Track'ish Oriented 99 Build (The other kind of forced induction though)
#22
First time doing a compression test so I definitely may have done this wrong. I performed the test while the car was cold and I didn't run the test at WOT either. I'm now reading that would be the correct way to run the test. Results are in order of cylinders from front of the car to back.
Cylinder 1: 184PSI
Cylinder 2: 166PSI
Cylinder 3: 195PSI
Cylinder 4: 150PSI
Seems kind of all over the place. I'll try re running the test warm at WOT. Should I be concerned about these results?
Cylinder 1: 184PSI
Cylinder 2: 166PSI
Cylinder 3: 195PSI
Cylinder 4: 150PSI
Seems kind of all over the place. I'll try re running the test warm at WOT. Should I be concerned about these results?
Nice build thread. This probably isn't a bad idea for me to do as well as a baseline for my 120k mile engine. The list of stuff keeps growing.
#23
Ultimately looks like the results aren't great but not horrible.. you could also rerun the results with a warm engine (unless this was warm) and see if the results improve. Ultimately not something to probably worry too much about if the car feels fine. Other things to keep in mind have you done a valve adjustment in a while? Definitely something to do if some are out of spec that will affect a compression test.
Nice build thread. This probably isn't a bad idea for me to do as well as a baseline for my 120k mile engine. The list of stuff keeps growing.
Nice build thread. This probably isn't a bad idea for me to do as well as a baseline for my 120k mile engine. The list of stuff keeps growing.
Thanks!
Compression test done while motor was hot and at WOT.
Cylinder 1: 195 PSI
Cylinder 2: 170 PSI
Cylinder 3: 200 PSI
Cylinder 4: 155 PSI
I noticed the tester came out wet after testing the fourth cylinder. Looking at the spark plug from the same cylinder you can see that the threads are wet. I'm not sure what this means. Will have to look into it.
4th cylinder spark plug shown on the right. The threads are wet. Seems to be oil. Couldn't be anything else, right? Didn't smell like fuel.
New plugs gapped to 0.044 per Treasure Coast Miata suggestion.
Out with the old in with the new at 102,105 miles.
#24
Cpt. Slow
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You've got something going on in cylinder 4. Plug and compression test shows it. Whatever it is, it might be happening in 2 as well, plug isn't showing it yet though.
Next do a warm leak down test to see if its rings or valves. Intake valves will leak out the throttle body, exhaust out the tail pipe, and rings can be heard/felt through the oil cap.
Just looked through your thread to see if you have a reroute, I noticed you didn't. IMO, hot side superchargers are the reason miata's got the reputation for melting #4 pistons. If you have an aftermarket ECU that's capable of it, you can enable individual cylinder correction, and add a percent or two of fuel to #4 to help it out.
But if you were to ask me, I'd be taking the winter to pull the engine, re-ring it, add a Supermiata reroute, send your ID1050x injectors out for cleaning, or buy them if you don't have them, and pull the supercharger for a turbo.
Next do a warm leak down test to see if its rings or valves. Intake valves will leak out the throttle body, exhaust out the tail pipe, and rings can be heard/felt through the oil cap.
Just looked through your thread to see if you have a reroute, I noticed you didn't. IMO, hot side superchargers are the reason miata's got the reputation for melting #4 pistons. If you have an aftermarket ECU that's capable of it, you can enable individual cylinder correction, and add a percent or two of fuel to #4 to help it out.
But if you were to ask me, I'd be taking the winter to pull the engine, re-ring it, add a Supermiata reroute, send your ID1050x injectors out for cleaning, or buy them if you don't have them, and pull the supercharger for a turbo.
#25
A few things. The -11 on the end of the plug part number is the gap. They are pre-gapped to 1.1mm, which is .043.
Stock NB1 coils aren't strong and may have trouble jumping that gap at 7,000rpm and 10psi. If, after rebuilding the engine and adding a reroute as Josh suggested, you get an intermittent misfire from spark blowout, don't reduce the gap. Do a Toyota or better yet, Audi R8 COP conversion and open the gap to like .05 or .06. Much better combustion with a fat consistent spark.
Stock NB1 coils aren't strong and may have trouble jumping that gap at 7,000rpm and 10psi. If, after rebuilding the engine and adding a reroute as Josh suggested, you get an intermittent misfire from spark blowout, don't reduce the gap. Do a Toyota or better yet, Audi R8 COP conversion and open the gap to like .05 or .06. Much better combustion with a fat consistent spark.
__________________
#26
You've got something going on in cylinder 4. Plug and compression test shows it. Whatever it is, it might be happening in 2 as well, plug isn't showing it yet though.
Next do a warm leak down test to see if its rings or valves. Intake valves will leak out the throttle body, exhaust out the tail pipe, and rings can be heard/felt through the oil cap.
Just looked through your thread to see if you have a reroute, I noticed you didn't. IMO, hot side superchargers are the reason miata's got the reputation for melting #4 pistons. If you have an aftermarket ECU that's capable of it, you can enable individual cylinder correction, and add a percent or two of fuel to #4 to help it out.
But if you were to ask me, I'd be taking the winter to pull the engine, re-ring it, add a Supermiata reroute, send your ID1050x injectors out for cleaning, or buy them if you don't have them, and pull the supercharger for a turbo.
Next do a warm leak down test to see if its rings or valves. Intake valves will leak out the throttle body, exhaust out the tail pipe, and rings can be heard/felt through the oil cap.
Just looked through your thread to see if you have a reroute, I noticed you didn't. IMO, hot side superchargers are the reason miata's got the reputation for melting #4 pistons. If you have an aftermarket ECU that's capable of it, you can enable individual cylinder correction, and add a percent or two of fuel to #4 to help it out.
But if you were to ask me, I'd be taking the winter to pull the engine, re-ring it, add a Supermiata reroute, send your ID1050x injectors out for cleaning, or buy them if you don't have them, and pull the supercharger for a turbo.
I can see a turbo in this cars future at some point but I don't think I'm ready for that. There's so much information to consider for a good reliable turbo build. I don't want to rush into that yet.
A few things. The -11 on the end of the plug part number is the gap. They are pre-gapped to 1.1mm, which is .043.
Stock NB1 coils aren't strong and may have trouble jumping that gap at 7,000rpm and 10psi. If, after rebuilding the engine and adding a reroute as Josh suggested, you get an intermittent misfire from spark blowout, don't reduce the gap. Do a Toyota or better yet, Audi R8 COP conversion and open the gap to like .05 or .06. Much better combustion with a fat consistent spark.
Stock NB1 coils aren't strong and may have trouble jumping that gap at 7,000rpm and 10psi. If, after rebuilding the engine and adding a reroute as Josh suggested, you get an intermittent misfire from spark blowout, don't reduce the gap. Do a Toyota or better yet, Audi R8 COP conversion and open the gap to like .05 or .06. Much better combustion with a fat consistent spark.
#27
Cpt. Slow
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Join Date: Oct 2005
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I would rebuild to OE spec, yes. more than likely you have an eroded piston you can see on a really good borescope, or the rings just got too hot and lost tension. You typically build for torque, not hp, but whatever you do I'd suggest forged rods, and if you want to go over 280-300ft/lbs, I'd suggest doing forged pistons as well, personally I like Wisecos.
If you want a really good, cost effective, yet capable engine, buy a ball hone. Dump ATF on it, put it in a drill on speed 1, 1/2 to full throttle, and go up and down 12 times, fairly quickly. That'll give you a decent cross hatch for new rings. Buy OE, STD rings, OE STD rod bearings, and OE STD main bearings. One of those bearing sets is expensive, like $125, I think it's the mains, rods are around $60. I've rain the Mahle mains, they're like $25/set on Rockauto. Throw this all together with some forged rods from Eagle, K1, Manley, etc. If you want to be extra careful, take the rods to a reputable machine shop and have them check the big end for roundness.
Boom, 300+ capable engine for about $1000.
If you want a really good, cost effective, yet capable engine, buy a ball hone. Dump ATF on it, put it in a drill on speed 1, 1/2 to full throttle, and go up and down 12 times, fairly quickly. That'll give you a decent cross hatch for new rings. Buy OE, STD rings, OE STD rod bearings, and OE STD main bearings. One of those bearing sets is expensive, like $125, I think it's the mains, rods are around $60. I've rain the Mahle mains, they're like $25/set on Rockauto. Throw this all together with some forged rods from Eagle, K1, Manley, etc. If you want to be extra careful, take the rods to a reputable machine shop and have them check the big end for roundness.
Boom, 300+ capable engine for about $1000.
#28
I would rebuild to OE spec, yes. more than likely you have an eroded piston you can see on a really good borescope, or the rings just got too hot and lost tension. You typically build for torque, not hp, but whatever you do I'd suggest forged rods, and if you want to go over 280-300ft/lbs, I'd suggest doing forged pistons as well, personally I like Wisecos.
If you want a really good, cost effective, yet capable engine, buy a ball hone. Dump ATF on it, put it in a drill on speed 1, 1/2 to full throttle, and go up and down 12 times, fairly quickly. That'll give you a decent cross hatch for new rings. Buy OE, STD rings, OE STD rod bearings, and OE STD main bearings. One of those bearing sets is expensive, like $125, I think it's the mains, rods are around $60. I've rain the Mahle mains, they're like $25/set on Rockauto. Throw this all together with some forged rods from Eagle, K1, Manley, etc. If you want to be extra careful, take the rods to a reputable machine shop and have them check the big end for roundness.
Boom, 300+ capable engine for about $1000.
If you want a really good, cost effective, yet capable engine, buy a ball hone. Dump ATF on it, put it in a drill on speed 1, 1/2 to full throttle, and go up and down 12 times, fairly quickly. That'll give you a decent cross hatch for new rings. Buy OE, STD rings, OE STD rod bearings, and OE STD main bearings. One of those bearing sets is expensive, like $125, I think it's the mains, rods are around $60. I've rain the Mahle mains, they're like $25/set on Rockauto. Throw this all together with some forged rods from Eagle, K1, Manley, etc. If you want to be extra careful, take the rods to a reputable machine shop and have them check the big end for roundness.
Boom, 300+ capable engine for about $1000.
#30
Since you are SC’d the overall torque at ~200whp and the torque delivery should be more liveable for a 5-spd.
That said, it’s a bit of a dice roll. I had a 5-spd survive thousands of track miles turbo’d at ~190-200hp (~200wtq in the mid range). I’ve seen other people lose the trans first time out with 150wtq.
If you plan on tracking your car with forced induction, you probably want a spare 5-spd around for the inevitable.
#34
Leak Down Test Results
Thanks for the advice guys. Was able to perform the leak down test today. The results are unfortunate but expected I suppose.
Cylinder 4:
Cylinder 1:
Cylinder 2:
Cylinder 3:
Cylinder 4 was the one with low compression. From my very limited understanding, the pressure drop isn't actually all that bad. About 15%. But it's definitely the rings because all the air was coming out of the oil fill cap.
Spark plug condition after about 60 miles for documentation:
1,2,3,4
4,3,2,1
I guess it's time to plan a rebuild. Is there a good guide out there? Video or written are fine. I found this video from Napp which looks to be detailed enough:
Cylinder 4:
Cylinder 1:
Cylinder 2:
Cylinder 3:
Cylinder 4 was the one with low compression. From my very limited understanding, the pressure drop isn't actually all that bad. About 15%. But it's definitely the rings because all the air was coming out of the oil fill cap.
Spark plug condition after about 60 miles for documentation:
1,2,3,4
4,3,2,1
I guess it's time to plan a rebuild. Is there a good guide out there? Video or written are fine. I found this video from Napp which looks to be detailed enough:
#35
Yep between the air coming out of the oil cap and the condition of that spark plug, either rings are toast or cylinder wall is damaged, or a combination of the two. Good time to rebuild before catastrophic failure.
Also not sure if someone else mentioned it already but oil on the spark plug threads when you remove them but not on the tip is most likely a valve cover gasket leak.
Also not sure if someone else mentioned it already but oil on the spark plug threads when you remove them but not on the tip is most likely a valve cover gasket leak.
#37
I started putting together a couple of lists for parts and materials/tools needed for a rebuild. I leaned heavily on 929 Racings article called Planning Your BP Engine Build and Napp Motorsports video called Building a High HP Turbo Miata Engine - Full Build! (linked in post #34). Also the information given here by members like @curly above. Thanks guys.
The goal is to build a track reliable motor that can handle moderate boost from either a supercharger or turbo below 8K RPM (using that benchmark to match 929's guide). Hierarchy of objectives is: reliability, cost effective, best performance. I want to take advantage of “free mods” like porting and polishing that just require time.
Screengrabs of the lists below. Link to the Google Sheet can be found here for easier reference as well. Disclaimer for anyone who might come across these lists in the future. I have ZERO experience building motors. I'm just trying to learn. This is only based on some research in preparation. It's more of a public journal than anything else.
Am I on the right track? Am I missing anything or going overkill on anything? Getting the total for parts down below $2,500 would be really nice but I also don't want to save a penny to lose a dollar. Feedback is appreciated, thanks guys.
The goal is to build a track reliable motor that can handle moderate boost from either a supercharger or turbo below 8K RPM (using that benchmark to match 929's guide). Hierarchy of objectives is: reliability, cost effective, best performance. I want to take advantage of “free mods” like porting and polishing that just require time.
Screengrabs of the lists below. Link to the Google Sheet can be found here for easier reference as well. Disclaimer for anyone who might come across these lists in the future. I have ZERO experience building motors. I'm just trying to learn. This is only based on some research in preparation. It's more of a public journal than anything else.
Am I on the right track? Am I missing anything or going overkill on anything? Getting the total for parts down below $2,500 would be really nice but I also don't want to save a penny to lose a dollar. Feedback is appreciated, thanks guys.
#38
Pulled the engine and trans this weekend. First time to do this on any car so I'm happy it went smooth. I would say the most difficult part was removing the two bolts at the top of the bell housing that holds the slave cylinder line and wiring harness.
Before starting
End of first day
End of second day (PPF, driveshaft, and exhaust removed under the car)
Third day
Separated the trans
And just some overall shots for those of you with a keen and experienced eye. If you see anything of concern, please let me know ✌️
I didn't realize I needed to source bolts long enough to mount the engine on the stand and all the stores were closed. So this was as far as I could get. I was anticipating to just use some of the bolts from the bell housing but they're too short... Need to find some M12 x 1.5 x 110mm (or 100mm) along with some washers.
Before starting
End of first day
End of second day (PPF, driveshaft, and exhaust removed under the car)
Third day
Separated the trans
And just some overall shots for those of you with a keen and experienced eye. If you see anything of concern, please let me know ✌️
I didn't realize I needed to source bolts long enough to mount the engine on the stand and all the stores were closed. So this was as far as I could get. I was anticipating to just use some of the bolts from the bell housing but they're too short... Need to find some M12 x 1.5 x 110mm (or 100mm) along with some washers.
Last edited by HalalBuilt; 12-26-2023 at 10:53 AM.
#39
A 1.5 hour round trip to and from McMaster Carr and I have bolts to mount the engine to the stand. First time going there for an in person pick up. Didn't even know it was an option. That's place is awesome. Anyway...
So the plan is to get down to the bare block, inspect the condition to determine if it needs to go to the machine shop, do some blueprinting (bought a set of feeler gauges and borrowed a set of micrometers, bore gauges, dial indicator, and a straight edge). Once either it's at the machine shop or we (hopefully with the help of you guys) determine no machine work is needed then I'll stop and give my garage a good cleaning/get it organized. Then I'll focus on getting ready for the rebuild.
Some photos of the eternal teardown:
Only a couple things stood out to me as mildly concerning. The intake manifold and ports were absolutely filthy. They had this shiny black crud build up. Is this normal?
And the second point of concern was some wear on the edges of the camshaft lobes. Normal?
So the plan is to get down to the bare block, inspect the condition to determine if it needs to go to the machine shop, do some blueprinting (bought a set of feeler gauges and borrowed a set of micrometers, bore gauges, dial indicator, and a straight edge). Once either it's at the machine shop or we (hopefully with the help of you guys) determine no machine work is needed then I'll stop and give my garage a good cleaning/get it organized. Then I'll focus on getting ready for the rebuild.
Some photos of the eternal teardown:
Only a couple things stood out to me as mildly concerning. The intake manifold and ports were absolutely filthy. They had this shiny black crud build up. Is this normal?
And the second point of concern was some wear on the edges of the camshaft lobes. Normal?
Last edited by HalalBuilt; 12-29-2023 at 08:57 PM. Reason: Speeling is hard