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Bruggles

N42 - E88 Build Questions

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I am working on a semi-budget build (I would like to keep it below $2000 including cam, flywheel, and header) on my engine, I would like more power and to fix some of the leaking seals... I will also add a light flywheel and headers. This engine is running  dome top SUs that are in good working condition - well it was before I took it apart to see what was in it and start the build process. I use this car for autocross and just having fun, it isn't a daily driver. I do want to be able to drive it around town, but am willing to live with a slightly less street-able car for power. I do plan on using high octane pump gas, not race fuel.

The engine is a N42 Block in stock condition (standard 86mm bore with dished pistons and no ridge in the cylinders) this was combined with a 8/72 E88 head (I believe this is just after the more desirable e88. Everything on the head appears stock). I do have an electric zx distributor and 2.5" exhaust, other than that no mods.

My general plan - increase compression, and increase head flow. There are tons of options on how to do this, but I have a few questions:

-Is the late e88 head going to cause problems with higher compression? I was thinking of going with flat top pistons and possibly shaving .010" off the head to get it around 10:1 or maybe even shaving .080" off the head and leaving the pistons as they are. If I were to keep this head I would increase valve size and change seats and guides to unleaded suitable parts. I would also port and polish the head and get a cam - likely isky regrind stage 2 or 3 and new valve springs. I have been reading and searching, and it seems like lots of people go with a p90 shaved .080", an N42, or an early e88 but finding cores on these seems quite difficult. Has anybody had success with a late e88? I have searched and searched and can't find info for late e88s or the e88 build info doesn't specify the type of e88. 

-When getting a new cam is it worth it to get internally oiled or should I just send in my old cam?

-On cam choice, would there be any reason to not get the stage 3 Isky?

-Does anybody have an N42 or p90 head for sale in good working condition?

-Any other recommendations on how to increase power without breaking the bank? I would like to stay in my HCS autocross class if possible, but it allows quite a bit of leeway on the drivetrain.

Edited by Bruggles

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Well, I ended up building this motor, the cost was closer to $3500 than $2000 :-(, but I ended up putting in ARP head and rod bolts and getting an aluminum cam oiler... I learned a ton through the process of building the engine and did all the little stuff like grinding the castings smoother and balancing the rods, and am pretty satisfied with the results.

 

I ended up going with and Isky stage 3 and I don't know why you wouldn't go with a cam that big, no idle problems, works great with SU's etc. I sent mine in for a regrind - a great deal and got an aluminum billet oiling bar to keep it oiled.

 

I kept my e88 head and did some light porting and moved to SS valves in the 280z sizes, I should be right around 10:1 compression. 

 

The car is pretty zippy and fun to drive. It does have some pinging only when letting off the gas completely, if I disconnect my vacuum advance this goes away. Under normal acceleration there is no pinging. Does anybody have a similar setup and if so how many degrees of vacuum advance do you run? Mine is set to 10 when plugged in and that is too much. I am also wondering if anybody has used a vacuum delay valve similar to https://www.oreillyauto.com/detail/b/bwd-3123/fuel---emissions-16775/emission-smog-parts-16465/vacuum-delay-valve-12054/0397dae098c9/bwd-2-port-egr-vacuum-delay-valve/ec314/2598329 (from the wikipedia article orange is a 2 second delay and white is forward direction - whatever that means) with the light flywheel it decelerates pretty quick and I think it just increases the vacuum almost instantly while the engine is spinning too quick. The benefit of the vacuum advance seems like it is mostly for cruising which shouldn't be impacted too much with a delayed advance.

 

With the ceramic coated headers it still over heated the carbs with the stock heat shield on the track, so I built a new heat shield to protect the carbs from some heat and plan to drill some holes behind the battery and behind the windshield fluid reservoir to let some engine compartment air exit easier. The engine temps were fine, but it would be nice to cool the compartment a little more anyways, if for nothing else than to get rid of some of the header heat.

 

I would also like to do an oil scraper, but am having a heck of a time getting one. I ordered one from https://www.crank-scrapers.com/Datsun-Nissan_L_SERIES.html about 3 months ago, and still don't have it and it is almost impossible to get a hold of them, my oil pressure is lower than I would like to see on the track. Any ideas where else I could get one? 

 

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Hi.

 

1.

Couldn't you disconnect the vaccum advance? Don't need it for autocross..

Mechanical advance is ~35 and 15 degress on top of that is a lot of advance.

 

2.

What cam did you end up getting? Any piston to valve issues? What did you do for valve train and lash pads?

 

3.

Are you getting low oil pressure in turns? Are you running slicks? I would think autocross is mostly quick shorter turns and not long sweepers.

I am running RS4 tires on a race track and haven't experienced any issues. I fill a little more.

 

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1. Currently vacuum advance is disconnected. Yes 35 + 15 seems like a lot but that is what was done on stock, so that is what I used as a baseline and bumped max vac advance down to 10 and it is too much so I disconnected. Not sure if it is worth fiddling with for a little MPG when I drive it on the street, but if someone has it working with a similar setup I would like to know how.

 

2. Isky stage 3. No piston to valve issues, I don't remember the clay measurements exactly, but it seems like it was in the .200 range. For valves I got SI stainless valves, springs are Schnieder cams springs, lash pads are MSA .205 ground down to center the lash. In retrospect, I am not sure that visual centering is the best method (i did measure the centering, but with calipers on the wipe mark - so visually), it seems like using a dial indicator for max valve extension would be a better way of "centering", but this was my first engine build so I didn't even think of such things. It would have been just as easy, but with a more consistent result. Next time I have the valve cover off I might take a few measurements just for curiosity's sake. The rocker arms were reground by my local machine shop since they had divots.

 

3.I guess I should have been more clear when mentioning the track. With autocross or just street driving I have zero issues with overheating carbs, or low oil pressure, it is on the race track that I had both of those issues. I am not on slicks, but on 200 treadwear falken azenis (they have been a pretty good sticky tire, but not as sticky as slicks). I wonder if the issue isn't the turns as much as the sustained high rpm (I didn't notice a drop in the turns, just after a few minutes on the track it was consistently measuring lower than normal) so the oil gets frothy and there is a windage cloud hanging out around the crank. I might try a little more oil, but if I could get ahold of a scraper (I might just make one) I would like to test that as a longer term engine oiling insurance policy so to speak. Out of curiosity on the track what does your oil pressure measure? on the street? Are you using a stock pressure gauge or aftermarket?

 

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Might sound crazy but maybe a little less oil so it doesn't get all churned up at high rpm by the crank...gets foamy and pressure drops. Watched similar results on engine dyno tests on motor trend. If I recall correctly they picked up horsepower and oil pressure with a little less oil.

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3 minutes ago, Bruggles said:

Yeah, I watched that same engine masters episode. My concern would be that in the corners there would be no oil left. Has anybody played with oil levels on the track to see what the impact is on oil pressure?

Yeah, probably not a good idea to drop the level unless you have a higher capacity pan 

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I am not 100% sure what the power band is for the cam, but I have more power now than I did before anywhere along the entire rpm range. It is hard to say since so many things were done at the same time, the e88 head with stock valves and stock cam limited power above like 5500 rpm. I can easily rev to 7000 now and, I never had to watch my revs before but now I really do when accelerating so I don't over rev it. it is still a timing gear run distributor and cast pistons so I don't want to take it over 7000. I think with compression around 10:1 this is great cam. Even at 2000 rpm it has great torque and response and doesn't have issues idling.

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Your oil temps will be hotter on track than autoX or regular driving. Hotter oil is less viscous and easier to pump, thus pressure drops. It's not necessarily a sign that something is wrong but if you're worried, install an oil temp gauge. If you're running synthetic, you should be fine to about 280°F.

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