www.gt4dc.co.uk :: View topic - Engine rebuild now ready to go

...... received my spun iron liners, magnesium bronze valve guides and ferrea 1mm oversize valves.

nice mat.

were the liners expensive..

best of luck buddy hope it all goes smooth 4 you..realy doo..

matgt4 wrote:

...... received my spun iron liners, magnesium bronze valve guides and ferrea 1mm oversize valves.

Good news Mat. I'm leaning the same way myself now after having a long chat with the Ferrea guys at Autosport Engineering. Seems a shame not to fit them seeing as how I've already got a gas flowed head

Mat what thinkness are the liners are they 4.5mm

yes using 1mm over size is a must, why so many have not gone this route amazes me..

every engine i have every built has had over size valves, my 1st engine build got me hooked on oversize valves

big gains..

good luck

Don get on and fit them to your head.

If/when I go down the OS valve route then I'll be fitting uprated valve springs and retainers as a matter of course. The compression ratio may also be lower than stock which will further help to reduce the chance of the valves bouncing or 'floating' at high rpm and possibly hitting the top of the piston.

IMO to really get the benefit of the better breathing from the larger valves the rev limit needs to be increased, although perhaps not to the 9,000rpm that Adrian is rumoured to be planning for his new big valve, big turbo engine build :twisted:

If you retain the stock valve springs and rev limiter with OS valves then I'm not sure you'd see a significant gain. You'd want to limit revs to between 6-6,500 to be safe. But maybe I'm being over-cautious?

Author:	matgt4 [ Fri Mar 03, 2006 1:30 am ]
Post subject:	Engine rebuild now ready to go
The last bits turned up today so the rebuild begins. received my spun iron liners, magnesium bronze valve guides and ferrea 1mm oversize valves. Will keep you all upto date with pics and progress. The crank polishing has begun...pics to follow when half complete

Author:	datajon [ Fri Mar 03, 2006 11:33 am ]
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nice mat. were the liners expensive.. best of luck buddy hope it all goes smooth 4 you..realy doo..

Author:	TrackToyFour [ Fri Mar 03, 2006 2:39 pm ]
Post subject:	Re: Engine rebuild now ready to go
matgt4 wrote: ...... received my spun iron liners, magnesium bronze valve guides and ferrea 1mm oversize valves. Good news Mat. I'm leaning the same way myself now after having a long chat with the Ferrea guys at Autosport Engineering. Seems a shame not to fit them seeing as how I've already got a gas flowed head

Author:	GTone [ Fri Mar 03, 2006 6:39 pm ]
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Your a lucky man

Author:	datajon [ Fri Mar 03, 2006 7:16 pm ]
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Mat what thinkness are the liners are they 4.5mm yes using 1mm over size is a must, why so many have not gone this route amazes me.. every engine i have every built has had over size valves, my 1st engine build got me hooked on oversize valves big gains.. good luck Don get on and fit them to your head.

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Engine rebuild now ready to go http://www.gt4dc.co.uk/forum/viewtopic.php?f=1&t=678	Page 1 of 3

Author:	CEL1CA [ Sat Mar 04, 2006 8:32 am ]
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Just a thought.. do o/size valves restrict the margin of error? in the event of over reving that could induce valve bounce, and from that possibly implications on the safer upper limit for maximum revs. Does a further safety factor have to be built in?

Author:	TrackToyFour [ Sat Mar 04, 2006 11:05 am ]
Post subject:
If/when I go down the OS valve route then I'll be fitting uprated valve springs and retainers as a matter of course. The compression ratio may also be lower than stock which will further help to reduce the chance of the valves bouncing or 'floating' at high rpm and possibly hitting the top of the piston. IMO to really get the benefit of the better breathing from the larger valves the rev limit needs to be increased, although perhaps not to the 9,000rpm that Adrian is rumoured to be planning for his new big valve, big turbo engine build If you retain the stock valve springs and rev limiter with OS valves then I'm not sure you'd see a significant gain. You'd want to limit revs to between 6-6,500 to be safe. But maybe I'm being over-cautious?

Author:	GT4WRC [ Sat Mar 04, 2006 11:08 am ]
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I've upped the rev limit to 7500 at the moment - peak power being @ 7200. When I fit the new turbo, manifold etc and get the ECU re-mapped, rev limit will be increased to 8000rpm. Anticipate peak power being at least 7500 - 7600. To date, no issues at all and the uprated springs are doing their job as intended. Gary

Author:	matgt4 [ Sat Mar 04, 2006 1:59 pm ]
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datajon wrote: nice mat. were the liners expensive.. best of luck buddy hope it all goes smooth 4 you..realy doo.. Cheers buddy. the whole lot cost £580. Think the liners were approx £280.

Author:	matgt4 [ Sat Mar 04, 2006 2:00 pm ]
Post subject:	Re: Engine rebuild now ready to go
TrackToyFour wrote: matgt4 wrote: ...... received my spun iron liners, magnesium bronze valve guides and ferrea 1mm oversize valves. Good news Mat. I'm leaning the same way myself now after having a long chat with the Ferrea guys at Autosport Engineering. Seems a shame not to fit them seeing as how I've already got a gas flowed head Head work in progress

Author:	matgt4 [ Sat Mar 04, 2006 2:03 pm ]
Post subject:
datajon wrote: Mat what thinkness are the liners are they 4.5mm yes using 1mm over size is a must, why so many have not gone this route amazes me.. every engine i have every built has had over size valves, my 1st engine build got me hooked on oversize valves big gains.. good luck Don get on and fit them to your head. There actually approx 3mm Jon, I think partly this is due to keeping the bore within the original bores. So as not to breach the water jackets. Hopefully will be nice and strong. The same liners are used by the firm on there 1250 bhp 7 sec drag car (read american horsepower though so probably 800 ) They run a high inteference also for a very tight fit, they will need cooling, heat the block and press the gits in...pics will follow.

Author:	matgt4 [ Sat Mar 04, 2006 2:12 pm ]
Post subject:
TrackToyFour wrote: If/when I go down the OS valve route then I'll be fitting uprated valve springs and retainers as a matter of course. The compression ratio may also be lower than stock which will further help to reduce the chance of the valves bouncing or 'floating' at high rpm and possibly hitting the top of the piston. IMO to really get the benefit of the better breathing from the larger valves the rev limit needs to be increased, although perhaps not to the 9,000rpm that Adrian is rumoured to be planning for his new big valve, big turbo engine build If you retain the stock valve springs and rev limiter with OS valves then I'm not sure you'd see a significant gain. You'd want to limit revs to between 6-6,500 to be safe. But maybe I'm being over-cautious? Last reply i promise Don totally agree. I have a set of piper double valve springs already with my 272inlet 264 exhaust cams. I expect the rev limit to be raised. How far I havent decided yet. I feel also that 7500-8000 isnt pushing my luck with a well built engine, but I will see how the power delivery is with this set up, and make that good old power/drivability/reliability decision. Don have you had any ideas on what retainers to use?? I have yet to get these and havent really started looking yet? I really do think Ill have to wait and see, I dont really know of any cars running this combination of specifications, a few firsts i believe. so its a wait and see scenario. cheers for all your support guys

Author:	stevenb [ Sat Mar 04, 2006 4:40 pm ]
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Very impressive Mat. Bet you can't wait to get it all fitted and set up.

Author:	MarkCL [ Sat Mar 04, 2006 6:49 pm ]
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Mat - with the 272/264 combo I'd say 8k rpm rev limit will probably be what you'll need to make the best power m8 - if my 264's are anything to go by at least. They won't peak till 7500 or so. Although you'll make good power with what you've chosen you would have a more responsive engine using a 264/256 combo (still good for over 450bhp I expect) I think - are you aiming for just a BIG power mota or what? Good luck with everything whatever m8! Cheers, Mark

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Author:	matgt4 [ Sat Mar 04, 2006 7:02 pm ]
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Well I am aiming for approx 500bhp at the moment. Although Ive deliberately over built the engine as you never know for the future. A bigger tubby and fuel rail/injector setup will see 600 i would say. whether ill want it (unlikely) is another matter. Ill see how it goes...if you dont try you'll never know! has anyone tried the 264/256 combo before??? or is that just guess work at the moment too?