cylinder walls of a BP engine

[mazpr]

I would like to know what other member think about the following pictures.

BP 1.8 engine block.













The engine does not smoke at all, it feels strong, only reason to open the engine was to install new HG.

It seems the damage is only in the top crown, they are SuperTech forged pistons 9@1. My plan for now is to install the new head gasket and use it until I can recover some money as the engine does not have more than 2,000 miles on it. Part of the problem was when at 1 bar the fuel pressure gauge vacuum line disconnected and the engine went lean to almost 15 afr, later when I started experiencing the engine to get hot.

Correction to post:

Under closer inspection the head gasket was fine, not broken at all. It seems the problem is with incorrect piston to wall, ring gap clearances. Same overheating problems even with 2 head gaskets installed with ARP studs.

[nos92mx3]

id clean up the piston and run it, just knock down the sharp edges

[Ryan]

yeah, I'd say that all looks fine, like nos92mx3 said, just debur that little part of the piston and go. You can shadetree check your head/block flatness with a level and a feeler gauge, or ask a shop to do it. Cylinder walls and valves look just fine.

3/4 to the H?

Thats nothing, my ZE sits at 3/4 to H in traffic.

Are those ARP head studs? Nice.

[mazpr]

Thanks to both of you, thats what I did...

I said f.. it and lets see what happens after I put everything back. The engine took a hit with that overheating and lean condition. I learned my lesson to zip tie all vacuum lines especially the one for the AFPR. The car was running fine until the moment I was pushing 15 psi to redline and all of a sudden the wideband went to 15 afr readings. I immediately let go off the gas and right after that in traffic the car started overheating. The vacuum line for the afpr got disconnected... It is incredible a almost $1,000 dollar engine almost went south with such stupid mistake.

The cylinder walls were cleaned with wd40 and some sand paper 400, 240, 180 and so on. I can see the piston crowns scuffed, but man those Supertech do deliver. Installed new head gasket re-torqued accordingly the arp studs, fresh coolant and to the road I went.

For now I lowered boost from 15 to 12, installed NGK7 to .025 gap, instead of previously with NGK6 to .040, and also adjusted for less ignition timing.

The car is running good, no smoke coming out of the exhaust, turbo spools, no leaks, no coolant consumption, etc.

I do know that I have to start saving money as that engine after this is a time bomb if I go higher on boost.

Let the engine idle for 10 minutes and no overheating, did multiple passes at 12 psi and no heating problems.

I am very happy that at least it runs. Will get a new block and build it from the ground up little by little.

[Josh]

I had a similar issue in the past. I was running way to lean and had a tendency to overheat.

Couple of things i did was to run colder plugs, which it looks like you are. Then I ran a colder Thermostat 180 deg i believe I think stock is like 192 or something, then I also spliced my AC fan into the cooling fan to run duels. Every little bit helps

[nos92mx3]

One thing i have learned , THe water/meth kit i used has saved my a-- so many times, From popping a motor.

I run a 60 trim t3 @ 18 psi, on the stock bp10 ecu all controlled by a aem fic. Ive bumped the base timing 3 degrees and have have ignition retard per boost.
One time i can remember i was doing some rather spirited driving and around a rather long sweeping right corner i got on it around the apex, Felt the car miss look down and see the air fuel sitting around 19-1, so i got out of it. Motor still runs good to this day, knock on wood. haha

[mazpr]

You know I was just checking into water/meth but man are they expensive, like 300 or more for a kit.


Do you use water/meth or only water?

What kit do you have? I see as well you have installed one of those aem fic.

Which one do you have?

I have an Apexi SAFC, the silver one with the 8 adjusting points.


***

On a side note, I think the work done at the machine shop was not good at all. They over-bored the block to 84mm, assembled it completely with new M-Tuned rods and Supertech pistons 9@1 180 compression.

I do not understand how is it possible that before the car ran much colder with 10@1 cast pistons, stock rods, without touching the motor at all with its stock 83mm bore. With the previous setup I had 210 compression, and everything has been cleaned and put new parts. Installed new oil pump, new HG, injectors sent to injector-rehab, new clutch, braided clutch lines, etc.

Before with the 210 compression Miata cast pistons I did not have to turn the fan on on heavy traffic (as the electric fan is set to manual on/off). The engine never ever saw more than a half, by the way the thermostat was stripped gutted out, and only left the plate for some resistance. The car running at 12 to 15 psi with the cast pistons and higher compression, gutted thermo, etc would run very well.

I dont know if the clearances are to tight, or the +1 boring of cylinder walls affected the temperatures. I also installed arp studs, which before it only had reused head stock bolts. It has me scratching my head as to why now it is giving me so many problems.

Also, on my first setup the only reason I tore the engine open was due to a failed oil pump shooting the oil gear pieces inside the engine. The top of the pistons never suffered a tad bit, and that was using a ghetto ebay afpr. Now I added a better afpr, and engine heats up to quickly if I do too much boost, and the top of the crown suffered on forged pistons. I just dont understand...

I kept the same turbocharger, same pipelines, bov, wg, turbo mani etc.

To make things worst went to Discount Tire to get my new set of wheels/ tire combo, MB wheels Weapon on Kumho tires 16"s. The tech asks for the vehicle keys, and I no, that I wanted to see the wheels first to make sure everything is ok. The first wheel is fine, 2nd and 3rd wheels scratched in the center like in a circle nearby the holes. I told them to keep the set and call me back when everything is ready. Jump into my car and it will not start, managed to turn it on, came home and did a compression test and is much worst than I thought.

Piston 1 - 140 psi
Piston 2 - 178 psi
Piston 3 - 120 psi
Piston 4 - 140 psi

When the engine was new all readings were at 180 psi.

http://s93.photobucket.com/albums/l70/p ... 0_0570.mp4

Here is a video when it had 10@1 Miata pistons w/ 210 compression, stock internals, if I recall it was like 12 psi. Clutch was slipping badly as it had a stock pressure plate Dakin with 4 pad disc. I went from all motor setup, slapped the turbo and tuned with the SAFC, adjusting the RX7 maf, and an adjustable fuel pressure regulator, 550cc RX7 injectors. It ran so much better with the old setup.