Sheepers other MS75 crown coupe

[sheepers]

Ive been continuing to pick away at the 7M motor.

@Roman dave made me some prototype pistons to try out some things.

with my big cams and increased lift there is still a million rooms between the valves and the pistons. im never going to keep this a non interference engine if im aiming for 11 to 1 so i might as well re-think the whole piston dome situation.

all those years building stupid two stroke engines might just pay off after all........

upshot is that i can run bigger valves without any clearance issues - only thing limiting this really is the 5M head's fondness for cracking between the valves and the spark plug hole.

the other thing ive done is to sort out the cambelt/front pulley drive on the front of the crank.

5Ms have a stepped crank at the front and the cam pulley has a larger internal diameter than the crank pulley, 7Ms do not, the 7M crank pulley is larger internal bore than the 5M.

 

so i machined the front of the crank and cut a new keyway in the crank so i can run the 5M pulleys on the 7M crank.

i did spend 2 hours machining the crank only to find that it was bent and the middle journal was running out by half a millimeter. i had a spare crank so i just used that in the end.

 

2022-04-10_04-22-50 by sheepers, on Flickr

 

2022-04-10_04-23-10 by sheepers, on Flickr

 

2022-04-10_04-22-58 by sheepers, on Flickr

 

2022-04-10_04-22-44 by sheepers, on Flickr

 

2022-04-10_04-22-30 by sheepers, on Flickr

 

 

2022-04-10_04-22-37 by sheepers, on Flickr

 

2022-04-10_04-22-22 by sheepers, on Flickr

 

2022-04-10_04-22-14 by sheepers, on Flickr

 

[sheepers]

fucking 10 years latter....

we were trying to sell our house and that fucked up many things including any progress on this engine.

 

anywho,

here we are. ive been doing many measuring and many modeling of things and i am 99% sure i have a piston shape that clears the bigger valves and the increased lift but yields 11.5 to 1.

i figure if the CR is too high i can remove material but if its too low that's a bit harder to fix...

so yea now i need to do a final check of piston clearance and then find someone to make a set of them to my drawing.

ill start the ball rolling with getting the head work done too.

with the head sorted and the pistons under control the rest of the project seems like its achievable.

however we shall see. 

still got a whole ITB system to craft for this as well as many other things.  

 

 

[sheepers]

Roman Dave,  who is a fucking super good cunt by the way, made me revision 3 test fit piston.

I stuck it in and measured the clearance and its super ace at 2mm between valve and piston.

So I'm calling that good and now is time to actually do something, so I've pulled the motor apart.

Now is time to get the block machined,   crank polished, bigger valves cut in and start actually assembling this bastard thing. 

[sheepers]

It's only taken special pistons in Melbourne  7 months to make a set of pistons for this. 

[sheepers]

I bet you'd forgotten about this. 

I certainly did. 

Literally. 

The machine shop rang me up and asked me if I was going to come and pick up this block.

I didn't know what they were talking about. 

in amongst building room on the old house, selling house,  buying new house and moving house I actually forgot about this engine. 

But here it is,  like a bad smell it just keeps hanging around. 

So the block has been cleaned,  main journals line bored, cylinders bored 0.50 over and decked. 

I've got a new everything for the bottom end and I'll put all that together. 

Cylinder head is being worked on.  Is getting 1mm over size valves, shortend valve guides and the valve seal spigot is being machined to accommodate the bigger cam lift. New cams as mentioned new springs and all that. 

but that's to come. 

[sheepers]

I had to do a few little jobs if the celicas but now I'm back into this. 

Ended up getting the crank ground just because. 

I've been measuring Mains and big ends to check oil clearances etc. Surprisingly enough when everything is new and crank is ground/ block is line bored then everything is in spec.

What comes as no surprise is that the China H beam rods are the thing with the widest variance and the closest to being out of spec.

And as is fitting for such an engine a toilet brush was the perfect tool for washing the bores. 

[sheepers]

Oil squirters.

I need your opinions people.

This being a 7M turbo block it has them but I don't think I need them. 

The pistons are basically  7M turbo pistons with a different dome so they have the transfer holes that stock 7M pistons have. 

But I dunno? I'm going to be running the larger flowing turbo oil pump but the question is, 

Should I run the squirters or not?

Keen to hear your thoughts. 

[sheepers]

the hive mind decided that I should use the squirters, so in they went. 

Then I put in the crank and torqued it all up. 

It still spins which is a bonus.

I also got all the pistons and rings assembled. 

Turns out when you buy expensive pistons made for a specific size bore the rings come with the right gaps. 

I checked every single one and they're all perfect. 

[sheepers]

Did a bit more. 

Pistons in and rotating assembly all together.  Spins freely which is a plus. 

Went to put the lay shaft in and things went wrong. Front bearing was to small. It was size for size which wasn't going to fly. 

So with the aid of some CNC (completely not in control) machining I opened the bearing ID up to the correct size. 

All gravy.

I need to figure out how I'm going to make a crank angle sensor happen as well as cam too at some point. Unno how to do that tbh, do i even need both? Do you still need both to run sequential injection and ignition? Fuck i dunno these days. 

anywho,  I'm piecing the garbage back together. 

 

[sheepers]

Oil pump.

Finally found a 7M pump.

that would allow me to mod the pickup and the crossover pipe to sit the 4M sump. 

I had almost everything I needed to run a dash 8 hose for the crossover pipe but I could also,  If I bought everything, fit a dash 10 in there. 

Bigger is always better especially when it comes to the main oil feed so dash 10 it will be. 

Need to make the relief spring spacer but that's no drama. 

Still haven't figured out triggers for the ecu yet. 

[sheepers]

And just like that,  dash 10.

There are some (many) clearance issues but I'm pretty sure I can overcome them. 

 

Mostly. 

Pickup will need to be moved/modified to suit 4M sump but I don't have a spare 4M sump so I'll have to fit that when I actually pull the other engine out. 

[sheepers]

ive sorted most of the clearance issues with the dash 10 crossover pipe but until i get a 4M sump i cant finalise everything there.

 

so now its time to get on with the head.

i needed to mock it all up again and remeasure everything because its been so long since i did it the first time id forgotten everything.

 

so i put it all back together and checked valve piston clearance again (have never checked it with the actual oversized valves so it was worth doing)  just to be 1million percent sure it was all going to play nicely together.

no dramas with all that so that's good.

 

what is a problem is the clearance between the spring retainer and the valve stem seal. currently there is negative 2mm which is about not enough.

i need to machine the valve guide pedestals down so there is a gap between the back of the valve retainer and the stem seal. i reckon 3mm should do it.

ill have to shorten the valve guides as well but that super easy.

now i had reestablished all my measurements (and written it down this time....) all that's left to do is to do a rough and dirty port job on it.

no sciences were harmed in the making of this porting job, i used the "hog it out a bit and hope for the best" method which has been used since the dawn of time.

to some degree of success.....

 

i actually have flow bench numbers for this head in totally stock form so once Ive finished butchering it ill re-do it and see if its made any difference.

[sheepers]

all finished.

was a pretty messy job and took two days but its done now.

i removed 400g of material from the ports.

it will be interesting to see if it flows any better. ill get it back on the flow bench as soon as i can and see how it compares.

fun fact, i ported one of these heads about 25 years ago and i cant remember how crazy i went with it (im guessing not very) but it made no difference to the motor at all.

tbh that motor was a stock turd with stock intake and exhaust so porting it was a fucking waste of time but that was the style at the time. i think i planed the head to try to raise compression but that's a waste of time too given the stock piston design.

 

ANYWHO, thats done. i took the exhaust from about 31mm to 37mm and removed a fair amount of material from the bowel, the intake went from around 31 to 38mm with the same stock removal from the bowel area.

 

[sheepers]

i was wondering if i could raise the oil pressure in the lifters just a bit to compensate for the heavier springs and increased ramp angle of the new cam.

the 5M head has a pressure relief valve which feeds the lifter bores. ive never really looked at it in any detail but its got a spring and a big nut to holding the spring in place, how hard can it be?

so i pulled it to bits and had a decent look at it.

what i saw was worrying and left me with a feeling of no confidence with this doohickey at all. but i had to remind myself that it does work and they have worked for many years and they're not raised as an issue that ive ever heard.

the problem is that the oil feed for the entire lifter circuit has to pass through a tiny hole, i couldn't measure it but it would be less than 1mm. so that's not very much oil flow. i couldnt open up the hole even if i wanted to so i just decided to settle for upping the pressure a bit.

i did some science and figured out roughly what pressure the relief valve opens and its approx 7.6 psi. i was thinking of raising the pressure by about 10 percent but that calculated out at a shim about 0.4mm thick.

but more importantly the errors in my measuring methods were more than 0.4mm. its pretty hard to accurately measure how much weight compresses a spring by exactly how much when you don't have anything but a vice and some weights.

so after some thinking about it and calculating what different shim sizes would do i decided to add a 1mm shim which should see the relief valve open about 10 psi.

fuck it, ill try it and see what happens.

 

 

 

[sheepers]

lifter discussion.

so Clint rightly pointed out (in the wrong discussion thread) that the increase in pressure or flow to the lifter gallery could result in lifter pump up.

i thought about this and did some more dummy assembly and reading.

the Toyota lifters dont work the same way as a conventional V8 style lifter. you dont pre-load the lifter in any way and according to the factory manual they should work at full extension at all times and if they compress any more than half a mm they should be replaced.

the lifters ive been using to test things have a spacer in them so they cant compress and are extend to max length, that way the clearances and interference i was measuring would be the absolute worst case scenario.

the thing thats interesting/a bit concerning is that the lifter is designed (as far as i can tell) to live its whole life at max, or close to max extension. in my mock up assemblies there is no clearance between the cam and the cam follower. so if things get hot an expand a bit in theory it will open the valve on the back of the cam. im a bit confused by this because everything in this collection of mating parts is stock. the base circle of the cam has not been altered, everything is as it should be.

i cant see how the non return valve inside the lifter can bleed a bit of pressure to allow the lifter to shorten when things heat up and expand?

maybe im over thinking it and it will all just be fine, as i say everything is stock so it must work somehow?

ill have to test it as i continue to build the motor.

one good thing about having the oil pump driven off a lay shaft is i can spin the pump while the rest of the motor is stationary. that will allow me to experiment with things and see if the lifter will compress with oil pressure behind it.

[sheepers]

No steps forward,

10 steps back. 

Crank end float. Was having issues with the crank not having enough end float so I lapped a bit off the bearings and it didn't change. 

Problem. 

After a bunch of fucking around it appears that the center cap (which was from another engine, because the original center cap for this block was destroyed by the bent crank) which was line bored with the block did not have the thrust bearing faces machined at the same time. 

I can't get the cap to bolt down and have the thrust bearing faces line up top and bottom.

So I've taken the whole thing apart again and it'll have to go back to the machine shop to get fixed. 

Cool. 

[sheepers]

So when I left off the motor was back to completely disassembled. 

I got the cap machined and now it's back together with the correct crank end float.

 

The other thing is that I got the head flow tested with the porting and bigger valves. 

It shows about an 11 percent increase over stock. 

I was kind of hoping for a bit more but using the "no science just hog it out" method is probably why 11% was the result. 

Anywho,  now it's time to get the head all sorted and I can bolt it on. 

Need new valve springs,  new spring washers and retainers - all of which will need to be custom or at least sourced from some other engine. 

In preparation for this I shortened the valve guides to suit the machining that the head needs to clear the higher lift.

3mm off the exhaust and 6mm off the inlets

[sheepers]

Sump. 

After a bit of soaking in evapo-rust it is now the cleanest 4M sump pan on the planet. 

It doesn't fit thanks to the dash 10 oil feed pipe.

Is was fucking close though so I thought if I machined the fitting down as tight as I could get it so there was only a tiny gap between the boss and the nut the sump might clear. 

It didn't. 

Like you could do up the sump bolts and it would work but it's still touching the pipe so I'll have to do something else

[sheepers]

Final oil pump and pickup setup. 

Slotted pump hole to rotate the pump a bit. 

Dash 10 crossover pipe with a bit taken out of the block to clear the pipe. 

7M oil pump pickup raised 8mm to clear the shallower sump and relocated pickup brace.

[sheepers]

Sump baffle.

Anyone who's driven the misery Inducing stock 4M will know that the stock sump baffle setup is a bit shit.

You don't even have to be hard on the brakes to get the oil light to flicker on.

And besides all that the stock baffle wouldn't fit now anyway. So I made a new one that might work a bit better to keep some oil around the pickup under braking.

Let's not kid ourselves and think that acceleration is going to be an issue. 

It won't. 

The baffle sits across between the pump and the pickup. 

The red lines on the block indicate where it sits. 

Now I'm going to paint it