Need Help on Rebuild....

[BuGS]

Ok So i bought this engine that has a rebuilt head but the bottom end has 144,XXX miles on it, So I havn't done a compression check but I am pretty sure it is around 160 or lower and so i am going to rebuild the bottom end. Can anyone help me on to where to get the parts and which ones I need. I am planning on going turbo, But the turbo won't come for 6 months at the earliest. I don't won't too high comp. because the closest dyno is 3 hrs away so all tuning will be ear tuning. So any help is greatly appriciated. Thank You!


Clayton

PS I also read the miata piston forum and am now more confused then before i read it so any help is good!

[John Long]

My BP has 100 miles on it now, and it is still going strong, lol. I did a lot of searching, and the best prices I found were at www.rockauto.com. They ship quickly and are very trouble free. I bought mostly Sealed Power (a.k.a. Federal Mogul and Felpro), but I also got some AC Delco parts too.

Even though your head was rebuilt, it doesn't mean the HLAs were tested or replaced. Make sure you check them. I had 10 that were going bad, so I bought all 16 new ones ($300, ouch). The one thing I missed were the valve springs. These are really cheap compared to everything else. You might want to search for some that are stiffer than the OE ones. I have heard they exist and they reduce valve float.

[BuGS]

stick with the stock pistons.... they are good enough for turbo

replace ALL the seals, water pump, oil pump, rod and main bearings

inspect the cylinder bores for taper and out of round... if they exceed specs, bore the block out and get oversized pistons.... if they are good, get the block hot tanked and then rehone the cylinders, and finally replace the piston rings

don't forget to remove the oil squirters before you do anything to the block, you don't want to lose or break them!

it maybe a good idea to have the machine shop repaint the block for you after they hot tank it... masking and painting is time consuming, but if you don't care and want the best job done, do it yourself

finally, it maybe a good idea to shotpeen the rods also, if you find the right place they won't charge more than 40 bucks for all 4 rods anyway.... the stock rods are plenty strong to begin with, but doing this is just extra insurance

And how much do you think this would cost all together?? With the two different optoions: 1; with overbore and new pistons 2; w/o overbore and new pistons.

[Tweeaks]

I have a thread in the photo gallery about my BP rebuild. So far I have spent almost $800 on parts. I haven't touched the pistons or rods. Basically everything OEM except for the seals, which are Topline, the oil pump which is a Toga high volume, and the rod bolts which are ARP. I have a list of where I got everything from and how much each item costs. I also am switching to fully senthetic motor oil so that was also included in that price. Heres a link.........http://www.wihandyman.com/forum/showthread.php?t=12586

[BuGS]

any other thoughts please???

[John Long]

I got mostly Sealed Power parts, and got good prices at www.rockauto.com.

Make sure you check your HLAs. They have a plunger right where they contact the top of the valve stem. If you can push in the plunger with your fingers then the HLA is bad. Ten of mine were bad, so I replaced them all. Even at rockauto that was about $300, but now I have the most click-free Mazda engine I've heard. Some people have posted that you can take them apart and clean and fix them, but I don't see how without wrecking the lip that holds the plunger in place.

I did not replace the valve springs but in retrospect I would consider getting some stiffer ones if they exist. Springs are very cheap and stiffer ones might help the top end. (any opinions?)

[naprotejay]

regarding the valve springs, if going turbo and using the stock cams, there's no need to upgrade the springs.... of course if they're out of spec, then yes replace them. as i understand it, though, the stock oem springs are good; the only time you need stiffer springs is if you're revving above ~7500rpm or using over 9mm lift cams.

www.flyinmiata.com and www.corksport.com sell them

[BuGS]

The head was totally rebuilt supposely. So I was just more wondering about the lower end. Does anyone know what is decent Compression on the engine if i am going to go turbo? "I don't want to fix it if its not broken... "

[1ofdfew323]

damn $800 just for the parts.

[John Long]

that 300 bucks on the HLAs I rather spend on a solid lifter conversion

yes, the sealed power/federal mogul bearings are very high quality, so are the seals... as for gaskets and other parts, definately get mazda ****

I thought about the solid lifters, but I was running out of time and I couldn't afford the dink-around time figuring out how to order the right solid lifters and hassle factor of shimming them. Getting the HLAs was a bit of a punt.

It's good to know the mazda gaskets are the best choice. I got all of my gaskets and seals in a single rebuild set. I think this set was a good choice because some of the seals - like the oil pump seal - seem to have options depending on the make and year, and the set has them all.