Yet another project....The uncrashed spitfire

[Lopéz]

Ah right, didn't know how runny it was meant to be. I should be using the topcoat for the first time tomorrow, will let you know how it goes on.

 

[Jonny69]

Don't use more than about 10% thinners and don't spray too heavy. As you probably found with the primer it stays wet for a long time then suddenly cures, so spray it thinly. It's great because you can spray it with orange peel and overspray and it just flats itself out unlike celly.

 

[Lopéz]

Don't use more than about 10% thinners and don't spray too heavy. As you probably found with the primer it stays wet for a long time then suddenly cures, so spray it thinly. It's great because you can spray it with orange peel and overspray and it just flats itself out unlike celly.

Yep, lesson with thinners has been learned!

 

[Mattius]

Project has stalled just now as the engine is getting on my ****, cant get it to run at all and looks like i might have a warped block. Head has been replaced 3 times now with a new gasket and yet i still have zero compression in 3 cylinders.

 

[Jonny69]

Er that's not good

Can I suggest checking the following:

Check the valves all close properly, check they seal properly. With the valves closed under load from the springs you should not be able to blow past them if you purse your lips around a port and blow as hard as you can.

Check the cam isn't holding the valve open a tad when it's supposed to be closed, I take it you did all your clearances, open them all up a bit and see if it makes any difference.

You got the cam timed in correctly? Lined up the marks in the right place? Double check. You sure it's not a mad mad mad cam grind that shows little compression when you spin it over?

Did you check the ring gaps? Are you using the right size piston for the bore, it hasn't been overbored like +30 thou and you're using stock pistons? Sounds silly but it's possible. Are the bores nice and round or are they worn oval?

 

[Lashout_UK]

I was going to say, sounds like a valvetrain issue.

Easy way to check the block is just put a metal rule across it - should sit dead flat without any distortions, same goes for the head.

Studs & bolts are holding fast under torque aren't they, they're not slipping? Some of those threads look quite shiny!

 

[Mattius]

Block is flat when i put a steel rule accross it, and the head is definatly flat been checked by the machine shop.
Valves arent sticking and are closing and sealing properly:

Bubbles are just from filling and chamber stayed full for 2mins before it started to evapourate.

It was originally thought to be head studs bottoming out, but i swapped them out to a better set and nuts which definatly arent, head is def torqued down to 55lbs.

Piston rings are good, bores are good.

Im of the opinion it was the cam timing off but i took the rocker gear off and did a compression test and still no compression.
Checked valve clearences 10-15 times slightly more and slightly less still noubt.

Only thing else that has changed appart from the stem seals being fitted (which def arent fouling), is fit a 1mm spacer in beneath the rocker gear to compensate for the skim but that valve clearences were done after so it shouldnt affect.

It must be something massive to cause compression that low.

 

[Mattius]

Well it must be the block, there is nothing else it can be, we checked the valve timing today and still nothing. Uber gutted here means a new engine as machining costs on this one would be more than a new short engine. This is gonna seriously hurt the respray fund, looks like im gonna have to paint it myself.

 

[Jonny69]

Was it a new cam? Couldn't be a faulty grind could it?

And it's definitely getting compression on one of them but not the other 3? What happens if you take the rocker gear off, turn it round so a piston is at bottom dead centre and then turn it up to tdc with your thumb over the spark plug hole? Do they all pump up then? It should pressure up and force air past your thumb.

 

[Mattius]

the cam hasnt been changed since it last ran.

i get compresion but nothing near enough, im round about 20psi. It is exactly as you would think when you put your thumb over the hole a little bit of preasure but not nearly as much as their should be.

 

[lordedmond]

put some oil down the sparkplug holes ( faily thick ) take the rocker shaft off and do the comp test again


if its still low its valves ( but your test rules that out ) or the head gasket block/head interface

if it improves then its the rings


hope you sort it

 

[Mattius]

Rings were checked that way compression only improves very very slightly 1psi or so, but piston rings wouldnt loose as much compression as this.

 

[JamesRJ]

Maybe the rings are carboned up and stuck in the ring lands with all that oil it was burning ?
If you can get it runing take it for a hard drive ?

 

[lordedmond]

Rings were checked that way compression only improves very very slightly 1psi or so, but piston rings wouldnt loose as much compression as this.

if oil in the bore only increases the comp by 1 psig then the trouble must be the head ,or a massive crack in the the block , its a bit of a puzzle

the only way to be sure is to rip it right down and check each part for a good fitt to its partner ( but you have done that )

PS when you crank it is there any way you could test for a pressure rise in the coolant space.

 

[Mattius]

none of the coolant system is linked up just now so as to eliminate that, i only have the bare minimum connected.

ok here is the plastacine test to check for block warping, made a bloody mess and doesnt seem to show anything.

Funky colours

i think they should make head gaskets this colour

Squish out

Squish in

Block

Head

Im confused there doesnt seem to be any problems

Did a compression test again just before i took the head off
1. 20psi
2. 16psi
3. 110psi
4. 5psi

 

[Lashout_UK]

Are you using the correct headgasket perchance?

 

[Mattius]

yeap all payen gaskets correctly for the engine.

 

[Hodders]

I'm trying to think of all the things that could be causing this and then think of a way to test it.

1) Piston rings - oil in cylinder and test compression - already suggested and no difference - Conclusion not rings.

2) Valve seals - could you put some silicon sealant or similar around the valves on the cylinder side ?

3) Head/block warpage - could you take the block/head to a machine shop for a test ?

4) Other things - get a pressure hose and make an airtight fitting for the plug hole. Pressurise each cylinder in turn and see if you can hear the pressure loss. For a cylinder to come back down to 20psi from ~100psi there must be a mssive leak somewhere !

Good luck - I still miss my old Spitfire...

 

[Jonny69]

I am looking at your block face and I can see all your bores are recessed. There is potential if the headgasket doesn't plug those recesses properly that they will leak between 1-2 and 3-4. This means it would have to be a stepped headgasket or it is supposed to be ringed? If so measure the diameter of the ring or the step and make sure they match. It should not be smaller than the bore, the headgasket is always slightly bigger diameter.

I can also see one other possible place where it can leak in this photo. On the bottom right of bore 1 and bottom left of bore 4 (assuming the arrows on the pistons point to the front) there are two oilways or waterways or plugs or something. The one near bore 1 is plugged with plasticene, are either of those broken through to the recess on the top of the bore?

Good luck cleaning all that stuff off, it looks like it has made a right mess

 

[Lashout_UK]

the headgasket doesn't plug those recesses properly that they will leak between 1-2 and 3-4.

That was what I was referring to earlier regarding the gasket set, if you get one for a non recessed block you can end up in all sorts of trouble

I may be wrong here though and it could be only the 1300s that have two types but additional info is always useful....