was open, so cam timing appears to be accurate. Rechecked the compression and it dropped down to 10-15psi versus the ~30psi we had a few days ago after oil was squirted into the cylinders.
Checking with a thumb placed against the spark plug hole, for compression stroke, there was heavy amount of suction on the intake stroke and minimal pressure on the compression stroke. So the motor has a lot more vacuum than air discharge.
Since we have fuel, spark and air, I don't understand why it wouldn't have compression. What if the timing chain is off by a tooth or two, would this create a no compression issue? If the cam was installed incorrectly first and then the valves were set to the incorrect cam timing, would this create no compression?
I'm ready to take a dynamite stick to rectify the situation!
#37
#38
Ilya, you may want to pull the timing cover and check the timing marks. These sixes (and Y blocks) have the marks offset from each other by 12 pins in the timing chain. If your builder assembled it "straight up" , (dot to dot) it will never fire. Easy mistake to make...
An old Motors repair manual has the diagram for correct alignment...
An old Motors repair manual has the diagram for correct alignment...
I gave the rebuilder the shop manual to aid him in assembly. I only hope that he referenced the shop manual.
I called the rebuilder after we were done, but there was no answer. He does work tomorrow and my friend, who's a much more knowledgeable mechanic than me, will call him tomorrow. I will then follow up with a phone call or an actual visit.
#39
#40
I think the only thing that could kill compression that uniformly on all cylinders is cam timing. Upside down rings usually just makes massive amounts of smoke.
Ilya, did the builder set the valve clearances? If he set them with the cam out of time, the clearances will appear to be "right", but at the wrong time. For example, the lifter could be halfway up in its travel but you could set the lash to be .018" or whatever at that lift. You'd end up with almost no valve travel.
I don't think the 215 is an "interference" engine, but it's possible the valves kissed the pistons and bent the valves. That will kill compression quickly. A leakdown test would show that right away.
Ilya, did the builder set the valve clearances? If he set them with the cam out of time, the clearances will appear to be "right", but at the wrong time. For example, the lifter could be halfway up in its travel but you could set the lash to be .018" or whatever at that lift. You'd end up with almost no valve travel.
I don't think the 215 is an "interference" engine, but it's possible the valves kissed the pistons and bent the valves. That will kill compression quickly. A leakdown test would show that right away.
#41
Doesn't matter what the year of the engine is Ilya, they all could do this. Just depends on what was done and how it's assembled. IMO, the older the engine, the more simple it is, though.
It sure sounds to me like the cam is out of timing. Even if the re-ground cam didn't have the longer pushrods that it may require, it'd still run and build compression. The valvetrain would just be noisy while it was running. They would have had to really grind the **** out of the cam in order for a stock pushrod not to allow enough air in. With your finger gettin sucked in really hard when turning over tells me the intake valve is not opening when it should.
It sure sounds to me like the cam is out of timing. Even if the re-ground cam didn't have the longer pushrods that it may require, it'd still run and build compression. The valvetrain would just be noisy while it was running. They would have had to really grind the **** out of the cam in order for a stock pushrod not to allow enough air in. With your finger gettin sucked in really hard when turning over tells me the intake valve is not opening when it should.
#42
engine
ok your engine sounds like the cam is out of time with crank a quick way to check this is with what we call the split overlap to do this take the spark plus out so you can turn the rngine over easley turn the engine in the normal rotation watch the exhaust valve open and then start to close as the exhaust valve is closing and the intake valve starts to open make both valves the same meaning the exhaust and intake are the same height in relationship to each outher then look in the #1 cylinder and the piston should be a top dead center DO NOT GO BY YOUR DAMPER as it could have sliped and not read true tdc this is called the split over lap and its allways at tdc even with a performance cam when the cam grinder ground your cam or reground your cam they don't take very much off of what we call the base circle even when regrinding the lifters they only take as little as possable as they will grind through the hardness of the lifter face and the cam and lifters will wear very fast most of the time when you have problems with your engine i would suddress that you pull your own engine back out because you will be more careful with the r/r then some guy doing it for free not that they want to have problems but sometimes something bumps into your new paint job or something comes up missing off your truck hope this helps john
#43
#44
There is hope for humanity
#45