Pop goes the something or other

Thor

Member
James, if you need another HG i have a HKS 2.0mm (used from my last engine without cracks etc) which i can send you!
 

campbellju

Moderators
Staff member
Thanks Sasha and Danny, very kind offers, I appreciate the backup.

In total I got in 5 hours today and not being a professional mechanic means I'm not the fastest but I have stripped off all the inlet side, taken the alternator off (wasted 30 mins on one bolt) but found the nut a little loose on the main alternator bolt that explains why I've been going through so many belts recently!

I then unbolted the exhaust manifold (wasting 1 hour on the annoying nut underneath in the centre as usual!)

I've lined up the the crank at TDC and taken off the camshaft cover. Inside you can easily see a puddle in cylinder 4. All the camshaft area is a little milky from the vented gas through the crank case I guess. There are no other obvious signs of contamination in oil or water.

Nothing really to report, I thought I would stop for today before I took the camshafts out to double check I've not missed anything in the manual.

Thanks again everyone for your support.
 
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campbellju

Moderators
Staff member
I got the head off yesterday morning and Stu kindly came over to give a second opinion. As always, thanks to Stu for putting himself out.

The block has had minor pinking damage around the top lip of the block. Over time this has nibbled just far enough to get to the HG which caused it to fail and cause the recent symptoms.

There might be some other reasons why but in short I've been putting the engine under a lot of stress for too long and I think its finally given up.

So the block is not usable and the car is unlikely to get fixed quickly.
 
P

pulsarboby

Guest
as danny pointed out this is quite a common prob and what he has suggested....or is about to makes perfect sense, hes a clever ol stick:lol:
dont know what size your pistons are jim but if there 87mm i may have a block thats marked but will take a bore which you can have for next to nowt if it helps out at all;-)
 

campbellju

Moderators
Staff member
Thanks Bobby, that's very kind. For the moment I'm going to put the car to the back of my mind, I've got a busy week now before I go away and its not going to get fixed quickly so I'll worry about it after JTS.

Danny, what's you're thinking on the head gasket? Is it the thickness or composition?
 

stumo

Active Member
Thanks Bobby, that's very kind. For the moment I'm going to put the car to the back of my mind, I've got a busy week now before I go away and its not going to get fixed quickly so I'll worry about it after JTS.

Danny, what's you're thinking on the head gasket? Is it the thickness or composition?
it's the size of the gasket compared to the size of the bore. ie the gasket is too big for the bore size.
 

PobodY

Moderators
Staff member
Is that a problem with any specific gasket; HKS, Tomei, etc? - I can see the logic in that; if it doesn't go to the edge of the cylinder, then you'd get a small region around the lip of each which gets excessive wear?
 

stumo

Active Member
Stu, whats a sniffer?
sorry, just seen this post....

a "sniffer" is often called a block tester or head gasket tester, comprises of a fluid that changes colour in the presence of carbon monoxide and a tool to suck the gasses through the liquid.



You run the engine with the rad cap removed and put the tool on the mouth of the rad and press the bulb to suck any gasses through the liquid.

If the gasket is gone (or a crack in the head etc) then the liquid changes from blue to yellow.
 

red reading

Active Member
Jim as has been said i think the bore size of the gasket is the problem. the last couple of hks gaskets i have measured have had a bore size of 88.5-88.8mm which on a 86-87mm bore engine is leaving a large area around the top of the bore with a sharp edge to be heated/melted/eroded by detonation. now any sharp edge in a combustion chamber is bad as we know so that is why i think the cosworth head gasket with the correct bore size should be used or the ultimate fix is the engine should be having liners fitted for high power as the liners that are cast into the block as standard do not reach the deck of the block and you have a potential weak spot.

the damage to the cylinder head's which is predominatley on the inlet side (same as the block too) can also be helped by re-shaping the combustion chamber slightly.

Myself and stumo and bob have had long conversations about this and other problems these car's have and this is one of them! that's why when you first posted i said what i did,the pop you heard may have been your radiator end tank blowing off btw.
 
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