3rd gen VQ35DE Full ECU Swap Progress Thread
10-20-2008, 08:28 AM
#41
got a question about the variable timing and the fact that you're probably putting in more aggressive cams..... are you going to have to totally re-map the variable timing points? cuz i guess the stock ECU's valve timing maps are "optimized" for the stock cam grind... whereas putting in different cams may throw that off a little bit
10-20-2008, 09:10 AM
#42
yeah, i figured it would still be in the ballpark, just not optimized. but given the *****-to-the-wall nature of Aaron's mods (and this 3.5 swap is one hell of a mod)... i wouldn't expect anything less of him.
10-21-2008, 05:14 PM
#44
Good stuff Aaron, looks like you got it well in hand though. The wiring isn't hard just time consuming like installing cams etc.
If you were in Fla this winter I would give you a hand, we are going down for another 3 months in Jan.
The 3.5 is an awesome engine and after having 3 of them I still haven't had one that burns oil even though I wind up to 7k+, so I wouldn't worry about it. My last compression test a couple of weeks ago was 165 psi all cyls so its not necessary to have 200 psi, what is more important is the difference between cyls. Having a built engine and trans is not necessary to go fast.
If you were in Fla this winter I would give you a hand, we are going down for another 3 months in Jan.
The 3.5 is an awesome engine and after having 3 of them I still haven't had one that burns oil even though I wind up to 7k+, so I wouldn't worry about it. My last compression test a couple of weeks ago was 165 psi all cyls so its not necessary to have 200 psi, what is more important is the difference between cyls. Having a built engine and trans is not necessary to go fast.
10-21-2008, 07:21 PM
#45
Good stuff Aaron, looks like you got it well in hand though. The wiring isn't hard just time consuming like installing cams etc.
If you were in Fla this winter I would give you a hand, we are going down for another 3 months in Jan.
The 3.5 is an awesome engine and after having 3 of them I still haven't had one that burns oil even though I wind up to 7k+, so I wouldn't worry about it. My last compression test a couple of weeks ago was 165 psi all cyls so its not necessary to have 200 psi, what is more important is the difference between cyls. Having a built engine and trans is not necessary to go fast.
If you were in Fla this winter I would give you a hand, we are going down for another 3 months in Jan.
The 3.5 is an awesome engine and after having 3 of them I still haven't had one that burns oil even though I wind up to 7k+, so I wouldn't worry about it. My last compression test a couple of weeks ago was 165 psi all cyls so its not necessary to have 200 psi, what is more important is the difference between cyls. Having a built engine and trans is not necessary to go fast.
Knowing that you got 165psi is nice. That is considered in-spec in the FSM. I hope to bench test compression tomorrow or Thursday when my 4th gen starter arrives! I was unable to mount the VE starter to the 4th gen torque converter housing.
BTW, the CPS didn't pose a problem with my converter housing. I think it came off a 98 Maxima. There was already a section cut out for it.
Everybody says rings are the problem for losing oil. But there doesn't seem to be a fix for it other than going with a Total Seal type ring. I just don't want to lose more than a half quart every 3K miles and I'll be fine. My VE with 203K miles lost about 1 quart every 3K miles. So I can live with that as long as it doesn't kill my HP.
10-24-2008, 07:18 AM
#46
I just got my hands on a 5.5 gen auto starter, LH engine mount bracket, and bolts for the tranny. The bolt size for the VQ is bigger than on the VE. And the correct size bolts do not exist on my VE parts car. So I had to find them elsewhere. Thanks to KRRZ350!
Oh well, I'm set now and hope to test compression soon.
Oh well, I'm set now and hope to test compression soon.
10-25-2008, 10:19 AM
#50
Today, I got a chance to finally test compression on this new engine.
Due to a bad valve gasket, there was a ton of oil on the spark plug #5. I bet it was somewhere around 3 or 4 cap fulls of oil. (The cheap oil caps, not the large caps on the Mobile 1 bottles).
I probably should have tried to remove the oil before removing the spark plug, but I didn't.
The rest of the cylinders looked clean:
Here are the numbers I got:
#2: 172
#4: 173
#6: 171
#1: 155 (170 after adding 1/2 cap oil)
#3: 155 (170 after adding 1/2 cap oil)
#5: 190 (had lots of oil in it)
So I'm guessing the only cylinders I need to worry about are #1 and #3. I bet #5 would have gotten around 170-175 if it wasn't for all that oil being in there reducing cylinder volume. But, #1 and #3 may be a bad head gasket since they are next to each other. But I added a 1/2 cap full of dino 10w30 oil and it raised the compression from 155 to 170 in both cylinders.
Do you think the rings are bad in those cylinders? More so than the rest of the rings? I've only put oil in #3 and 5. I haven't added oil to the LH bank (2,4,6).
And I could only get this engine to spin over about 150-170rpm and the FSM says it needs 300rpm. I'm still charging the battery, but it seems to be fully charged.
Anyway, the most important thing is whether I should still remove the heads to inspect everything or should I just return it? I don't want to have to replace the rings in this engine if I don't absolutely have to. If anybody has any suggestions or thoughts, please post. Thanks.
Due to a bad valve gasket, there was a ton of oil on the spark plug #5. I bet it was somewhere around 3 or 4 cap fulls of oil. (The cheap oil caps, not the large caps on the Mobile 1 bottles).
I probably should have tried to remove the oil before removing the spark plug, but I didn't.
The rest of the cylinders looked clean:
Here are the numbers I got:
#2: 172
#4: 173
#6: 171
#1: 155 (170 after adding 1/2 cap oil)
#3: 155 (170 after adding 1/2 cap oil)
#5: 190 (had lots of oil in it)
So I'm guessing the only cylinders I need to worry about are #1 and #3. I bet #5 would have gotten around 170-175 if it wasn't for all that oil being in there reducing cylinder volume. But, #1 and #3 may be a bad head gasket since they are next to each other. But I added a 1/2 cap full of dino 10w30 oil and it raised the compression from 155 to 170 in both cylinders.
Do you think the rings are bad in those cylinders? More so than the rest of the rings? I've only put oil in #3 and 5. I haven't added oil to the LH bank (2,4,6).
And I could only get this engine to spin over about 150-170rpm and the FSM says it needs 300rpm. I'm still charging the battery, but it seems to be fully charged.
Anyway, the most important thing is whether I should still remove the heads to inspect everything or should I just return it? I don't want to have to replace the rings in this engine if I don't absolutely have to. If anybody has any suggestions or thoughts, please post. Thanks.
10-25-2008, 04:16 PM
#53
The biggest reason I don't want to mess with rings is b/c then I'd have to spend a lot more money on prepping the block and honing or boring it over so the new rings seat perfectly. Plus, it's a lot more work to remove the crankshaft and pistons. I'm hoping that the cylinder difference is just from the inaccuracy of doing it on a cold engine. The engine hasn't turned over since sometime in July 08 probably.
10-25-2008, 07:20 PM
#54
The 3.5 is an awesome engine and after having 3 of them I still haven't had one that burns oil even though I wind up to 7k+, so I wouldn't worry about it. My last compression test a couple of weeks ago was 165 psi all cyls so its not necessary to have 200 psi, what is more important is the difference between cyls. Having a built engine and trans is not necessary to go fast.
Originally Posted by Aaron92SE
"Plus, it's a lot more work to remove the crankshaft and pistons."
Last edited by Weimar Ben; 10-25-2008 at 07:26 PM.
10-25-2008, 07:43 PM
#55
Here are my latest compression test results after letting the engine sit for about 8 hours while the battery was on the trickle charger.
Keep in mind that #5 got a lot of oil right from the get go. #1 and #3 got a 1/2 cap full already. And #2, #4, and #6 haven't got any oil so far.
2: 162
4: 175
6: 175
1: 182
3: 178
5: 192
So the results are definitely inconsistent from my afternoon test. Similar, but still inconsistent. Here is the average test results from this afternoon:
#2: 172 (dry)
#4: 173 (dry)
#6: 171 (dry)
#1: 155 dry (170 after adding 1/2 cap oil)
#3: 155 dry (170 after adding 1/2 cap oil)
#5: 190 wet (had lots of oil in it)
So, I figured I'd put an entire cap full of oil in the LH bank to level the playing field with #5, so to speak. And I also put another 1/2 cap full in the #1 and #3 cylinders to try to match them to the LH. And #5 already has plenty of oil in it, so I put a few drops just to wet it a tiny bit.
Here are the results after doing that:
2: 190 (1 cap total)
4: 196 (1 cap total)
6: 188 (1 cap total)
1: 193 (1/2 cap added to make 1 cap total)
3: 188 (1/2 cap added to make 1 cap total)
5: 198 (few drops added since it already has 3-4 caps in it)
Now these numbers make me feel a whole lot better. After doing lots more research on cold compression tests, I have come to the conclusion that the results could vary a lot between cylinders. But, there is a lot of contradicting information about cold compression tests. Some say that is the best and most accurate method, while the majority (and FSM) say a warm engine is best.
One person did a cold compression test on his BMW engine that sat for several months. The cylinders varied much more than mine. But when he got it running and tested compression again with a warm engine, all his cylinders were within 10 psi.
Keep in mind that #5 got a lot of oil right from the get go. #1 and #3 got a 1/2 cap full already. And #2, #4, and #6 haven't got any oil so far.
2: 162
4: 175
6: 175
1: 182
3: 178
5: 192
So the results are definitely inconsistent from my afternoon test. Similar, but still inconsistent. Here is the average test results from this afternoon:
#2: 172 (dry)
#4: 173 (dry)
#6: 171 (dry)
#1: 155 dry (170 after adding 1/2 cap oil)
#3: 155 dry (170 after adding 1/2 cap oil)
#5: 190 wet (had lots of oil in it)
So, I figured I'd put an entire cap full of oil in the LH bank to level the playing field with #5, so to speak. And I also put another 1/2 cap full in the #1 and #3 cylinders to try to match them to the LH. And #5 already has plenty of oil in it, so I put a few drops just to wet it a tiny bit.
Here are the results after doing that:
2: 190 (1 cap total)
4: 196 (1 cap total)
6: 188 (1 cap total)
1: 193 (1/2 cap added to make 1 cap total)
3: 188 (1/2 cap added to make 1 cap total)
5: 198 (few drops added since it already has 3-4 caps in it)
Now these numbers make me feel a whole lot better. After doing lots more research on cold compression tests, I have come to the conclusion that the results could vary a lot between cylinders. But, there is a lot of contradicting information about cold compression tests. Some say that is the best and most accurate method, while the majority (and FSM) say a warm engine is best.
One person did a cold compression test on his BMW engine that sat for several months. The cylinders varied much more than mine. But when he got it running and tested compression again with a warm engine, all his cylinders were within 10 psi.
10-25-2008, 08:44 PM
#57
ok I asked a old skool muscle car buddy of mine and he said warm and this is why
when the engine is warm the rings will expand also with other parts of the engine and will change your readings
his car has a sb 327 that was setup to read around 12/1 cr cold and 13/1 at warm and this was done by playing with ring gap and expansion rates
I can not give you any info about my motor cause I did not even bother cause when I torn into the motor everything looked fine and I only had 3 days to get my car back on the road so I could go to work
when the engine is warm the rings will expand also with other parts of the engine and will change your readings
his car has a sb 327 that was setup to read around 12/1 cr cold and 13/1 at warm and this was done by playing with ring gap and expansion rates
I can not give you any info about my motor cause I did not even bother cause when I torn into the motor everything looked fine and I only had 3 days to get my car back on the road so I could go to work
10-25-2008, 10:26 PM
#59
well aaron, i know you said you only had worries about 1 and 3... but you're just gonna re-ring all 6 anyways aren't you? as well as new headgaskets? or you're only doing what you have to to it?
10-25-2008, 10:43 PM
#60
looking good so far aaron. Any chance your putting in some nice spacers?
oh yeh...I'd like to run mid 12s //all motor\\. But it all depends on how this engine build goes.
what about some nitrous? or is that not an option with this build...?
oh yeh...I'd like to run mid 12s //all motor\\. But it all depends on how this engine build goes.
what about some nitrous? or is that not an option with this build...?
10-25-2008, 11:35 PM
#61
I am just wondering if he is going to make a tb spacer that will have a spot for well maybe a nitrous nozzle
10-26-2008, 05:52 AM
#62
Hi Aaron, piston ring are not that expensive I would replace those while the engine is open, I would hate to see you remove the engine in a month or so, after all that hard work, trust me been there done that.
Keep up the good work, that car is going to be a real beast with the 3.5
AA
Keep up the good work, that car is going to be a real beast with the 3.5
AA
10-26-2008, 06:33 AM
#63
Supporting Maxima.org Member
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Join Date: Oct 2002
Location: Ontario, Canada
Posts: 1,204
I agree with doublea completely.
I opened up my VQ35 swap motor (02 w/ 30K) after it failed a leakdown test miserably.
The walls were all in good shape, so I just yanked the pistons and installed new rings.
It also gave me a chance to clean up the heads, lap the valves and do a little bit of porting.
It is now 2-1/2 years and 24K (not winter driven) later and it does not burn any oil whatsoever.
I opened up my VQ35 swap motor (02 w/ 30K) after it failed a leakdown test miserably.
The walls were all in good shape, so I just yanked the pistons and installed new rings.
It also gave me a chance to clean up the heads, lap the valves and do a little bit of porting.
It is now 2-1/2 years and 24K (not winter driven) later and it does not burn any oil whatsoever.
10-26-2008, 07:22 AM
#64
i know your getting new valve covers!!! and gaskets ! right? if not ill 
http://forums.maxima.org/5th-generat...overs-pic.html
save ya some $ there !
http://forums.maxima.org/5th-generat...overs-pic.html
save ya some $ there !
10-26-2008, 08:47 AM
#65
if you are interested in replaceing the internals i got some 350z pistons and rods i won't mind slanging your direction!
also are you going to convert to return fuel? if so it's actually simpler than people make it out to be. You just need to get another fuel inlet damper( i think thats what nissan calls it) the one that has a hose connections, and a FPR, and it gets pretty straight forward from there.
also are you going to convert to return fuel? if so it's actually simpler than people make it out to be. You just need to get another fuel inlet damper( i think thats what nissan calls it) the one that has a hose connections, and a FPR, and it gets pretty straight forward from there.
10-26-2008, 09:32 AM
#66
if you are interested in replaceing the internals i got some 350z pistons and rods i won't mind slanging your direction!
also are you going to convert to return fuel? if so it's actually simpler than people make it out to be. You just need to get another fuel inlet damper( i think thats what nissan calls it) the one that has a hose connections, and a FPR, and it gets pretty straight forward from there.
also are you going to convert to return fuel? if so it's actually simpler than people make it out to be. You just need to get another fuel inlet damper( i think thats what nissan calls it) the one that has a hose connections, and a FPR, and it gets pretty straight forward from there.
i think u will have to convert to a return system if u use anything other than a 3.5 specific pump.
so im assumming ur gonna use the stock tank, and fuel system form the 3rd gen???
10-26-2008, 01:19 PM
#67
And of course nitrous will be sprayed. Just not right away. I'm sure I'll have some All Motor fun in the beginning.Hi Aaron, piston ring are not that expensive I would replace those while the engine is open, I would hate to see you remove the engine in a month or so, after all that hard work, trust me been there done that.
Keep up the good work, that car is going to be a real beast with the 3.5
AA
Keep up the good work, that car is going to be a real beast with the 3.5
AA
I agree with doublea completely.
I opened up my VQ35 swap motor (02 w/ 30K) after it failed a leakdown test miserably.
The walls were all in good shape, so I just yanked the pistons and installed new rings.
It also gave me a chance to clean up the heads, lap the valves and do a little bit of porting.
It is now 2-1/2 years and 24K (not winter driven) later and it does not burn any oil whatsoever.
I opened up my VQ35 swap motor (02 w/ 30K) after it failed a leakdown test miserably.
The walls were all in good shape, so I just yanked the pistons and installed new rings.
It also gave me a chance to clean up the heads, lap the valves and do a little bit of porting.
It is now 2-1/2 years and 24K (not winter driven) later and it does not burn any oil whatsoever.
i know your getting new valve covers!!! and gaskets ! right? if not ill
http://forums.maxima.org/5th-generat...overs-pic.html
save ya some $ there !
http://forums.maxima.org/5th-generat...overs-pic.html
save ya some $ there !
if you are interested in replaceing the internals i got some 350z pistons and rods i won't mind slanging your direction!
also are you going to convert to return fuel? if so it's actually simpler than people make it out to be. You just need to get another fuel inlet damper( i think thats what nissan calls it) the one that has a hose connections, and a FPR, and it gets pretty straight forward from there.
also are you going to convert to return fuel? if so it's actually simpler than people make it out to be. You just need to get another fuel inlet damper( i think thats what nissan calls it) the one that has a hose connections, and a FPR, and it gets pretty straight forward from there.
Yes, I'll stick with the stock VE fuel pump.
10-26-2008, 01:24 PM
#68
what about using the vq30 fuel rail. its a return system right?
i havent looked at injectors at so for all i know vq30 fuel rail will plug n play wit vq35, thus having a return system.
which for the ve fuel pump im 99% sure u will have to convert to return system
i havent looked at injectors at so for all i know vq30 fuel rail will plug n play wit vq35, thus having a return system.
which for the ve fuel pump im 99% sure u will have to convert to return system
10-26-2008, 01:44 PM
#69
As has been said, it's a trivial thing to convert the VQ35 to a return style fuel setup. Many aftermarket companies make return systems for this motor.
Of course, you could always look into the 4th gen VQ35 swap threads, there are instructions there for cobbling together a return system.
10-27-2008, 01:44 PM
#73
If you open the engine, checking the cylinder wall concentricity will be your no # 1 priority, with a bad block everything will happend. If the engine was run properly then the cylinder concentricity/wall, should be fine, you would only need to deglaze them, put new ring before you re-assemble, new heads gasket, HR heads bolts etc etc.
It only depend on how far you want the etc to go. Lol
It only depend on how far you want the etc to go. Lol
10-27-2008, 01:52 PM
#74
If you open the engine, checking the cylinder wall concentricity will be your no # 1 priority, with a bad block everything will happend. If the engine was run properly then the cylinder concentricity/wall, should be fine, you would only need to deglaze them, put new ring before you re-assemble, new heads gasket, HR heads bolts etc etc.
It only depend on how far you want the etc to go. Lol
It only depend on how far you want the etc to go. Lol
I guess my next step is to remove the heads and inspect the cylinder walls. Or do you think I should bother with a leak down test first? I can get a tester pretty cheap. But, I am not willing to spend the money on boring the cylinders right now. I'm already way over my budget because of the, "while you're in there, you might as well", mods.
10-27-2008, 05:15 PM
#75
Yeah. Whenever you replace rings without boring out the cylinder, you are only making things worse unless the rings are in really bad shape, then anything would be better. If all you do is break the glaze with a light hone and use stock rings, it will seal just that much less.
I guess my next step is to remove the heads and inspect the cylinder walls. Or do you think I should bother with a leak down test first? I can get a tester pretty cheap. But, I am not willing to spend the money on boring the cylinders right now. I'm already way over my budget because of the, "while you're in there, you might as well", mods.
I guess my next step is to remove the heads and inspect the cylinder walls. Or do you think I should bother with a leak down test first? I can get a tester pretty cheap. But, I am not willing to spend the money on boring the cylinders right now. I'm already way over my budget because of the, "while you're in there, you might as well", mods.
I wire-brushed the heads and block, wire-brushed the cruddy piston tops till they were clean, and laid out the 2005 350Z three-layer head gaskets and bolted them down with 2005 OEM head bolts.
Seems to work for me - so far...
10-27-2008, 05:18 PM
#76
I've been running with a bone-stock 2002 short block (except for ARP rod bolts) and I feel just fine about that...
I wire-brushed the heads and block, wire-brushed the cruddy piston tops till they were clean, and laid out the 2005 350Z three-layer head gaskets and bolted them down with 2005 OEM head bolts.
Seems to work for me - so far...
I wire-brushed the heads and block, wire-brushed the cruddy piston tops till they were clean, and laid out the 2005 350Z three-layer head gaskets and bolted them down with 2005 OEM head bolts.
Seems to work for me - so far...
10-27-2008, 05:24 PM
#77
I had to catch myself because it was quickly going from a few dollars here and there to a few hundred
you should see the tab on my truck motor ................. sorry I passed out for a second just thinking about it
10-27-2008, 07:21 PM
#79
Did you happen to test compression or do a leak down test prior to removing the heads?
I did another compression test tonight and got even more consistent readings.
2: 183
4: 185
6: 183
1: 190
3: 186
5: 188
I don't know if I'm rationalizing or not. But the numbers keep getting more level after adding that 1 cap full of oil a couple days ago. Did I just cheat or has the engine been sitting for so long that the dry compression numbers made it skewed?
If anybody else has any thoughts, please post. I am ready to either do a leak down test or remove the heads so I can inspect these cylinder walls.
I did another compression test tonight and got even more consistent readings.
2: 183
4: 185
6: 183
1: 190
3: 186
5: 188
I don't know if I'm rationalizing or not. But the numbers keep getting more level after adding that 1 cap full of oil a couple days ago. Did I just cheat or has the engine been sitting for so long that the dry compression numbers made it skewed?
If anybody else has any thoughts, please post. I am ready to either do a leak down test or remove the heads so I can inspect these cylinder walls.
10-27-2008, 07:50 PM
#80
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Join Date: Oct 2002
Location: Ontario, Canada
Posts: 1,204
I'm more concerned with the new rings sealing properly to the 50K mile old cylinder walls. I've heard a lot of stories of people burning oil when all they did was rering it and not overbore the cylinders.
So with the new rings, you passed the compression and leak down test with flying colors? Did you hone the block or bore it when you did the rings?
So with the new rings, you passed the compression and leak down test with flying colors? Did you hone the block or bore it when you did the rings?
My leakdown numbers went from about 40% to about 5% on a cold engine. Originally I was leaking air past the rings and through a few of the exhaust valves.
If you are pulling the heads anyways then don't bother doing a leakdown.