Low Cylender Pressure

[Big Ratfink]

Ok guys, I screwed something up and looking for ideas before I rip it back out and tear it down.

A couple years ago I put together a mostly stock 1600 with dual port heads. The Chinese stock replacement heads had the step machined off. The cam is a 2228 Eagle Racing Camshafts - Gas Saver Special Grind Cam, New pistons and cylinder set from AA Performance. Full flow oil filtering.

In the process of figuring out why it wouldn't start, I proved The carb was getting fresh gas, and the spark plugs were sparking at about the right time. With the crank at TDC # 1 cylinder has .006 clearance on both valves.

My cylinder pressure gauge needle doesn't wiggle when the engine is cranked. What could I have possibly done? When I was a kid we put a Briggs and Straton together with NO rings, we made that run!

This is what happens on a hurry up job - must have overlooked something.

[Big Ratfink]

forgot to mention- This is the initial start up. Built it a couple years ago but never finished the job.

[Ol'fogasaurus]

Are you sure that the crank and cam are properly aligned and not, say, 180° out?

Lee

[sideshow]

Try your compression tool in a running well engine (verify first it is also 14mm straight thread) as you noticed even a less than perfect ring seal will run'ish

The econ leak down tool of a rubber tipped air gun can narrow down piston seal or valve seal

[Big Ratfink]

Is it possible they can be 180 out if there are timing match-marks? I do know at top dead centre that both valves are seated, and the rotor is pointing to that cylinder.

When I pull the motor I'll try pressurizing the cylinder to see where the leak is.

If I forgot to put the rings on... Quite possible. I may have done a quick mock up while i was messing around setting up the solid rocker shaft geometry, and then with the distractions of life forgot what the heck I was doing. Lots of crap has happened in the last few years.

[Ol'fogasaurus]

4 stroke engines revolve 2 times between firing. If your cam or dist.(?) is installed wrong you could very possibly have no cylinder pressure.

https://dannysengineportal.com/top-dead ... ts-stroke/

Lee

[Ol'fogasaurus]

I totally understand the getting distracted and making the mistake thing.

If there is a question then maybe the best and safest thing is to pull it apart to make sure everything was done right. It can save a lot of frustration and maybe some $$$.

Lee

[Tom in PA]

Any update on the low compression issue? Is the gauge working ok? Did you narrow it down yet? Inquiring (quarantined) minds want to know:-)

Tom

[Big Ratfink]

I'm sorry I haven't been around in a while, but as soon as my new Ice cold garage starts warming up I will tear into the engine. Little did I know when i was posting that I would be selling and moving in less than 2 months! Right now I'm putting my kids stock 1600 back together after an engine fire. He was having intermittent shorting of the charging circuit. We found the problem- the generator or voltage regulator shorted and smoked everything up to the battery. Actually, I had the charger on it and was inside having a cold one after work and a friend (volunteer firefighter} pounded on the door and yelled the car was on fire! Then proceeded to put it out. Dang. If I only parked closer to the garage and he was a few minutes later...

[Big Ratfink]

You know, I had a bus that had an electrical fire that I will attribute to rain and a leak, I had a rabbit that leaked over the fuse box and gave me fits, I had a sirocco that had intermittent shorts in the ignition circuit....The previous owner was an electrician and couldn't figure them out,

I'm an industrial electrician / technician. I fix stuff for a living. Is it just me, or is this normal?

[Big Ratfink]

I'm going to stick my neck out there and bet my low/no cylinder pressure was caused by my distributor drive gear being 180 degrees out. I'll find out in about 3 months.

[Big Ratfink]

I really need to review before I post. Engine had rings in it, when I tore it down I saw nothing unusual, I'll figure it out when it warms up. distributor drive wont affect compression, only when the spark happens.

[Piledriver]

Had a motor in my sons bus, about 15k miles one hole started oiling plug, no compression..

looked great when torn down.

the rings gap had self aligned on that hole.