trails

iTrader: (41)

good luck Silent, hope you get a nice suprise when you do crack it open

Welloilbeefhooked

iTrader: (3)

Nick,

Is it not worth taking the crank to a scooby specialist (not the one you used!) or an engine reconditioning place for them to mic up the crank?

Just thinking that is what I would do, unless you REALLY enjoy building engines? only joking mate, but I would get it checked out.

Wayne.

cookstar

iTrader: (6)

I thought a crank was relatively inexpensive anyone for a new one?

Welloilbeefhooked

iTrader: (3)

Yes, but this is a "Budget" build so no extra costs. If the one in the CDB is ok then there is no need to buy a new one.

Wayne.

silent running

Yes it definitely IS 'budget' and I'm trying to keep to that ethos of not buying new stuff unless I have to. Hence I'm reusing headbolts, a water pump and I'm still undecided about the oil pump. I remeasured the oil pump that I got out and I'm not that happy about some of the marks inside the cover, so I may get a new one rather than rebuild. But then, I can get one brand new from Subaru for £115 roughly and do the 'mod' myself. And I'm hoping that my CDB reveals loads of stuff I can reuse.

A crank is relatively inexpensive compared to having rebuild an engine again, but relatively pricey compared to what I paid for the CDB. Basically there are some jobs which I know I can't do - getting the CDB properly cleaned and tested, getting its crank tested as well, rebuild costs on whatever heads I end up using (which will definitely not be the ones I have on at the moment). It's not that I'm cutting corners by trying to reuse a crank, it's more a case of spending the limited money that I do have only where it can't be avoided.

If I'm very thrifty and sell on unneeded parts as I go, I believe I can build up a closed deck block with forged pistons, steel H-beam rods and STi heads for around a grand all told. Put it that way and £400+ for a crank doesn't look such good value. I'm still toying with the idea of cutting the budget right down to the bone and reusing the rods and pistons from the CDB. I don't know what they're like yet but I'm assuming they're the STi spec items. Anyone know what sort of power output one can expect from an STi 2 bottom end before having to change stuff?

exvaux

iTrader: (1)

i think the rods are the weakest point but andy forrest ran 440 bhp on standard internals on his old RA with CDB which took a lot of abuse.if your gonna rebuild just buy the best bearings you can afford,i went for aclones thatwere left over from another rebuild the garage were doin so i got them at a decent price

Tim W

iTrader: (1)

As an alternative to new aftermarket pistons and rods why not consider (if you can find them) a set of new-age turbo 2 litre or 2.5 litre rods (WRX or STi, 2 or 2.5 litre they're all the same) they're better than the ones used in classics and good for around 400lbft of torque which should be more than enough.

Similarly Sti forged pistons are also very good quality, again safe in a 400lbft build. You'll need a set of pistons from a phase 1 or 1.5 engine (Sti 2, 3 or 4) , however you will need a set that matches the bores of you CDB. The block will be marked on each side with the size of piston used in each bore, ie an A or B piston. You will need to find the correct number of A and B pistons.

One way of saving some money and building a true budget performance engine

silent running

Some good ideas there. I've got the ACL Race bearings on the way already. As far as rods go, aren't STi and WRX rods the same? The difference being that the STi pistons were forged but the WRX cast?

I am seriously wondering whether to reuse the pistons and rods that are already sitting there in the CDB - presumably they are STi 2 (to be confirmed!) That will give me a setup that will do 400bhp without a problem and save me £500 for an aftermarket setup. The only thing was I'd planned to send the block off for a 0.5mm overbore to drop in the 92.5mm Wisecos, but if I'm keeping the existing pistons if they do turn out to be forged, will any remedial work need to be done to the bore, and if so, will this make the pistons unuseable because of too much clearance? Problems, problems...

Tonight I've not got an awful lot done, but at least stripped the block off of all the pipes/hoses/take-offs/pulleys/pumps. I'll knock the sump off tomorrow and then should have the thing apart in an hour or so, now I actually know what I'm doing. It's amazing how much faster you can work if you've done it once already; no stressing about bagging up bits and bobs - I now recognise what comes off where.

The closed deck block (CDB) up on the stand ready to be worked over. No engine crane required. It's heavy, but by bolting on the mount to the block, I was able to lift it off the floor (just!) and slot it onto the stand.



Water pump looks pretty new, hopefully will be worth reusing:



Front of block cleared of bits and bobs - water pump, oil pump, cambelt pulleys and cogs, belt tensioner and mount all gone:



Engine flipped over and showing modine oil cooler coming off. Use a deep 24mm socket for this, or a deep offset spanner if you have one. All you need to get the sump off is a 10mm socket (narrow bodied if you can) and a big mallet.



I'm toying with the idea of re-using these pistons. I bought this CDB out of an early STi Type R hoping it would have under-piston oil sprays, a good standard crank, forged pistons, a good oil pump and water pump, and possibly even a decent modine (maybe I'll reuse it, but not sure yet...) If so it'll be the basis of a strong engine and I will have saved myself a lot of lolly on parts. But anyway, the pistons look really good from the top, much better than mine out of my old WRX lump:

Tim W

iTrader: (1)

Are you sure that was an Sti engine? The pistons look identical to the cast ones from your old WRX...

Errr, yeah...which is what I said

silent running

Well they seem the same from the outside, but I'm hoping when I get them out they will be lighter and much 'cleaner' looking on the underside, i.e. no casting marks. I assumed they looked the same from the top? AFAIK the block was from an STi Type R, early obviously. It may be an early WRX block though, tbh there are so many variations, it's impossible to be sure. I do hope I find the oil sprays in there though.

mickywrx

iTrader: (29)

Nice write up

I may have missed it, most likely. What was wrong with the CDB that you're splitting?

silent running

Nothing AFAIK. I've been told the lump had a head gasket failure, and rather than face a rebuild, the owner simply dropped another block in and didn't reuse the CDB. Originally I was looking at it just to rob the crank out of, but for not much more than I would have paid just for the second hand crank alone, I got the short block.

I'm mainly taking it apart just to check that everything's OK, but I am toying with the idea of simply putting it back together with new seals and bearings, and checking/refurbing the oil and water pumps, plus a new modine and then the job's done. That's if the pistons actually are forged STi. If not, I'll replace them and the budget has to accomodate that extra cost.

exvaux

iTrader: (1)

the first typeR was the version 3 from 97 iirc i thoughtthe CDB was from the earlier RA cos i know mine isnt closed deck,just had it rebuilt...unfortunately at slightly more cost than your budget build but good luck,will be keeping an eye out as i want to buy a scrap block and do the same for when something else breaks on mine

GingerbreadMan

iTrader: (1)

Do this! You've got to draw the line somewhere.

Reuse pistons and rods where possible. If the cylinder faces aren't too bad, they should just need a light hone and should be okay for standard pistons with new rings.
I know budget is paramount but maybe consider spending some money on getting the rods/pistons balanced, along with the crank/flywheel/clutch/front pulley. And maybe heads cleaned up,skimmed, new seals etc

This is your first rebuild so learn what you can and save your money -make the next one something special. You'll be more confident and keen to throw your money at it then.

Good thread, keep it coming.

silent running

So let's say I do go with that plan. What you're saying is that I can reuse my existing pistons and by honing and fitting new rings it will all work? I had been thinking that if I cleaned up the bores at all I'd have problems with the pistons being too 'loose'? Need more info on the ins and outs of this. If this block did have a HG failure, is it likely that the deck would need a light skim? There's definitely plenty of gasket stuck on still. Is stuff like chemical cleaning and crack testing of the block essential or can I get away with blasting it down at the jet wash?

LOL @ 'the next one' - I'm hoping there won't be a next one for another 100k miles!

Tonight's work has been good news and bad news. Good news is the water jacket crankcase bolts, one of which in the other block caused me a major headache because there wasn't enough clearance between the cylinder and the crankcase wall, were a doddle - no problem at all. I wonder if the tougher deck of the CDB keeps everything better aligned? Bad news is that the single 10mm bolt, that pins together the front half of the crankcase underneath, is slightly rounded off already and there's not enough clearance to get a socket or even a ring spanner onto it cleanly - it runs close to an internal water crossover pipe. I don't remember this being a problem at all on the first block, so why is it a problem here? The only thing I can think of is get a diddy 3/8 or even 1/4" drive socket set with a thin wall 10mm socket on it that I can get to sit down properly onto the bolt so I can crack it. Any other suggestions?

silent running

Yes, sorry I meant RA. I was wondering whether to put my now redundant WRX crankcase up on ebay to see if anyone wanted it for a project. You can still see the honing quite clearly from the rebuild 10k ago.

I've also decided I'm going for an oil pump rebuild, and been down to Subaru today to order a new plunger and spring for my oil pump. Interestingly the one that I am going to use (off the CDB) has a 'shim' i.e. washer in the bottom of the plunger and my original one didn't. Presumably this increses the preload on the spring so it cracks at a slightly higher relief pressure than normal. The CDB's pump is totally within spec and now it's had a quick bath in the parts washer looks almost new.

psigeek

iTrader: (17)

Subscribed. Very interesting reading!

marv wrx

iTrader: (1)

i'm doing a budget rebuid to mate,no 2 con rod bearings decided they had had enough ...hoping to get away with a crank regrind & some acl race bearings then have fun putting it all back together reuseing most of the parts with the exception of oil pump...hope it all goes well mate keep the updates & pics comming (might help me rember where it all goes lol)

silent running

OK latest news is that the block's split now, I couldn't get the pistons out of one side because there was a weird bit of metal webbing half across the access hole. So I've gone to plan B - left those two pistons in, turned the block on its side so they are at the bottom and pulled the 'empty' crankcase half off. I should now be able to just undo the big end bolts and caps for the two pistons which are still in the cylinders, pull the crank out and then knock the two pistons out through the deck, complete with pins and rods still attached.

Bad news and good news again - the pistons are bog standard cast and not forged, but the oil sprays are there which is good.

This small crankcase bolt just inside the front of the block is causing me a big problem. There's too little clearance between it and the casting behind it to be able to get a socket or ring spanner to it. In the end I went and bought a good quality (Laser) stubby 10mm ring spanner and it had a thin enough wall to crack this bolt loose. A 1/4" or 3/8" drive ratchet with a 10mm socket would probably have done the job too, but I didn't want to fork out £15-£20 for a little 3/8 set that I would never use for anything else. 1/2" sockets do just about everything, but just a tiny bit too big for this job.



ACL Race Series main and big end bearings have arrived:



The piston access holes plugs/covers are the same in the CDB as the original open block I dismantled. However, this one inside the bellhousing, for #3 cylinder has a weird metal webbing across it so a third of the hole is covered up. It's physically impossible to get a gudgeon pin out through it. Am I missing something really obvious?



Close up of CDB deck structure. Note the clearance to get a socket down into the water jacket for the crankcase bolts is much better formed and I had none of the problems I had with the other block:



Result! Under-piston oil sprays are present and correct. You can see the jet if you look closely:



CDB split and crankshaft half out. Two pistons have been totally removed and the other two are still in there, because of the webbing that prevented me from getting the pins out. Tip - if the block doesn't want to split with a bit of pressure from a bottle jack, I guarantee you've still got a bolt in there somewhere that you overlooked. Once the bolts were ALL out, both of my blocks just popped open quite easily.

mickywrx

iTrader: (29)

Best to err on the side of caution and check it, like you are.

Best of luck with it, I would have the cajone's to do this myself.

silent running

The CDB's crankshaft measures up well, pins at 51.93-51.94mm, journals at 59.92-59.94mm, both well within spec for standard size bearings. Just for reference the thrashed #3 pin on the original crank was down at 51.6mm, well below the grinding limit.

Tim W

iTrader: (1)

When you get the pistons out of the side with the 'webbing' blocking the hole, can you take a pic down the bore showing the gudgeon pin access holes on the obscured side?

I've never seen a web there before and had a thought...the pic will dispel that thought

scouse2

iTrader: (2)

Not an engineer or that but is it possible the liner has moved in some way?
therefore not allowing access to the gudgeon pin.
btw keep up the great work

danny

silent running

You're dead on. I investigated last night, but too late to post up. Anyway, the liner HAS rotated slightly so that the two access holes in it have moved round and the one that should line up perfectly with the hole through the crankcase for #3 cylinder is half covered! This is really bizarre, because being a closed deck block I can't see how that can happen unless it occurred at the time of manufacture? I mean, how are these things fitted? Are they pressed into place down onto the main bearing cradle and then the deck pressed down on top of that? Is the whole lot bonded together, interference fit, or welded somehow?

I can't see how it would affect the performance of the engine apart from the difficulty in getting through the access hole when you need to. Even that is a problem that can be got round, as I demonstrated myself by simply splitting the block and pulling #1 and #3 pistons and rods out still connected to the crank.

Tim W

iTrader: (1)

The liners are normally cast in situ at the foundry

It certainly is unusual for a standard block to have this happen, if the liner has shifted it might explain why the head gasket went on the original engine it came from. I'm not sure if it would be wise to use the block as it stands tbh, what ever it needs checking

silent running

Yes it is definitely a weird one. At first I had the idea that I could wedge a big bar in there through both holes and just give it a bloody great whack to turn the liner back again. It just seems a weird way for a liner to move, especially as everything looks so solid. There's no obvious damage to the deck that I can see, and what on earth would cause a liner to spin? I could understand, maybe, if the top or bottom of the liner had come adrift and then rocked one way or the other, but to actually rotate and leave no sign of what had happened?

Tim W

iTrader: (1)

Don't do that, the liner will more than likely shatter!

It's possible it's always been like that, but unlikely

Until you get that block good and clean it will be very difficult to see if the liner has shifted. Even then it only takes a shift of a thou to lead to a blown (stock) headgasket

silent running

Here are some photos of the spun liner. They aren't great, because it's so hard to get the camera in, but it's pretty clear that it's rotated about a cm round to obscure the access hole in the bellhousing by about a third.

View from the top. If you use the main bearing cradle at the bottom as 'vertical' references, the two access holes in the side of the liner are obviously a bit off!



A closer shot:



The #3 access hole in the bellhousing, partly obscured by the spun liner. It's moved by about a cm:



A different overview:


I knew this wouldn't be as straightforward as I'd hoped...

Tim W

iTrader: (1)

Right that's it, I'm dragging this over to 22b for a techy argument

silent running

Found the thread, but can't get logged in there. It does seem exceedingly odd. I just can't believe that there can be enough force of some kind in there to twist a liner round yet not disturb the deck at all. It's a real shame that it looks dodgy now, I loved finding those oil sprays in there and was even thinking of putting the whole CDB back as it was and running it like that, which would have been a super cheap option.

After a bit of measuring and checking it turns out that from my two blocks, after chucking out those parts that are damaged or out of spec, I've got 7 rods, 7 pins (which weirdly don't want to fit back in through the pistons at all any more, although they go nicely into the little ends of the rods?), three LH pistons and one RH piston. Bummer.

Just to go back to the original big end damage in my open block, not only was the #3 crank pin down to 51.6mm and the shells totally wrecked, but the big end of the #3 rod looked like the shells had been moving around a little too. The surface wasn't all scuffed up and rough looking.

The upshot of all this is that a cheap 'put everything back' rebuild is not on the cards at the moment, so it is looking more and more like putting a Wiseco/Eagle set into my standard v4 block. Or even, a set of forged pistons for £200 and stick with the standard rods.... opinions on this please? My aims are 350bhp but I want to be able to run at full throttle for some time without having to worry about the engine failing (obviously it will be having a remap when the time comes). I'm not going to need 8000rpm so surely standard rods will do the job?