Open it up or leave it alone?
 

My son and I are planning on roadtripping his Ventura 1800 miles to the Duct Tape Drags in October. We spent the last year going through the chassis-related items - suspension, brakes, steering, as well as the cooling system. He's been using the car as his daily driver around town for the last 8 months with minimal issues.

One thing we haven't touched is the engine. It's the original '74 2bbl 350 with 46 screw in stud heads. It has a little over 100k according to the odometer. The engine appears to have never been opened up or out of the car. When we first got it, I ran a compression check and cylinders 5 and 7 were around 80psi. The others were at 120. Since he's been driving it, 5 and 7 now measure 100psi. I originally thought the lower compression might be due to the head gasket between the cylinders, but since it got better after driving maybe it's the rings? I did a coolant check and it came back negative for combustion material.

When we fired it up after sitting a few months while we worked on the chassis, it had a lifter tick, but it went away after it ran for a short while and we dismissed it. A couple weeks ago my son changed the oil and I had him put 6 quarts of Driven 15-50. Soon after it the lifter tick came back. The dipstick was reading high, so he drained some oil to put the level where it should be and the tick mostly went away. He pulled the rocker covers and everything looks good with no sign of a flat cam lobe checking out. I finally put an oil pressure gauge on it over the weekend, and to my surprise the pressure is great.

I'd like to avoid getting stuck in the desert on the way to Arizona. I'm thinking the best course at would be to minimally disturb things ahead of October, but I don't love the low compression, and I wonder if tick could come back to haunt us. I'm leaning towards installing the 4bbl, removing the valley pan to get a look at the lifters and cam and going from there. Thoughts?

Trust what ya got or, a opened up engine? A lot of what if`s come in on new engines.

I’d be most concerned with the condition of the timing chain.

Pop the distributor cap and watch the movement of the rotor while you turn the crank back and forth.

If the chain appears to have too much slop in it then consider replacing that. Otherwise leave well enough alone.

If you have AAA consider upgrading to their highest membership tier for towing, you’ll need to do it at least 30 days in advance of your road trip.

sounds like you have a good handle on it. Pull the valley pan and check it out. Of course, with that many miles there are lots of things that could go south on an 800 mile trip. Such as. a broken timing chain, oil pump failure, etc.. Anyway, if you really don't want to get stuck in the desert then take your daily driver, or, bring your tools, a few spare parts and keep your fingers crossed.

Feels like you are trading risk for unforeseen problems and delays in the engine work for risk of an engine failure on a long trip.

Not a simple question as you know!

I can tell you my 4bbl, cam, and lifter swap snowballed beyond reason (I don't even want to talk about it), but that's me and not you.

You do such nice work I don't see you settling for just swapping lifters. Mission creep beyond what you hope for can happen, so planning for the worst might help you prepare.

Maybe compare "what's the worst that can happen" for the two scenarios?

I personally have never done a leak-down test, but that might help you understand the source of the low compression pressure?

We have AAA, I'll double check on the plan. I hadn't considered following him in my daily driver. It's not quite as fun, but it's more practical - more room to store tools and parts and back up transportation in case something breaks.

I checked the timing chain for slop a while back when and didn't notice anything excessive. The fuel pump is another risky item. If we do the 4bbl swap, I'll change the pump. Might be a good idea to buy a backup for the trip.

I thought about a lifter swap, but that feels a little risky. I'd hate the wipe the cam. I do have a cheap leak down tester, but I couldn't get it working right. Maybe I'll give it another try.

I'm the cautious sort .. first, don't risk anything that could leave you in a life threatening situation in a desert.

I like the chase car idea, but yes, not as fun. AND when you get back home and the Ventura ran perfect the whole time you'll be pissed that you took a chase car. But if you DON'T bring a chase car then something will go wrong :)

I'd second checking the timing chain, assuming it's already been changed once if it's got that kind of miles on it, if it's never been changed then it's amazing it hasn't let go yet.

Spare points, condenser, coil, fuel pump. OEM lifters have to be on their last legs, but from what I have seen and badly worn original lifter won't prevent the car from being driveable, just makes it noisy and down on power.

Not sure what your situation is, or what plans you have for the Ventura at the event ... but there is always the option to trailer the car, you get to be in the same vehicle for the drive, no worries about the Ventura breaking down.

You need to check the condition of that timing chain and doing such can be done in less then 30 minutes without pulling the timing cover off.

It's likely the timing chain has been changed over the years. If it has, it's been a while. I'll check the slop again now that the hood is off. If I pull the intake and valley pan, it's not that much more to do the timing cover. It needs a new seal anyway. Slippery slope...

Thinking more about swapping in a fresh set of lifters to get rid of the tick. What's the level of risk of putting a new set of Johnson lifters on a 50 year old OEM cam?

I carry those items mentioned and spare water pump,belts,hoses,parts to repair alternator,and my qjet spare parts.When I took my street driven TA to Norwalk took extra driveshaft. I even took spare distributor, push rods,rockers,nuts few gaskets for intake. My friends would laugh in a kind way what I took. Always be prepared.Show on Saturday, race on Sunday.

I would pull that noisy lifter out and take it apart to, 1) see how much play the push rod plunger might have in the body and if varnish might be restricting the movement of the plunger, and 2) see if there’s any crap in it .

Surely by now the original cam has at least one or two lobes going flat.

Waste of time putting new lifters on a worn out original cam.

Leave it alone. Rent a U-Haul car trailer to pull it through the desert. Enjoy it at the destination-drags. Tow it home.

As practical as that is, he really wants to drive has car on a road trip. He's been talking about it since we bought the car. We're also limited on tow vehicles. Following in my daily would probably be the best option.

You're probably right. I was more concerned about a new lifter wiping a lobe and taking the whole engine out, but I'm sure the cam is on it's last legs. I also don't really want to drop a new cam in a 100k mile engine unless I'm going to go through the whole thing.

This is probably the most practical place to start in terms of the valve train - take it apart, inspect and clean the lifters, and put it back exactly as it was.

I am making plans to attend that event, but it is much closer to me.

Me? I'd throw in a mild cam/lifter/timing chain set (Summit 2800 for the win?), stick on the 4bbl, and go nuts. Pack snacks, drinks, and a fire extinguisher.

I would also want the experience without the trailer or chase car, but definitely get the previously mentioned insurance.

You probably haven't had the chance to do something so reckless and ill-advised since you were in college. Your son will learn about managed risk. And both of you will have perma-smiles for several months/years!

Ok, this is what I really want to do, but have been talking myself out of it due to the high mileage and low compression. I think I even have the 2800 in my Summit cart.

It looks like we'll be caravanning with a few of his friends who are trailering a car, so that adds a little bit more of a safety net.

When it comes to cam/lifters with that kind of miles, usually several of the lifters have a considerable dish to them, with the associated lobs worn to match. Yep, it's all or nothing when it comes to replacing those parts at that mileage.

Perhaps bring a "tow bar"? I don't know much about them, but maybe it could be a backup to get the car where it needs to be fixed if necessary.

If needed you can usually rent a u-haul and a tow dolly for the trip home if something breaks down permanently. Have fun!

Do what you posted back in number 14, but the very very first thing to do is to yank the plugs out , kill the power to the ING system then remove both valve covers and crank motor over looking for each push rod to be spinning like they should once you put a mark on them to make viewing easy.


While doing this you need to note if there are any that are spinning slower then the others, because they are going south and would be reason enough for me to replace the cam and lifters now.

Cam and lifters waring a that fine grit getting into the oil supply speed up engine ware.