Hi Guys-

I have a massive compression leak after major rebuild (all timing components, rings, skimmed head, etc) documented in a different thread here. I struggled to run a leakdown test due to a simple hose mismatch, but I just discovered the leak is so massive I didn't need it. I fired up a Romeo y Julieta robusto and blew it from the spark plug hole out the supercharger right hand (US driver's) side. I can turn the crank while blowing and while it never actually resists the blow, it does change slightly. When it changes, it seems like it may come out a different spark plug hole. So something is wrong, and wrong in a big way on the intake side. Cylinders 1, 2 and 3 have no compression whatsoever and #4 has about 90.

Any ideas jump to front of mind? I did have the head skimmed, valves out and lapped by hand, but they tested good with vacuum at the machine shop. The cam was off but torqued back down to spec. I feel like timing isn't the issue at this point, because there's never enough resistance to indicate the valves are EVER closed. I didn't have the block out of the car but it checked out with a straight edge and I don't think it could be THIS far off.

It's got to be something simple. I'll take the cam off next (maybe it got skewed?), but hoping to not have to remove the head again. ANy ideas appreciated.

 

well, at least I now know WHAT it was. The spark plug tubes were slightly bent and the valve spring retainer was rubbing up against it. Cylinders 1-3 were basically prevented from returning all the way up, preventing the intake valves from closing. 4 was better but still touching.

oh well at least I didn’t need to tear into the head. Bent them back and reassembling...

 

So...turns out the angled spark plug tubes were a symptom of something else I had done wrong. I installed the bar that connects all of the intake rockers backwards. That's right, backwards. It has indentations for the spark plug tubes. If installed incorrectly, it pushes the plug tubes towards the front of the car and into the valve springs, preventing the valves from closing all the way. I'm surprised no one's done this before; I found nothing online. Maybe I'm the only one to admit it? Or maybe it's just that stupid that no one could even make such a mistake. Anyway I did. It's fixed now and the rebuild is complete. Car runs great.