9 replies to this topic

[minivanman8]

Evening all,

 

I've got a supecharged (Eaton M45) 1293, which I built about 2000 miles ago. Its a suck through setup with a 5th generation blower.

 

It now uses max to minimum on the dipstick in about 100 miles which varies on how much fun I have over those miles! ;)

 

I'm going to strip it over the winter and try to find out what is causing it.

 

I'm hoping just for rings causing the problems, but what is the best way to decide if I've got a bore/piston issue? What measurements should I have (bore and piston) if everything is as it should be?

 

The pistons fitted are the omega forged 18cc dished ones, so I am hoping I can re use! If I need a re bore, whats the best/recommended  size to go up to and with what pistons?

[RossKnight]

Does it smoke?

[minivanman8]

Like a goodun!

 

Definitely being burnt. Crank case breather smokes now, and oil is spat out of the dipstick hole when its out.

 

I've got a fuel pump breather as I'm running electric pump now.

[RossKnight]

I'm having the same symptoms with my 1293. About the same oil consumption rate too.

 

I'm ruling worn valve guides out as mine seems to smoke under load. Although it does seem worse at startup after it's been left a while and then started.

[minivanman8]

Mines exactly the same. I had it on choke at the weekend and it was pouring blue smoke out. It does calm down when its warm, but not enough!

 

I'm not sure if thats because of my pistons taking a while to heat up and expand as they're forged. Then when warm, the tolerance is tighter between block and O/D of piston.

 

I had new guides and stem seals when I rebuilt it.

 

Possibly a combination, but I've definitely got a ring/bore problem too. 

[matty...]

Do a leak down test, the testers are fairly cheap, but you'll need an air compressor to.

You wouldn't want anything more than 10% leakage max. A fresh engine would be around 2% leakage.

If you have high leakage, poor some oil in the bore and repeat test, if the leakage reduces substantially then its your rings that are worn.if no change then it would likely be a leakage through valves, and that would possibly rule out rings passing oil, but not completely rule them out.

[imaparana]

I Had this problem and found a snapped ring

[minivanman8]

Got any links to leak testers?

[Midas Mk1]

Ive got a pretty much same problem with the 1312, but doesnt smoke at all, on start up or under hard load, stumped! Interested in these leak down kits, I was just going to do a compression test.. :) 

[matty...]

Something like this should be fine.

http://www.ebay.co.u...=item3cede2052d