327 help

[cardo0]

Valve springs and or restricted exhaust is my guess.

[tenxal]

Saw something similar the other day. A fuel filter placed before the mechanical fuel pump was clogged with rust and debris from the tank.

[prairiehotrodder]

i ran it off a gas pail and that didn't help. The engine is well grounded and the new msd distributor was well grounded. None of that helped. The valve spring idea seemed likely but i can't see anything or feel anything. By hand they all seem good and strong. It has headers with dual exhaust. I'm going to check the exhuast more closely today.
Brian

[prairiehotrodder]

exhaust system is fine. Engine grounds are fine, Found out a little info about the mystery cam.

204 / 214 .420 lift sounds like basically a stock cam. That shouldn't cause the problem its having but explains the 180 cranking pressure i guess. I am about at the point where the motor is going to have to come apart for further investigation.

[F-BIRD'88]

This is not likely a internal problem

Most likely ignition.
Taylor sparkplug wires? Cap rotor carbon tracked.
Did cap centering burnt
If internal it will be flat cam lobe or fubar lifter.
Observe valves rockers motion cranking or idling.

[DCal]

This may be a stretch but try this before you tear it apart, if you have a big plug gap try closing it down to .025 just for grins. Cost you nothing.

[PRH]

I know of a few situations with similar running characteristics.
Basically ran fine to a fairly low rpm, then it just kinda lays down as you open the throttle more.
Both BB mopars.

In these instances it was the cam installed 2.5 teeth advanced.
Dot on top gear straight down.......keyway in crank straight up.

[travis]

I know of a few situations with similar running characteristics.
Basically ran fine to a fairly low rpm, then it just kinda lays down as you open the throttle more.
Both BB mopars.

In these instances it was the cam installed 2.5 teeth advanced.
Dot on top gear straight down.......keyway in crank straight up.

I’ve seen it before as well. Especially if you have a low compression engine that cranks higher than it should. This could well be an 8.5 compression 327 with that small cam seriously advanced. Makes the cranking numbers look good, makes it run decent on the bottom end, and flat dies as the rpms come up.

It sounds like it has a generic “performer” cam in it. 204/214, .420/.442, 112 lsa. Reboxed and sold by pretty much everybody...edelbrock performer, Mellings mtc-1, summit k1102, etc. If the cam timing is right it would need 10-10.5 compression to make 180 psi. That would mean a domed piston in a 327 which would be easy to check for just feeling around in the chamber with a piece of wire or something

[Geoff2]

For F-Bird'88, repeat, HEI does NOT need a grd strap from the f'wall to the engine. And adding a grd strap will not change ign performance one iota with HEI. Nor is a grd strap needed with points ign if the coil is mounted on the engine.

The grd return for the HEI ign coil is: coil -ve, through the ign module, dist body, engine block. Nothing to do with the car body or f'wall.

[CharlieB53]

Verify TDC with a piston stop, degree wheel or good timing tape on the balancer.

Pull a valve cover and start measuring opening/closing points to see just where that cam is installed.

You have already tried multiple carbs and ignitions, my money is improper cam timing.

[prairiehotrodder]

cam is getting checked and changed today. Thanks for all your suggestions guys.
Brian

[prairiehotrodder]

THE RESULTS ARE IN !!

I think someone mentioned it. The dot on the cam gear was lined up with the keyway on the crank. Making the crank / cam timing way out in left field.

thankyou to all who gave suggestions .

Brian

[PRH]

It actually happens pretty often.

However, most of the time the cam is long enough so that when it’s installed about 35* advanced........ the intake valves all crash into the pistons.

When that happens....... the “symptoms” are a little different

[prairiehotrodder]

the customer wanted a bigger cam anyways. I'm installing a comp thumper cam. The smallest one 227 / 241 .479 / .465 107 LSA
Brian

[rfoll]

That's a lot of cam for unknown compression ratio. Rebuilder pistons .045" in the hole and head gaskets .025" thicker than stock could make the static in the low 8s.