ram_ra7760

My '68 cutlass restoration is finally complete! I do have work though, which is prompting questions. If anyone has any mechanical knowledge or had similar issues I welcome any comments.

The last thing to work on during my restore was exhaust. It was so rusty, my restore guy cut off the exhaust close to the block. This made it loud, of course. After the new exhaust system, my restore guy heard concerning noises. He checked and found water in the pistons. He removed the engine, fearing a crack in the block/heads. Fortunately it was only 25yrs of midwest weather causing leaky seals/gaskets.

They honed cylinders, checked pistons, and squared up heads on this 350 rocket engine. They also did a extra work as valves were shot, and the cam was worn so it was replaced. They switched to a w-30 performance cam. They did great work I feel, but were in a tight spot. I had a hard-date of transporting the car from NE to AZ. They literally got the car put together and roughly checked out the night before transport.

They did adjust timing, but did 2 things to get the car to run: 1) premium gas and 2) unplug vacuum advance from HEI distributor to the carb. Regular gas caused a bad pinging noise. They said they did this as they weren't able to properly tune the car before transport, and because I have a high compression engine (10.25:1) giving early detonation. The idle was poor and would almost quit at every stop, but I was able to drive it 30 hwy miles with no problem, to the trailer for transport. Sounded smooth on the highway.

Now car is in AZ and I took it to a shop I thought I could trust, for the tune-up. They convinced me to put on an edelbrock 1406 (replacing my rebuilt holley carb). That slightly helped improve my hard braking problem slightly (vacuum pressure issue due to the different cam), but created more issues.

The tune-up. The incompetent auto guy, in hooking back up the vacuum advance from distributor to carb, turned the distributor. He had to have turned it a lot, but denies it. It was originally set at 4deg...and when I adjusted the timing back myself, it wasn't even registering on the scale. I reset the timing back down to 4deg, per my restore guy's recommendation and for the most part, the pinging is gone. There is a faint ping when the engine revs really high, before switching gears and at that same point when it coasts down. If I "Sunday drive", it is not a problem. If i hook up again the vacuum advance to either port or manual sides of the carb, the pinging will show up louder. So currently, the vacuum advance is not hooked up. When I'm moving, the car moves fairly well, but at a stop, has no get-up and go.
So....the slight pinging and the get-up-and-go problem: Ideas? Suggestions? Questions? With this compression, am I stuck with higher octane gas?

Thanks,
Rob

Fun71

Welcome to Arizona!

I hate to tell you, but your main problem is a W-30 spec cam in a 350 engine. That cam has a LOT of duration so it needs high compression, a fairly high stall converter when used with an automatic transmission, and low rear gears. You didn't say much about the rest of the setup, so go ahead and post as much info as you can about the car so we know what you're working with.

HEI initial timing set to 4º likely translates to ~20º total advance, which will severely reduce power (total should be ~34º for max performance). I know it's set down to prevent pinging, but it really needs to be higher for a smoother idle, more vacuum, and more power.

Olds64

Rob, you should be running premium gas if your compression is 10.25:1. Did you replace the harmonic balancer on the front of the engine when it was rebuilt? The outer rubber piece of the harmonic balancer has been known to slip. This means the timing indicator will read TDC but you're actually advanced or retarded.

Timing is set initally with the vacuum advance unplugged, but you should be able to plug-in the advance if the engine is tuned correctly. Are you using a standard points distributor or did you change to HEI?

oldcutlass

Waiting on the distributor answer... And yes you need to run the highest octane fuel available, preferably 93.

Fun71

He said what distributor it is in his post.

w314speed

Did you build with a roller timing chain? It is easy to use the advance or retard marks in error when installed. It will run, but no power. Remove the coil wire, remove #1 spark plug and turn engine over to bring the piston to top dead center on the compression stroke (the compression will push your thumb away from the spark plug hole), Use a flywheel wrench (preferred) or socket and pull bar on the harmonic balancer bolt to move to TDC. The timing marks should be on 0. To be more accurate, remove the LH valve cover and insure both the #1 rockers have no pressure on the valves. You could still have a harmonic balancer that has spun, but unless it has been saturated in oil, unlikely. Mark on the distributor housing where #1 plug wire is located, then remove the distributor cap and see what the location of the rotor button tab is in relations to mark on housing. It should be right on with timing marks on 0 at the balancer. If any of these are off, it will be harmonic balancer or the timing chain setup improperly. Other problem with ping, is how much did they shave the heads. If to much was removed to true the deck surfaces, you would have to use a thicker head gasket to get back to standard clearance. Just some things to THINK about. Hope its SIMPLE! Good Luck!

oldcutlass

How many times has a person said they have an HEI and it turns out they have a Pertronix points replacement....

Fun71

Good point.

As for running 93 octane fuel, not in Phoenix. Premium here is 91 octane with 10% ethanol. There are some truck stops near the race tracks that have 101 but any of those are way too far from Gilbert to consider.

oldcutlass

Yeah, I remember you saying there was no 93 there which is also an issue.

w314speed

I remembered another issue on all the Olds engines. As the rocker arms are not adjustable, the valve stem length has to be precise. When doing the valves, the valve stem needs to be machined down to insure a minimum clearance when installed in the head. As the seats are ground and valve faces are machined the valve length will get longer so the stem needs to be machined. If they didn't, the valves will keep the valves open when they should seal during the compression stroke. Olds had a special tool made by Burroughs BT-6428 that allows you to check the installed height One of the best special tools for Olds performance. Here are the pics of the tool. It can be used with the head installed or on the bench.

ram_ra7760

Hi everyone that fed back suggestions,

Thanks for all the replies and inputs. Been busy to respond right away, and also trying to get additional information. I'll feed back the information I was able to get so far.



Kenneth, Thanks a lot for the information. I will relay your information on the cam matching the engine to a mechanic when I find one, seems there are a few options north of Gilbert where I live (Mesa, Apache Junction, Phx). My mechanical ability is still a big work in progress.



The car has been 'ok' driving around the local streets, while I find some place to really get it fixed. the higher octane pretty much has taken care of the pinging, but there is no 'power'. I took the car out on the highway the other day and something broke, it is hammering big time, similar to when the timing was way off from the 1st mechanic I took it to. Even at park, at idle, like when a quarter is banging around in the dryer. Ugh...not good. I don't want to even try to turn it over now.

I spoke again with the mechanic who worked on the car initially. And this is what he mentioned:

He's still pretty confident on the cam being OK with the car. The heads barely needed any work, a very small amount of planing. He added thicker head gaskets to accommodate the higher cam lobes, and there is a little extra tolerance cushion in the lifters.

The harmonic balancer wasn't replaced, but it was checked out and looked to be in good shape, never soaked in oil. Could possibly be slipping, although he didn't think it was likely from when he checked things out.



Will have to let an expert check it out further at this point. Thanks everyone.

Fun71

Those statements bother me.

For the W-30 cam to work well in a 350, it should have had large valves installed and some port work done.

Thicker head gaskets will reduce compression somewhat and do not have anything to do with camshaft lobe lift.


Give Tony a call. He's an Olds Club of Arizona member and knows Oldsmobiles very well. His shop is in Scottsdale:

http://www.tonysrocketgarage.com/

Good luck with getting it straightened out.

OLDSter Ralph

OLDSter Ralph

I am thinking the poor gas, high compression and ambient temp in AZ and "off brand" carburetor are the important things. Perhaps some kind of "octane booster" could help. Good luck.

oldcutlass

What are your timing settings? Initial with and without vacuum advance, total with and without vacuum advance? What rpm is your idle speed, at what rpm does your mechanical advance stop?

OLDSter Ralph

oldcutlass

I think you do need to find someone else to look at it.

1970greensupreme

If you are relying on somebody to fix it, just do that instead of beating yourself up. If your trying to fix it, to start with, HEI needs battery volts to run, if it was originally points, it's probably stepped down to 9.5 volts. HEI's stock replacement are set up for a crap load of vac advance, you should have an adjustable vac adv can. With no vac advance and only on mechanical advance, you should likely be best around 34-35 degree's. You want to make sure your at true TDC which involves installing a piston stop in the number 1 plug hole and rotating to stop in either direction and splitting the differance, that's your true TDC. If none of this makes sense, you should find somebody qualified that knows old cars and start from there. I just got done setting up a 400 pontiac similar to your set up and had to adjust fuel, re-cure the distributor etc and it was set up by a pro, LOL. After all that there's the ported vac versus manifold vac and how much advance with vac adjusted properly.

OLDSter Ralph

I hope he keeps us updated. I am sure he has a real sick feeling in his tummy.

Fun71

I agree, which is why I recommended a local Oldsmobile expert shop:

http://www.tonysrocketgarage.com/

ram_ra7760

Thanks again everyone.

I don't have the timing gun anymore (borrowed it at the time). I don't recall noticing a difference with and w/o the advanced vacuum attached, as far as the timing went. Pretty confident I did check both. In the end, it was adjusted w/o it, as the pinging was noticeably worse with the vac advance, port or manifold connected.



For the cam, I don't have any real information there on the cam or valve lifts. Living 1200 miles from the restoration work, I wasn't as actively involved as I would have liked. The car was near the small town where I grew up, and where it collected dust and rust, so it was easier for many reasons to just begin the work there. Now with the concerns I have, I'll have a professional look at it for sure. It's beyond my expertise and my forehead is already bruised.



A sick feeling is an understatement. The car has a lot of sentimental value and after all the work I've had done on it, has a lot of $ value too. Wife ain't going to like this one, as supportive as she's been.



I did get a few referrals to tony's rocket garage, and also a Premier Performance and Restoration, in Apache Junction. Not sure if you know anything about Premier. I did initially email Premier but had hear nothing back yet. I will give them a call, and Tony's.

1970greensupreme

You just need to find somebody in your area, does not need to be a "olds" expert per say. Anybody who's decent with older cars can help you. I wish you were in this area, I'd have it running perfect for you. In talking with people, you need to ask if they can check for proper TDC on your balencer. Check and set your total timing with mech, then perhaps an adjustable vac advance. Welding bungs in your exhaust and buying a wide band air fuel meter for about $200. A little car tuning and you'll be happy. I just did a similar job for a guy with a beautiful 67 Firebird Conv, 400 4spd. I didn't even get to optimize it since he had a quick oil leak to fix the night I was tuning it and he does not want me to touch it since it was pining so bad, hard to start, hesitated etc. he's happy as it is, LOL.

OLDSter Ralph

Best of luck to you !!!!! Please let us know what happens.

Sugar Bear

What is the engine temp? Are the spark plugs the correct heat range? It is common for cars with HEI to run wide plug gaps, I've read that wide gaps can cause pinging due to the larger flame kernel. A colder heat range plug gapped tighter may help, even with HEI you could run the original plug/factory spec and gap.

A 10.25 CR may need octane booster with 91. Many of these cars said from the factory Premium Fuel Only on the gas cap and air cleaner.

Good luck!!!

Orlando 1

Thank you. I retarded 7 deg and ping is gone. I also have the octane boost so I may put a few degrees of advance back in so as to get as advanced as possible without ping. This is the first factory performance grind I've ever tried so, it is a big learning curve at the moment. The ISKY Mega torque that was in this engine last was a nice cam and with a better idle. But I don't want nice. To quote James Garner: 'All you need is a set of headers and slicks and you can go racing with a w31.' Just noticed Lunati no longer has the separate w-30 and w-31 grinds. They have a 310 dur, 480 lift which is more like a w-30 and they call it a w-31 so, whatever. Next step is to set total advance.

Tedd Thompson

Not my era of car but I have to ask have you checked your vacuum advance to see if it is in fact working at all?....Tedd