273 assessment

My son is trying to ready a 66 Baracuda for the road. It has 128k miles on the 273. Last year when he got it, he got it running off an IV bottle. We have already removed the oil pan, intake and valve covers and cleaned out the gunk as well as replaced the valve seals. Rebuilt the 2V and replaced gaskets. Got it running tonight and allowed it to run on its own and get warm and the blow by on the right bank is very noticeable. Did a compression check and the manual says it should be 135 psi but they checked 90 to 105 and one hole checked 115. The solid lifters are making a little noise.
What’s the realistic prognosis for this engine if he wanted to try and get a couple of years out of it? Is it dead? Could a hone and ring job help? Are the cylinders likely to be in need of boring? Could it get better with oil changes and driving?

You pretty much spilled the beans by saying you have already cleaned out the junk. Hate to be the grim reaper, If its huffing out the breather its time to pull it out and rebuild it,

If it was mine I would try changing the oil after driving it on several long trips, 100+ miles to get the oil hot so it will help it clean the gunk off around the oil rings and then try another compression check and watch the blow by coming out of the breathers with the PVC valve pulled off the valve covers, if it is getting better drive it until you don't like it again.

hi
yes if you have it running drive it so it goes through a dozen heat cycles then recheck it .

it may just need to be run a little.

add 4 0z of tran fluit to the engine oil 50 miles befor each oil change , it will wash out the gunk around the rings !

Agree with giving it some driving time to give rings a chance to free up, if they're stuck. How can you tell how many cyls are the issue? Whatever you see coming out breather, may just be all cyls combined spewing out.

What are the chances the lifters need adjusting since this is a solid lifer engine? There is some slight ticking but I am not heard a solid lifter engine in years. I know they are not as quiet as hydraulic lifters anyway.

Valve adjustment can affect compression testing numbers as well.

You did do the test with the engine warmed up?

The compression test was while it was warm.

I would suggest he drive it & have fun with it & continue to learn from it & in the meantime start building a 360 or better yet a 408 (4" stroker cranks & the KB swap pistons are reasonable). Noone who I have ever spoken with who has done this has regretted going this route.

That is exactly the plan. We are hoping to take it on the HRPT long haul this year as it is. Then next year have a 408 ready for it. This isn’t his first rodeo but it is his first Mopar, finally.

273's are great little engines. I had a 65 Coronet with one. No matter how many times I adjusted the valves though, it always sounded like a sewing machine. If the solid lifters are too noisy for you, just swap in a hydraulic valvetrain from a 67 up 318. The factory did just that in the 68-69 273's. I have a 68 273 that came out of a Dart I had. Before I got it, someone put a 69 340 intake with a 600 Eddy carb on it, a set of Hooker headers and 3.55 gears and it ran surprisingly strong. We pulled it in favor of a warmed over 360, but I kept the 273. Never know when I'll need a dependable engine.