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DIY Engine build


SimonB

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Simon

what are your plans for the engine, rev limit, power level, etc

 

I'm thinking probably 8k rev limit. I'm sticking with my T67DBB turbo, although I may possibly go from a .68a/r housing to .85. So around the 650-700bhp mark.

 

Every garage should have a fireplace... ;) I plastered over the fireplace in my lounge when I moved in so I could put a dirty great TV in front of it!

 

I can tell you the weight of the rods when I get home as it's on the label. I'll get the machine shop to weigh the pistons, I haven't got an accurate scale.

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Risking taking this dangerously off-topic; what determines rev limit. Weight/strengh of bits moving quickly/changing direction, timing of what's possible regarding getting fluids/gasses in & out - is that the crux of it?

 

Good luck with the build, subscribed & learning as we go along... :)

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I'm thinking probably 8k rev limit

 

nice project very interested as i will probably be doing a re-build later in the year, a question on lightweight head internals is there any advantage in using titanium valves etc when not raising the rev limit (reciprocating mass ?), the reason i ask is i am currently re-building a head and the valves and guides are shot so i thought if i have to buy some why not spend a bit extra, keep the pics coming or we'll nag the hell out of you :p

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nice project very interested as i will probably be doing a re-build later in the year, a question on lightweight head internals is there any advantage in using titanium valves etc when not raising the rev limit (reciprocating mass ?), the reason i ask is i am currently re-building a head and the valves and guides are shot so i thought if i have to buy some why not spend a bit extra, keep the pics coming or we'll nag the hell out of you :p

 

Probably not is the answer, but the Ferrea valves aren't that expensive. In fact I don't think they're much more than standard ones if at all. I bought oversize ones as I was planning on a stroker and figured that would be best.

 

As for what determines the rev limit, you're pretty much spot on there Steve I think. Basically the faster you rev the faster the piston's velocity and the more momentum they have when changing direction, so the more strain you put on the rods, pin etc. Plus if you go too high you can get the situation where the valves don't have enough time to close properly - valve float. You'd have to be pretty high for that to happen I think though.

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Ok, here's the weights I know of.

 

Carrillo rods 602g (431g rotating, 171g reciprocating). That's from the card in the box so should be spot on. It includes the bolts I believe.

 

JUN pistons 343g, pins 104g (that's from the spec on JUN's website, I'll confirm it when the machine shop weighs them).

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any more pics simon, as i am now in re-build mode myself, i found an engine at the right price, had it put in the back of the wifes car then realised how the feck am i going to get it out so i stripped the whole thing in the back of her car its amazing how much room they take up in the garage once down to component level :D

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Not much else going on until it all comes back from the machine shop - it's going up there this weekend. Here's a couple of things I did after stripping it down as a quick check.

 

First the crank. The correct way to check for straightness is to put it on V blocks but I haven't got any so we'll cheat ;). Basically this involves putting the bottom halves of the front and back main bearings (after cleaning them up of course) in the block, oiling them and putting the crank in so it's only supported by those. Then you use a dial test indicator on the centre journal of the crank and spin it round and record the difference between the smallest and largest values. That gives runout. It's a bit of a fiddle setting up the DTI so you can spin the crank without the counterweights hitting it or the probe hitting one of the oil holes in the journal. The maximum runout according to the manual is 0.06mm. Mine was 0.05 - not ideal, but good enough. The crank will be polished so that should bring it back a bit anyway.

 

Next up is the alignment of the main bearing bore. To check that you take the block off the engine stand and lay it upside down on a bench or whatever. The engine stand could introduce a slight warp otherwise. Then you fit all the main caps and torque them down to spec. I'll go into how you do that when I come to fitting them for real. Then you need a precision straight edge - a ruler won't do here. You lay the straight edge on the bottom of the main bearing bore and try and get a feeler gauge between it and the block. If it's straight you shouldn't be able to. I used the smallest feeler I had, which was 0.0015inches, and that wouldn't go, so that's good enough for me!

crankcheck.jpg

mainborecheck.jpg

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Great thread mate very interesting. I've been getting the urge to do mine but once we've moved house later this year when hopefully I wont need to rely on a car for work.

 

Nothing beats the feeling of firing up your own work for the first time either.:)

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good idea for checking the crank Simon i was going to take mine into work but i'll probably do it at home now, have you checked the main bearing journals on the crank yet my mic is not big enough so will have to borrow one from work, i am really hoping they are within tolerance because the local machine shops barely have a good enough reputation for a re-bore never mind a crank grind :(, been reading a couple of books on engine rebuilding one is saying get the crank balanced but A. Graham Bell states "unless the engine is to run at sustained peak rpm it is not worth the expense", got any thoughts on this

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I've had a good close look at the journals, they look pretty good. I haven't measured them yet, but when I stripped it down I had a look at the old bearings and they all looked ok, so I'm pretty sure it will be fine after a polish and won't need regrinding. I'll get the machine shop to measure them after they have polished it so I can get the bearings ordered, then I'll probably double check it when I get it back.

 

I'm going to get them to balance the crank, rods and pistons. I'm going to re-use my crank pulley and flywheel so can't get them to balance with those attached. I'm not expecting it to be out of balance anyway so it shouldn't cost very much.

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Dont forget guys when you remove the crank and store it, you should always store it vertically, resting on the flywheel end..

 

If you leave it horizontal on the ground for a long period then they can warp... (yes, really!) or at least thats what my engine building books all say.

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Dont forget guys when you remove the crank and store it, you should always store it vertically, resting on the flywheel end..

 

If you leave it horizontal on the ground for a long period then they can warp... (yes, really!) or at least thats what my engine building books all say.

 

I guess it only needs the tinyest little warp to throw the rotation off balance.

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Dont forget guys when you remove the crank and store it, you should always store it vertically, resting on the flywheel end..

 

If you leave it horizontal on the ground for a long period then they can warp... (yes, really!) or at least thats what my engine building books all say.

 

oh c**p, runs out to the garage to stand the fecker up, thanks fella

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I'm going to get them to balance the crank, rods and pistons. I'm going to re-use my crank pulley and flywheel so can't get them to balance with those attached. I'm not expecting it to be out of balance anyway so it shouldn't cost very much.

 

yes that makes sense as the new pistons and conrods will be different weights to the stock items

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Well, I've taken everything to the machine shop now, so yesterday I was driving probably the only twin-engine Supra ever. :D The block, head, crank and new stuff all fitted in the boot no problem, although it did look like I'd had only the rear suspension lowered afterwards. :)

 

The place I am using is called Gardias Engine Services or GES, in Witney, Oxford. He is the guy that Owen Developments use for machine work and head porting etc.

 

So now the engine is out the way I'll clean up the garage again, and wait for the measurements to order the bearings.

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Really? You should have called in as I'm in Witney and about 2 minutes from there!

I know Gardias, IIRC the guys name there is Paul? Didn't know they did that kind of stuff though. I'm planning on using Oselli motorsport which is also in Witney. It's a little hotbed of machine shops!

 

Have cracked on with stripping mine down and will post up a similar thread. Great stuff though Si! :thumbs:

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Simon

Cant help notice but your main/rod bearings have changed from Clevite to Power Enterprise (feel free to flame me if i've imagined this) i have just about got my head round the main bearing sizing but the big ends are still a bit hazy as yet but i'll get there :blink:, my mains are all toyota size 3 apart from bearing number 4 which is a size 2, now how the hell does an ACL/Clevite "standard" bearing set work when i obviously have two bearing sizes on my mains :wtf:, i am back at work tommorow so will borrow suitable measuring gear to start checking everything and i am in half a mind to just fit new Toyota bearings of the correct size, i know PE do all the sizes but for an engine that probably wont exceed 600 fwhp i cant really justify the expense :(

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