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PollyMobiles Rebuild

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pollyp

pollyp

Club Member
proceeded to grind the valve seats, so the valves start like this



applied fine grinding paste and after afew mins of grinding with the dremel i get this



abit of t-cut to polish it and got this



the ports start with this



after grinding paste



after t-cut



and a POV shot of the method

 

Stani1029

Club Member
Looking good paul, im used to the old wooden stick with rubber suckers for grinding the valves in, you made that look easy :)
 
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pollyp

pollyp

Club Member
thx stan. yea i found the old wooden stick at the very back of the tool shelf, was a reason its there cos its shyte.

the rubber is so porous n cheap it barely holds and requires a very smooth valve face, the sucker is too large it catches the edge, and a dab of moisture to help maintain a seal just makes it slip off-center. complete unnecessary pita, hence the better "power drill on the stem" method

the dremel wont be thanking me as it tries to spin each 16 valve at low revs, low cooling, high loads that the motor's smoking abit n too hot to handle. had to leave it free-spinning at mid rev after each use to try get cool air through the motor
 
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pollyp

pollyp

Club Member
fitted new stem seals

DSC08038.JPG


valves fitted

DSC08039.JPG


didn't wanna pour water in the ports n contaminate the oily stems & guides so i poured it on the cylinder side of the head and it shown no signs of leaking at all:)

DSC08041.JPG


now cleaning it up, re-tap n install the surrounding fixtures, inlet manifold, clean the block deck and soon ready to reinstall the head back on
 
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pollyp

pollyp

Club Member
I've been updating my fuel bill logs and mpg records and noticed an interesting pattern.

here's three graphs of the average mpg under specific driving styles between the stock, janspeed and turbo setup

exhaust-setup-&-driving-sty.gif


under light throttle/loads they all produce pretty much the same mpg.

under hard urban driving the stock & janspeed setup are also similar mpg (don't have records of motorway driving on the stock setup back then so can't compare that).

but it's when we push the turbo setup hard (urban or cruising) that we see a bigger drop in mpg compared to the janspeed setup
(more air + more fuel = more power but less efficient)
 

Low Rider

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oh the surface area, pretty much the same just tbh and abit shinier/better seal cos it was just a light lap & polish rather than removing loadsa metal with coarse grit
Ok, I was curious as I am trying to note stock figures with respect to porting and seat work.
 
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pollyp

pollyp

Club Member
another point about the valve seat surface area is I think they're all actually the same width but because the outer ridge of the hole (arrowed red) isn't cut consistently and sometimes slightly off-center towards the cylinder wall, it gives an optical illusion that the valve seat is thinner than it is.

copy.JPG
 
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pollyp

pollyp

Club Member
Ok, I was curious as I am trying to note stock figures with respect to porting and seat work.
hmm u just got me thinking about the issues of porting, re-cut seats and bigger valves after looking at the other 'Engine Tune' thread.

the exhaust valve seat is important to keeping the valve head cool within it's material limit (else it'll melt n leak ) by dissipating the heat it's collected from the hot gases flowing over it to the head (and some via the stem) and into the coolant.

the conductivity, quality and surface area of the contact generally influences how much heat it dissipates and sealing ability.
lower the contact area = less heat dissipated = hotter valve.
lower contact conductivity (soot buildup) = less heat dissipated = hotter valve.
lower contact quality (uneven soot buildup/debris/damaged surface) = poor seal & less contact area = lose pressure/power & hotter valve

-increasing the port bore dia could reduce the contact area = hotter valve
-could maybe grind the valve head & seat deeper into the head to increase the outer dia of the sealing surface but the sharp lip has less material to withstand the heat (like welding at the edge of thin sheet metal) and could burn away
-could maybe grind the valve seat deeper and adapt larger dia valves to increase the outer dia of the sealing surface while retaining the thick round valve lip and then one could increase the port bore until the sealing area surface area matches the original
 
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pollyp

pollyp

Club Member
interesting article about valve seat installation
http://www.enginebuildermag.com/Article/1946/valve_seat_installation_procedures.aspx?page=2

"Seat width is also important for good heat transfer, proper sealing and long valve life. If the seat is too narrow, wear resistance and heat transfer can suffer. And if the seat is too wide, there may not be enough pressure to provide a tight seal. A wide seat also tends to trap deposits that can hold the valve off its seat. This too, can reduce heat transfer as well as compression. As a rule of thumb, the ideal seat width for intake valves is usually around 1/16˝. For exhaust valves, it’s 3/32˝ – or whatever the manufacturer specifies.

The point at which the valve and seat mate is also important. If the area of contact is too high on the valve face (too close to the margin), the valve may be sunken into the head. This increases installed height, upsets valvetrain geometry and restricts free breathing. If the area of contact is too low on the face (too far from the margin), the valve will ride too high on the seat. As the engine warms up and the valve expands, the contact point moves down the valve face away from the margin. The valve may lose partial contact with the seat causing it to lose compression and run hot.

Ideally, the valve should contact the seat about one third of the way down the valve face (about 1/32˝ from the margin) so there is about 1/64˝ of overhang between the margin and top of the seat.

BACK TO BASICS – Valve Seats
The most critical sealing surface in the valve train assembly is between the face of the valve and its seat in the cylinder head when the valve is closed. Leakage between these surfaces reduces the engine’s compression and power and can lead to valve burning. To ensure proper seating of the valve, the valve seat must be:

  • Correct width
  • Correct location on the valve face
  • Concentric with the guide (less than .002˝ runout).
The ideal seat width for automotive engines is 1/16˝ for intake valves and 3/32˝ for exhaust valves. Maintaining this width is important to ensure proper sealing and heat transfer. However, when an existing seat is refinished to make it smooth and concentric, it also becomes wider. Wide seats cause the following problems:
  • Seating pressure drops as seat width increases.
  • Less force is available to crush carbon particles that stick to the seats.
  • Valves run cooler, allowing deposits to build up on them.
The seat should contact the valve face 1/32˝ from the margin of the valve. When the engine reaches operating temperature, the valve expands slightly more than the seat. This moves the contact area down the valve face. Seats that might contact the valve face too low might lose partial contact at normal operating temperatures."
 
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pollyp

pollyp

Club Member
cleaned the head & deck & head bolt threads. sucked out any liquid in the head bolt hole with a syringe to prevent hydrolocking when torquing.

DSC08042.JPG


new HG

DSC08043.JPG


head fitted.

DSC08044.JPG


note: every time I used to torque the head bolts there's always afew bolts that creak/grab from stage 1 tightening, which messes up my torquing procedure, even though I've thoroughly cleaned, retapped, greased the bolt head, oiled the bolt thread.

but after stage 1 I removed the creaking bolts to re-oil/grease then hand tighten/loosen/work it in & out of the seat several times to get the lube flowing through the threads/washer and then it tightens smoothly.

so the lesson is to clean/retap the bolts, apply the lube, insert and fully screw the bolt by hand in/out of the thread several times to spread the lube before I begin torquing.
 
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pollyp

pollyp

Club Member
Oh good lawd I just re-read the last paragraph and the naughty brain just noticed the awquid innuendo lol
 

Low Rider

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Faffing with the stock head bolts, although not a huge issue, was one of the reasons behind opting for a stud and nut conversion on our build.
 
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pollyp

pollyp

Club Member
Faffing with the stock head bolts, although not a huge issue, was one of the reasons behind opting for a stud and nut conversion on our build.
yea the creaking from trying to tighten a long flexing bolt is annoying. would be interested in a stud conversion to make things easier n consistant. cos head bolts are a sorta tension spring, how would they compare to the stock bolts spec? same? and where to source?
 
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pollyp

pollyp

Club Member
tday managed to fit the cams, cover, injectors, turbo & alternator

DSC08045.JPG


next is getting ready to remove the gearbox & flywheel to replace the rear main seal and service the LSD
 
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Low Rider

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yea the creaking from trying to tighten a long flexing bolt is annoying. would be interested in a stud conversion to make things easier n consistant. cos head bolts are a sorta tension spring, how would they compare to the stock bolts spec? same? and where to source?
I would have to ask my engine builder. as he spec'd them through ARP.
 
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pollyp

pollyp

Club Member
Lookind good Paul, whats the story with your forged block at the moment?
The forged engine short block & head is in storage at the mo. Just need to acquire a piston ring gap tool (£60 on eBay from USA) to correct the end gaps then its ready to fit & bed-in.

Curious question is should I have purchased & fitted a torque plate to simulate the head bolt stresses and present a more accurate representation of the block in use, reducing the reading error from warpage, before measuring the bore dimensions and ring end gaps?

When I was measuring end gaps, the position of the end gap had a big effect on the clearance reading as though the bore was slightly oval, which I think might be due to warpage on an unloaded block.
Need to find out if this block was honed with or without a torque plate.
 

Low Rider

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The forged engine short block & head is in storage at the mo. Just need to acquire a piston ring gap tool (£60 on eBay from USA) to correct the end gaps then its ready to fit & bed-in.

Curious question is should I have purchased & fitted a torque plate to simulate the head bolt stresses and present a more accurate representation of the block in use, reducing the reading error from warpage, before measuring the bore dimensions and ring end gaps?

When I was measuring end gaps, the position of the end gap had a big effect on the clearance reading as though the bore was slightly oval, which I think might be due to warpage on an unloaded block.
Need to find out if this block was honed with or without a torque plate.
I bet there's more induced distortion from a hot block than there is from an installed cylinder head.
 

frank

Club Member
i forget if your forgie is a closed deck block paul ? but you can get nylon blockguards for boosting the QR,s eh :cool:
and there is very little room to get a socked down to tighten arp headbolts, they have to use special nuts eh

BlockGuard.jpg
 
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pollyp

pollyp

Club Member
Tis a closed deck auto block frank, and good point bout the tight gap for any head stud nut socket.

Lowrider, aye hot dimensions will technically be slightly different but end gap specs are usually measured at room temp and I just need to configure the block close enough to its final fitted state (so if it was honed 100% round with a torque plate, I need to recreate that state to maintain roundness) to check the real end gaps are within spec.

Could get really obsessive bout recreating the exact block temp distribution, pressure distortion etc but tis not worth the time, effort n money for just simply checking if the endgaps are large enough. Just do enough, and no more.
 

Low Rider

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Room isn't an issue for head studs, they're fine and there's room for a socket :)

Someone many years ago tried an ARP setup on the CG and made a mess of it and so they wouldn't fit, (forget who it was). That stuck around for a long time and people were lead to believe it wasn't possible.

A nylon block guard? It'll hold out for the chocolate ones :p
 

frank

Club Member
Room isn't an issue for head studs, they're fine and there's room for a socket :)

Someone many years ago tried an ARP setup on the CG and made a mess of it and so they wouldn't fit, (forget who it was). That stuck around for a long time and people were lead to believe it wasn't possible.

A nylon block guard? It'll hold out for the chocolate ones :p
you need the 12 sided/splined nuts eh (and a suitable socket that will fit down the gap and will stand 100nm) and that pic ^ was from a 500hp build thread dave ;)

arpnut.jpg
 

SirChris

Educated Bodger
Yup, standard setups from ARP.



A $50 plastic block guard on a 'big bhp' build sounds like a noob move to me.

I'd much rather opt for the below option :)
View attachment 21962
whats one of these? Guessing closed deck, but are they solid inserts? where is the cooling? That engine i got of you is closed deck eh? I can see those piddly holes, surely thats not enough
 
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pollyp

pollyp

Club Member
thx frank n lowrider bout the arp.

phwoa lowrider that precision cut block guard is just car porn, makes a certain fizzing sensation :p

chris, yea wonder why they're only featured on auto blocks?
 

SirChris

Educated Bodger
Paul, when painting you engine, how did you go about it mate? I have seen a few pics, but I have not seen you're preparation on the engine or box? Did you see any flaking to the paint?
 
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pollyp

pollyp

Club Member
Paul, when painting you engine, how did you go about it mate? I have seen a few pics, but I have not seen you're preparation on the engine or box? Did you see any flaking to the paint?
I wirebrushed the forged engine block and gearbox to bare metal, degrease with carb cleaner, base silver ht paint, then laquer to provide a slippery glossy coating to keep muck off for longer. But its inevitable that it'll get mucky again.

Long as its smooth n non-greasy prepped, it shouldn't flake off
 
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pollyp

pollyp

Club Member
gearbox removed

DSC08046.JPG


tiny bit of splashing in the bellhousing

DSC08047.JPG


clutch seems dry

DSC08048.JPG


flywheel face is dry. clutch still not fully bedded into the flywheel yet

DSC08049.JPG


flywheel side of clutch only 1/4 bedded in

DSC08050.JPG


the PP side is 3/4 bedded

DSC08051.JPG


only outer portion of PP is bedded in. either the flywheel & PP are slightly concave or the helix plate is tapered with a thicker outside and thinner inside?

DSC08052.JPG


back of the flywheels dry. so not enough oil leak spatter to say its the rear seals

DSC08056.JPG


the bottom 1/2 of the rear main seal is certainly oily but not 100% certain cos that primary oil gallery plug at the top right shows signs of leakage looking at the dark muck attached to the oily staining.

DSC08053.JPG


maybe as well as worn rear seal, the oil gallery plugs leaking too? can't remember if I did take out that plug for flushing the galleries but think i should replace the copper seal.

DSC08055.JPG


pryed out the old seal

DSC08057.JPG


having a cuppa before fitting the new seal and assess the gearbox
 
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pollyp

pollyp

Club Member
to fit the new main seal I'd prefer to find some big socket/cup rather than unevenly knocking it in with a punch.
but then I found that the inner cup of the 3-piece flywheel fits nicely

DSC08058.JPG


between the outer & inner side of the seal face

DSC08059.JPG


so I could hammer the seal in flush

DSC08060.JPG
DSC08062.JPG


removed the oil gallery plug

DSC08063.JPG


gonna replace the copper washer

DSC08064.JPG


gearbox cover off

DSC08065.JPG


was gonna disassemble the gears but then figured there's no need cos I simply engage reverse, the cogs hold the diff steady and I undo the exposed allen bolts

DSC08066.JPG


LSD cover off and Oh FFS not again Gripper :mad:

DSC08067.JPG
DSC08068.JPG


this gripper LSD is not turning out to be reliable :(

twas rebuilt back in feb 2012 with supposedly a newer tougher preload spring,
had 2 trackdays in march & april 2012,
then wasn't used till aug 2012,
roadtrip in sept 2012,
then it wasn't used very much as I was job searching till the exhaust valve leaked.

DSC08069.JPG


gonna measure if the rings have worn much

DSC08070.JPG


thought I was gonna finish it by this week but this is a bit of a setback and I predict will be another expensive month.
first my insurance renewals bout £580,
if i can't fix before 12th march then I have to insure to drive moms car for another month £28 while fixing the diff,
then I guess Gripper's gonna rip my arm off again with either the cost of sending a replacement preload ring next-day for £?
or having to mail the whole diff out for £10 to be rebuilt over next few weeks for another £120

all of that on a very low wage. not impressed

phone call to gripper first thing on monday about this defective part and best case is they'd better send me a new preload ring free so I can get on with reassembling this gearbox asap and maybe finish in time before my temp insurance on moms car runs out on 12th march.
 
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Low Rider

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Very interesting that yours looses pre-load quickly Paul. Maybe it's a torque thing or perhaps the fact that we have an odd sided diff to get an OEM speedo ring in there. I'm wondering if one of the standard type diffs would be the same.

Are you still running the recommended Lodexol 80w140?
 
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pollyp

pollyp

Club Member
no idea why it's failing other than defective material properties or quality.

don't think the one-sided clutch pack configuration caused it cos the ramp action produces the same amount of force on both sides of the pinion whether single or double sided (on mine, one pushes against the diff body while the other side pushes against the clutches) and the splined fingers only permit linear movement towards the preload ring.

only possibilities i believe are:
  • uneven force distribution over the preload ring if one corner of the splined clutch plate was sticking (rather than all sliding evenly) causing a localised pressure spot and cracking the ring
  • another defective material quality control
  • spring rate too soft and/or too brittle to withstand the force produced by the ramp under 160ftlb of torque (surely they'd design the ring to withstand the ramp force within the max supported torque and this type of diff's prob been used on cars with much higher torque)
  • clutch engagement too aggressive on trackdays shocking the diff ramp with peak-torque beyond the 160ftlb sustained torque
and yes I've always been using the recommended lodexol 80/140 oil and changed it after every trackday and back in aug 2012 when i put it back on the road before a roadtrip
 
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pollyp

pollyp

Club Member
so the plates measure (before/after)

outer plate 1 (1.90 -> 1.89)




inner plate 1 (1.75 -> 1.74)




outer plate 2 (1.11 -> 1.10)




inner plate 2 (1.55 -> 1.54)




outer plate 3 (0.95 -> 0.95)




inner plate 3 (1.53 -> 1.53)




outer plate 4 (1.55 -> 1.55)




inner plate 4 (1.55 -> 1.55)




planet driver



overall only bout 0.04mm worn.
hardly needs servicing, just a new preload ring that's preferably tougher
 
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