View Full Version : to skim or not to skim
well since my engines stripped now should i get the head skimmed?
the headgasket wasnt gone or anything and wasnt overheating or using water
autoworksnovasport
02-03-11, 09:33 PM
doesnt matter mate when you undo head bolts the head moves in different ways (same as tightning down) so your best off getting it done to be safe
it dosnt really bother me if i have to or not just thought id ask first :)
Nah reuse the old gasket and some sealer..............
Skim it.
rock on the fight due once someone else sees this thread lol
If there is nothing wrong with it, why would it need it?
12 huge bolts holding it down to a huge iron heat sink.. It will be fine.
autoworksnovasport
02-03-11, 10:22 PM
If there is nothing wrong with it, why would it need it?
12 huge bolts holding it down to a huge iron heat sink.. It will be fine.
think how you tighten a head down it pulls it down flat yes:thumb:
so when you release the pressure off the bolts the head will come off at different angles theres no way off taking it off without needing it done, it may only be mili mili meters but thats enuf
lol you wont bend it by unbolting it... If you did then the cam wouldn't turn... Skimming it wont fix that.
Check it with a straight edge, and if there is no damage to the face then there is no need at all to get it skimmed !
it dosnt really bother me if i have to or not just thought id ask first :)
so the point in this thread is...........? :)
autoworksnovasport
02-03-11, 10:38 PM
lol you wont bend it by unbolting it... If you did then the cam wouldn't turn... Skimming it wont fix that.
didnt realise i said it would bend the head:wtf:
brainsnova
02-03-11, 10:40 PM
Thread waster lol
didnt realise i said it would bend the head:wtf:
Read what you said, its close to it..
autoworksnovasport
02-03-11, 10:55 PM
ok arguement over i give up lol lol
so the point in this thread is...........? :)
Because it's a public forum and someone else might news this info :)
When I said it spent bother me getting it done I thought I'd ask here first as it could be £30 spent on something else
autoworksnovasport
04-03-11, 06:37 PM
got a negative rep for my comments for some reason?????
if somones silly enough to fit a head that has been removed and not checked( even if good prior to removal ) then thats fine i deserve it!! sounds like a few people work at halfords or dodgy back street garages
daleNOVAbrennan
04-03-11, 07:04 PM
ive removed good heads and put them back on without skiming, never had any problems
autoworksnovasport
04-03-11, 07:09 PM
im not argueing again if you do a job right you do it once!!!!!
stevenf
04-03-11, 07:11 PM
as was said earlier check it with a straight edge. you will soon be able to tell if you need to get it skimmed :thumb: personaly i think its up to yourself really
daleNOVAbrennan
04-03-11, 07:13 PM
whos argueing, i just put my experience of removing and fitting heads, all mine have worked spot on and never had a problem, aslong as you check it with a straight edge, it will be fine. i done the job right then as i only done it once!
No, re-use the old bolts, tighten them down through a further 5 degrees.
Re-use the old gasket but put some silicon sealer on the face of the gasket.
No, re-use the old bolts, tighten them down through a further 5 degrees.
Re-use the old gasket but put some silicon sealer on the face of the gasket.
sarcasm? lol
stevenf
04-03-11, 08:37 PM
just a little lol
Pistol Pete
04-03-11, 09:13 PM
Not needed IMO. If it hasnt over heated and the gasket hasnt failed, then bung it on with a new gasket.
I've done i think about 10 head gasket changes (different cars) Never had to have one skimmed.
I'm sorry, but just unbolting a head will not damage it.
autoworksnovasport
04-03-11, 10:48 PM
I've done i think about 10 head gasket changes (different cars) Never had to have one skimmed.
I'm sorry, but just unbolting a head will not damage it.
i do this for a living mate done a few more than 10 head changes, i agree just unbolting a head will not damage it but to do it proply get it skimmed you know it will be right then not just hopeing its ok, it may be fine it may not
scottish
04-03-11, 10:50 PM
use some sense dont chuck your money away if it dont need done dont do it
use some sense dont chuck your money away if it dont need done dont do it
post of the thread! :)
i do this for a living mate done a few more than 10 head changes, i agree just unbolting a head will not damage it but to do it proply get it skimmed you know it will be right then not just hopeing its ok, it may be fine it may not
I also do it for a living, and if there has been no issues then theres no need to get it skimmed ... thats not in a dodgy back street garage either !!
tbh...25quid to skim it...might as well...bit more compression too
autoworksnovasport
05-03-11, 12:02 AM
tbh...25quid to skim it...might as well...bit more compression too
and you know its 100% then aswell!!! i give up have fun everybody
daleNOVAbrennan
05-03-11, 07:30 AM
well aslong as i check the head with a straight edge, i know its fine, id rather save 30 quid, ive never had problems doing it before and sure i wont have problems doing it again.
i do this for a living mate done a few more than 10 head changes, i agree just unbolting a head will not damage it but to do it proply get it skimmed you know it will be right then not just hopeing its ok, it may be fine it may not
Ok, am not being rude to you. Sorry but i just don't believe in it, it's what garages do all the time. So now people think it has to be done when it doesn't need it.
Check it yea, but you can do that with a straight edge. Only time it will need skimming is if its
A been boiled dry/driven with no water to build up huge pressure.
B the mating surface has damage damage.
Ok, am not being rude to you. Sorry but i just don't believe in it, it's what garages do all the time. So now people think it has to be done when it doesn't need it.
Check it yea, but you can do that with a straight edge. Only time it will need skimming is if its
A been boiled dry/driven with no water to build up huge pressure.
B the mating surface has damage damage.
thats correct benn, just read this and all these so called mechanics aint got a clue and surely like wasting money lol
"you'll bend/warp a head when bolting/unbolting it" thats kwik fit talklol
autoworksnovasport
05-03-11, 11:39 AM
thats correct benn, just read this and all these so called mechanics aint got a clue and surely like wasting money lol
"you'll bend/warp a head when bolting/unbolting it" thats kwik fit talklol
so bolting a head downn in the wrong sequennce wont damage it???:wtf: are you forr real??
so bolting a head downn in the wrong sequennce wont damage it???:wtf: are you forr real??
we all know that, but its not done like that just to prevent warping the head, its also to compress the gasket the correct way, but if you take a head off that hasnt been overheated with no know problems, then you do not have to have the head skimmed, its as simple as that really
daleNOVAbrennan
06-03-11, 10:06 AM
so bolting a head downn in the wrong sequennce wont damage it???:wtf: are you forr real??
the head gasket will be damaged befor the head, and when removing a head its best to go in reverse order of the tighting sequence, letting a little off at a time so theres no chance of warping the head.
autoworksnovasport
06-03-11, 07:59 PM
the head gasket will be damaged befor the head, and when removing a head its best to go in reverse order of the tighting sequence, letting a little off at a time so theres no chance of warping the head.
this is exactly what ive been saying all the way through but youve all argued that i was wrong
i really can't be bothered to put right all the wrong info on this thread...
i was out last night & still haven't recovered properly....
Ive done a few headgaskets and dont skim any head that doesnt need it.
If its overheated seriously, or the head face is damaged, then its a skim job.
If not, clean up and bolt back on
C612DNM
06-03-11, 09:47 PM
Having built a number of championship winning engines, and having a hand in a number of others too, I can honestly say I have NEVER had a head skimmed when there were no indications to there being an issue.
And I would never ever ever never ever (get the picture) ever EVER consider re-using stretch-bolts, or compression-composite headgaskets.
Copper headgaskets - yep. Re-anneal and on again (unless damaged).
The old rule applies still - "if it ain't broke - don't fix it"
daleNOVAbrennan
06-03-11, 09:52 PM
this is exactly what ive been saying all the way through but youve all argued that i was wrong
so what your now saying that you wont damage the head ??????:confused:
http://www.engineersedge.com/calculators/torque_calc.htm
using their calculations, an m12 bolt pulled up to 100lb/ft (approximation) gives 12000lb of clamping force. multiply that by 10 bolts then allow for frictional losses due to age of the block threads etc, you still have somewhere in the region of 100000lb(45t) of clamping force to keep the head onto the block. then it warms up to nigh on 100deg C within the first few minutes. but the combustion chamber temp is obviously way higher, causing localised fluctuations in the head. unbolt the head & it is slightly warped.... because it is warped to suit the block it was fitted to. it will then bolt up to the block in the same place as before.
if you skim the head, you should skim the block too, then get a thicker gasket to suit. back in the old days (1980's) major manufacturers did give the different sized gasket options mostly for diesel engines, and you ordered them if you needed a head skim.
apart from cleaning the old gasket off the face of the head, or if there is damage or pitting, the vast majority of heads don't need it, yet everyone in the motor trade seems to think it necessary and i always suspect this is because they can make money on the skim, and also drag the job out to make more money... gm used to quote in their service book 2.75hrs to remove, strip down a 1200st head & put it back on... most garages seem to take an awful lot longer than that.....
now getting a head skimmed for performance is a much more complicated job. the cam timing will be out, thus you need a vernier pulley to get it correct, the performance gain over std using original pistons etc is always overstated, with a high lift cam, there is more risk of valve-piston impact etc.etc..
autoworksnovasport
06-03-11, 10:01 PM
ive just read through all my messages ive put on this thread and appears some off the stuff ive said was not exactly what i ment just writing quik and blurbin stuff out not going back on what ive said though (mostly) but if you have PERSONALY removed a head and KNOW it is good then it can be refitted i was going on the fact i dont know the engine or the history may have been put back together before:wtf: ie unknown condition
i should have read the original post properly before commenting :thumb:
As said, reuse the old bolts, tighten down through a further 5 degrees, re-use the old gasket with silicon sealant. Why is this thread still going?
because you keep posting the same rubbish on it then ask 'why is it still going on???'
This 'rubbish' is your advice u prat!
ok, use the search facility, and try to find just where i said use old bolts, and overtighten them, and reuse old gaskets with a skim of sealant....you will find that i never said that, i would never say that
stretch bolts are designed for one use only.
composite gaskets are a one use only item... copper sheet gaskets are a different matter, but i don't use race gaskets on the stuff i repair
and the business about the silicon sealant was from sloth, and he actually was going on about drag racing hemi engines, where they really did use sealants instead of gaskets ...
Right it's getting skimmed but how do I remove the pipe looking part in the corner
It looks like a locating dowel
let the skimmers do it, or just use a plier or water pump wrench & wriggle it out
well dropped it in today at the engineers
i also snapped a bolt that holds the thermostat housing on too so hopefully they can repair that
if you asked them to, it is an easy fix. steel reacts with aluminium & seizes solid. lightly oiling threads does help.
yeah he said he should be able to get it out
that why i copper grease nearly everything when i bolt it back up
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