Cracked head??

[paulandabbe]

Hello all please can someone advise me? We went to vanwest the weekend and our bus ran horrid, the day before i tinkered witht he carb and checked for air leaks, it wouldn't idle and sounded like it was running on 3, chufing too, I have just pulled the lump out and removed one head, it has cracked between the valves and spark plug, this may seem a daft question, does that mean its knackered?? and I need a new head? I just want a second opinion, repair? or replace? new or second hand? cheers dudes I'm gonna take the other head off now,

 

[Loxy]

Hello all please can someone advise me? We went to vanwest the weekend and our bus ran horrid, the day before i tinkered witht he carb and checked for air leaks, it wouldn't idle and sounded like it was running on 3, chufing too, I have just pulled the lump out and removed one head, it has cracked between the valves and spark plug, this may seem a daft question, does that mean its knackered?? and I need a new head? I just want a second opinion, repair? or replace? new or second hand? cheers dudes I'm gonna take the other head off now,

Replace it, I think they can be re-welded but its probably not worth it for a stock head - new or old may depend on the other side - check the valve sizes and make sure you get one that matches, new mexican heads can have smaller valve sizes (possibly due to them being used on injection engines??)- if you do go second hand its probably worth getting the valve guides replaced & possibly the seats.

 

[paulandabbe]

Other head not so bad but cracked between valves, I can only find brazilian heads, and as loxy said they have smaller valves and I think different long reach spark plugs, anyone used them? Is there issues and problems I don't know about, or is it straight forward swap? cheers

 

[Benyon]

I have just had new valves and guides in my heads, cost £200 +VAT inc 8 new valves and guides but the machine shop had them for over a week for a job which took less than a day :evil:

Heritage used to do head on exchange but no longer do - might be worth trying The Engine Shop?? Alternatively SSP do a range of aftermarket heads...

 

[Araon]

yeah they can be welded, the cost of the work may outway the cost of good second hand pair of stock heads....

you never said if its TP or SP.....

SP heads are a little cheaper.....

 

[paulandabbe]

yeah they can be welded, the cost of the work may outway the cost of good second hand pair of stock heads....

you never said if its TP or SP.....

SP heads are a little cheaper.....

Its a TP, it must be a common problem, is it due to overheating? or do they just crack over time? thanks

 

[paulandabbe]

I have just had new valves and guides in my heads, cost £200 +VAT inc 8 new valves and guides but the machine shop had them for over a week for a job which took less than a day :evil:

Heritage used to do head on exchange but no longer do - might be worth trying The Engine Shop?? Alternatively SSP do a range of aftermarket heads...

I'll have a look for the engine shop now, Up to now im probally gonna buy the top end rebuild kit from heritage, the 1600cc one is £379.95 and the 1641cc is £449.95, I think I will get the 1600 its only 1.5mm difference, thats the complete heads, barrels, pistons, pushrod tubes, crankseal, gaskets and a 009 dizzy, dont want the dizzy as I have the vac one, but the cheapest pair of tp heads are £300 from gsf, don't want the bare ones as my valves probally wont fit, thanks for your help

Does anyone know if theres alot of power difference between 1600cc and 1641cc ????

 

[Clem]

It wasnt that long ago heads were £100 each .... :shock:

1641 offer about 5% more power ... many say its not much cop in a loaded van, as the barrell walls are thinner and the weight of a bus 'may' cause warping issues? I guess many have no problem with them though. Id err on the side of caution and retain the 1600's.

My old engine was found to have a cracked head as you describe. A mechanic friend said he couldnt see what the problem was, so I rebuilt it, and ran it for a number of years, including two trips to the South of France and back! Dont take this as licence to do this however!! :lol:

Its a twin port weak point, to be sure.