273 refresher

[paulclark]

I've just scored a running (but smoking) '67 273 to replace the long-gone 273 in my 64 Dart GT. The plan is to get it back together without delay, which means without turning it into an extended project.

What would you do to refresh a solid motor? Assuming nothing is worse than I think, can I get away without a trip to the machine shop? That said, since it's already out, what should I consider doing that would be harder later on (clutch disk for sure). I'm thinking:

rings
main & rod bearings
gaskets

but what about:
cam bearings
valve faces - lap 'em?

what am I forgetting? And also:

can I run a compression/leakdown test just cranking the starter alone?

Since I'm in there, I admit I'm thinking about a mild cam swap, maybe something to increase lift without raising the rpm. And yes, I am thinking about a 4-barrel. See what I mean? it's tempting to go crazy... and I really want to wrap this up and get it back on the road.

Thoughts? Advice? What have you done in similar situations?

Thanks,
Paul

 

[krazykuda]

If it's in ok shape as you say...

Skim it with a ball hone.

Main & rod bearings.

Inspect the cam bearings to see how bad they are and replace if needed...

Get a good valve job and have hardened seats installed on the exhaust valves...


If you keep the trans hooked up outside the car, you can take the positive cable and a battery and jump the starter to run a compression test.

If you want a better cam, now is the time for it, There are a few threads on 273 solid camshafts on here, do a search...

Mancini Racing has "refresh kits", but you will have to see if they offer any for the 273, as they usually don't stock the 273 specific parts, but can order them for you..

Here's a main page for their Kits, A & B are nice quick and cheap, you may want to look into a kit C if you need freeze plugs and oil pump, but pistons may be a little tricky, but the price is reasonable... Your call...

http://www.manciniracing.com/enrebkit.html


Here is a good timing chain that I have run in all of my engines for many years, it is one step above the stock 340 double roller and will fit the 273...

http://www.manciniracing.com/edelbrock4.html

 

[paulclark]

great info, thanks!

 

[R0K3_B3aRd]

stroke the sucker the more you stroke it the more power it gets, bigger cam, bigger heads, 4bl intake, holley 4b carb, msd distributor, and headers. If I'm not mistaken just need to make it into a 273 commando. not sure tho but all those things listed will wake that engine up hard.

 

[krazykuda]

Oh yeah, Welcome to FABO!

 

[66fs]

It should be a forged crank, so should not be much wear if any. rings, bearing, gaskets and seals, brass freeze plugs, cam bearings should be good, double roller timing chain set, It should be a solid cam and lifters around 260 duration up to .450 lift, I would mill the heads and get a valve job. Pilot bushing, clutch and pressure plate (10 in scalloped from Brewers Performance (as a stock one will not hold up long), Performer Intake and a 500 cfm Carb ( I would use an Edelbrock Thunderer or Street Demon), Get a good distributer with a quick curve and all in by 2,500 RPM. Don't buy anything till you get it apart, a lot of this may have already been done or the cylinders may be worn too much and need pistons. Enjoy and Welcome!

 

[RedFish]

You may find the valves recessed into the seat area of the heads. Some have found edges of valves worn to razor sharp.
Any shop that would rebuild it for you and provide a warranty would do freeze plugs, cam bearing, the works.
A lot of it goes to how long you expect it to run. If you'll only drive it occasionally and accumulate only 40 to 60 thousand miles without issues, short cuts like knurling the valve guides and piston skirts will work.
The one extremely important component that so many ignore is not bolted to the engine. RADIATOR ! They'll wait until their reman'd engine runs hot and question why.

 

[cosgig]

I would consider changing the freeze plugs, any gaskets that are leaking, and any related wear items that are harder to change when the motor is in the car! Geof

 

[paulclark]

Sounds great, thanks everyone for the advice and links. Compression test next, then a stripdown. I'll post updates as they happen. A couple points I'd like to confirm:

Sounds like no need to separate pistons from rods, assuming they inspect and mic Ok and there isn't significant wear at the wrist pins?

Should I plan to bring the block and crank to the machine shop or just the heads? I'm assuming for a freshened street engine that won't see race duty I can keep it simple unless something appears wrong. Or is that overoptimistic?

Should I plan to remove the crank entirely or is this a situation where the bearings can be slipped in without doing that?

 

[gtsdude]

When I bought my dart it was running, but pulled it out to do a refresh like you are planning, it had sat for 7 years. Machine shop put new cam bearing in and hot tanked the block, checked the bores and did a hone job on cylinders. I was able to reuse my pistons, did not have to take rods off. Installed hardened seats on exhaust only, had several sunk seats. Had machine shop check the crank and polish it. After getting all the parts back I put new freeze plugs, new gaskets, new cam, new timing chain and oil pump. Checked my clearances and put it back together. That was in 2001, still running strong, no smoke and has 180lbs compression. As far as what to take to machine shop, its going to depend on condition of the parts when you get it apart. My cam bearings were wore, I wanted the crank checked out before putting it back together also. When I took the freeze plugs out, the back ones on the side of the block were full of sand and I think rust, so I had it hot tanked.

 

[BlueDream]

Sounds great, thanks everyone for the advice and links. Compression test next, then a stripdown. I'll post updates as they happen. A couple points I'd like to confirm:

Sounds like no need to separate pistons from rods, assuming they inspect and mic Ok and there isn't significant wear at the wrist pins?

Should I plan to bring the block and crank to the machine shop or just the heads? I'm assuming for a freshened street engine that won't see race duty I can keep it simple unless something appears wrong. Or is that overoptimistic?

Should I plan to remove the crank entirely or is this a situation where the bearings can be slipped in without doing that?

I'd strip it down to a bare block and have the machine shop hot tank it and install new cam bearings. It's not hard to pull the crank out once you've got the pistons and rods out. Mic the journals to see how much they're worn. I did a re-ring on my 318 and did some mild upgrades and it ran good. All new bearings, rings, timing chain, oil pump, core plugs, cam & lifters, carb, and intake. If your cylinders are't worn very much and the crank is in good condition, it should be pretty straight forward.