So as many of you know, my cherry '89 has a rod bearing problem, and i think I have decided to just do the rebuild myself. I found a motor for cheap, but it has high miles and i dont want to have to do this all over again so i think a rebuild (done right) is the best way to go. SOOO a have a few questions for all of you MASTERS...

I have about $1000 to work with, and i will be doing the R&R myself. Time is really no issue as i have been riding my motorcycle (thank god/ prey it doesnt have problems).

So i really need some input on what parts to use. I want to get a nice performance increase, and still get another 100K out of it. I havnt really looked into any of this, so if you guiys could just throw some reccomendations out there that would be great. So far I plan on doing a mild bore, w/ oversized pistons, and maybe a mild cam. What else can be done on these 4.3's internally that i wont have to reprogram the computer for, and thats not too wild?

Heads? crank? etc, etc help me out guys...

Thanks

 

can anyone help me out on this???

 

Wow... Well, I had thought out a nice response to this as I read it and did not have time for a response right then. Now I have completely lost my train of thought due to the unnecessary bumping of this post... I'll have to retrace my thoughts when I have some time in the hopefully near future...

*EDIT*

I will ask for a few things... Budget? Expectations? Experience level (ie. what you are comfortable doing)?

 

Thanks i appreciate it swartlkk....

Budget: around $1000
Expectations: To have a completely "new" motor... like it came from the factory, but with maybe 25-50 hp increase
Experience: done numerous motorcycle rebuilds... never an automobile. Time is not an issue, and i'll have the help of my neighbor who is a mechanic when needed. I'm gonna have to sub out the machine work, but everything else i can do.

I guess i need some guidance on what to go through when I'm in there... any trouble spots on these things? Also need some guidance on where to go as far as parts... kit/indv. parts.

I have a feeling Im gonna need to have my crank redone, and i dont want the bearings to go again... = oversize? Heads? Cam? etc etc

As you can see, i'm pretty lost on the parts aspect. I know that i want to do 30 over bore, and aftermarket headers/ full exhaust. Will this get me the performance increase im after?

Otherwise id like it to be as reliable as a brand new motor.... I guess I have high expectations, but i just want to make sure i do this RIGHT so i wont have to worry about it again.

Any help is much appreciated!

 

A budget of $1000 should be easy to work with.

For an overview, you will need new pistons (due to the 0.030" overbore if you go that route), rings, main/rod bearings, new cam bearings (if you choose to - I would recommend they be replaced), at the least a polish job on the crank journals, the bore on the cylinders, etc (for the stuff I probably left out).

Ok, onto the work you need a machine shop for. The boring of the cylinders requires the expertise of a machine shop. You will have the shop bore the block, check for a flat deck (head mating surface), and install the new cam bearings (if you choose). You can also have the shop rebuild the heads for you if you choose. They should be checking the flatness, doing a valve job (which will re-cut the valve sealing surfaces), install new guides (if necessary), lap the valves to a perfect seal, and install new valve seals.

Then there is the crank. You really have to determine if the crank is salvagable first by inspecting the journal that was affected by the lost bearing. If the journal can be cut down, you have a choice to make. Cut one journal and only get one oversized bearing for that journal, or cut them all to keep them uniform. If it were me, I would try to source a used, but good crank that would just require some polishing and install stock bearings. With the "split pin" design of the crank in these engines, it is quite difficult to cut a journal properly.

As far as performance goes, I would highly recommend an aftermarket cam be added to the mix (pretty much requiring new cam bearings). However, this might bust the budget as new lifters should also be installed. A full cam/lifters kit should be available from places like Summit Racing or Jegs.

Sorry this seems short, but I just realized what time it was... This article - 3/4 350 should shed some light on some things that can be done. As the article suggests, the cam is the biggest expense in the build, but is key in making power! Here is another thread posted by another member - CLICK HERE - may help some as well.

 

Thanks for the reply man... Il have to call some shops to see what they want for the bore, valve job, and possibly crank polishing. Then Hopefully i'll have enough to go with header/ exhaust and cam kit.

Couple question:
1. What is a good brand piston? Ive always used weisco on my bikes, but have no idea with these...
2. What all gaskets are nessesary for the job? Again, can you suggest a good brand?
3. What about valvetrain? Does it need to be replaced as well?

Thanks for all the help!

 

Since you aren't going to be testing the strength of the piston (ie. not huge power numbers), anything will do. Just go for a master rebuild kit that gives you the option of larger pistons, rings, and oversized bearings.

 

Somthing like this

What about the valves, valve springs, pushrods, etc etc???

 

That set would do nicely provided your rod journals did not change... The valve seals are included in that kit. The push rods can be reused as can the valve springs. You would still need to assess the condition of the valve guides (disassemble the heads and feel for play in the guide).

 

Okay thats good to know... How do the quality of those kits compare to oem?