2 out of 4 Cylinders

1977 · Jan 3, 2017

Hi there I have 2 misfires on my petrol 2.25L. 3rd and 4th are not working at all i can take the HT leads off, replace them, replace the spark plugs, replace the coil or try any firring order on these two, but they just wont work!
there is defenlty a spark and fuel. the only change recently is a new distributor, as the last one total died. but this seams to deliver the spark at the right time.
I can still drive on the flat but up hill is tough.
HELP!

blue beasty · Jan 3, 2017

Assuming you have fuel and a spark at the right time then it's probably compression.

Have you taken the rocker box off and checked valve action?

freelance · Jan 3, 2017

Or headgasket gone between 3 and 4

blue beasty · Jan 3, 2017

freelance said:
Or headgasket gone between 3 and 4

A compression test would be a good and easy place to start

Stretch · Jan 3, 2017

If the engine was running on four cylinders before you changed the distributor then I'd suspect the timing on the distributor.

Don't forget this is a four stroke engine - there are "two TDC's" within the entire cycle. To make sure you set the distributor at the correct position, cylinder #1 needs to be at the end of the compression stroke. This means that the next valve to open on cylinder #1 will be the exhaust valve.

1977 · Jan 4, 2017

here are the results of pressure testing the engine which has a 8:1 compression ratio.
cylinder - Bar
1 - 2
2 - 2.5
3 - 0
4 - 0
Based on this it would appear that the head gasket has blown. I have ordered another one now, but do you thing that will solve everything?

SpringDon · Jan 4, 2017

Depends what's wrong. If you take the head off and there is evidence of a blow then the headgasket should make it good to go. Assuming it's flat.
If there's no blow then maybe the valves are blowing.

As you're taking it off, it might be a good idea the touch up the head anyway

freelance · Jan 4, 2017

Be a good time for a decoke and reseat valves

Grem · Jan 4, 2017

2 bar on the other cylinders really isn't a lot

Stretch · Jan 5, 2017

Grem said:
2 bar on the other cylinders really isn't a lot

I agree - the specs for a 8:1 compression ratio engine is 160 PSI ~ 11 bar

I'd be really surprised if an engine would run on 2 bar pressure. I suspect something is wrong with the compression test

1977 · Jan 5, 2017

Ok so the Head is off and a channel 22mm wide in the copper gasket between 3rd and 4th conformed the problem. But I suspect that the reason for this is a crack 1mm wide and deep in the head. it started in number 4 cylinder along one of the groves left by skimming the head. There is another crack 8mm long from 4th heading to its inlet push rod following another grove. What can i do?

Dippypud · Jan 5, 2017

1977 said:
Ok so the Head is off and a channel 22mm wide in the copper gasket between 3rd and 4th conformed the problem. But I suspect that the reason for this is a crack 1mm wide and deep in the head. it started in number 4 cylinder along one of the groves left by skimming the head. There is another crack 8mm long from 4th heading to its inlet push rod following another grove. What can i do?

Throw it as far as you can and get a replacement or have it welded and skimmed ... then hot pressure tested ...

Stretch · Jan 5, 2017

If you've found a damaged head it is probably going to be cheapest to replace it with a good used. Don't forget to check the upper surface of the block too (there's no point putting a good head onto a warped surface).

SpringDon · Jan 5, 2017

Quiksteel in the cracks and new head gasket. Then sell it.

(Probably best not to use the for sale sub forum on here now the cat is out of the bag)

Colthebrummie · Jan 29, 2017

SpringDon said:
Quiksteel in the cracks and new head gasket. Then sell it.

(Probably best not to use the for sale sub forum on here now the cat is out of the bag)

This is not a way forward I would recommend, how would you feel if you bought a landy that had been deliberately bodged in this way. If you sell it on, be honest about the head fault, otherwise get another head, they are not that hard to find.

Col

John S · Jan 29, 2017

Turner Engineering for a new head. For Series engines they prefer exchange but if the head is cracked I'd speak to them to see what kinda deal is on offer. A refurbished cylinder head will transform performance.

2 out of 4 Cylinders

1977

Member

blue beasty

Leaks an prone to bits dropping off

freelance

Well-Known Member

blue beasty

Leaks an prone to bits dropping off

Stretch

Well-Known Member

1977

Member

SpringDon

Well-Known Member

freelance

Well-Known Member

Grem

Active Member

Stretch

Well-Known Member

1977

Member

Dippypud

Never Knowingly Understood

Stretch

Well-Known Member

SpringDon

Well-Known Member

Colthebrummie

Well-Known Member

John S

Well-Known Member

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