31 replies to this topic

[Jaffamini]

Hi changed cylinder head as the original was cracked, found a replacement of the same no, replaced valves and lapped in,changed oil seal, new gasket set and refitted. Car will not fire at all now, got petrol plugs get wet, replaced points and coil, sparks on each plug. Haven't touched dizzy so timming should be ok. Have I missed something when doing work on the head. Compression is 148psi. Help? Kevin

[MiniMadRacer]

148 seems a tad low.. have you reset the tappets?

[Dusky]

Compression test numbers say very very little about health. Too much variables ( starter, tester, battery,..)

[Magneto]

Did it run before you pulled the head off?

[cal844]

You did reset the tappet clearance when you fitted the rocker shaft?

[steeley]

As above

Check tappets

Use the rule of nine

[sonscar]

Easy first check,plug leads in correct order.Steve..

[Cooperman]

Plug leads not connected to correct plugs. That is the usual reason.

[Jaffamini]

Hi done that changed points, coil, condenser, plugs getting wet so I assume it's getting fuel. Just has no intention of foreign at all. Could I have cocked something up on the head ?

[richmondclassicsnorthwales]

How fresh is your fuel, past 6 months it will be pretty low in octane - worse than what you buy it now at the pumps.

 

Try some easi start whilst cranking, if it fires and runs momentarily while you are getting someone to do the honours of spraying easi start, there is a bit of a clue.

 

You need just 3 things for an engine to run - spark - in the right place - fuel and air

[steeley]

Have you checked tappet clearances

[croc7]

Agree with previous post. If static timing is ok, with good spark and fuel delivery, I would check valve tappet clearance.

Edited by croc7, 08 March 2021 - 07:27 AM.

[T.Harper]

Check dizzy cap is on the right way around.  Take the dizzy cap off, rocker cover off and check that rotor arm is pointing to cylinder 1 when it's on its compression stroke (valves closed at TDC).

[MiniBGT]

Is the new head cracked and letting water in?  Are plugs wet with petrol or water?  Had a similar problem with an MGB head last year.

[MiniBGT]

See my comments of your post earlier that day.