Hi all,

 

Started to clean my engine head today (MH 1.3 55hp). It seems the valve seats are in good condition and there are no cutter scratches. Just did some visual observations but the head looks good despite some kind soap stucked in the water holes (which can be cleaned if taking the necessary time or have the necessary tool like ultrasonic).

 

But then I found this damage where the thermostat is mounted on the head. The material is gone, it's like a small crater of 1-2mm deep. I doubt the thermostat seal will work with such thing (maybe adding some magic black silicone ? but I doubt and not a big fan of such solution).

 

 

I've put a lot of hope in this head but now I'm quite disappointed. I don't know if this can be repaired by professional shops and I wonder how could they repair it (how much...) ?

This head was one of the 2 heads I have and which had the lowest mileage. The other one was working but had one exhaust valve bent causing compression leak on one cylinder.

The top has the higher mileage the bottom the lowest :

 

 

Now I'm confused in deciding which one will I use and if later on some day I can take the 1st one to a professional shop, how will they repair such thing, how much will it cost, etc...

Edited 22 November, 20214 yr by cedreex

which has least guide wear?

 

a machine shop could skim /cut a small amount to make it smooth again , or if less money to spend clean it up and smooth with jb weld 

Edited 23 November, 20214 yr by steveo3002

It seems like these head are aluminium made, are they ? I have an arc welder (mma) so I doubt it can weld aluminium to add material if so. From what I understand, JB weld is kind of epoxy isn't it ? I have no knowledge about jb weld. Will it support the heat there ? 100 celcius (or less) ? how long does it last ?

 

The higher mileage has least valve guide wear than the lowest mileage. The difference is not big but both engine seem to have acceptable valve guide clearance. Even if I'm going to use new rings and bearings, I think I can use one head for some time and bring it to a professional shop one day but not soon for control, resurfacing and else. I'll clean both heads for now and check flatness very basically with what I have and perform valve break in (with a new exhaust valve for the other head). Then I'll check both for valve leak again. Next I'll have to decide which head to use 1st but my feeling tells me the damaged one should be a "no go" to use in a car right now.

 

Moreover, the damaged one would need more cleaning since there are some kind of soup soap pouder is inside the head (and probably inside the bottom too). I don't know what happened causing this damage and the presence of this soap. Maybe the thermostat housing is a metal one (will check that) and the previous owner could have ran the engine very warm without proper cooling etc... Or maybe a head with a bent valve to replace could be a safer choice than this head (or safier ? safiest ?). I don't know if that's my best bet.

the "soap" looks like old antifreeze and the start of corrosion , it inhibits rust/corrosion as well as stopping things freezing

 

jb weld would hold up fine on a clean surface , someone on here used it inside the intake ports  

I'll check more info about the metalic epoxy (don't know if this is the same thing as jb weld). The bottom of the crankcase is a little bent from outside. So that could be a good candidate to test how solid is the metalic epoxy. Having a flat epoxy would be another problem though.

21 minutes ago, steveo3002 said:

the "soap" looks like old antifreeze and the start of corrosion , it inhibits rust/corrosion as well as stopping things freezing

 

jb weld would hold up fine on a clean surface , someone on here used it inside the intake ports  

 

I didn't find such soap material in the higher mileage engine (only in the lowest engine of the mk2f). That brings a lot of doubts on how the previous owner have maintained the car. Anyway I shoud clean those "soap" shouldn't I ?

 

The jb weld seem a good alternative if so. Thank you for pointing it. I've never head about these products.

I'll have to find one or exactly the jb weld product then test it on the bent crankcase 1st. This will give me time to finish preparing the heads and see how to use the weld.

And yes the lowest mileage head looks more rusty than the one with higher mileage (especially in the water conducts/channels). Don't know if this is worth to mention.

Edited 23 November, 20214 yr by cedreex

whats bent on the crankcase?

Just now, steveo3002 said:

whats bent on the crankcase?

 

Outside near where the crankcase seal bolt is a small bent like if the car were too low and crush there. I'll take a pict to show it

Here is the picture of the crankcase

 

ok so just cosmetic?  i would leave it alone

I don't think it's leaking but I'll check. Not sure if the French MOT will ignore it during their control so it may a good thing for me to test the jb weld on it (the less things the note the best it is). Moreover this allow me to test the product and there should be enough for the head also.

The bent or deformation of the crankcase it approx. 3-4mm deep (not sure if this is visible on the picture)