3.0 Overhaul

[Rye]

I'm new to this forum and I'm looking to rebuild my 1989 3.0. If anyone could give me any tips it would be greatly appreciated... I know that there isnt' many or any real performance parts out there but I was wondering if anyone knows of small things I can do to beef up the V6, I already have a ported plenum and a 52mm Tb. Someone told me I could replace the Camshafts with that of a SOHC Mitsu. Montaro, just wondering if thats true. I know for a fact that the valve guides need to be replaced seeing how I'm burning oil. Should I get new heads that have already been ported and rebuilt or would it be cheaper to get a machine shop to work on mine. My main goal is to supercharge the engine, are the stock internals strong enough to hold the boost?

Thanks, Rye

[mwinkle353]

Don't bother with the Montero cams. They have the exact specs as the Chrysler 3.0L units. The only true "factory upgrade" is to use the FWD 3.0L Mitsy cams. The Diamante units have increased overlap/duration on the exhaust lobes.

As for beefing up the 3.0L...... It doesn't really need beefing up. The connecting rods are the same as the Twin Turbo rods in the Stealth/3000GT's. The pistons are cast, and are as good as you'll need for anything not using boost. But if you are going for boost, don't go over 13 psi of boost with the cast units. Even then, the slightest bit of detonation will start to crack them. These motors have been proven to hold up to 13 psi with superchargers without issues. However, I'd recommend using forged pistons, due to their ability to handle a few cycles of detonation better than the cast units can.

Heads.... If you can afford to have your motor out of commission while you have your heads worked on at a machine shop, then this would be the least expensive way to go. Or you can have your heads swapped out at a rebuilders shop. Choice is yours.

Good luck,

Wink

[Rye]

So I should look for mitsu. Diamante cams then? What about exhaust should I try a 2 1/2 inch or 3 inch if I supercharge?

[Ondonti]

Wink

No offense to Rob,

But I can tell you are using information from his camshaft spreadsheet.

If you look at the cam specs, you will see he did the total durations absolutly wrong.

The cams actually have 10 deg more intake and 11 deg more exhaust. I have no idea where he came up with those total duration #'s because they are wrong.

[3rdGen3.0]

Anyone know of a reputable rebuild kit? I've seen that topline have re-ring and master kits... I'd like to get forged pistons and rebuild components that will put up with increased load of boost... I've seen that toga bearings are offered...

[Ondonti]

clevite 77 are cheaper and better.

[Boogieman142]

yup, i use clevite 77's and no issues, have used them on all my motors when a re-build was needed

[3rdGen3.0]

where to get said rebuild kit?

[Ondonti]

you better think about this more

Rebuild kit and forged pistons dont work together.

If you want forged pistons, then you need to find a set of rings you want, then get the specs on them then call your forged piston dudes and tell them the specs on the ring.s

[Boogieman142]

You should get an underdrive pulley for it too.

[crazyace]

No matter what way you choose just avoid Top Line brand parts. The piston tops are thin, proven when Rob's 10:1 motor split the heck out its parts. They are noticeably thinner with the eye even. Their rings badly measured even against the piston they send with the kits. Over all bad quality. The Clevite 77 bearings should be available through any NAPA. As for the heads - have the valves back cut and then a 5 angle valve job. I am not sure yet of how good of quality the metal of the valve is or I would suggest having the stem undercut too. If you can afford to have them ported of course do so, just do not get carried away. A lot of guys make the mistake of getting a race port job done to a mostly daily driven engine and sacrifice driveablity. As long as you keep everything on the same level of modification you should have a very good running engine.

[phantomrt]

I was looking at getting some new pistons for my Chrysler 2.7, and I found them on the internet for a really cheap price-- like $230 for a set WITH rings. They were made by TOP LINE. From the dealer, the piston/rod assembly (the only way they sell them) was $147 with my 20% discount and does not include rings.

Yea, they're pretty cheap. I emailed the seller asking him about wether or not they have the moly lube on the piston skirts and wether there is a weight specification to the remanufactured rods he sells and wether or not these reman rods were original bore size... they are powder forged rods, which means you cannot re-size them to original, but you can enlarge the hole and use thicker bearings.

I got no answer, so I ordered them up at the dealer. I am sure I will be much happier that way. There is a REASON for the difference in price.

[Ondonti]

Quote:

Originally Posted by crazyace No matter what way you choose just avoid Top Line brand parts. The piston tops are thin, proven when Rob's 10:1 motor split the heck out its parts. They are noticeably thinner with the eye even. Their rings badly measured even against the piston they send with the kits. Over all bad quality. The Clevite 77 bearings should be available through any NAPA. As for the heads - have the valves back cut and then a 5 angle valve job. I am not sure yet of how good of quality the metal of the valve is or I would suggest having the stem undercut too. If you can afford to have them ported of course do so, just do not get carried away. A lot of guys make the mistake of getting a race port job done to a mostly daily driven engine and sacrifice driveablity. As long as you keep everything on the same level of modification you should have a very good running engine.

My machinist doesnt seem to like our stock valves at all. I am gonna need new valves for my motor anyways, (around 10 bucks a valve, and only the exhaust valve is stainless for replacement valves). I guess Im gonna bend over and buy some custom valves at about 20 bucks a valve. If I didnt have the 1/2 scholarship I probably wouldnt do it. :P Anyways that doesnt seem like a horrible price. THese are not going to be from ferrea obviously.

My machinist and his workers rebuilt thousands of 3.0 heads back in the early 90's. Im pretty sure Im the first to actually play around with it.