Hey guys,

I'm in the middle of a budget build of a VVT motor. I am pretty much just throwing a set of rods in and keeping all else more or less stock. I don't want to put the money in for machine work but I want to use a set of lower compression pistons. You guys think using "DNJ" pistons from Rock Auto will be as safe as using a set of Mazda OEM 94-97 1.8 pistons?

http://www.rockauto.com/catalog/moreinfo.php?pk=1808976

 

New pistons and rings = you're doing machine work or the rings will never seal.

 

I'm asking about the quality of the pistons above (or any other aftermarket oem) vs using Mazda pistons. I know I have to hone the bores and replace rings at the minimum. I just don't want to bore the block for larger aftermarket forged pistons.

 

I know you're going for budget build, but just FYI, my block's at the machine shop now getting tanked bored/honed/decked for $325 and I know Soviet was getting the same for $360.

You're already putting a lot of money into it on rods, bearings and the plethora of gaskets and seals to close it back up. It's not too much more to go another step...just wanted to make sure you knew what the cost's were.

Bird

 

Damn you guys, you're supposed to convince me that cheap is ok.

The rods are ebay rods btw. I've gotten quotes for $500-600 for the machine work locally, and proper pistons will be another $500-600. The bleeding has to stop somewhere.

 

Check my build thread...I tried to go cheap...my goal was to buy used.

There's a lot of blood there....


Bird

 

I'm not really looking for anything used though...except possibly used 94-97 pistons vs some china made oem spec pistons.

I'm following Pat's budget build idea (don't remember thread title or actual user name).

 

I meant I had tried to buy used to do a 'budget' build. My budget got blown out of the water....


I was just trying to get at sometimes it's cheaper to spend more...



Bird

 

If I wanted to stay cheap I'd reuse the pistons, get $200 ebay rods and hone myself.

you can actually skip all the machine work if you decide not to resurface anything and hone yourself.

you can also skip all the measuring tools besides plastigage. just get everything standard and cross your fingers that the oil clearances come out alright.

but still, at the miniumum:
- new rings
- ring filer
- feeler gauges
- ring installer tool
- bearings
- all the damn seals

 

and if you're taking it for machine work i would AT LEAST bore it out.

 

If I get forged pistons, then boring is required. I am going to be honing myself.

The main question is whether or not to get Mazda pistons or China pistons. I don't want to reuse my pistons because they are higher compression.

 

my biggest concern with using OEM/China pistons is that you wouldn't know what piston/wall clearance you will end up, unless you're baller and have 3-4" inside and outside micrometers.

but since you want to be ultra mega cheap, skip getting the parts separately and just get a rebuild kit from fleabay.

http://www.ebay.com/itm/Mazda-Proteg...ht_4150wt_1164

 

You're correct. I would have forgotten about that until I got the pistons here and realized I would need to get the block bored anyway. I'm going to consider reusing the 01+ pistons. Pretty sure they'll support my power goals fairly easily anyway.

 

I am bumping this thread in order to get some closure on this subject since I am on the same boat. I have a VVT engine which I plan to turbo. Only thing is whether I should use the 02' pistons or get 94-97 pistons which have a lower compression ratio. My power goals are sub 250whp. I also plan on getting rods. I took the 02' engine apart the other day because of unknown condition and saw the pistons had some scuffs and scratches on the skirts. Not horrible but noticeable. Re-ring or buy new pistons?

The actual combustion chamber looks fine and has cross hatching still visible. Rock Auto pistons? Keep 02'? Buy NA 1.8 pistons? Ive read about coating them but at my power goals I dont feel it would be necessary.(EL CHEAPO)

PS: Can some of you veterans direct me to y8's build thread? Ive been searching to no avail. From the lurking I have done it seems his build thread would be to my interest.

 

I have done at least 2 engines like this so far:

bp4w/bp6z long block + OEM 94-97 pistons + high quality rings + hone + all new gaskets/bearings.

Works like a charm, despite all the nancies in here screaming that it will blow up in your face. This is of course if you understand that its a budget street motor, and don't expect to flog it on the track too much or put insane power or high rpm through it. It works if done right (and that's a big IF). Another big factor is what kinda condition the motor was in prior to build. Some that are high mileage/abused/broken may and WILL require more than just those basics I mentioned. This would be completely up to you to make that judgement call. In the end, if you're wrong, all that money you spent may be wasted.

I would not go with the china pistons because nearly no one has extensively tested them to be as reliable as stock, and unless you want to be the guinea pig, I'd stick with oem.

y8s doesn't really have a build thread.

 

That is perfect since this is a street motor and I have no intentions of tracking it. The most this motor will ever see is the occasional auto-x.

Another question. Is it normal for an engine with around 88k to have scuffs on the pistons skirts? It wasn't enough to eliminate the cross hatching on the cylinder walls but its noticeable on the pistons themselves. In any case thank you for the reply and it looks like 94-97 pistons will suit me well for my goals.

Also I was doing some reading and the VVT oil pump is different due to the it needing to pump extra oil. Being that its different and flows more, is it stronger than other 1.8 pumps?

Im also on the edge on ARP hardware. I see people running stock head bolts and being just fine and since AGAIN I am not tracking nor expecting SOVIET power goals, does this seem more like a waste of money? Sucks he doesn't have a build thread but if I remember correctly shieund on here had a stock VVT motor running for 3 years on low boost.

 

Would you be willing to trade pistons? I have a set of 94 pistons sitting in my old block that I would trade for some 01+ pistons. I may also want your old stock rods.