Hello from Dorking!

It's easy for me to say sitting here but I would be tempted to use that block.
It's the least costly option and with careful cleaning, a sound head and that 3mm gasket you may just get away with it.
I have found that pitting isn't as bad as you think but warping definitely is.
The twin cam engines I have built for rallying are all old engines. The Toyota 2TG and 4AG (A86) are all between 40 -50 year old! Pitting is part of the game but it has to be in reason of course.
I am not a fan of sealants but they can work well. I would be tempted to use it sparingly on the pitted areas only and not all over the block.
That 3mm gasket is thick and should compress enough to get away with it. Toyota gsskets are 1.5mm usually but I use Cometic 1.0mm MLS steel gaskets to get an extra 20 thou of compression.
If you go for another engine I would be going for at least a complete block.
Putting used crank and pistons in to another bare block means at the very minimum new shells, piston rings and thrust washers.
I sincerly wish you luck in whatever way you choose.

How much could it be to repair 100% your current engine?
Parts and the work you cannot do yourself

As a new member, years ago I read a post from Cobber about the coil pack on the engine. He was disparaging (nothing new there) but everything he said made sense (not always the case), a misfire was traced to this. It was removed & cleaned up & it served for a while, until one section failed, the eBay replacement was as grotty as the originals first going over.
I’m a bit of of s magpie & collected a set of coils of a 160 which hung around for a while until after some more misfiring I converted one to the other.
This isn’t necessarily a recommendation, it an alternative route if problems occur, replacement’s are much less expensive.
I spend a fair amount of time designing various add on for special applications, I share some on here & why not.
M

Red110 wrote:

How much could it be to repair 100% your current engine?
Parts and the work you cannot do yourself

How long is a piece of string... Joking aside, I think to address the block I would be looking at an extra £1K at least, whichever route I would go.. Either buying a secondhand engine/block with all the gubbins (and hoping for the best) or buying a clean upgraded block and filling it up with a mix of bits from mine and new ones.
Given all the pretty expensive upgrades I have found on the car so far, chances are that some nice goodies could have also been put into the bottom end, like upgraded pistons, conrods or crank which I'd like to retain, not to mention new block and head would effectively mean I'd be on a new engine and I'd like to maintain some originality in the car..

At the moment I'm fairly set on risking it with the current block, hoping the thick new gasket, new head, and some gentle application of sealant to address the pitted areas should give me sufficient sealing to avid future problems..

Thanks
M
 

Airportable wrote:

As a new member, years ago I read a post from Cobber about the coil pack on the engine. He was disparaging (nothing new there) but everything he said made sense (not always the case), a misfire was traced to this. It was removed & cleaned up & it served for a while, until one section failed, the eBay replacement was as grotty as the originals first going over.
I’m a bit of of s magpie & collected a set of coils of a 160 which hung around for a while until after some more misfiring I converted one to the other.
This isn’t necessarily a recommendation, it an alternative route if problems occur, replacement’s are much less expensive.
I spend a fair amount of time designing various add on for special applications, I share some on here & why not.
M
 

Thanks @Airportable one to put on a future upgrade list I think..

I think you have made the right choice going forward.
With unlimited funds to keep it original you would skim the block and put new internals with strengthened bottom end etc but it is serious money.
I put forged conrods and pistons in my Toyota engine. £600 for conrods and £1000 for forged high compression pistons then lightened flywheel, balanced crank and clutch, piston rings and shells..well over 2k before you even get to head work.
The one thing I do see is that you are going about it dilligently and appraising as you go.
I can't speak for you but there is nothing about the block that is screaming No at me.
Just check for straightness and warps but if it is good in that way those pits should be ok.
Good luck mate.

After some more research I decided to get some JB Weld Extreme Heat to fill in just the pitted area and flatten it  before I install the HG. Time will tell if it is the right decision, but having now seen some more cases of pitted engine blocks that people chose to reuse, I agree that mine is nowhere close to some of the "bad ones" I've seen and with the location of the pitting I am feeling more confident the fix will work

I think you will be ok 😉

Hey All

Another small update, and another case of "1 step forward, 2 backwards": The reconditioned head from mgfntfbitz arrived today, earlier than expected, but unfortunately whoever did the reconditioning seems to have made a mess of it: 
They appear to  have they skimmed it with valves in place so as a result any valves in open position ended up getting ground on edges

 

 

 



To add to the misery, not sure what they used to skim the head, but it's certainly not even, with the biggest issue being between cylinders 2-3 where they seem to have created a bowed profile and I was able to squeeze anywhere from 0.15 to 0.35mm feeler gauge under a straight edge in places.

 

 



I got in touch with them and supposed to hear back tomorrow morning from their technical guy to talk through it, but definitely not impressed with the shoddy work. Not happy to use the head in it's current shape, and this being the only reconditioned 120 head they head in stock, the best I can hope for is money back and the need to source another head which means another delay..

Question to more MGF knowledgeable folk: I can see that they seem to have a 135 head in stock - other than the coil pack change, are there other differences between the early 120 heads and the later 135 ones? IOne other I thing I recall reading was  that the mounting holes for the tensioner were different as the 135 used automatic tensioner, but are there other changes I should be aware of?
Thanks
M

Well whoever ground the head was an idiot of the first order! 
By the look of it the valves might have been open when they ground it, so the cams must have still been in, still it would've been prudent to remove the valves before grinding, then washing the  bare head clean afterwards to get rid if all the grit and swarf before reassembling the head and lapping he valves in before sale and fitment.
As it is, even if they didn't damage the valves the head would have grinding git and swarf all though it! 

Not good.
That gap under the straight edge is way too much..gaskets can easily seal pitting but a warp that big is a no no.
I would get my money back.
Up here engineering firms won't skim a head tp 10 thou..only 20 thou minimun.
Aluminium tears when you skim it compared to steel.
I can't remember but how straight was your otiginal head?

A very poor do all round. Work like that should be undertaken by folk who are sympathetic to the job. Would I send a head to be refinished with parts still fitted? Even as a kid when I took A series heads in to Wear St Engineering for work they would be stripped & clean. Unheard of, especially from Bitz, this is the first negative comment I have seen.
M