1977

Member

• Jan 3, 2017

• #1

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

Leaks an prone to bits dropping off

• Jan 3, 2017

• #2

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

Well-Known Member

• Jan 3, 2017

• #3

Or headgasket gone between 3 and 4

 

blue beasty

Leaks an prone to bits dropping off

• Jan 3, 2017

• #4

freelance said:

Or headgasket gone between 3 and 4

Click to expand...

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

 

Stretch

Well-Known Member

• Jan 3, 2017

• #5

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

Member

• Jan 4, 2017

• #6

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

Well-Known Member

• Jan 4, 2017

• #7

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

Well-Known Member

• Jan 4, 2017

• #8

Be a good time for a decoke and reseat valves

 

Grem

Active Member

• Jan 4, 2017

• #9

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

 

Stretch

Well-Known Member

• Jan 5, 2017

• #10

Grem said:

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

Click to expand...

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

Member

• Jan 5, 2017

• #11

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

Never Knowingly Understood

Full Member

• Jan 5, 2017

• #12

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?

Click to expand...

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

 

Stretch

Well-Known Member

• Jan 5, 2017

• #13

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

Well-Known Member

• Jan 5, 2017

• #14

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)

 

C

Colthebrummie

Well-Known Member

• Jan 29, 2017

• #15

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)

Click to expand...

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

 

J

John S

Well-Known Member

• Jan 29, 2017

• #16

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.