Mmm is that skimmed or not. ???

[W.olly]

looks like the crack is between the water jacket and away from the valves should be ok

yes, just spitting my dummy out sat the minute. it only shown up as i was cleaning it back properly.

i need to check if the head is true yet. if not then its going to be sacrilege and stick a bloody outboard on it.

 

[brightspark]

yes, just spitting my dummy out sat the minute. it only shown up as i was cleaning it back properly.

i need to check if the head is true yet. if not then its going to be sacrilege and stick a bloody outboard on it.

stick it on your lasses granite worktop using micrometer blue or some float glass unless you have a surface plate

 

[8ob]

Unless its something a bit special or hard to find I would scrap it, runs away a bit by the time that's welded, pressure tested ,skimmed and rebuilt. I wouldn't bolt that to a rebuilt bottom end and fit it all in something as horrible to work in as a boats engine compartment.

Bob

 

[W.olly]

stick it on your lasses granite worktop using micrometer blue or some float glass unless you have a surface plate

got a milling machine and DTI i can use.

 

[tom2207]

are heads scarce or expensive ?

 

[Burdekin]

That's the late B20 carb head with the big valves. You can tell by the P shape castings on the top of the head, these were machined to hold the injectors in the fuel injection engines. I don't know the compression ratio the pentas ran or if different to the car engine but you should be able to get a late model B20 head pretty easy. If you ask on one of the Volvo Amazon groups on Facebook you might find someone selling a head.

 

[W.olly]

are heads scarce or expensive ?

not to easy, ad trouble to get one last year

That's the late B20 carb head with the big valves. You can tell by the P shape castings on the top of the head, these were machined to hold the injectors in the fuel injection engines. I don't know the compression ratio the pentas ran or if different to the car engine but you should be able to get a late model B20 head pretty easy. If you ask on one of the Volvo Amazon groups on Facebook you might find someone selling a head.

yes, not to easy to find. reason last time i bought a full engine a sit was easier to get a head. i have a couple more heads here. if this is not true, i am going to check it with a DTI on the milling machine this week. ill try one of the others but tis is in lot better condition but for crack. if this is flat then ill fill it and carry on.

 

[brightspark]

will take a fair bit to set up on the miller surface plate or glass and paste easier

 

[W.olly]

will take a fair bit to set up on the miller surface plate or glass and paste easier

just dont have either though. i check the true of the mill bed and its within a thou on full bed length. am i correct in thinking if i set the head on a couple of precision blocks and check the head is true that way ?

 

[minimutly]

Take it to your engine reconditioner - he will have a ground straightedge and feeler gauge. Faffing about on a mill table is a waste of time.

 

[W.olly]

Take it to your engine reconditioner - he will have a ground straightedge and feeler gauge. Faffing about on a mill table is a waste of time.

Well I will.find another machine shop.

 

[Burdekin]

Well I will.find another machine shop.

I've used Coventry Boring and Metalling and did a good job. That was on a B20 I built a few years ago.

 

[W.olly]

I've used Coventry Boring and Metalling and did a good job. That was on a B20 I built a few years ago.

Bit far kida.

Is there a specific type of granite I can use for this ?

 

[minimutly]

Bit far kida.

Is there a specific type of granite I can use for this ?

Yes, a flat one, but that's not going to do it, a dti is useless at checking for flatness (well not useless, but nearly). Ground straightedge is the way, takes 30 secs.

 

[JOEPRO]

A large polished porcelain tile may be an option, that's what I used to test the flatness of a small head recently.



600x600 is a common size. 800x600 and larger sizes are also available. Go to local tile place and blag a sample tile or buy one in homebase etc.

Apply a thin even coat of the blue to the tile. Then rub the head across it and see if the blue coats all surfaces evenly.

 

[W.olly]

Yes, a flat one, but that's not going to do it, a dti is useless at checking for flatness (well not useless, but nearly). Ground straightedge is the way, takes 30 secs.

Bloody nora. One person says it will do next won't.
Could of got a 600mm square 25mm thick bit aswell.

 

[Stueeee]

are heads scarce or expensive ?

not to easy, ad trouble to get one last year



yes, not to easy to find. reason last time i bought a full engine a sit was easier to get a head. i have a couple more heads here. if this is not true, i am going to check it with a DTI on the milling machine this week. ill try one of the others but tis is in lot better condition but for crack. if this is flat then ill fill it and carry on.

Do you have access to Oxy Acetylene kit? If it's going to be a pain/expensive to find another head, you could vee out and braze that crack. I've done braze repairs on two cylinder heads in the past and they're still both working.

You can pre-heat the bare head in a domestic oven up on max for a couple of hours (wife/girlfriend/significant other definitely needs to be out when you do this) use a big nozzle, 13 or 18 slightly carburising flame, if you can have a mate there who can provide general heating of the head with a propane torch at the same time as you do the final heat/braze that would be good. I've always used a Manganese Bronze rod for work on Iron castings. Allow a slow cool, file off most of the 'proud' bead and get the head skimmed on a milling machine.

 

[daedalusminos]

There's a load of granite surface plates near me just waiting to be blued up...

 

[colnerov]

Are these still available?

 

[minimutly]

Bloody nora. One person says it will do next won't.
Could of got a 600mm square 25mm thick bit aswell.

The problem with bluing and a stone is that is doesn’t give a reading, just blue or not. A feeler gauge and straightedge tells you how low the lows are. If you blue and rub that I guarantee you there will be clean spots all over it, unless you load up the stone so much it’s useless..