Pistons

[snot35]

Cranks and bore spacing are the same. I haven't heard of 5K liners, so it may be a custom job? Given the 75mm bore vs 80.5mm of the 5K, that's probably too much overbore without doing a hell of a lot of work.

[philbey]

Yes cranks are the same, you could most likely bore a 4K out for 5K pistons. Probably easier to just get 4K pistons from mahle, or alternatively build a 5K block.

 

Great racecar by the way, got any other pics?

 

LOL snot beat me too it, should refresh my page.

Edited April 28, 2011 by philbey

[pinsx3]

yeah, I called mahle, no luck. Venolia will build them cheapest $400 or so. Here are a couple more pictures. Since these were taken we fixed some minor rust in the towers and where the fenders met the fire wall and we added a proper braking system with a new pedal and new reservoir. We also put in a stainless exhaust.

 

BTW I went and looked at my TRD 3k race pistons and the pins are LARGER than stock. WTF? I'll send pics of those too, later. Maybe someone can ID them.

[snot35]

Yeah, they should be larger. If they are the real deal they should have 20mm pins and be 79mm bore according to the old Tosco manual.

 

Sweet sprinter by the way :)

Edited May 2, 2011 by snot35

[pinsx3]

so if the pins are larger, what rods do you use? The pins are also higher up in the piston and skirts are pornographically short. One ring too. Could these go in a 4K?

 

Seems taht they would not be "long lasting" pistons.

 

Pete

[snot35]

You want to have a look through this if you haven't already. It sounds like you have the stage III TRD 3K pistons, which is kind of neat except that you're going to find it impossible to find parts.

 

http://www.scribd.com/doc/32994691/TRD-K-Engine-Manual

 

I couldn't find a rod part number in there, but my browser kept crashing. From the description it sounds like they did have a TRD rod made of a different material to suit these pistons.

 

The main thing will be to work out what the rod length is. The 4K has a longer stroke, but also a taller deck to compensate. From memory all the rod lengths are the same. Theoretically if you have the right rods already in the 3K, they will go into the 4K without any trouble. I'm not sure how the 4K block will cope with that sort of over bore, but it might be OK?

 

One ring and a short skirt is definitely a racing piston though. Lucky it's in a racing car! :)

 

If you can make the 4K combination work then I'd do that. Keep the pistons and replace the block when the bores get too loose. You'll struggle to replace those pistons.

[silverra23]

Arias pistons in the US would be worth a look.. 800 for pistons for my 18rg and that was before the excellent conversion rate of the moment

[kickn5k]

Seems taht they would not be "long lasting" pistons.

 

Pete

what makes you say that? The pistons I make at work have a "measure point" of around 5mm dia. It will just eat the rings a bit quicker. A bigger pin = stronger as it will spread the load better. But then you need either Trd or custom conrods.

Also cheaper ain't better!!!!!!! Arias, Ross and JE are the only three in the US to use. Much better material than anything else over there.

 

Stu.

Edited May 3, 2011 by kickn5k

[pinsx3]

Stu,

 

I agree, I should have said, not a long lasting set up meaning, I am a cheap bastard and I don't want to build a grenade motor.

 

How can I find rods that will fit these pistons into a 4K -- good luck huh?

 

I wish there were more of these rigs in the US.

 

Pete

[corollaart]

There was rumor and i say rumor that 350 chev rods fitted in a k engine ,might be worth looking in to.

[pinsx3]

I talked to venolia, wasn't sure i wanted to spend the coin and wait 3 weeks....

 

Special rods are big bucks for an old school set-up. OK for a teardown after every race, not for a motor that you want to teardown every 4-5 years.

 

I'm just vintage racing.

[camerondownunder88]

Hi,

I think I posted this on the old Toyota forum at Yahoo.

 

To use TRD/TOSCO 3K rods you get stock conrods push the bushing out and polish them and you get 20mm pin to fit. That is how TRD did it. They used prepped stock rods and these pistons. Cost a lot to prep and I would agree with you. No bushing just using the polished base metal I don't imagine you would get great longevity.

 

Cheers

Cameron

[Spencer[RL]]

My 5k Crank is stamped 4k so they are the same

[kickn5k]

Stu,

How can I find rods that will fit these pistons into a 4K -- good luck huh?

 

Pete

"Spool imports" do a 5k(as advertised) conrod they can be purchased on the net and shipped to you(Aus based company). Compared to custom made ones are very reasonably priced $550aud is better than what carrillo would ask. I think there would be enough material in the to machine the little end out and push in right sized bushes.

 

Are you able to "eye up" measure the difference in compression height between the trd ones and a STD 4k piston? Maybe a good chance to look at a little offset grind stroker. Might be able to find an offshelf conrod that may work, to do something a little different. I have a bit of info at work in our books I may be able to let you know what rod will work.

 

If you end up buying to venolia pistons later. Pm me and I can help you out with making them last a bit longer. Just take an hour of your time.

[kickn5k]

Ok dug up a few bits of info off the spool website and 4/5k rods are:

pin dia = 18mm/.7087"

big end = 45mm/1.7717"

center to center = 120mm/4.7244"

what you'll need to do is measure compression height difference between a 3k and 4k piston and what ever the difference in piston height(center of pin to deck) is what you'll need in rod length change but with a bigger pin dia.

Now I have some info I can hunt a bit for you at work and see what I come up with.

 

Stu.

Edited May 8, 2011 by kickn5k