My engine freshen up......

After more than a few years away from racing due to various reasons, the Green Monster is finally getting a freshen up!!!

The motor I ended up with a couple of years ago is an ex rally stroker, Dat2kman, knows the builder of the bottom end having navigated for him many years ago.

The motor when originally built had an E88 head on it, but this was replaced by my N42 head that I had previously used on my L29.

After having the motor on the dyno and it being very fumy it was decided to give the bottom end a freshen up, hopefully getting away with rings and bearings plus a hone for the bores. With the N42 breathing a lot better than the old E88 head, and giving the motor much higher compression the bottom end cried enough, showing signs of distress with a lot of blow by and no.2 cylinder down on compression when done dry and testing good with a wet compression test, as did the rest of the cylinders.

Unfortunately things didn't work out that well, on pulling the motor down I had some good news and some not so good news......All the pistons were broken with pieces being held in by the rings only. The good news was that the capacity was measured to be just over 3350cc when taking into account the combustion chambers volumes as well as the swept volume of the motor.

Some more bad news was that the pistons used are no longer available, so a new set will be manufactured to suit and be as close to the originals as possible in terms of piston height, though I will getting them with a small dish to drop the compression from 12.8:1 back down to something a little better for pump fuel.

The cam has also been damaged so a new 74degree cam will be sourced as will a new set of rockers. Not too much more needs to be done to the top end so I will still be getting a "budget" rebuild.

The plan is to build the motor to the same spec as I had with slightly lower compression from the dished pistons and obviously some new bits for longevity. To keep the motor reliable I am looking for torque more than outright power, which I should get with around 3.3 litres. The cam will give maximum power around 6800rpm and pull from about 3500rpm, so no need for any work on the bottom end.

Hopefully this will be finished in the next couple of weeks and I can get back on the track and hopefully be doing the times the car is capable of and maybe scaring a few of the quicker Z up here. I should leave Dat2kman in cloud of tyre smoke and him not seeing which way I went

3.3 litres

Who's doing your new work if you don't mind me asking, I take it they're local? I was originally going to do everything that I could myself, but now I'm thinking I might jsut get Stewart Wilkins to build me one. We'll see.

Not quite 3.3 litres....Engine builder made a small mistake in checking measurements.....so it is the traditional just under 3.1.....

Piston has been sent away as a sample and the new ones slightly changed to give me a more useable static compression of around 11 to 1, just acceptable for pump fuel.

The engine builder is local and has some very good ideas for Zeds and is doing a few motors for a few of the guys around brisbane. We were looking at different rod and crank ratios this morning and came up with some very interesting hypethetical builds for L28's and L26's that would be hand grenades but interesting to see what they would do.

As for a Stewart Wilkins motor, a lot of dollars and also a logistics nightmare when he's Sydney based for the initial set up and tune, though I would like to get one.

If you're serious and want a motor good to go, buy John McKewons race Z that Dta2kman put on the forum, Stewart built the drivetrain for that car originally.

Hopefully the rebuild will be finished in the next couple of weeks

3.3 litres

 

Who's doing your new work if you don't mind me asking, I take it they're local? I was originally going to do everything that I could myself, but now I'm thinking I might jsut get Stewart Wilkins to build me one. We'll see.

Try Jim Milner at Stafford. Its hard to get his time but I hear the results are worth the wait.

Try Jim Milner at Stafford. Its hard to get his time but I hear the results are worth the wait.

That's who is building my motor.

Time wasn't a problem, just need to work in with him and the current work load. I was supposed to have my motor ready for the 1st March, but the problems we have had with the bottom end, broken pistons necessitating custom built replacements, and the cam and rockers has blown the time out by a few weeks.

He will build the motor you want and one that will work, won't be the cheapest around, but from my experience so far, he is very knowledgable with the L series motor and knows how to screw them together right.

My motor will get back to me run in and tuned so I can hit the track straight away.

I believe the budget we are working to and the total cost will be more than reasonable for the result I am expecting. If my entry at Cootha is accepted, it should be fun

any details on the hypothetical builds???

im trying to see what can be done with an original l24e in the skyline.... sorry to verge off-topic

any details on the hypothetical builds???

im trying to see what can be done with an original l24e in the skyline.... sorry to verge off-topic

Just playing with crank, block and bore sizes and different rods to see what could work if I were to be playing the class game. If something comes of it for me I will let you know

At this stage I am using the bottom end I already have with the new pistons, a hone for the block as it is liveable and I haven't really got the dollars to prep one of my spare blocks at the moment. That will be the next build, done properly, ie bloody expensive!!!!!! The top end will get new cam and rockers and the new injectors put in that I have had lying around for a while.

When it'd finished it should be a very nice grunter that will rev to around 7400, though I will only use around 6800-7200.

anything over 6000 rpm sounds fairly insane!!! luvin it!

Any news on the engine?  Cootha Classic is drawing nearer......

Any news on the engine?  Cootha Classic is drawing nearer......

Block has been honed, bores aren't the best but we can live with the end result, motor will have some blowby, but nothing like what I had before the rebuild It only needs to last a couple of years, so around a dozen events or so before the next motor is built, which will be one of spare blocks taken out to 89mm and the money spent on the prep as all the bits in the current build will just swap over. We may look at running a funny crank/rod combo to build a real screamer, but only if we can get a decent amount of torque out of it, and also depends on the final theoretical capacity to see what class I would fall into.

Pistons are in the shop and hopefully the motor will start going back together next week.

If all goes to plan I will be giving the Z a shakedown at Lakeside on May 3 with the MX5 Car Club track day.

At the end of the day I would expect to see the same amount of torque as I had with old build, and hopefully around 30-50 more horsepower as I won't be running with broken pistons anymore. So I should have around 170-180 HP at the wheels with teh same very flat torque curve that pulls from 3500 right through to 6000 with max. power around 6800rpm and a safe rev range up to about 7400, with my normal gear changes at 7200 as per the old build.

There maybe some change to this as the pistons that were in the motor are no longer available and the new ones are a slightly different design with a full dish to allow for use of pump fuel with out having to drown the engine with fuel.

Called into to see how the build was progressing, and I won't be doing a shakedown run on the 3rd May  :'(.

As above, the block is sitting waiting to be assembled as are the pistons and rods. The crank has been checked and polished and good to go back in.

Last time I called in the head hadn't arrived back from the machine shop, but is now back and looking very shiny and new. Nothing much needed doing, just a little clean up of the chambers to get it breathing a little better than what it did.

All going well, I should be looking at getting it back in the hole in the next couple of weeks, and when it get delivered back will be tuned and run in for me so I can go hard straight away at the Cootha Classic, if my entry is accepted, hopefully this year I won't have my entry fee returned......

It will be interesting to see what power it makes and more importantly what torque, though the best dyno is always the stop watch and the track,

How do they run it in? Would be great to see a small vid if its run in on a engine dyno     

How do they run it in? Would be great to see a small vid if its run in on a engine dyno   

Basically throw the motor back in the hole, fire it up make sure the timing is about right, no leaks, or anything that rattles that shouldn't etc, then let it run for about 20 minutes to run cam in and also bearings.

Then it's off to the dyno for a couple of hours to tune it and at the same time run it in. As it is a race motor and will only have around 20-30 hours run time, at most 50, before that motor is scrapped and a new block prepared with the current head it doesn't need the few hundred kilometres that a road motor needs. Also helps that the oil is changed before every event, cheap insurance.

Unfortunately, I will be out around Warwick in the Southern Darling Downs when it is being sorted on the dyno so won't know how it goes until I get back from work... :-\

May have to ask and crawl and grovel to get that great bloke up the road from me, who races old datsuns, to help out with some transport and housing whist I'm away.....

All sounding good Matt. Let me know if you need a hand with anything.

Not sure what I can bring to the table though haha.

All sounding good Matt. Let me know if you need a hand with anything.

 

Not sure what I can bring to the table though haha.

Shaun, if I get to run at Cootha some nice photos to use for marketing at work would be good

It's been a a while since the last update due to being away in Warwick for work for a couple of weeks.

But the engine has been finished and after a few frustrating days it went back together and really screams.

Power is a shade under 200rwhp at 5600, and I will have a little more after a quick mod to the ignition system, swapping out the standard 280ZX module for a more modern Bosch unit and also modifying the intake so the air filter will sit at the throttle body and will be shielded from the exhaust to keep the heat out. This should give me a bit more power a little higher in the rev range and it will also get a bit more timing back into it as it is currently running very little total advance.

I will throw up a copy of the dyno sheet if I get a chance over the weekend.

The car feels a hell of a lot quicker and was able to light up the rears at pretty much anytime with too much throttle as I went up the hill at the Cootha Classic, will take a little while to get used to the new motor, but the car should be bloody quick once I get some track time to get used to it again.

Shaun, if I get to run at Cootha some nice photos to use for marketing at work would be good

I think we know of a good marketing shot if your business involves selling bollards

I think we know of a good marketing shot if your business involves selling bollards

nah....those were shit, i drove straight through them, only damage was a cracked front spoiler

Ooh souded very gnarly at Mt Coothe hillclimb, well done Matt.

Toldya Jimmy m puts a decent one together.

We been talking hypotheticals, and came up with using a tiny stroke L24 crank, knifeedged, nitrided etc, a L28 F54 block, get it soniced to check wall thickness, and if good, whack it out to 89mm bore, forged (approx) 29mm pin height slugs, and some REAL LONG forged rods, approx 140mm? whatever, to suit crank centre to deck height, steel flywheel, blah blah, a p90 head, 47mm valves (int)with 4mm sliced off the face, the special timing chain tensioner, and OER 48mm itb's, it would need mating to a close ratio box, and as it will produce root all torque but BAGS of high 9000 RPM HP, it has to go into a lightweight ( VERY) shell.

Hey guess what, there is the Lime Green240  here in Brissie, and it;s owner is seriously thinking about it! ( The supercharged L28 in it ATM isn't his, it has to go back to the engine owner , 'sides the SC sucked ballz, and wasn't set up and never worked too good eneways)

Jason, yes Jim screws together a very good donk. And it also sounded pretty good from inside the car.

Jon was very impressed with the first takeoff on Sunday , but did compliment me on how it did go when it wasn't wheelspinning. Jim will have the timing and the intake sorted before it goes out next. I will be running at Morgan Park in the 1 hour enduro in September, and will doing a shakedown the first Monday of Spetember at the MX5 club track day.

We also played the hypotheticals, and also looked at a L20 crank to see what class that would put the car in. Would be an interesting. but very expensive motor to run keeping it together at 9k!!!!!!

From what I've heard around the traps, I think I have an inkling as to why the look at the different motor.

Well it's taken me a while to get off my arse and get the dyno sheets scanned, work has kept getting in the way of getting the Zed sorted.

I ended up with a very nice torquey motor for not a lot of dollars, especially with some of the extras needed like new clutch, radiator and some other fabrication work that was easier to get done all at once.

The motor ended up giving a maximum power reading of 195.5rwhp at 5600rpm. Torque we got was a max. of 212 ftLb at around 4300rpm, looking at the dyno sheets it will drive very nice from about 3600 through to 6000rpm with the current set up. Certainly can light up a pair of 230 wide slicks off the line.

I plan to make a couple of changes before it goes out next, basically replace the 280Zx ignition module as it doesn't like having a lot of advance at the moment, basically sitting around 8 deg BTDC, any more and it pings at high revs and number 2 plug gets too hot. The other mod is to put some heat shield between the manifolds, even though the extractors are wrapped it still looks like too much heat is getting into the inlet manifold. I will also be moving the air filter from out the front of the radiator up to the throttle body if I can get it to fit around the dizzy. This should see some more timing back in the engine and subsequently a bit more power and a few more revs. With the bottom end I'm running it should rev to around 7400 safely, though I won't need to go over 6800 and the rev limiter is set at 7000.

Great stuff! Good to see some results Matt.

Mind if I ask how much is not much?

Great stuff! Good to see some results Matt.

 

Mind if I ask how much is not much?

For the rebuild, around $7k for everything including new forged pistons, all head and block machining all the replacement parts for the engine. there were extras for my build including getting the clutch rebuilt, dyno time, new radiator, injectors cleaned and tested, plus some other work done.

Helped that my head didn't need to much done as all the combustion chambers were pretty right and only needed a touch of machining done to unshroud the valves and the ports were all ready done for producing torque. Block only needed a hone, well should have been bored out, but just on the acceptable limits for what i want to do and it's already at 89mm.

I tend to work on $1000 per cylinder to build a good street motor built from a standard motor and you can go as high as your wallet allows for a race motor.