View Full Version : welding a c20let head
a few weeks ago i bought a c20let that had melted pistons. i took the head off today and the pistons have a small bit of melting, looks like a bit of pitting.
now my real problem is the head took most of it. there is deep pitting in it about 2mm in cylinder 2&3 like the picture below.
has anyone ever got a head with this problem welded up before and skimmed?
i could just get another head and i still might but this one had work done by regal porus head mood and ported inlet and polished exhaust.
http://mervart.eu/C20XE/h1k_rep.jpg
Jon_nova1
02-06-12, 05:22 PM
You can weld heads, but not sure the best way to go with yours, it looks like your pointing out the pitting that is on the edge of the skimmed part, it may be possible if you had mild steel (around 3MM) profiled to the shape of the combustion chamber and place it where you want it welding and tig weld the face, the mild steel will cool the weld down quickly and the alumium won't weld to the mild steel
that sounds like a plan, ya it is just right on the edge of the head and near the skimmed part.
Jon_nova1
02-06-12, 05:35 PM
Unless someone else has a better idea i'd do that, but when making the steel bit keep in mind the weld will take that shape so make sure the diameter is as close as you can get it, make sure the parts that are getting welded are clean too otherwise it might come off, i'd personally use a dremel or similar with a grinder on it
sometime soon i will get called names from a certain website, but here goes.
as much as you want to keep the porting/porous(crack from bad design) mods, i reckon the head is pretty much scrap. its been cooked good & proper, and tbh, a let/xe head is far from rare. what i would suggest is to get an xe head, and get some dental moulding putty. then you can mix some up & stick it down the ports on both the let & xe heads, wait for it to set, pull it out & compare the ports, then get the dremel out on the xe head in the same places as the let...
i think the mapping needs looking at too, cos it really shouldn't be leaning off like that if its correct.
i think i will just get another head better to be safe than sorry.
Round here they charge £30 to weld the pits and £30 to skim.
And i would bet my last quid if your chambers are like that then your valve stems will be just as bolloxed also.So add in new valves/guides to the equation and your not far off a replacement head
therealnovaboy
02-06-12, 08:56 PM
I remember in PPC mag they used araldite or belzona (cant remember) to repair a block before skimming. it was probably an old ford engine so wouldnt make much odds if it blew up. I thought it was a bit rough but probably worked. itll depend on how bad your head is.
therealnovaboy
02-06-12, 09:01 PM
I remember in PPC mag they used araldite or belzona (cant remember) to repair a block before skimming. it was probably an old ford engine so wouldnt make much odds if it blew up. I thought it was a bit rough but probably worked. itll depend on how bad your head is.
just saw the pic it finnaly loaded, i wouldnt put anything there, PPC just repaired the parts that were covered by the gasket IIRC. that would probably be ok and would run fine providing the gasket seals. Altho for a high performance engine id scrap it and get a good one.
probably will just scrap it, mine is a lot worse than that pic and it is on cylinder 2 and 3.
some of the engineering in ppc mag is inspirational..... some of it is downright shocking..... using a chemical compound to fill ing engine damage is highway bodgery.
ps. when i was a real youngster, i went for an interview at a race engine builders.. (i was actually too old for them to get yts money so didn't get the job) they had a 3valve per cylinder v12 ferrari lump in that had had a serious load of damage from a snapped valve bouncing round.. they had rebuilt the head with ally weld, and then re-machined it back to as new..it had cost thousands, but the engine was pretty much irreplacable
Talking of bodgery i once bought an xr3 that had liquid metal in place of a core plug-unfukking believable isnt it?!!
thats impressive.......... not.....
back in my tractor dealership days, we had a mf135 3 cylinder tractor come in from an auction, and it ran funny....
no.2 piston & rod were missing, no.2 injector had been hammered shut!!! & no.2 big end, which was shot, had sealant & a jubilee clip on it to keep the oil moving up the drillings!!!! it ran quite well considering........
Old man Jimbo
03-06-12, 10:03 AM
Not quite sure why people are so "shocked" at chemical metal etc being used. Some of the biggest Vauxhall tuners out there often use araldite etc if they break through when porting heads etc.
Ok,a £5 tube of chemical metal in place of a 70pence core plug?? Alright then lol
Not quite sure why people are so "shocked" at chemical metal etc being used. Some of the biggest Vauxhall tuners out there often use araldite etc if they break through when porting heads etc.
some of the biggest tuners are actually bodging con merchants too....
i did see a racing quad cylinder head, where they had used chemical metal to build up a port to straighten it out... but it had a design life of very few miles...
we are also talking about ports, not combustion chambers or gasket surfaces...
back in the olden days, people like vizard were routinely breaking thru ports into the cooling jacket & then drilling holes to insert pipes to bypass the holes.. but head design has moved on somewhat... the std xe probably flows better than the original dfv did..
Old man Jimbo
03-06-12, 12:25 PM
Okay,
Back to the OP's question about welding the head and skimming. Yes had it done a few times with no ill effect. Just make sure the pitting is only in the chambers and not spread anywhere else.
its a turbo head that had been detonating, thus its been cooked & run lean..it will not be up to much after that
Old man Jimbo
03-06-12, 12:57 PM
its a turbo head that had been detonating, thus its been cooked & run lean..it will not be up to much after that
Some quick pics nicked off someone else as I've never bothered to take pictures of one I've had done TBH. Although I've had heads in much worse condition than OP's done.
Before:
http://i140.photobucket.com/albums/r18/jimbo_090/det04.jpg
After welding and a skim:
http://i140.photobucket.com/albums/r18/jimbo_090/head03.jpg
Main issue with welding the heads is they end up soft afterwards.
A friend of mine had to get the wire ringing on his head welded up as he went from using wire rings to 2 cometics, quite a extensive job. When the engine was stripped after the next race meet the rings on the cometic had left a big dent in the welded section.
I've had heads welded myself and not had a problem but it's not a guaranteed fix.
As for chemi metal, another mate of mine ran a drag rx7 which blew 2 new engines on the rollers ( one after another ) on inspection the block had been filled with chemi metal where the rotor tips had come off on previous failures, certainly not ideal and it hadn't exactly bonded on all that well either ! I'll dig out a pic.
i did a head gasket on a cavvy sri once with the ecotec lump. the gasket had gone between cylinders 2 and 3 and as such had eaten away at the head as well. took it to my local engineering place and they welded it and ground the combustion chambers back to how they were supposed to be and then skimmed it for £60, was a pukka job and was fine for as long as he had the car
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.