Project Heavy Metal - an all steel classic, remastered

[Jonny042]

Yesterday I removed the MFI pump from the motor and disassembled it - well, not completely, but I had a good look at the linkage and relationship of the throttle input and resultant movement of the main rack - with the pump not spinning there is a fixed relationship and not adjustable via the flyweight springs, as the stylus simply runs along the zero (bottom edge) of the map machined into the space cam.

I made a few tweaks, hopefully they give me a bit of improvement in the part throttle operation. Like I said I will try to document this in another thread - watch this space!!

I've got 100km on the motor so it's time for the second oil change, too.

[Jonny042]

Well I seem to be moving in the right direction - got it all back together and it keeps running better and better, and I'm slowly unlocking the mysteries of the MFI pump. Not saying I'm an expert (yet) but by the time I'm done I will be!

The car continues to be an absolute riot, going up through the gears. Trying to show some restraint, of course, seeing as how it's still in the break-in period...

[jpnovak]

No restraint! Break in hard. pick a gear (2nd or 3rd). Run it up to high rpm, coast it down. Find some empty roads. Repeat for 250Km. It should just get more loose and more crisp during this time.

Stoked to hear your MFI tuning is working out.

BTW, by my calculations (including a correction factor for Global Warming) you have about 5.7 weeks of summer driving season left in Canada. Get busy driving.

[Marwil]

^^^^^ Funny, but true-ish 33º C (92º F) and humid yesterday but 1º C (34º F) here on Sunday. Straight downhill from there, this year, once again, summer was a Wednesday. Don't envy you folks in the hot South though.

@Jonny042 - great thread and car. Fantastic attention to detail, I have followed this thread closely.

[Jonny042]

Originally Posted by jpnovak

No restraint! Break in hard. pick a gear (2nd or 3rd). Run it up to high rpm, coast it down. Find some empty roads. Repeat for 250Km. It should just get more loose and more crisp during this time.

Stoked to hear your MFI tuning is working out.

BTW, by my calculations (including a correction factor for Global Warming) you have about 5.7 weeks of summer driving season left in Canada. Get busy driving.

LOL! You got that right. I've been pretty busy relaxing, since patio season started yesterday... but that means the mosquitos will be out in a few days and I'll be back at it tinkering with the car.

I guess my version of restraint is limiting the RPM to 7000..... for the most part. Still seeing a bit of blue smoke after prolonged periods of coasting/high vacuum but it's getting better every time I drive it. I've got the AFR's in a reasonable range now so I'll hit the highway and get the break-in done in the next few days, in the manner which you describe.

The MFI tuning is certainly a weird science. I thought I hit a wall but have managed to find a way through/over/around it. Lots of fun.

[Jonny042]

Originally Posted by Marwil

^^^^^ Funny, but true-ish 33º C (92º F) and humid yesterday but 1º C (34º F) here on Sunday. Straight downhill from there, this year, once again, summer was a Wednesday. Don't envy you folks in the hot South though.

@Jonny042 - great thread and car. Fantastic attention to detail, I have followed this thread closely.

That's funny - we declared yesterday a Weekend Wednesday and spent the afternoon and evening drinking Aperol and Prosecco in the back yard. Has to be at least SOME advantages to being locked down and unemployed

[Focker]

Originally Posted by Jonny042

LOL! You got that right. I've been pretty busy relaxing, since patio season started yesterday... but that means the mosquitos will be out in a few days and I'll be back at it tinkering with the car.

I guess my version of restraint is limiting the RPM to 7000..... for the most part. Still seeing a bit of blue smoke after prolonged periods of coasting/high vacuum but it's getting better every time I drive it. I've got the AFR's in a reasonable range now so I'll hit the highway and get the break-in done in the next few days, in the manner which you describe.

The MFI tuning is certainly a weird science. I thought I hit a wall but have managed to find a way through/over/around it. Lots of fun.

Sorry if this is the wrong place to ask, but is breaking in a Porsche similar to how a motorcycle is broken in (I know you ride, so why I'm asking). I've only had fresh motors on race bikes, but we broken them in on the dyno. The old saying was break them in gentle, they'll be slow. Break it in hard, it will be fast.

[scootermcrad]

Driving video!! YES! Congrats, man!

[Jonny042]

Originally Posted by Focker

Sorry if this is the wrong place to ask, but is breaking in a Porsche similar to how a motorcycle is broken in (I know you ride, so why I'm asking). I've only had fresh motors on race bikes, but we broken them in on the dyno. The old saying was break them in gentle, they'll be slow. Break it in hard, it will be fast.

Maybe a bit of a balancing act as the different parts of the motor will want different treatments - so for instance the cams want a good fast steady running in at decent enough RPM that they get lots of oil for the first bit, which might not be best for the rings.

So my approach, do the proper cam break-in if you have new cams and rockers, change the oil, and as much as possible after that, get on it and get the rings seated ASAP.

[Jonny042]

Originally Posted by scootermcrad

Driving video!! YES! Congrats, man!

Thanks, Scott!! I promise more/better video soon...... BUT. Goddamn Beru plug wires are junk. I thought I had them sorted but they are still falling apart. They've caused more grief than anything else on this break-in phase so they are going in the bin. The car is going on stands for a decent check-over/valve adjust/head stud check before I run it again. A bit premature but I need to do something while the Clewett plug wires arrive.

Going to also go through the entire car top to bottom to make sure nothing has come loose and all is good before driving it any more.

The MFI tuning WAS going well. Car starts reliably from cold, idles, and yesterday I put a good 50km on it without any drama and without having to drive around any rich or lean spot. Full throttle AFR between 13.5 and 12.5. Still continues to impress..... then it started to run poorly and miss at full throttle so I limped back to the shop and going to sort out the plug wires before I do any more tuning.

[Trackrash]

Originally Posted by Focker

Sorry if this is the wrong place to ask, but is breaking in a Porsche similar to how a motorcycle is broken in (I know you ride, so why I'm asking). I've only had fresh motors on race bikes, but we broken them in on the dyno. The old saying was break them in gentle, they'll be slow. Break it in hard, it will be fast.

Auto-crossing is a good way to seat in the rings IMO.

[Brookieslayer]

Originally Posted by Jonny042

Thanks, Scott!! I promise more/better video soon...... BUT. Goddamn Beru plug wires are junk. I thought I had them sorted but they are still falling apart. They've caused more grief than anything else on this break-in phase so they are going in the bin. The car is going on stands for a decent check-over/valve adjust/head stud check before I run it again. A bit premature but I need to do something while the Clewett plug wires arrive.

Going to also go through the entire car top to bottom to make sure nothing has come loose and all is good before driving it any more.

The MFI tuning WAS going well. Car starts reliably from cold, idles, and yesterday I put a good 50km on it without any drama and without having to drive around any rich or lean spot. Full throttle AFR between 13.5 and 12.5. Still continues to impress..... then it started to run poorly and miss at full throttle so I limped back to the shop and going to sort out the plug wires before I do any more tuning.

Nice work on the MFI!

[jackportia]

Jonny, I have nothing more to add to the accolades other than to tell you how much I appreciate not only your fabrication and engineering skills, but also your language skills. Thank you.
Jack

[Jonny H]

If the problem persists after swapping plug wires, you might try making the second spark interval a bit longer on the CDI+ box, say 500 us (microseconds).

I’ve seen this occur a couple of times but typically on high compression and Turbo motors.

[Jonny042]

Originally Posted by Brookieslayer

Nice work on the MFI!

Thanks, I appreciate that! I promise you'll get a ride soon....

[Jonny042]

Originally Posted by jackportia

Jonny, I have nothing more to add to the accolades other than to tell you how much I appreciate not only your fabrication and engineering skills, but also your language skills. Thank you.
Jack

Thanks, Jack! Glad you are enjoying the thread. Unfortunately there may be a bunch of unpleasant language for the next little while.....

[Jonny042]

Originally Posted by Jonny H

If the problem persists after swapping plug wires, you might try making the second spark interval a bit longer on the CDI+ box, say 500 us (microseconds).

I’ve seen this occur a couple of times but typically on high compression and Turbo motors.

Thanks, Jonny, for the input.

Indeed, the problem has persisted, much to my frustration. It was just running so well.... too good to be true lol. I don't suspect the spark interval as the issue cropped up mid-drive, everything was fine and then the miss started. I will def. add it to my list, however. Not sure you'll remember, but I'm running the PK black coil. I do have the original black coil as spare to try.

I was going to wait and probably should have, for my own sanity, but I cobbled together a good set of plug wires (mainly using the old SC wires). The car idles so nice and smooth now, it's great, but the miss persists.... and it's the hardest type to deal with, high load/high RPM only, and more than one cylinder (not like one broken valve spring thank goodness).

I did check fuel pressure (not delivery volume, yet, I hate playing with gas) but nothing else, yet, so it's premature to ask for any more input on what it might be.... BUT..... it sure does feel like weak spark. Quite a few variables, with all the messing I've done, I'll start in doing a systematic check tomorrow, starting with throwing a timing light on it.

Stay tuned......

[AG81]

Originally Posted by Marwil

^^^^^ Funny, but true-ish 33º C (92º F) and humid yesterday but 1º C (34º F) here on Sunday.

^
Those types of temp swings are hell on lots of things................ Specifically exterior wall cladding.

[Jonny H]

If it misses when ‘lugged’ in 5th gear, low speed (35mph) with WOT then do check spark interval. Coils can change behaviour when warm.

[Jonny042]

Originally Posted by Jonny H

If it misses when ‘lugged’ in 5th gear, low speed (35mph) with WOT then do check spark interval. Coils can change behaviour when warm.

Not to worry I don't think it's a spark issue!

It turns out the easy check I was going to do turned out not to be so easy. Well, easy to do but hard to make sense of..... I mentioned I did a fuel pressure test yesterday. Simple enough, put the banjo bolt adapter fitting in one of the lines that goes to the pump, plug in the gauge, 12 or 13 psi, same as I had on the test rig.

Today, I did a volume test - 30 seconds to fill a litre bottle. 120 litres per hour should be plenty. However when I did the test I simply disconnected the return line to the tank and put a new hose on the fitting and fed it to my test bottle. I noticed the fuel pressure (that the MFI pump head would see) was zero.

So, I kinked the hose, the pressure shot up to over 20, and stayed there, once I unkinked the hose. It also stayed there when I turned off the electric fuel pump? When I had the fuel system mocked up on the test rig, it would always behave exactly as expected, so there is something definitely wrong here.

I took the "fuel overflow valve" off and tested it with an air regulator, no issues there, so I'm thinking clogged fuel filter.

The symptoms I am experiencing are consistent with fuel starvation. It's a little tricky "reading" the situation with the AFR, I thought it was spiking towards lean because of a misfire, but I guess that's the effect, not the cause, after all.

I did install this in the line between the fuel pump and the filter console - Aaron Burnham advised me that he wouldn't rely on the filter console for filtration so I added a filter - it's supposed to be a 30 micron screen so should catch some particles.



It's relatively microscopic, however, so I think it might be easily clogged if there is for some reason debris in the fuel system.

New tank, new tank strainer, new lines, new pump, new filters..... I can't imagine how this has happened. Will report back tomorrow when I have a chance to get that filter apart and assess the condition.

Fingers crossed, because it should be an easy fix.