Mk1 engine woes, possible cracked block??
Discussion
I'll try and keep this as succinct as poss, car is a 1992 Eunos 1.6 bought with query HGF.
I removed the head and sent it for a pressure test / skim, water jackets looked really manky and furred up, maybe had radweld or something through it before?
Head replaced with new head gasket, new water pump, belts etc.
Starts straight up, idle adjusted, seems to run fine, no fluid leaks or anything.
Took for half hour test drive, no problem other than some steam from rad cap after switching off, I assume this is an air lock.
Next day go back out for another test run having topped rad up, runs fine but after approx half hr seems down on power,shortly after down to two cylinders and James Bond style smoke screen from exhaust. Limp to layby, switch off.
Seems to have consumed all the water in the rad.
What can I do next from a diagnosis point of view? I assume the engine block is cracked or I have badly messed up somewhere fitting the head gasket. If it was the latter though, surely it wouldn't have run so well after going back together?
Any help greatly relieved.
TL;DR - head gasket replaced 20 miles ago, seemed to cure, now have even worse HGF symptoms
I removed the head and sent it for a pressure test / skim, water jackets looked really manky and furred up, maybe had radweld or something through it before?
Head replaced with new head gasket, new water pump, belts etc.
Starts straight up, idle adjusted, seems to run fine, no fluid leaks or anything.
Took for half hour test drive, no problem other than some steam from rad cap after switching off, I assume this is an air lock.
Next day go back out for another test run having topped rad up, runs fine but after approx half hr seems down on power,shortly after down to two cylinders and James Bond style smoke screen from exhaust. Limp to layby, switch off.
Seems to have consumed all the water in the rad.
What can I do next from a diagnosis point of view? I assume the engine block is cracked or I have badly messed up somewhere fitting the head gasket. If it was the latter though, surely it wouldn't have run so well after going back together?
Any help greatly relieved.
TL;DR - head gasket replaced 20 miles ago, seemed to cure, now have even worse HGF symptoms
I'm not that handy with the spanners, I'm fortunate enough that one of my best mates is an ex-Mazda tech and has the luxury of a double garage and snap on tools.
The reason I didn't swap the engine initially was that the lump in it seemed quite strong and peppy and I thought a £50 gasket set would cure the problem. A warranted engine is £400+ vat from Autolink (could probably get it cheaper for cash) and with a cheaper engine off eBay it's an unknown quantity.
With regards to having a look once the head is off, when we changed the gasket it was clear that the gasket had seen better days and there was evidence of water getting into one of the cylinders as the valve seats were a slightly different colour. The Pistons and stuff all looked OK as far as I could see, and would a crack in the block necessarily be a) external and b) visible to the naked eye?
The reason I didn't swap the engine initially was that the lump in it seemed quite strong and peppy and I thought a £50 gasket set would cure the problem. A warranted engine is £400+ vat from Autolink (could probably get it cheaper for cash) and with a cheaper engine off eBay it's an unknown quantity.
With regards to having a look once the head is off, when we changed the gasket it was clear that the gasket had seen better days and there was evidence of water getting into one of the cylinders as the valve seats were a slightly different colour. The Pistons and stuff all looked OK as far as I could see, and would a crack in the block necessarily be a) external and b) visible to the naked eye?
The head was skimmed and pressure tested.
I think I didn't do the head bolts up enough, from memory they were a bugger to crack off, and I think we put too much trust in an ageing torque wrench to do them up to the right level.
I reckon with my recent practice I can have the head off in a couple of hours, plan is to disassemble, check for obvious carnage and damage to new gasket, re-assemble with much tighter head bolts, coolant flush and then cross fingers.
I will endeavour to keep you updated, your input has been much appreciated.
I think I didn't do the head bolts up enough, from memory they were a bugger to crack off, and I think we put too much trust in an ageing torque wrench to do them up to the right level.
I reckon with my recent practice I can have the head off in a couple of hours, plan is to disassemble, check for obvious carnage and damage to new gasket, re-assemble with much tighter head bolts, coolant flush and then cross fingers.
I will endeavour to keep you updated, your input has been much appreciated.
Gassing Station | Mazda MX5/Roadster/Miata | Top of Page | What's New | My Stuff