Club126UK
Fiat 126 Chat => Tuning & Customising 126 Models => Topic started by: 126dave on November 28, 2006, 06:36:12 PM
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hi guys,im gona freshin up my 650 in the new year,at the mo my panda 30 head is standard,im thinking of skimming a bit off to up the compression,nanni recommended a ratio of 10.5 to 1 for the cam they supplied 40-80-40.......now,any ideas on the amount i should be looking at to remove?
engine spec at the mo is,cam as mentioned,652cc, panda head,40dcoe weber carb and sport exhaust..........
any thoughts would be usefull.........i guess normal 652 head skimming amounts would do?...the panda head just different in the porting etc?? :???:
i should mention i use super unleaded with lead/octane boost additive
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just checked the blitz site...they reckon on 1.4mm to 1.6mm.........anyfeed back would be welcome from members or surfers.......
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I would think that camshaft with 40/80 (300deg opened valves) would need quite a high compression. 10.5:1 seems to be quite right. I am not sure if the camber in Panda head is the same as in 650E but I would think that 1.6mm will not be enough for this camshaft.
I had ~1.5mm skimmed head on the standard camshaft and it was working quite well (95 octans and 13deg ingnition). Later I got it to 2.5mm and with standard camshaft it had "pinking" problems. With 98 octans it was just right.
But: Last setup for my engine included 282deg camshaft and 4.5mm skimmed head. On the 95 octans it was possible to set it so it would not detonate but with rally setup ("racing" exhaust and 99 octan) it was mad.
I would suggest to take the head of and measure camber volume (with oil/petrol) and then you will know everything. It is always better to cut the head less then too much.
other tips:
1. f you cut more then 2.5-3.0 mm and/or have camshaft with greater valve lift check if valves will not hit the pistons (I had to do 2mm pockets for my inlet valves)
2. try fitting a copper gasket - it will lower the temprature of the head and they are usually thinner then standard ones.
3. with skim: ~3.0mm and more you might not be able to set the valve/rocker gap properly - have to shorten pushrods (not so complicated as you may think)
4. the "pipes" containing pushrods will need shortening as well (only 650 - as panda ones should adjust by themselfs)
hope I didn't make too many mistakes :roll:
If you have any questions just ask.
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fantastic,this is just the sort of info ive been searching for..........im not starting any of this till next year,im gna fit a bis box in at the same time as the freshen up.........i've spent a lot of time getting the carb mounts etc right,now is the time to pull the motor out and do all the details,i will be asking you for more info later im sure,thanks again :cool:
im using 650 push rod tubes at the mo,what is the difference with the panda ones?.is it worth me changing to them when i skim the head?
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Panda ones are shorter and they have sth like this at both ends (don't know how would you call it):
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So they can be "squized"
Panda (second picture from the top):
http://motonews.pl/sh_forum.php?op=fvt&t=12052&c=0&f=25&start=20
650/600:
http://img337.imageshack.us/my.php?image=p10100233zs.jpg
Similar project to yours:
http://www.fiat-furious.pl/html/artykuly/krowa.htm
I know it is in polish but it might be interesting for you.
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thanks,i think you mean 'concertina'........i will try and find some
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also,thank you for the link to fiat and furious........that carb support looks doomed to failure tho!........i've tried so many..the one i have now seems ok
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(http://home.btconnect.com/CPR-CREATIVE/1108/head.jpg)
Dave
This is the head I had on my car, you can see how much I had taken off, some of the racers run without head gaskets or have thin copper ones made up as well.
Having all the engine internals ballanced would have helped reduce the vibration thats breaking your carb mounts. It never goes away I had to replace the rubber bobbins that formed part of the mounting of my twin choke carb every six months, when I replaced it with a single choke FZD I ended up with more power throughout the rev range and because it is smaller and lighter than a twin choke it did not need any extra support – no good for you though, my head was a single port not a twin port.
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i see,almost down to the first cooling fin!.......a local guy has an engine from poland,the head is so skimmed he couldnt get the engine mount under the elbow.............im told
no balencing localy...(cant even get those dodgy dutch discs skimmed here)and sending the motor away stripped would be a shot in the dark,i dont have any contacts in the uk for that kind of thing
the vibes are still there,but my latest set is dampning them ok so far
once ive worked out whats what,im gna have to send the head away to be done.............the few firms here are crap really..........
times like this id like to be in the UK
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i am going down to see a vw tuning guy i know he wants to look at doing my engine , lightenning and balancing , polishing and porting etc . copper gasket made up. if it sounds good i shall go for it . i will keep you posted on what comes out of it.
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you can save a lot of head work if you just go for the twin port panda head.......but then you need a dellorto /weber carb and decent cam................ :roll:
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to be honest i dont want a really big carb to eat all my petyrol . i want to try and keep it a little bit ecconomical but more fun. plus my wife would throw a fit she wont notice too much of a change in the carb dept!
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perfectly sensible approach......will save ££s on panda 30 head etc
then stick a bis box in mick,you'll grab a few more mpgs from that on your runs to work
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Dave
If you need some details of engine ballancing companies over here who know 126 engines then please let me know.
Did you get the flywheel lightened last time you had the car apart?
nigel
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thanks nigel,no i didnt lighten the fly wheel but going too this time,and also gna try the bis clutch idea.
any info on good companys/how much to remove from f/wheel etc welcomed!
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im getting diff information from diff people on how much to remove from the head.................2mm seems a good bet???...the blitz site says 1.6 for 9-1...i need 10-1 really
im going to be using a ''race'' copper gasket from nanni.
all the info i have is for the 650 head not panda.........
i think ill risk it for biscuit and go for 2mm.......might have to pocket the pistons but thats cool............ :cool:
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im getting diff information from diff people on how much to remove from the head.................2mm seems a good bet???...the blitz site says 1.6 for 9-1...i need 10-1 really
im going to be using a ''race'' copper gasket from nanni.
all the info i have is for the 650 head not panda.........
i think ill risk it for biscuit and go for 2mm.......might have to pocket the pistons but thats cool............ :cool:
Go for 2mm. It will be fine. I didn't have to do pocketing with 3mm head but it also depends on sive of the valves, how deep valve seats are and of cours on the camshaft.
Remeber that you can always take off more :twisted:
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thanks,its all gona happen in the next two weeks or so............ :roll:
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up date,i was introduced to a gentleman engineer today,he worked for weslake cars when they were building the eagle weslake V12 F1 cars in the 60's he actually was one of the engine builders/developers working for Harry Weslake...........he has offered to cut and reface the head and match and relieve my inlet /exhuast porting for me..............also to lighten my flywheel.................................. :D
has also given me an original eagle weslake transfer that was fitted to the nose of the f1 cars..........i am just not worthy................
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and who said theres no one on your island?
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too right mick,i stand corrected. :oops: .................you just dont know who or what is around..................for example,im on the track of another aircooled ON ISLAND......... :shock:
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he he he he......flywheel and head gone for much cutting and machining today............... :twisted:
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update.....head back with helicoils fitted to plug holes,and 2mm off the face......... valves lapped in,ports cleaned and matched to elbows,all cleaned and first polish done,final polishing with brasso this weekend....... :smt028
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have you got a dremel ? if not get one they are ideal for getting little polishing jobs done . dont use brasso or any of that sort of stuff get yourself some polishing soap (blue for your ally head) . polishing is my favourite pastime , which is very very sad...... :oops:
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have a dremil mick,and first polish was with fine lapping compound/cutting paste,its all shiny,but brasso gets it perfect without affecting the ally....and i havint any blue
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all done,ports polished to a shine.......elbows ground out and polished as well..........all bolted up with copper gaskets and stainless fittings.....and valve's/ springs etc all refitted with new oil control seals......
an ideal sunday methinks.... :smt028
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sounds like a good days work Dave, just one question how the hell do you get the nylon valve spring oil seals on. when i tried i ended up flatening them so i ended up putting the old nylon ones back on,
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hi pete,i never did find the correct panda ones.......god knows where to get them......i fittted 850 ones....black rubber with a steel insert at the bottom and spring at the top,very tight to fit,i made a small tool from an old ''tophat'' wheelchair wheel bearing and used that to tap them on gently.
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never had any trouble with the black rubber ones with the spring clips but the white nylon ones that came with the h/g set thats another story.
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my panda head did come with white nylon ones,with an outside circlip,i searched every where for them,in the end a guy from the fiat uk site offered some early panda ones,(not 850,sorry),he used the rest of the gasket set for 850 rebuileds and had these over....they are the closest i could find.and seem to be ok.....panda 30 parts seem very hard to find,as does info on the cam/dizzy used etc......got to be more to that 30bhp than carb and head?
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well,i guess this one for the browsers..........getting close to putting engine back together,and have been today checking out the pushrod tube fit with the new skimmed head,2mm off remember........i reckon the standard fsm 650 126 oil seals at the top of the tube,and a RTV/silicon seal at the bottom will do the trick......the tubes fit tight down on the block,and the top seal gets compressed when i tighten the head down,i dont realy want to cut the tubes so im hoping this will be ok,i cant see why not,anyone else see a problem???..... :shock:
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heres a tip,with 2mm off the head you need to shim the rocker gear up the same amount,under the pedestal,other wise the shouldered and flared oil feed pipe holds it off the head..... :cool:
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so your saying because you have lost it from the face of the head you must replace it on the rear in order to allow correct fitment? will that affect the working of the tappets as you have changed the angle they are in relation to the valve stem tops ? ie the area they normally sit on will be different? :???:
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hi mick,mmnn,the spacers have put it all back as it was before,i was going to take up the 2mm on the tappet adjusters,but now all should be back as ''normal''........well for me anyway...... :shock:....the motor is going to get a nice run period anyways.....the face will run at a slight diff angle but all should be ok,anyhooooo,i cannot workout how to cut the pipe and reflare ACURATLY... :roll:
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you know,there's lots of problems like this when modding a 126,the guys that sell cams/heads/exhausts etc just dont bother with the details eh?...its a bluddy mine field when going for panda head etc...... :roll:
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Dave
Don't suppose you would like to write an article for my Retro500 site would you? Are you taking pics as well?
Nigel
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hi,well,i reckon i could put a few words together,maybe a pic or two, :smt024 at the very least it would show how not to do things!!.cant promise when tho :smt028
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in the end i used fsm 650 rubbers on the bottom of the tubes and skinny 500 ones at the top with rtv at both ends...i also trimmed the tubes both ends so they dont hit the cam followers,and,at the top allow the oil to return to the cam etc,the skinny 500 seals left the tubes too 'proud' in the head and would have starved the cam followers...so as of 6.30pm the head is torqued down and the valves seem to miss the pistons ok.....just the bottom end to finish and then dial in the cam...... :D