20 replies to this topic

[eden7842]

ive been having head gasket trouble, and the head im using was on a engine that over heated to the point
of piston 4 melting. so is there a good chance the head is warped?

thanks

[MINI 1]

yes , it could well be , best to get it checked out .


ash

[eden7842]

il take it off today and have it done tomoz

thanks

[MRA]

not generally an issue with cast iron heads I would guess that you have had the block skimmed recently or refitted the head with a higher torque figure which has pulled the top thread out of the block thus stopping the head from sitting correctly

[m1tch]

not generally an issue with cast iron heads I would guess that you have had the block skimmed recently or refitted the head with a higher torque figure which has pulled the top thread out of the block thus stopping the head from sitting correctly

Or perhaps not torqued up evenly?

[MRA]

absolutely

[mini7boy]

absolutely

it's definitely possible to warp cast iron heads and I have seen it firsthand.

If a piston melted, that engine got super hot. Heads can warp without melting pistons.

don't rule out the overheat as being the cause if the head turns out to be warped.

You shouldn't have pulled the threads up from the block deck UNLESS:
1) you SEVERELY over-torqued the nuts/studs
2) the block had been skimmed severely leaving it less resistant to the threads pulling.

Keep in mind that if the head is severely warped, skimming it until it's flat may result in chambers that
are of widely different volumes. Depending upon how much they vary, some corrective actions
may be required(as in opening out the smallest to match the largest)

[Cooperman]

By way of light relief, the famous Mini driver, Timo Makinen, once lost a core plug during a rally. He continued until the engine got so hot it seized and all the BMC green paint on the engine burned off, leaving the block a sort-of brown colour. Timo's comment to the service crew, in his 'Finnish-English' was "Car not go, engine wrong colour"!

[eden7842]

the block has never been touched and is in mint condition,
i took the head off today and it appears to be slightly warped in between cylinders 2-3, as it keeps blowing between the two.
its going morspeed tomoz to be skimmed so hopefully the issue shall be solved

[Spenner]

Plz keep us informed im having the same problem i can do around 1500 miles before i need to change the head gasket we have checked the block and head and all seem fine.

Edited by Spenner, 20 July 2009 - 08:01 PM.

[eden7842]

will do mate, thats sounds very weird

[mini7boy]

the block has never been touched and is in mint condition,
i took the head off today and it appears to be slightly warped in between cylinders 2-3, as it keeps blowing between the two.
its going morspeed tomoz to be skimmed so hopefully the issue shall be solved

the narrow strip of metal between cylinders 2&3 is a common problem area.

In addition to making sure the head and block surfaces are absolutely flat in this area, you need to make sure
that you are using a good quality head gasket and torquing it properly. If the head nuts are not
torqued correctly, you can cause the metal fire rings that surround each cylinder to flatten and
break up. Make damned sure that you use the right torque figures for the lubricant used on the nut/stud threads.

If you haven't already done so, you should read this article: http://www.minimania...27/ArticleV.cfm

[eden7842]

i shal be sure to torque it up properly dont worry about that. so its back from being skimmed, and ive cleaned it all out
and reseated the valves.

it shall be fitted tomoz and il compression test it straight away.

[eden7842]

so its all back on and running well, has made a lot of difference in the cars pick up.

haven't compression tested yet. quite scared to do so in case its low

[mini7boy]

now that you've skimmed the head, installed a new head gasket and torqued it correctly, you probably won't have any more problems
with sealing between the head and block.

However, as a warning to you and others, if your car ever starts to misfire badly and you suspect head gasket problems, especially between
cylinders, do NOT continue to drive the car with it running this way. I have seen several heads and blocks where the METAL surfaces of the head
and block were BURNED AWAY. I know this sounds crazy, but I have seen it on several different engines. In each case, a small "ditch" was formed
and the metal was burned down to a depth of approx. 1/16 of an inch. This takes a serious skim to clean it up and if either the block or head
is already severely skimmed, it may not be an option to do a skim of the required depth to restore the usefulness of these parts.

It's amazing just how powerful the "burn power" is when you get firing between cylinders across the narrow area of metal between adjoining cylinders.
All that has to happen is for the head gasket to get burned through in this area and it opens up quite a "tunnel" through which flames can roar back
and forth between the cylinders as each cylinder takes its turn firing. Next thing you know, these super hot flames start removing metal in a hurry.
This is a classic meltdown cycle in which the damage is done quicker and quicker as the size of the inter-cylinder tunnel grows.

Best to be safe rather than sorry. Pull over and get your car towed to a place where you can work on it.