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Engine & Drivetrain

Post messages here about engine mechanics, exhaust, intake, etc. Anything to do with the engine system as a whole.

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Help With SPecs

July 22, 2004 by Deus Ex
0 replies

1.1k views
Hey Guys, Good to see that the page is up and running again, just have a few questions in order to better decide the next step of my engine. If anyone knows any of these dimentions it would help alot. Just to note i am running triple 45 Webers on a P90 (soon to be N42). Runner Dia @ head Runner Length Runner FLow COef (theres a hard one) Cam Lobe Separation (in cam degrees) Cam Duration @ .200" (crank degrees) Rocker Arm Ratio (intake and exhaust) Thanks guys

Last reply by Deus Ex, July 22, 2004
Guess what my MPG is on new L28? 1 2

July 8, 2004 by EricB
18 replies

5.6k views
Hi all, I'm still reeling... pardon me. So I just finished my first full tank after the initial approximate 500mile break-in period of my F54 L28 with early E88 and larger N42 valves. On 12 gallons I managed 246miles... Granted 75% of the driving was on the freeway at a constant 70-80mph but NEVER did I expect to be getting slightly over 20MPG!!!!!!!!!!!!!!!!!! I have an O2 sensor plumbed in the exhaust just beyond the header collector and it shows barely a tick over stoichiometric, I've checked the plugs and they look fine too... Wow... It appears to be running just fine, feels plenty more torquey than before - love it! Even more impressive is that my tired matching # L2…

Last reply by kmack, July 22, 2004
detonation damage?

July 21, 2004 by halz
6 replies

2.5k views
When I bought my Z the PO kindly included the original cylinder head and I took a close look at it for the first time on the weekend (see picture). A question: It this damage the result of detonation/pinging? If so, here are a couple of interesting observations: Firstly, the damage appears only in the chambers of no.1 and no.6 cylinders, not across all six. Secondly, the damage appears to be localized around the exhaust port in each chamber, presumably due to its greater relative heat. Has anyone observed similar? Are Zs susceptible to poor cooling around the no.1 and 6 cyclinders? Is this just a one off?

Last reply by Zedrally, July 21, 2004
spark plug gap question

July 21, 2004 by 280zgod
3 replies

1.8k views
Hey everybody. Ive got an L28 that I'm setting up for high end power. I've got a stage3 cam on the way and some minor mods and i was wondering if i needed to change my spark plug gap to accomodate these new changes with the cam and all. At the moment I have the gap at .040mm and the car seems to run smooth at low rpms but backfires like mad at high rpms and sometimes it lags when i try to accel so should i be running my gap lower say .025 or what? Or if anyone could explain to me the science of gapping I'd be very happy. Thanks everyone.

Last reply by 280zgod, July 21, 2004
i'm running on 4 cylinders (cold)

July 9, 2004 by e_racer1999
9 replies

1.8k views
okay, my car's been terribly hard to start recently (72 240z) and i figured it was the carbs (being poorly adjusted). however, this morning (after tampering with my carbs last night) i did some experimenting and i am only running on 4 cylinders (at least when cold) the ones that aren't firing are the #4 and #5 and i'm not sure why. my car's symptoms are, when starting in the morning, it takes a few minutes to get my motor going and when it does it idles very rough around 200 rpm. after trying to get it to idle higher (pulsing the gas) it rises VERY slowly, and if i try to get the revs over abour 1100 rpm it pops and drops back down to 800 (still very rough) once it warms …

Last reply by e_racer1999, July 20, 2004
Where to find this fitting? 1 2

July 8, 2004 by Inf
17 replies

2.5k views
The little water outlet on the thermostat housing (the one thats supposed to run through the intake and around the back of the motor to that little y pipe) has pretty much had it. (see picture) Does anyone know where I can find this? I tried several parts stores, which told me to check out some hardware stores, no luck there either. I'm not even sure what type of threads this has. I found a few fittings that had similar diameter tapered threads, but the pitch seemed to be off ever so slightly. How are tapered thread dimensions specified? If I know that, I can probably find something that will work on mcmaster-carr or something when their website is working for me again…

Last reply by Inf, July 20, 2004
Outside air temp affecting running, what gives

July 10, 2004 by 77 Z
1 reply

1.1k views
The hotter the day gets the better my 77 Z runs, the engine temp does not rise according to the temp gauge, but when the outside temp is in the upper 80's to the mid to upper 90's the car just gets better and better , the engine smoother and smoother..can someone tell me why this is happening.. Again the overall engine temp is great , could it be a air fuel mix that as the air becomes hotter it allows for the engine to run smoother or what... Could I have possible when looking at the inside of the air flow meter ( a lttle more than looking) accidently without knowing it made a change that would make for someting like this to happen) ... 77 Z

Last reply by 77 Z, July 10, 2004
Outside air temp affecting running, what gives

July 10, 2004 by 77 Z
0 replies

1.2k views
The hotter the day gets the better my 77 Z runs, the engine temp does not rise according to the temp gauge, but when the outside temp is in the upper 80's to the mid to upper 90's the car just gets better and better , the engine smoother and smoother..can someone tell me why this is happening.. Again the overall engine temp is great , could it be a air fuel mix that as the air becomes hotter it allows for the engine to run smoother or what... Could I have possible when looking at the inside of the air flow meter ( a lttle more than looking) accidently without knowing it made a change that would make for someting like this to happen) ... 77 Z

Last reply by 77 Z, July 10, 2004
Embarrassing Question 1 2

July 8, 2004 by Zrush
12 replies

2k views
Please don't laugh but I must ask this question. OK here goes. When you modify the internals of an engine, does it change the bore and stroke? If it does, how would one go about finding out the new figures. Vicky

Last reply by 1971rb26dett, July 10, 2004
Dyno results - what do you think? 1 2

June 26, 2004 by 240ZMan
17 replies

3.8k views
I just got back from our local Z club event at the dyno. Results are attached. My engine is as follows: - N42 block with dished pistons (~80k miles) - E31 head (stock valves, ~10k on rebuild) - MSA 6:1 header w/2.5" exhaust - Pertronix electronic ignition - SU round tops with ZTherapy bodies, and .099 nozzles and SM needles I live at 6500 ft elevation although the shop was about 1000 feet lower. They say the results are corrected for altitude, temperature, etc. I tried 2 other runs. On one I turned the mixture nuts in (leaner) 1 full turn. On the other put the mixture back, and advanced the timing 4 degrees. In both cases peak HP dropped ~3 hp. So I figure I…

Last reply by 1971rb26dett, July 10, 2004
Engine guru rebuild question

July 7, 2004 by xtinc
5 replies

1.7k views
Hi, I'm in the process of rebuilding my motor, an L26 block and early E88 head. I purchased the block from a guy who gave up on his Z project, it had been rebuilt by a reputable shop, bored .030, polished crank, and balanced. I noticed the spec sheet indicated the deck had been shaved, but didn't indicate exactly how much. I'm assuming very minimal to clean the deck surface. The E88 came off my L24, I wasn't the original owner so not sure of previous head work, but the machine shop also shaved a very nominal amount to clean up head surface, timing components are new. I installed the timing set with everything at TDC, lined up the bright links with timing marks using…

Last reply by xtinc, July 8, 2004
Hmm......?

July 7, 2004 by MrMarcDude
5 replies

1.7k views
(78 280z) Sorry if i sound super dumb here but bare with me, im new ta this . While cleaning up the engine bay today i noticed that there is a belt missing from the engine. It is the belt that goes to that giant thing that looks like a pump or motor of some sort. I traced the lines and it connects to what looks like a smaller radiator thats in front of the real radiator. I was wondering. What is that giant pump lookin thing, and can my engine fare without it? That thing with all of the hoses, and lines really creates a lot of clutter. Just trying to make underneath the hood look a little better. Thanks guys

Last reply by MrMarcDude, July 7, 2004