JamieP Posted September 17, 2008 Share Posted September 17, 2008 Im aware im pushing things a tad running 1.6bar on a stock engine and as i plan on pushing things a bit further, im thinking of building up a spare engine over the winter as if i have any problems with mine i dont want the downtime while sorting parts and the build etc. I dont want to spend mega money but do want a strong build. Im not interested in any stoker builds. My thoughts are buying a brand new complete shortblock and simply swapping the pistons for something like Jun in stock size? Keep stock rods but changing the bolts to ARP. Regarding the head do you think having it ported is worth it? or bigger valves? to keep costs down im thinking of just changing the springs and caps, i have some Jun 256/256 cams coming and leaving everything else as is? All suggestions/advice welcome. Id be looking at asking our Mr C Wilson to do the build for me. Regards Jamie. Quote Link to comment Share on other sites More sharing options...
AndyT Posted September 17, 2008 Share Posted September 17, 2008 Not sure on the rods Jamie, but a port job is always nice to have. Get the gases going. Quote Link to comment Share on other sites More sharing options...
SimonB Posted September 17, 2008 Share Posted September 17, 2008 You can't get JUN pistons in stock size, only 87mm (1mm oversize). I think porting the head is definitely worth it, but doesn't come cheap. Quote Link to comment Share on other sites More sharing options...
b_have Posted September 17, 2008 Share Posted September 17, 2008 Nice idea J, but you may have a problem with piston sizing.If the 86mm Juns/Wiseco etc are any smaller than the oems it won't work. Would love to see an 87mm stroker feeding a T67 though Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 You can't get JUN pistons in stock size, only 87mm (1mm oversize). I think porting the head is definitely worth it, but doesn't come cheap. Ahh, didnt really want to go with the expense of a rebore, CP come in stock sizes? What sort of money are we looking for porting and can anybody recommend somebody? Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 Nice idea J' date=' but you may have a problem with piston sizing.If the 86mm Juns/Wiseco etc are any smaller than the oems it won't work. Would love to see an 87mm stroker feeding a T67 though [/quote'] Stroker would be nice but way over budget sadly bud. Quote Link to comment Share on other sites More sharing options...
paul mac Posted September 17, 2008 Share Posted September 17, 2008 Regarding the head do you think having it ported is worth it? or bigger valves? i've spent a lot of time researching this Jamie and i have had a cylinder head sat on my bench in the garage for a very long time while i deside what to do with it, my conclusions are Toyota has done an excellent job of replicating the work done by a certain Keith Duckworth (of Cosworth fame) and there really are no big gains to be had (unless your looking for insane power figures), if you start enlarging the inlets you will lower the gas velocity which hurts low speed performance, increasing the valve size again is a big power top end thing so unless you are planning massive power you are going to loose some bottom end tractability for little or no gain. On my head I have desided to use Ferea valve guides as bronze guides transfer heat away from the valves much better, i have polished the exhaust ports to discourage carbon build up and port matched the head to the manifold (this is important when using aftermarket manifolds) i may cut the valve guide and boss back on the exhaust side as with anything on the exhaust side you want the gas away as quick as possible. On the intake side i have knife edged the centre web and opened up the injector area a bit, but thats it, no polishing or port matching to do as Mr T has got it spot on. I am also going to cc the head to make sure all the combustion chambers are the same volume. I am doing all this myself, if i had to pay someone i probably wouldn't bother and if i did i would want to see a dyno print out before spending my hard earned to prove its actually going to do something positive. Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 Thanks for the advice, keep ya thoughts coming please:) Quote Link to comment Share on other sites More sharing options...
TLicense Posted September 17, 2008 Share Posted September 17, 2008 Ahh, didnt really want to go with the expense of a rebore, CP come in stock sizes? The place I used charged me £96.00 to rebore my block, and to what I can measure it's absolutely cock-on. http://www.oselli.com Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted September 17, 2008 Share Posted September 17, 2008 Jamie I spent a LOT of time talking to Mark at Phoenix on this subject and he felt the best build for a T67ish size turbo was to start with a new bottom end, replace the rods and bolts as they are the 'weakest link' keep stock pistons, and a built head with uprated retainers, springs and head bolts, hope to be proved right with my set up this week during mapping Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 The place I used charged me £96.00 to rebore my block, and to what I can measure it's absolutely cock-on. http://www.oselli.com Thanks for the link, but if they come in stock sizes i still dont see the point in a rebore, i suppose if i was to go for a secondhand block it would then be worth it. Quote Link to comment Share on other sites More sharing options...
dandan Posted September 17, 2008 Share Posted September 17, 2008 Im aware im pushing things a tad running 1.6bar on a stock engine and as i plan on pushing things a bit further Pushing further in terms of RPM or boost? Big difference. Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 Jamie I spent a LOT of time talking to Mark at Phoenix on this subject and he felt the best build for a T67ish size turbo was to start with a new bottom end, replace the rods and bolts as they are the 'weakest link' keep stock pistons, and a built head with uprated retainers, springs and head bolts, hope to be proved right with my set up this week during mapping See i may be wrong but i have always been under the impression the stock rods are fine, (never heard of one failing anyhow) its the stock piston rings that are the weak point, my first engine failure was down to ring failure. Pushing further in terms of RPM or boost? Big difference. Boost/cams/intake manifold/race fuel map Quote Link to comment Share on other sites More sharing options...
TLicense Posted September 17, 2008 Share Posted September 17, 2008 Thanks for the link, but if they come in stock sizes i still dont see the point in a rebore, i suppose if i was to go for a secondhand block it would then be worth it. As has been mentioned, if you want to go with Juns then I think you'll need to bore out. However, CP do a line in 86mm's, although if you were just wanting a well built engine, and were going to buy a stock shortblock, I would just get someone to strip it, make sure there are no fubars and nail the thing back together using some decent rod and head bolts. Maybe check the main / big end bearings are optimum, but other than that..... Quote Link to comment Share on other sites More sharing options...
TLicense Posted September 17, 2008 Share Posted September 17, 2008 See i may be wrong but i have always been under the impression the stock rods are fine, (never heard of one failing anyhow) its the stock piston rings that are the weak point, my first engine failure was down to ring failure. Boost/cams/intake manifold. What caused the ring failure? They don't "just go"! Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 What caused the ring failure? They don't "just go"! I dont know, no sign of det, the ring was in a couple of bits and the block scored. Ryan also advised me the stock rings are the weak point at high boost, so he must have seen this aswell. I might still have a pic on the old pc, ill have a look tomorrow. Quote Link to comment Share on other sites More sharing options...
Wez Posted September 17, 2008 Share Posted September 17, 2008 my ring failure. ouch Quote Link to comment Share on other sites More sharing options...
Kev.O Posted September 17, 2008 Share Posted September 17, 2008 See i may be wrong but i have always been under the impression the stock rods are fine, (never heard of one failing anyhow) its the stock piston rings that are the weak point, my first engine failure was down to ring failure. I've been told the same which is why when CW built mine he used the stock ones. I have CP pistons but I know Chris didn't like them that much. I've used ARP for the main crank and rod bolts and head studs. Also fitted HKS 264/264 cams. Quote Link to comment Share on other sites More sharing options...
TLicense Posted September 17, 2008 Share Posted September 17, 2008 I've not heard of anyone running a normal amount of boost having a ring go? Any thread links? Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted September 17, 2008 Share Posted September 17, 2008 Could the ring failure be due to a poor rebuild and not the boost levels perhaps Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 (edited) I've not heard of anyone running a normal amount of boost having a ring go? Any thread links? Im planning 2bar and race fuel, when the red car let go that was on 1.8bar T88. Edited September 17, 2008 by JamieP (see edit history) Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 Could the ring failure be due to a poor rebuild and not the boost levels perhaps It was a stock engine. Quote Link to comment Share on other sites More sharing options...
Mike B Posted September 17, 2008 Share Posted September 17, 2008 mine had cleavite bearings fitted, and aside from that stock pistons (which are forged anyway) and eagle rods. the engine if far more athletic to drive, and I much prefer it to the heavier stock engine. can't you get it stroked for minimal cost? better than than oversizing the valves etc.. it's always spool/response that lets the whole thing down; nothing else on the road is running the kind of power a t67 on 1.8bar can produce... response is the achillies heel. Quote Link to comment Share on other sites More sharing options...
JamieP Posted September 17, 2008 Author Share Posted September 17, 2008 nothing else on the road is running the kind of power a t67 on 1.8bar can produce... response is the achillies heel. You running 1.8bar Mike on stock pistons?, if so im gonna put my boost up now. Quote Link to comment Share on other sites More sharing options...
TLicense Posted September 17, 2008 Share Posted September 17, 2008 Ah sorry I didn't realise you were going to run that much boost. If you're going to run 2 bar of boost, I wouldn't fit anything other than Juns. Quote Link to comment Share on other sites More sharing options...
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