Update on 440 motor condition

[Polsky]

Hi crew,

Last week I started a thread on a possible 440 budget build, since my car is going through over a 1/2 quart of oil every 500 miles. As promised, I did a compression test. Here are the results:
CYL:
1-151
3-149
5-142
7-151
2-150
4-145
6-152
8-136, wet 145

I added some oil to the lowest pressure cylinder and tried the test again. The garage was at about 50 degrees but the car really smoked for the first 2 minutes of start up. The car is running a little rich if that matters. Oil pressure was at 75psi cold @1300 rpms and 50 psi at 165 degrees and 1000 rpms. The cylinders are just in the 10% rule of thumb for the test; but does this look ok? I am almost looking more toward a valve seal/guide problem. I look forward to any suggestions. I do not have allot of info on the motor internals beside it has a 484 MP cam, 906 heads that look clean, and what I am assuming is stock 1968 bottom end with a windage tray. Last, if it looks like a head issue, would I be able to run a set of stealth or e street heads with the stock valve train and still make it on 91 octane? Thanks in advance for any advice.

 

[451Mopar]

Is it blue or white smoke? My old 440 had a blown head gasket that smoked white till the engine warmed up.

I would pull the heads then inspect the cylinder bores for wear. If the cylinders are good, drop on the new heads. I'm not sure what difference there is between the Edelbrock #5090 and #5093 except chamber volume?, but the #5090 is only $1299.50 /SET from Summit Racing (plus free shipping.)
I looked at Hughes Engines web page, and they list the #5090 as 75cc (same as Edelbrock), and the #5093 as 84cc (Maybe Edelbrock has a typo, they list 74cc?)
From the Hughes page, it looks like the E-Street flows very well. Any of the aluminum heads will need a head bolt kit that has the smaller bolt heads. I have never used the E-Street heads, but if they have the angled spark plugs like the RPM heads, it may cause clearance issues with some exhaust and headers. The 440 Source Stealth heads have a straight plug location if exhaust fitment is an issue.
To me the E-Street #5090 looks like a good fit, and least expensive?

 

[Polsky]

Would a blown head gasket account for the use of oil as well? The smoke looked to have a blue hue to it; but it was tough to tell given the temperature in the garage. If it is valve seals, can it account for that much oil?

 

[451Mopar]

Would a blown head gasket account for the use of oil as well? The smoke looked to have a blue hue to it; but it was tough to tell given the temperature in the garage. If it is valve seals, can it account for that much oil?

That sounds like valve seals and valve guides. The 906 heads also do not have hardened seats, so the valves may be eating through the seats (Usually the exhaust valve will be higher than the intakes if you place a straight edge across the valve stem tips.) I'm not sure how much it costs to rebuild a stock head with new valves, guides, hardened seats, and valve job? I had it done to my 906 heads for a 383 back in the 1990's, and it cost around $600+ and that did not include new springs, locks, retainers and seals. And, that was unported stock heads. I am more interested in performance than originality, so I have been using aluminum heads since then. The aluminum heads really are not much more expensive, and flow way better. Plus they are easier to repair if they are damaged (dropped a valve in my 451 with B1 B/S heads, and had the damaged chamber welded up and repaired.)

 

[AR67GTX]

You probably need to run a leak down test. It's more useful than a compression test. I would run it on a warm engine. Listen for where air is leaking (exhaust or carburetor or oil breather) and that will tell you where the weak link is as far as valves or rings.

 

[Meep-Meep]

Those compression numbers don't look too bad at all but I suspect that slightly lower one is due to a poorly seating valve. Valve seals are pretty much guaranteed to be toast, but that scenario will typically cause smoke on first start up after sitting over night. Being that you have been running it for several hundred miles and it still smokes, I'd say it's time to pull the heads. I will also agree about doing a leak down test before you pull it apart. Very useful info.

 

[GTX MATT]

5 and 8 are slightly lower, but those look like decent numbers for a budget engine with a 484 cam. That 135 should be higher though. I'd agree with the above, you've probably got a poorly seated valve on the lower cylinders. Guides are probably a little too worn.

 

[cdr]

throw some valve seals on it.if it does not help no big cost,just labor