madkaw

Well I am taking this opportunity to fix my intake flange position for the TB . I had the angle wrong and it made running the piping difficult . Also going to weld build the runner flanges to get rid of the step washers required with the Cannon intake . Doing all this why going with a bigger cam . While the head is out I am going to open up the ports at the neck . Currently intake runners are tapered to 37mm at the head . The head ports taper down to barely 32mm . This is one of the first MN heads I ported . You can’t hog these like some of the other L heads . I have learned after slicing up a head that I can get closer to 35mm at the smallest ID at the neck . I guess I am pleased I did 230 hp with the port pinched this much . I’ve been able to get 34.5mm just before the bowl in some of the other heads I’ve done . One person I sold a head to got 220 hp with a 2.9 running the head I built for him . This is at the tires ! Im also going to smooth out the ports a bit . I opened up the ports at the head opening to 37 - while the head was on the engine . Needless to say not optimum - but I was careful not to get shit in the motor . With it on the bench I can do a better job . Also going to CC the head and possibly do some work in the chamber . I’d like to bump up the CR to 11:1 for the next - more aggressive cam . It will be 565 lift and I believe 290 duration. I never had any detonation issues with the current set up . Once I crack the engine open I will see how the pistons look . I think with the closed chambers and 93 octane I can get away wit more CR . I can always drop some timing if needed or retard the cam timing a bit if it’s too much . Lots to do before driving season !

I might have an extra set from a roof part out. I’ll see if I can get them off

I thought mine came with instructions that stated the increments . I thought it was 2 degrees which kind of makes sense because the total amount of change available is the same as the stock sprocket

Valve seats replaced ? I’d recommend to at least going to 35mm exhaust valves - it’s kind of necessary for a performance . If the seats need to be replaced might as well go the bigger size . OEM exhaust valves are good and can be had cheap

I would wire it whatever way the tach will still work . I would highly recommend a 123 ignition set up for that engine . Though I know it’s $$ and the Rebello already hits the purse hard

SOLD Ready to go . Had this set up on my stroker and managed 226 rwhp ! Notice- 14mm fuel rail - but the injectors do seal on the stock intake . Bracket in pic is used as a stand-off for cable linkage . I used a 3ft Lockar Minor port work to match TB and blend openings at runners 500$ obo

No relay for the fuel pump?

Duffy, Do you know if the stalks can be modified on those coils ? I’d like to use them on my truck but I would need to have a 45 degree angle off the spark plug . Id need to go around the fuel rail .

Well about ready to tear things apart again . I need to cut off the mounting flange for the TB so I can get it better angled to the core support . The angle now puts too much bind on the piping leading to the core support . While it’s off I will also weld build the intake manifold flange mounting ears so I don’t have to run step washers . Very difficult to tell if I am installing the step washers correctly and it’s a vacuum leak ready to happen . Also need to church up some of my welding of the plenum . My welds sucked and left pitting that needs addressed . Im going to make all this happen in conjunction with a bigger cam . Want to get a little more duration in order to match cam to intake . I will probably bump compression closer to 11:1 also . I will also address anything that needs to be done to the ports based on finding with the CFD model . I think I can open up the ports a little more , but won’t do that unless the model suggests that. I’m about at the limit now with port size

Like to find the limits of the linered exhaust port as far as flow and see what we can do with the liners pulled . My friend Andy is working on some old Volvo heads now that have a worse short side radius on the exhaust valve than what the MN has with liner pulled . He has some interesting ideas to improve the flow to get the flow around the sharp edge of the seat . Id say either subject has not been dealt with any amount of effort . Most just went on to a different head

Not sure there is a way to weld the short side radius which is arguably the most important . I had it welded under the seat on the long side - that was tough enough

One of the things I’m hoping to verify . I will be doing a head that has liners removed

One of the Maxima heads I have - might be the one on my stroker- was previously on a turbo motor . The later heads seem to be better castings and I think for low boost motors it would be fine .

The process has started . First the silicon model and then 3D scanning and then computer porting . Love science

Ran this stock 71 radiator in my stroker no issues . It’s been cleaned by radiator shop that was impressed how well these 3 rows flow . No leaks but lower outlet is dented . Probably be straightened fairly easy . 75$ plus shipping in the USA obo

Clean exhaust manifold for your turbo 250$ shipped in the USA

Probably going to give a LOT more info before anyone can give you an intelligent answer. History on the car? Any maintenance done lately? In gear of out of gear? etc….

I would just get a standard dizzy shaft and sell the turbo one

Currently contemplating my next move . I think a cam with more duration would work well with this intake . Need to take about .020 off the head surface to raise compression . Maybe cut it open and install some velocity stacks on top of those runners and make them a bit longer . Also have another head I’ve been messing with . Liners removed on this MN . Also have a friend that can 3D scan my combustion chambers and ports and give me some recommendations on how to manage these exhaust ports . Short side radius suffers without the liners . Maybe his computer program can find me some CFM

That AFR gauge is a curse sometimes . I think I’m your build that I would want one . Even with my NA build I obsess over that damn gauge . I have dual exhausts and a O2 sensor in each bank and they can be off from each other as much a 2.5 pts . I guess it’s the way the air moves around in the plenum . I think you will have to just go to the rich side and be happy with that ?

I appreciate your attention to detail. You are taking on a tough task of pressurizing those carbs . Can’t wait to see the end result . I thought about it with my Mikunis . I even had my MS3 running ignition with the carbs . In the end I chickened out - lol

What idle rpm do you shoot for ? I let mine idle pretty high - 1000rpm. I figure it keeps oil on the lobe and easier to find a happy spot for the engine to idle . I use stepper IAC myself , and it’s been a challenge . Getting the idle to come back to the same spot every time with a big cam was also part of the challenge . I also think my 3/8 I’d hose is too small for this engine . I need to put a 1/2” since that what a lot of OEMS use .

Thanks , I wish I knew who started the fab on this and wonder how they were planning to finish it. . Still impressed how well my n42 did with its smaller runners and pure log design .

Update : new intake is on . So far so good . Still have lots of tuning to do . My power band did move up . I feel this set up allows more power at the top end . I have lost some low end at low rpm’s . I smacked my rev limiter ( 7500rpms) easier than before . It seemed like I was just beating on the motor at those rpm’s with the N42 intake . I think the TPS is screwing with me so my accel enrichment is not right

yeah - what ecu?