Cincinnati Rick

When I start my car it seems to run and idle smoothly. As it warms up the idle increases and it starts to sound out of sorts. A friend of mine who has built several Oldsmobile engines took a look and did the following:

May not have been in this exact order and he did start the car with basically the same result in between each thing he tried.

Checked vacuum and replaced intake gasket. Vacuum went from 4 to 14psi
Replaced blackened spark plugs
Swapped out carb
Swapped out distributor
Set timing
Ran car directly from a can of fresh premium fuel
Checked compression. 200 PSI +/-

He is recommending that I pull the motor and let him check the timing/degreeing of everything. (not sure if that's the right terminology) He also said to replace the intake with a cast iron OEM type and a quadrajet carb. When he was re-installing the intake he said it had slop between the sides and the heads. Thought maybe the heads were milled too much. He said we could change the heads or use thicker replacement gaskets. He thinks the intake that is on there may have a small fracture that is causing a vacuum leak as it gets warm. He is willing to do whatever I want but he said pulling the motor apart will erase all doubts and get to the root cause one way or another.

As always, I look forward to your responses and appreciate you taking the time to help me out.

Here's what we're working with:

1970 442
455 bored 30 over
Pistons are unknown
OEM W30 intake. Looks beautiful from the top. Pulled it off to find the ugliest welds I'd ever seen. Definitely a prime suspect
HEI
E Heads
750 Edelbrock carb...no choke hooked up

Thanks
Rick

GAOldsman

Changing the intake would be way easier than pulling the engine. I'd try that first.

Octania

The engine can be degreed in place

It's not as easy, sure

beware the mightaswells

70Post

Post pics of the welds on the intake.......they may be factory "welds" and inconsequential. I recall seeing this before on W-455 intakes....I can look at some factory intakes here in the next couple days to see if my recollection is correct.

Are you saying the intake port surface/side of the heads may have been milled?? Decking a block and/or surfacing the gasket surface on the heads WILL NOT make the intake fit "looser" from side to side....sure, the intake port/gasket surface will be LOWERED a bit but not widened.

Cincinnati Rick

Here are some pics of the manifold.

I just realized my original post did not totally explain all the symptoms. I originally had my buddy look at the motor because it seemed to run fairly strong once you got it going a little from a dead stop. It would hesitate and make for a jerky start. Once it did that, it had good power but was pinging a little. I couldn't get the idle set at a happy place so that's why I asked him to look at it. Now the car starts off a little better but it starts pinging like crazy as soon as I try to accelerate quickly.

Thanks guys for your input so far.

Rick

D. Yaros

I do not know what the problem is with the engine.

I do know, those are not factory welds!

Fun71

From your first post, I would have a couple questions:
What is the initial timing set to?
Does the HEI have the original weights, center bar, and springs?
Did your friend do anything with the distributor vacuum advance canister?

With 200 psi cranking pressure and iron heads it seems that your timing curve would have to be dialed in to prevent pinging.

Cincinnati Rick

Kenneth.

I will get you some answers as soon as I get in touch with him.

Rick

Cincinnati Rick

I never heard of that term until I bought this car and now I I have a complete understanding of it!

Cincinnati Rick

Scot, That's what I was leaning towards but he keeps telling me there's something else going on with the engine. After seeing some of the other work the previous owner had done I'm inclined to believe him.

Rick

Cincinnati Rick

Kenneth,

Initial timing was set at 6-7 degrees BTDC
HEI is all original
I forgot to ask him about the canister. What should he have done?

Rick

Cincinnati Rick

Patton,
The way he explained it to me made sense but I trust that what you say is true.Should the intake fit snug or should there be side to side movement?

Rick

70Post

Rick - I did check out the underside of one factory alum (W455) intake today and have to agree w/you and D. Yaros and his observation.....the "welding" I've seen on the underside of factory intakes isn't in the heat riser areas but instead looks like it's probably some repairs the foundry made to the casting stuff and it's located between a couple intake ports. Much less apparent/thick and in a completely different area on the intake underside. So...I also agree that what you show in your pics looks like welding done to repair cracks in the heat riser sometime after the car/motor was sold and used.

Does your guy have a machinist's straight edge?? A long one that you can lay across both machined surfaces of the intake port gasket surface on your intake. Any decent machine shop should have one. That would be the first thing I'd check.

As far as side to side movement...can't say I've paid much attention to that in the past. At a minimum you can get a visual idea by setting it on the motor and just taking a look while remembering a gasket has to fill the gap on both sides. You could even mock one up by temporarily installing a metal "turkey tray" gasket or some different thickness composite gaskets. I would think any movement, side to side, after you've dropped the intake down onto the gaskets may be cause for concern. Sure, there will be some gasket "crush" occurring as you tighten things down but any obvious movement/gaps down either side, probably isn't going to be eliminated just by tightening the intake down.

Another "WTH..let's try this" thing to try would be to lay the intake in place, again with gaskets BUT WITH NO END RAILS ON THE BLOCK LIFTER VALLEY ENDS. See what kind of gap you have there. Excessive machining of the intake's gasket surfaces would eventually cause the machined underside end rails on the intake to come in contact with the machined block end rails. This seems like it would be a huge red flag as any contact there (WITH intake gaskets in place while mocking up) would limit/prevent any gasket crush from even occurring since the intake is "stopped out" from moving down any further by the lack of any end rail gap when you tighten it down......just another "try this maybe" idea. Remember, the gasket crush is achieved by pushing the intake DOWN into the valley....not by "spreading" the intake itself.

I'm no engine builder so I'm speculating at this point but I sure would start with a flatness check on the intake's gasket surfaces. Who knows?...maybe they followed up the heat riser welding with some overzealous machining of the intake gasket surfaces and went a bit too far??

As you guys probably already know, there are typically a few different thickness of composite intake gaskets available. I know when I installed an alum intake on my Buick the folks I got the gaskets from offered 2 or 3 different thicknesses. I think those gaskets were from SCE.

Here's a 24" machinist's straight edge as an example:

olds 307 and 403

You need another 10+ degrees initial and unhook the vacuum canister till you get an adjustable canister.

oldcutlass

Your HEI is not stock to your car and the timing needs to be set accordingly. 6-7 deg btdc is probably the main cause for your car to be running poorly. Just a thought, with your timing set so low and if you are still running a thermostatically controlled vacuum switch, as the engine increases in temp, the switch opens and allows manifold vacuum to your vacuum advance which will raise your idle speed.

Fun71

As already said, your initial advance is way low with that distributor. Factory HEI distributors have ~14º or so mechanical advance, so in order to achieve 32-36º total advance (initial + mechanical) the initial must be set to ~20º. Unfortunately, this WILL NOT help your pinging issue as the higher initial advance will cause pinging.

Years ago I installed a Moroso HEI advance curve kit and its center bar and weights gave 24º mechanical advance, so I was able to set the initial to 12º to get 36º total. You could do this and use the stiffer springs in the kit in order to have the mechanical advance come in later to reduce pinging.

As for the vacuum canister, I found the original on my HEI gave 24º vacuum advance (there's a number stamped on the top of the mounting bracket adjacent to the vacuum diaphragm) which was too much. I made a stop using instructions I found online, but you could buy an adjustable one and tailor the vacuum advance.

Cincinnati Rick

I appreciate the suggestions and I will discuss them with my buddy. I know he was trying to advance the initial timing but then the engine would not shut off. It kept dieseling. I think that's why he wants to tear into it and see whats going on. He keeps listening to the motor and messing with the timing and says there's something else wrong.

I guess at this point I'd feel better having him pull the motor apart just so I can see what I have. A member here on CO has graciously given me a cast iron intake to try when we put it back together and I have a Quadrajet that can be used after I have someone rebuild it. I'm still trying to decide if I want to keep the electronic ignition or go back to points.

I'll let you know what we find

Thanks Again,
Rick

bw1339

Some years ago I put a HEI distributor in my 455 and set it to the factory initial timing. I drove it like that until I found out HEIs have less centrifugal advance. Once I set it to about 20deg BTDC, it was night and day!

Cincinnati Rick

Did you have any pinging issues? Did it diesel after shutting off ignition?

bw1339

It did have some minor part throttle pinging on the highway.

Advancing your timing will help with dieseling, as you'll idle with a lower blade opening in the carburetor.

Before you do anything, set your total timing at 35 degrees at 3000 RPM (no vac) and see how it does.

Cincinnati Rick

Besides a major vacuum leak in the W-455 manifold that doesn't appear to be repairable we also found the valve train is pretty much wiped out. I was excited to see the Harland Sharp roller rockers when we pulled the valve covers off. That excitement was short lived when we found bent push rods and chewed up rocker bottoms. I was told this motor was built by a professional engine builder in Virginia. Maybe he should find another line of business. What started out to be a rough idle/pinging problem is probably going to be a total engine rebuild. I'm sick to my stomach thinking about how much money I paid for this car and how much money I now will have in it just to make it a nice driver.
Anyways, has anyone seen rockers get torn up like this before? What would cause this to happen?

Bummed out in Cincy,
Rick

oldcutlass

Didn't see that coming...

edzolz

It appears to me that the rocker bottoms had been milled to clear the stud hex but didn't get them deep enough. Something that a reputable machine shop should have know better than do. I doubt the geometry in the valvetrain was correct is why the bottoms were so chewed up. Probably the pushrods were too short. Can you tell what brand the rockers are?

Cincinnati Rick

Harland Sharp

Cincinnati Rick

This thread went from something as simple as setting the timing and adjusting the carburetor, to a full blown rebuild. There is hardly anything that can be salvaged on my motor. The block and crank can possibly be saved but it will require some work that I myself can't do. Now that the motor has been torn down it's obvious why the idle was messed up and the pinging was excessive on the top end. We found Pontiac pistons that produced way too much compression. Over 200 psi in each cylinder. The ratio worked out to be about 12:1. There was so much debris in the bottom end that it was scoring the hell out of everything. There was a retaining clip missing from one of the lifters, every push rod was bent, the rocker bottoms were gnawed away, the valve guide seals were destroyed and on and on and on.
This thing was ready to grenade. It literally was blowing itself up. I'm far from an expert but I know connecting rods aren't supposed to have bends in them. This thing must have been pre-detonating like crazy. And with all that said, it actually didn't sound or run bad all things considered. It's amazing how tough these Olds motors are.
So thankfully I have a friend that has a virgin block and a usable crank that he is practically giving me. He has been talking to Lynn Mondello and between the two of them, they are going to set me up with some new heads and valve train. They will be E heads but I'm not sure what the rockers and valves will be. The machine shop guy said he'll bore the block 30 over and get a set up to have about a 10-1 ratio. I'm struggling on which way to go as far as cam, intake, carburetor etc. This car was bought to take to shows and raise a little hell on the streets. I don't want a drag car and I don't want a stock driver. I'm open to hear of any set ups that you guys have in your cars that would meet my expectations for my car.

Rick

My442

Here is a combo I used in my 70 442 that worked really well:


Forged pistons with a 9.75 to 1 compression ratio


Ported stock heads


Engle 20-22 cam


Comp roller tip rockers


Edelbrock O4B intake with a Ruggles Q-jet and distributor


Balanced, decked, align honed


This combo had 14" of vacuum, a good idle, and ran great on 93 octane gas.


The dyno said 428 HP and 540 TQ


Pulled HARD to 5500 RPM

Cincinnati Rick

Nice!
Exhaust?
Stick or auto?

Rick

babs68

This is what I am going through now. Though it started with a loose rocker arm and now the block is going to the machine shop next month. Here is the original thread on my simple and then full blow disassembly of my engine: Should I Tighten This?

It's not fun, but at least now you will be able to choose what you want in the block and that might give you some piece of mind.