304 - R.I.P. (Rest In Pieces)

Exhaust manifold.

 

(Smacks self in head. Homer Simpson voice.) Doh!
Say, Tim (or anyone else that wants to answer!), would you use existing headers, or stay with the factory exhaust manifolds? (And try to find a drivers side manifold to clear steering.) Just weighing options and since I'm broke down, I might want to make some minor changes... like a new dual exhaust exiting out back...

 

Well, things are moving along. Sounds like I have a lead on two 360's, should know in the next few days for sure. I'm hoping I can just pull and replace without doing a rebuild on the 360. At least for the summer! I want to be wheeling, not rebuilding!

 

I think that tubing headers are a maintenance headache - strictly race car tech. The stock AMC V8 manifolds are pretty smoth, as cast iron manifolds go. I'd also go with a stock-style crossover and a single free-flowing muffler, exiting at the stock location. I think you can get about the same gain in hp by just increasing your pipe diameter slightly, and the logistics are way easier.

There was a post about this a couple of days ago.

 

Thanks! I'll search for that thread as soon as I get some free time.
I may also port match the motor if it needs it...

 

I gotta dis-agree, Dude. In most cases headers will wake up an engine, with the corresponding parts to complement them. There are some cast logs that will flow like a header, but not many (and I have no idea how AMC stuff flows...) I sure won't be replacing my headers with cast stuff in the Jeep, I like the way they peform.
Sure they do take a little maintenance to keep the bolts tight, but it's an excuse to get under the hood anyways....or get stage 8 header bolts and never tighten them at all.

Port-matching is a waste of time on a mild rig like yours, mike.

 

R)R)R)
(WWF announcers voice, "And in this corner...")

Just doing a lot of thinking out loud, and getting input from everybody.
Heck, I've even thought about shorty headers with a 2-into-1 exhaust factory exit.
Bottom line, I've found a Waggy for $500 (maintenance guy here at work, wifes rig), ran great when he parked it. Front windscreen shattered (kids!) but otherwise straight. He said he would make sure it ran right before selling it to me. Also, packrat2A has a line on a motor. Looks like I gotta see who comes through first.
(You know, if I didn't have to spend so much time here at work, I could get something done!)

 

No question that headers can improve performance. Some engines have particularly restrictive exhaust tracts, but the conventional wisdom says that the Gen 3 AMC V8s are not among them.

It's also clear that headers are hot, noisy, fragile, leaky and expensive compared to OEM cast iron exhaust manifolds. Whether you think the performance improvement worthwhile depends on your priorities.

 

The only people I hear complain about that stuff with headers... are the people that buy cheap headers, or do not buy the good gaskets and bolts for them, or have the exhaust hung properly. Manifolds are just as hot and transfer just as much heat if not more to the engine compartment IMO, My YJ bakes under the hood with manifolds, at least with headers you can run header wrap and almost take care of all the heat.

Noisy is a personal preference R)

I know a guy that bought headers for a Chevy pickup, always complained about them, but they were the cheapest ones he could find, he used the cheapest paper gaskets, and hung them with his old manifold bolts.

Good headers are expensive, but you get a good return

 

A buddy of mine just posted a tidbit about this topic, Funny enough its on a Ford Truck Forum...

Original post (page 2)
http://www.fordification.com/forum/viewtopic.php?t=23220&highlight=

 

You don't port match an exhaust port to the header you do it to the Gasket, polishing the exhaust port will do alot of good . Anti reversion headers were a big deal back in the early 80's, Cylcone lost out when most of the hype about them was proved wrong or useless. The AMC dog leg exhaust ports worked better cause heat rises and the dog leg forced the exhaust to the roof where it wanted to go anyway. The port was changed for performance not just emissions.

 

Just a quick question...
While I have the engine out (and maybe tranny/TC) is there anything you all would check/replace/change? I figure that if it's accessible,, now is the time to fix it.

 

CLUTCH! unless it looks REALLY good! you don't wanna have to be pulling the tranny out again any time soon! LOL

maybe input bearing on the tranny? I don't really know how those are for those going out.

speaking from Ford experience, I always replace the timing chain on a stick-it-in-and-run-it engine. saves a lot of hassles later. Dunno about AMC. might be a good idea.

Then while your in there.......

 

Clutch parts are a good suggestion. Definitely
- throw out bearing
- clutch plate, maybe the cover depending on history
- lube pilot bearing

IMO R&R of a T-15 or T-14 and Dana 20 isn't that hard - I've done it in my driveway with just a scissors jack and muscle. So, unless you have suspicious noises coming from the transmission, I'd leave it alone. Same with the transfer case. Anybody out there with a T-15 that's worn out the front bearing?

If you're not going to overhaul the engine, I'd for sure replace the timing chain. I think the Cloyes chain&gear is well regarded. Inspect the timing cover and oil pump parts and bring them up to spec. Since you asked about oiling problems, I presume you know about that.

The problems I read about most often are a bad rod bearing or a flat cam lobe. I'm not sure if there's an easy way to inspect the cam, but depending on circumstances you might want to pull the pan and plastigage the rod bearings. If you can run the motor in the car, and the hot idle oil pressure is good, say 20 psi, I'd probably run it. A flat cam lobe should be obvious then too (tic tic tic).

Rear main seal replacement would be be worthwhile - much easier with the engine out. You'd have to take the pan off, but you might want to look for evidence there anyway.

 

Clutch is 'supposedly' new.

Great ideas.

Nope, no strange noises...

Uhm, yeah... that's kinda why I'm doing all this!R)R)R)
Timing chain... easier to do it now, and cheap insurance, OK.

I will try and run the motor if possible. If my cam from the 304 is in 'perfect' condition, can I use it? (It's a mild 'RV' cam.)
I like the idea of using plastigage, that way I can inspect everything while I'm at it! (No more dry bearing journals for this ol' boy!)

Actually, that is the one thing I did plan on.

Thanks for the ideas, gentlemen!

 

you'll need to use the lifters (in exactly the same/corresponding holes they came out of) to re-use your cam. Might be a good idea to use the rockers, also.

For a 360, it will become a slightly less of a mild RV cam (remember, its ground for a 304), but still useable.

 

That's right, I had forgotten that the cam and lifters become matched to each other. Or I could just use new...:twisted:

 

I'd use new lifters if I swapped the cam, unless the lifters are near new. Depends on how tight money is...

 

Gotta sell my boat to pay for the Jeep
And I guess I'll use some of the $$$ to work on the Scout.
Figures, go from one expensive hobby to another!R)

 

Considering what has happened, I will be inspecting everything I pull off the 304 with a fine tooth comb! And if there is any doubt, it will be replaced with new.