Slowest RestoMod Ever

gortnipper · Nov 21, 2017

I shipped my FA head to Mr. C from and to NZ. Would do it again and I have only run it up ad down the drive half a dozen times. Lol.

quikbrew · Nov 21, 2017

Right fellas, cleaning-up and cutting and shaping new fins it is then. Any thoughts on what grade alloy plate I should be using? Hydroblasting before or after welding?

Fast Eddie · Nov 21, 2017

I’d blast it first. I’d also boil it in a big pan to try and get as much oil out of the pores as possible.

Not sure what grade alloy to suggest, but I’m sure someone will do so shortly...

kommando · Nov 21, 2017

I have had a few Brit alloy castings welded over the years, according to my local welder they are a pleasure to weld compared to Japanese castings. If an FA head costs £3000 even if you discount the cost of the better porting and other improvements made you are still looking at a lump of metal worth £2000 if fully repaired. I would expect to only have to pay a few £100 for all the welding needed, in fact I saw a Tiger cub head where one of the middle fins was broken recently (broken piece was kept) and that had to have the fins above broken off for access to the broken fin and then these fins re-welded, it was economic to repair compared to the cost of a good secondhand head with no broken fins. You just need to track down a welder used to alloy welding, doing the pre-weld dressing yourself and having the replacement fin pieces ready will keep costs down.

quikbrew · Nov 21, 2017

Fast Eddie said:
I’d blast it first. I’d also boil it in a big pan to try and get as much oil out of the pores as possible.

Not sure what grade alloy to suggest, but I’m sure someone will do so shortly...

Detergent in the water?

quikbrew · Nov 21, 2017

kommando said:
I have had a few Brit alloy castings welded over the years, according to my local welder they are a pleasure to weld compared to Japanese castings. If an FA head costs £3000 even if you discount the cost of the better porting and other improvements made you are still looking at a lump of metal worth £2000 if fully repaired. I would expect to only have to pay a few £100 for all the welding needed, in fact I saw a Tiger cub head where one of the middle fins was broken recently (broken piece was kept) and that had to have the fins above broken off for access to the broken fin and then these fins re-welded, it was economic to repair compared to the cost of a good secondhand head with no broken fins. You just need to track down a welder used to alloy welding, doing the pre-weld dressing yourself and having the replacement fin pieces ready will keep costs down.

Yeah, I really would like to repair it if its possible. To be honest, I just don't think the first welder who looked at it was very keen on doing the work. I'll have a look around for a good welder. Cheers

kommando · Nov 21, 2017

Try asking RGM who they use.

gortnipper · Nov 21, 2017

You might want to look at having the welder dill in the chunks of the mating surface, as toubwill want to have the head skimmed flat after all of this to get a nice bolt up to your new barrels, which you also will want to skim.

This is the pic that worries me.

Fast Eddie · Nov 21, 2017

quikbrew said:
Yeah, I really would like to repair it if its possible. To be honest, I just don't think the first welder who looked at it was very keen on doing the work. I'll have a look around for a good welder. Cheers

And he probably didn’t know what the head was, he must have thought you can just nip down the breakers and score another !

kommando · Nov 21, 2017

Look out the local go to guy for welding cracked car alloy wheels.

quikbrew · Dec 8, 2017

Good cylinder head news!

Found a local engineering company (http://www.impressltd.co.uk/). They've examined the head and they can weld the fins no problem. So, I need to get it stripped. Other than a rocker spindle extractor, valve spring compressor and valve guide removal/insertion tool are there any other specialist tools that I need?

Also, any tips guys? I know that I need to heat the head to between 150 and 200 degrees C to get the valve guides out.

And...as I'm stripping the head are there any advisable / appropriate / desirable modifications to consider doing while its in that state?

Danno · Dec 8, 2017

The head should also be heated to extract the rocker spindles. A good, 3-angle valve job is some cheap performance waiting to be applied.

quikbrew · Dec 8, 2017

Danno said:
The head should also be heated to extract the rocker spindles. A good, 3-angle valve job is some cheap performance waiting to be applied.

Cheers Danno. What kind of heat needs to be achieved to remove the rocker spindles?

"3-angle valve job" - sorry to sound thick, but what does that mean/involve exactly?

grandpaul · Dec 8, 2017

Any competent welder with the right equipment should be able to do a decent job welding broken fin bits back in place.

Best situation is having the original fin bits. Second best is having British fin bits, cut to match dressed profile of broken head. If nothing else is available, Japanese fins work just fine, but may be slightly thinner material so will be noticeable on close inspection (so what?).

Danno · Dec 8, 2017

quikbrew said:
Cheers Danno. What kind of heat needs to be achieved to remove the rocker spindles?

"3-angle valve job" - sorry to sound thick, but what does that mean/involve exactly?

heat should be similar to what's used to pull the guides. I have done it with a propane torch heating locally for one shaft, but since you're pulling all 4, heat the whole thing.

A 3-angle valve job cuts the seats at 3 angles, one to match the valve and one on either side to improve flow. I've heard there is now a semi-circular "no-angle" valve seat cut, but unknown who would have the cutters handy. They are probably custom made for particular diameter seats.

kommando · Dec 8, 2017

The best way to get the guides out without messing up your head in a way that will mean you forking out for an FA head is to first bore them out and also remove the section inside the ports, you can then push them out at a lower temp without the carbon deposits on the guides ruining your guide bores in the head.

Danno · Dec 9, 2017

Yes, if your head is carboned up, a vapor blast before pulling the guides is a good idea. Should be no such issue for the rocker shafts.

quikbrew · Dec 10, 2017

grandpaul said:
Any competent welder with the right equipment should be able to do a decent job welding broken fin bits back in place.

Best situation is having the original fin bits. Second best is having British fin bits, cut to match dressed profile of broken head. If nothing else is available, Japanese fins work just fine, but may be slightly thinner material so will be noticeable on close inspection (so what?).

GP, all the fins are long gone...somewhere in the wilds of Nigeria, so they will be completely new. Engineer is confident that it will look good as well as function well though. I've looked at some of their other work and it's amazing, so fingers crossed

quikbrew · Dec 10, 2017

Kommando, Danno - carbon doesn't look too bad as far as I can tell, but will bare in mind your advice. Thanks guys.

This is all very useful to me, though a little daunting! Still, going to give it my best shot...and hopefully learn a lot in the process!

I think my next step is to get (re)organised...the shed's a bloody mess. Bits of Commando everywhere and nowhere to move. Got a bench to put together and get a vice sorted. Need some heating in there though, it's bloody freezing! Christmas holiday project I think

Fast Eddie · Dec 10, 2017

I’m a bit OCD with my shed compared to most. Nevertheless, I’d strongly recommend taking the time out to get your shed nicely sorted.

It will increase your motivation to spend time there, which will increase the actual amount of time you spend there, increase the efficiency of the time you do spend there and ultimately show in a better finished job.