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Expensive 8mm washer
paslow22 - January 9th, 2018 at 07:49 PM

Hi,
I was sick of having trouble adjusting the air mixture scew's on a set of twin carbs ( bugger of a job) so I decided to install off set manifolds, ( thanks ROD) pulled everything off and installed manifolds, adjusted the carbs and all was fine

Test drive all ok, until about 1 klm then an almighty engine knock,
At home did the screwdriver test and found that it was No.3 cylinder.

So, pulled out the motor and found a small broken washer embedded into the head near where the barrel meets the head and all the pistons and chamber charboned up. with some slight damage to the top of 3 piston which cleaned up very nice.

I am sure ((99%) I did not drop the washer down the manifold as I was super carefull.
I can only think that I dropped the washer down alongside the manifold previously and when I changed the manifolds and it bloody well dropped down into the motor, that's my theory and I'm sticking to it.

At least I found that the compression is low and will be fixed, that's one good thing

So I went to see Rod thinking that I would change the cam anyway, he mentioned that the compression ratio is to low causing it to charbon up,
I have checked it and it is at 7.8
I will have the heads machines to remove the damaged section and raise the compression to 9, I may head washers?

Now I'll match port the manifolds to the heads, just for something to do.

So that whats happening, apart from fitting new passenger scrapers, bailey channels and door glass due to scratches, and a passenger door mirror, Drivers door to go. and a kill switch, and fire extinguisher.

Just found the throttle cable frayed as it goes into the fan shroud, that,s all I need.

Ok, Thanks for listening

bushed - January 9th, 2018 at 07:55 PM

I hear ya...very loudly

commiserations

take care

Bizarre - January 9th, 2018 at 08:03 PM

Well - it sounds like it was all for the better

7.8 is way low (in my opinion)

9.0 is good.
Add a decent cam
95 or 98 octane and you will be surprised the ponies you will pick up

No head washers

paslow22 - January 9th, 2018 at 08:25 PM

Quote:
Originally posted by Bizarre
Well - it sounds like it was all for the better

7.8 is way low (in my opinion)

9.0 is good.
Add a decent cam
95 or 98 octane and you will be surprised the ponies you will pick up

No head washers


I run 98 fuel and have a Scat C35 cam and with 9/1 compression it will be better.
The washer was very small thankfully about 6mm.
Thanks

mactaylor - January 9th, 2018 at 08:54 PM

I have in the past used valve grinding paste to lap the barrels to the head just to see if the machining was ok! It was supprising the results!

paslow22 - January 10th, 2018 at 06:00 AM

Quote:
Originally posted by mactaylor
I have in the past used valve grinding paste to lap the barrels to the head just to see if the machining was ok! It was supprising the results!


Thanks, sounds like a good idea,
I will most probably be using copper head gaskets to get the correct ratio as it depends on how much needs to be machined,

What was the result, machining not so good, ????

Bizarre - January 10th, 2018 at 11:21 AM

Just be careful with the copper gaskets as they change the deck height
Same goes with cylinder spacers under cylinder

I have always been told to shoot for 1mm otherwise you affect the amount of "squish" which affects the burn / explosion

Normally if i have needed to lower the CR my head guy opened up the chambers
If we needed to increase CR he had the heads fly cut

But we always aimed for the 1mm deck height

paslow22 - January 10th, 2018 at 02:16 PM

Quote:
Originally posted by bushed
I hear ya...very loudly

commiserations

take care


Thanks

paslow22 - January 10th, 2018 at 02:24 PM

Quote:
Originally posted by Bizarre
Just be careful with the copper gaskets as they change the deck height
Same goes with cylinder spacers under cylinder

I have always been told to shoot for 1mm otherwise you affect the amount of "squish" which affects the burn / explosion

Normally if i have needed to lower the CR my head guy opened up the chambers
If we needed to increase CR he had the heads fly cut

But we always aimed for the 1mm deck height



Hi,
Rod Penrose is sending them to his machinist for a quote on cleaning up and try and remove the damage and the lip in the chamber, then suss out the ratio.
Heads are 61cc at present, I need 51cc for 9/1 ratio

mactaylor - January 11th, 2018 at 11:05 AM

Quote:
Originally posted by paslow22
Quote:
Originally posted by mactaylor
I have in the past used valve grinding paste to lap the barrels to the head just to see if the machining was ok! It was supprising the results!


Thanks, sounds like a good idea,
I will most probably be using copper head gaskets to get the correct ratio as it depends on how much needs to be machined,

What was the result, machining not so good, ????

It was back in the day working at a vw workshop that had heaps of hippies walk in with bugger all money! So we would just fix what we had to without breaking their budget! Results were good! Always had to check everything twice as much thou!