Damn cars!!!

[YellaBelly]

Apologies for the essay, but it may help with diagnosis

Thought I was going to make another milestone on the Midget restoration today, but it was not to be. Got everything ready to start and discovered a water leak from the weep hole in the water pump. Bought a new one, fitted it and after around 30 mins was ready to go again. Car started within about 15 seconds which aint bad for a car that's not run for 5 years! It ran for around 10-15 secs then died, but I think I flooded it. Anyhow, turns out the settings on the SUs were waaaay too rich. Leaned out and tried again. Car started straight away but was lumpy as hell! Removing plug leads one-at-a-time proved 3 & 4 were not firing. I thought it might be a carb issue as each one feeds a pair of cylinders. But I did a compression test on them and 3 & 4 have zilch! So I'm guessing the head gasket has gone between 3 & 4.

Anyone had that happen on a newly rebuilt engine before?

I'm just hoping it ain't something more sinister

I will get this damn car on the road   

[Bulldog Bri]

Sorry to hear of the problems John. Looks like it's a head off time. Did you have the head off during the re-build?

There is a product I've seen on sale at the local motor parts shop that is supposed to fix head problems like that without taking it off! I can try and find out more if you like.

I've just got hold of a set of twin carbs for the new engine, need a few extra bits for the job but in the meantime will be doing a lot of cleaning anyone got a sand blasting cabinet?

[YellaBelly]

Hi Brian.

Yep, head was off, ground in valves, super-cleaned the head and surfaces (didn't check for level though, maybe should have).

New gasket, torqued it as close as I could get it. Maybe the torque wrench is off-calibration or the head bolts have stretched? Either way, it's Peeing me off a little 

Steve (fullpint) might be able to help with the sand-blasting mate

[Quarrycars]

Make sure the valves have clearance.

[Daley Down Under]

Echo quarrycars.  Good luck JB

[YellaBelly]

Thanks guys. I did set the vave clearances and when I took the rocker cover off they seem to be about right but I will have to check again with the feeler gauge. I would have expected at least a little compression though unless the gaps were obviously large? Plus it is not likely that both cylinders have sticking valves, but you never know....

My guess is though that the head gasket has gone between 3 and 4 so I need to check the head for warpage. I'm also going to get new head studs in case the old ones are stretching which will prevent the proper torque on the nuts.

Anyone know of a cheap head skimmer in the area!

[fullpint]

Ive always re-used head bolts but they do say buy new ones.. They do stretch whilst being done up go I guess using old ones could result in over torqueing issues.. Hope you sort it JB.

['The Gaffer']

Just a thought, did you remember to put all the pistons back in?

Hope you get it sorted.

[Moleman]

I do know a place on filton ave if you do need to get your head skimmed. my local garage always use them for that sort of thing.

[YellaBelly]

Steve, I agree, think for the sake of £20 it's gotta be worth buying new studs

Phil, I didn't remove the pistons, but I like you style

Anyhow, took the head off and guess what?





Well, being a tight-a**e, I decided that I would have a go at skimming the head myself. I have a largish engineers plate which is flatter than a flat thing, and I stuck aluminium oxide paper to it using a smearing of grease, then put light oil on top and spent about 1 1/2hrs whizzing the head backwards and forwards over it. The result is as below:

Before:



Looks like 1-2 was about to pop as well. Maybe my compression will be better than 120psi by the time I get finished?

I reckon about another hour of backwards-and-forwards on new grit should sort it. I have about 3-thou of gap in the middle of the head now so getting there

[fullpint]

I reckon a bit of arm-ache in the morning for someone  Looking good though. Hopefully that will do the trick.

[YellaBelly]

Yep! Shoulders and upper arms are screaming now, so god knows what they will be like in the morning

Still, sense of acheivement and all that

[Moleman]

nice work tightass!! 

[Daley Down Under]

Good grief JB - above and beyond in my book.  Love your dedication.  Does that head gasket take the BKCC award for shortest lived?

Cheers Adrian

[YellaBelly]

Nope Adrian, not above and beyond, just a tightass like Colin said

[peterw]

Do you want to do mine as well, only I got two of them !!!!!
Could have a good side line going there

[Hairy Santa]

the old way used to be plate glass with grinding paste, used to be pretty accurate

is that the only type of gasket made for that engine, might pay to have a look at different makes !!!

also might pay to put a bit of "Wellseal" on the mating surfaces

[Daley Down Under]

Pete makes a good point about gaskets.  Monotorque seem to have a good reputation on A series engines.

Adrian

[YellaBelly]

the old way used to be plate glass with grinding paste, used to be pretty accurate

is that the only type of gasket made for that engine, might pay to have a look at different makes !!!

also might pay to put a bit of "Wellseal" on the mating surfaces

I was going to use grinding paste Pete, but I didn't want to ruin the surface plate.

[Bulldog Bri]

Looking at the pics, did you spray the face before starting to help show up any pitting?

Think I'll be doing that with the old head on the Triumph block I've still got kicking around in the garage, then I can move it on. What grade paper were you using?

[benchmark51]

Are you using a new gasket?  Not gonna try ironing the old one? he he

[YellaBelly]

Are you using a new gasket?  Not gonna try ironing the old one? he he

Hmmmm, any idea what setting to use, and should I do it dry or with steam?

Bri, I didn't spray the head to tell-tale pits it was just like that when I took it off I used 80 & 120 grit paper to get the worst off, but will use 200-220 for the final bit as too rough a finish will more than likely give me more leak problems

I'm also going to check the calibration of my torque wrench to make sure it is within  tolerance (using weights and a tape measure, didn't think I was going to pay to get it done did you?

[benchmark51]

Got my torque wrench re-calibrated at Garafit, Brislington. Can't remember price, but quite cheap.

[YellaBelly]

Got my torque wrench re-calibrated at Garafit, Brislington. Can't remember price, but quite cheap.

Thanks for the info chap To be honest, I think my problem is the fact the head is out of true, common on the old BL engines I believe. My torque wrench is probably within spec anyhow, I just wanted to make sure. Not sure if everyone is aware BTW, it is best to leave your torque wrench on the lowest setting (i.e. back the adjustment right off) because it prevents the spring being loaded up all the time which affects calibration over time. This is for the 'click-type' wrenches with the rotating barrel.

It seems that there have been plenty of cases where guys have had 2 or 3 gaskets go in a very short space of time, so at least I'm not the first

Anyhow, we'll see how it goes......

[Daley Down Under]

JB - remember to check out those Monotorque gaskets

Cheers Adrian

[Quarrycars]

I have a largish engineers plate which is flatter than a flat thing, and I stuck aluminium oxide paper to it using a smearing of grease, then put light oil on top and spent about 1 1/2hrs whizzing the head backwards and forwards over it.

I've always used the metal block with a flat face and wet & dry paper soaked in paraffin, a good check for flatness and removing minor irregularities.
BTW you are not looking for a polished finish, you want some roughness to give a bit of 'bite' for the gasket, a 20 micron finish spec comes to mind but I may be completely off. 

[Lucky Ed]

JB - If you get tired of pushing that thing to and fro, try Bowden Engineering, Patchway

They only charged me £30 to do my head and they're good old boys

[bluehornetrider]

Can't believe any cars ran with such tight gasket gaps, has been known for heads to be run without a gasket, stops the weak point giving.  Just hope your heads as flat as your blocks going to be.