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DIY Engine build


SimonB

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He also balanced the pistons for me - they were actually a fair bit out (when I say a fair bit, I mean 0.5g :)). They are now within 0.1g - the heavier ones were lightened slightly by chamfering the ends of the pins slightly which avoids having to dress the pistons. The rods were also end-to-end balanced to within 0.1g by shaving the top and/or bottoms slightly where needed.

 

The actual weights of the pistons were 447.3g (with pins but not rings) and the rods were 601.2g. For context, I believe the stock pistons are 539g with pins and the stock rods are 761g (not sure if that includes the bolts or not).

 

The other thing I had him do was clean up the sumps and oil pickup in the washer - they came out lovely and clean which saved me a horrible job!

 

First thing I did after I got it back (after nearly giving myself a hernia getting it out the boot) was to clean the block up. It had been cleaned anyway, but no harm in doing it again to make sure there was no metal particles left from machining. I washed it with detergent, a pressure washer and some engine cleaning brushes for the oil passages then dried it and used a blowgun on my compressor to make sure the machined surfaces were perfectly dry before spraying them with WD40 to stop them rusting.

 

I then painted the block which was a bit rusty and manky looking using POR15 engine enamel from Frost. I used their metal ready which is an etch primer first on the block and then a couple of coats of black enamel - it looks pretty good now I think!

 

With that done it was back on the engine stand. I then set about removing all the old silicon gasket material from the sumps, rear oil seal housing and bottom of the block. Not a nice job! You definitely want Loctite 7200 gasket remover for this - it softens up the silicon but you still need a razor blade scraper and plenty of patience to get it all off.

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bore.jpg

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Valve time. I checked the valve stem to guide clearances. To do that you measure each valve stem using a micrometer. Then measure the guide bore - I used a small hole bore gauge for this. You put the gauge into the guide and turn the knurled end which expands the gauge until you feel light resistance. Then you take the gauge out and measure its diameter with the micrometer. Subtract the stem diameter from the bore diameter and it should be between X and Y for intake, X and Y for exhaust. If it's too tight you would need to ream out the guide - mine were all spot on.

 

EDIT:Ooops, just noticed I never filled in the actual values (X and Y) - I'll do that later when I get a chance!

Edited by SimonB (see edit history)
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Time to lap in the valves - the seats have been cut to the valves, but lapping them in confirms they are seating properly. To do this you need some fine lapping paste and a stick - this is basically a wooden stick with a couple of rubber suckers on. You apply a fine line of lapping paste on the face of the valve, then slip it into its guide and onto its seat. You stick the sucker on the center of the valve head, apply light pressure and rotate it back and forth between your palms. It starts off making a course gritty noise which quickly smooths out - once it has you wipe off the paste from valve and seat and you should see a thin continuous satin-finished pattern the same width round the valve and the seat. I've tried to show this in the pics but it's hard to take a photo of! They only took a few seconds to lap in. This pairs valves with individual seats, so you need to keep them organised afterwards so you know which one goes where. To do this I used a bit of carboard and poked the valves into it as I lapped them.

 

The first pics are an unlapped valve and seat, then the lapped ones. The next pic shows the lapping paste applied, lapping a valve and finally my hi-tech valve organiser!

unlappedseat.jpg

unlappedvalve.jpg

lappedseat.jpg

lappedvalve.jpg

paste.jpg

lapping.jpg

organiser.jpg

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Charlie (b'have) kindly popped over this afternoon with his Mercer bore gauge so we are able to answer the "do you need to line bore/hone if using ARP main studs" question. We started by measuring the out-of-round with the stock main bolts torqued to spec. We measured 0.01mm out on 1, 0.015m on another. Then I installed the ARP studs and again torqued to spec (70ft/lbs with assembly lube). Somewhat suprisingly as I expected it to make no difference, we measured them as absolutely bang on round. In any case 0.01mm out-of-round is fine. So I guess the conclusion is you should be absolutely fine using the studs without line boring, but it's nice to check!

 

We also checked the cylinder bores for taper and out-of-round. We measured the worst one at 0.02mm taper (i.e. there was a section that was 0.02mm wider than the rest). We concluded this was pretty much fine, don't know if anyone else has an opinion?

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Lesson learned - don't bother removing the core plugs from the head!

 

nice to see this thread back in bussiness, i wish i had read the above about 2 weeks ago :( as i am in the middle of porting the head, i decided to remove a head plug to see if the water ways run dangerously close to the valve guide boss, you can guess what happened next ally head, steel plug that hasn't been out since the engine was built, off to the machine shop at work doh !, have you had any flow testing done on the head Simon as i am seriously considering making my own flow rig so any comparative figures would be good, excellent info on the ARP studs aswell

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We also checked the cylinder bores for taper and out-of-round. We measured the worst one at 0.02mm taper (i.e. there was a section that was 0.02mm wider than the rest). We concluded this was pretty much fine, don't know if anyone else has an opinion?

 

That's fine just over 1/2 a thou. Nice job, should make a good engine. You are going to radius off the head chamber edges, they look a bit sharp, straight from the surfacing? Good to see things done properly :)

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That's fine just over 1/2 a thou. Nice job, should make a good engine. You are going to radius off the head chamber edges, they look a bit sharp, straight from the surfacing? Good to see things done properly :)

 

Well spotted indeed! The block edges are nicely radiused off but the head ones weren't. They are now! :)

 

nice to see this thread back in bussiness, i wish i had read the above about 2 weeks ago :( as i am in the middle of porting the head, i decided to remove a head plug to see if the water ways run dangerously close to the valve guide boss, you can guess what happened next ally head, steel plug that hasn't been out since the engine was built, off to the machine shop at work doh !, have you had any flow testing done on the head Simon as i am seriously considering making my own flow rig so any comparative figures would be good, excellent info on the ARP studs aswell

 

Are you doing it yourself? You're a braver man than me! It wasn't flow tested no, the guy who did it doesn't have a flow bench he does it by eye and experience.

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Next up, file fitting piston rings. This sets the ring gap. Starting with the 1st compression rings, then 2nd compression rings and finally oil control rings you put each into its cylinder. To make sure the rings are square in the bore you can use a special squaring tool, or do it the cheap way and put a 2nd compression ring on a piston and carefully put it into the bore from the top :) as the 1st pic shows. The ring stops against the block surface leaving the piston square in the bore. You then measure the ring gap using a feeler gauge (pic 2). If it's too small you need to file the ring - I have a ring filer which has a wheel you turn, see pic 3. After it's the right size I used a fine stone to duburr the edges.

 

The gaps were specified in the info I got with the pistons - 0.25-0.35mm for the 1st, 0.3-0.5mm for the 2nd and 0.2-0.45mm for the oil rings. The compression rings are marked to show which side faces up. Afterwards you need to keep the rings organised as each will be sized to the particular cylinder. To do this I got a bit of wood and hammered a load of nails in and hung the rings on once I'd done them. See final pic!

squaringring.jpg

gapping.jpg

filing.jpg

organiser.jpg

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Are you doing it yourself? You're a braver man than me! It wasn't flow tested no, the guy who did it doesn't have a flow bench he does it by eye and experience.

 

i have done quite a bit of 2 stroke porting in the past so roughly know my way around :D, i am an avid reader of books and read anything car tuning related be it Supra or not, A. Graham-Bells books are my bibles, so i started on the cylinder head but as with all things i seem to do on the car things spiraled out of control and what started as a head clean up has now developed further when i found an excellent book "How to build, modify and power tune cylinder heads", it even has a section on building your own flow rig with vacuum cleaners :D, keep the posts coming fella excellent work

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Quick update. I have now checked the main bearing oil clearances and crank thrust clearance. Thrust clearance first, to check that you install the upper main bearings, drop the crank in and put the main caps in place with the thrust washers. No need to tighten to full torque for this one. Then you set up a dial test indicator so it's against the nose of the crank. You then lever the crank back as far as it will go (carefully!), zero the DTI (or just remember the reading), lever the crank as far forward as it will go and take the difference of the DTI readings. The engine manual says it should be between 0.020mm and 0.220mm. Mine was 0.120mm, so that's fine.

endfloat.jpg

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Now main bearing clearance. To check this I used plastigage. If you haven't seen this stuff before it's basically a thin tube of plasticine that you put between the bearing and crank journal. You then torque the caps and the plastigage gets squeezed. After removing the caps you measure the width it got squeezed to against a scale that comes in the pack - the wider it gets squished the tighter the clearance.

 

So I did that. The engine manual specs are that it should be 0.026mm-0.040mm for normal sized journals with a max of 0.060mm or 0.025mm-0.061mm if you ground the crank to 0.25mm undersize (and are therefore using 0.25 undersize bearings). I was aiming for the wide end of the standard range. What I measured was 0.050mm on all but one which was about 0.042mm. So a bit wider than I was hoping for. I measured the width of the bearings with a mic and found they were a bit smaller than I was expecting. The specs I found on ACLs website say max wall at crown 2.004mm - I measured them at 1.992mm. So that explains that one!

 

That leaves me with 2 options. I can go with 0.050mm clearance - it's still within the max in the engine manual and for an uprated engine like this I think you want larger rather than smaller clearances. Or ACL also do a set of 0.025mm undersize bearings (i.e. they are 0.025mm thicker). I can get some of those (if I can get hold of them) and mix them - in other words use one standard and one 0.025under bearing for each journal. That would give me 0.0125mm less clearance or around 0.0375mm. Haven't decided which to do yet!

plastigage.jpg

installedcrank.jpg

plastigage2.jpg

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Has anyone attempted to get the oil pump drive and front seal abutment off the nose of the crank? I keep meaning to try this, using heat and some sort of puller, but have never got around to it yet.

 

I certainly haven't! I remember looking at the stroker kits when I was deciding what components to use. Some of those require you to do exactly that - butcher a standard crank and re-use the oil pump drive. I definitely didn't fancy that!

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Did they suggest HOW they thought it was best removed? I assume it's just a shrunk on fit, and not keyed.

 

That would be too easy! If you look at this pic of the Brian Crower crank you can see there's no oil pump drive gear on it:

 

http://www.mvpmotorsports.com/merchant/catalog/jdm/t/supramkiv/p/bc/bc_2jzcrank.jpg

 

I think the thread I saw on Supraforums about it they were talking about having to cut it off!

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One more thing I did yesterday was the final bit of prep before assembly - finding the torque to tighten the rod bolts to. The specs for the Carillo rods with Carr bolts are given as bolt stretch. You basically get a rod, measure the length of the bolts, then tighten them to gradually higher torque values until they stretch the specified amount. Record that torque and that's what to torque them all to when installing.

 

I haven't got a bolt stretch gauge so I used a micrometer. The bolts have a dimple for the stretch gauge to center itself in - I used a ball bearing sat in this to get an accurate measure.

 

The specs say you want a stretch of 0.127 to 0.178mm with a maximum torque of 65ftlbs. I measured 0.150 and 0.157mm stretch at 60ft/lbs, so that's what I will torque the rod bolts to when installing them.

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  • 2 weeks later...

Thanks guys, especially Chris, always good to hear you're doing it right!

 

Last time I said I was deciding whether to put up with slightly bigger than ideal oil clearance or order some undersize bearings. Well, I decided it would irritate me knowing it wasn't quite perfect so I have ordered a set of 0.025mm undersize bearings - I'll mix those with the standard ones to get the perfect clearance.

 

While I'm waiting for those, time to work on the head. I'm using Ferrea dual springs, which use the standard valve seats plus Ferrea valve seats (the second spring sits on these). Then there's the valve seal (again Ferrea ones as I'm using their guides too), the dual springs and then a Ferrea retainer and valve locks - you need the Ferrea ones to go with the retainers. The first pic shows these bits laid out.

 

So, assembly time. First I cleaned the head again, then I started with the intake valves. For each I put the stock seat in, followed by the Ferrea one. Then I sprayed some assembly lube into the guide and seal and put the valve seal in. I used the handle of a screwdriver to push home the seals onto the guide. Then I sprayed the valve stem with assembly lube and slid it into the guide. Finally it's in with the springs and retainer, the next pic shows them going in. I attached the spring compressor - you can see that in the next couple of pics. Then it's the incredibly fiddly job of putting the locks in. You do get the hang of this but it's still a PITA. I found it easier to attach the compressor then screw it tighter, then slacken it with the screw before unclamping it. The Ferrea springs are pretty stiff so this makes it easier.

 

Finally I had done all 24 valves, phew!

valvetrain.jpg

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compressor.jpg

compressor2.jpg

fitted.jpg

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done2.jpg

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