I give up! - advice on who can help - oil everywhere post rebuild

I just dug out one of the old 1600 barrels which looks identical in terms of seating heights and there were no inserts on the old heads.

Here are pics of piston also.

 

Some of the damage ring wise may be due to the fact that the garage it went in to failed to spot the loss of compression and ran it for quite a bit with the piston in this state, including telling me it was fixed and me driving 2 miles on it!

 

Here is also a pic of one of the other pistons

 

I thought pitting like that is due to detonation - timing being too advanced or lean. There is metal being eaten away from the top of the piston, if it is getting rough , not just a crack - its got very hot.

Its quite possible to have more than one thing wrong at a time.

It could be leaking fuel when stopped, but running lean when running, with an overenthusiastic distributor adding to the chaos - some of those Chinese ones stuck under points replacement modules throw in a few more degrees advance because it feels zippier..

Fuel and timing reasons will persist across an engine rebuild. Unless the root cause is cleared up, your new engine might go the same way.

 

Keep the oil filter, ditch the external oil cooler Just forget to put it back on.

 

If you have a cooler use it. It will help more than not having one.

Not always necessary to have a cooler, and not every bus has to have a facsimile of @snotty's gold painted engine accessories either...

 

Finally...a pic of the offending piston. That’s a weird one. Post it on the Samba. It will keep them busy for years to come.

 

Good call , it`ll just confuse the issue , a stock (ish) engine should be happy enough without one - you can always reconnect ...

EDIT .. just looking at the `good` piston pic it`s a weird burn pattern and there is obvious detonation on the crown - be careful and check everything on the timing and fuelling side .

 

Would it help if i clean the good piston top up a bit for diagnosis. I think its hard to see in a pic but i'm not sure there is pitting there as such- i think its just very sooty which makes it look yhat way - i thought from the over fuelling. It also rubs off real easy as its sooty but a nearly new piston underneath so the shiney bits are where its been touched i think.

You could have a point on the distributor though. Would you recommend for safety i switch to a 009 to start with so i can be more confident on the curve that the svda?

 

An SVDA is fine as long as the timing’s set correctly.

Scrub the edges of that big hole up and take a pic, so we can see if it’s melted, cracked or whatever.

 

I just checked my pertronix and think its only compat with the svda dists so cant easily just go to a 009 which i'd have to buy anyway. I have a second svda which i could put on to test with the pertronix i have though. I am yet to set the timing but recall vaguely i am supposed to static time it at 7.5 btdc to get it started then adjust to a max advance with the vac line plugged at around 28-30. Then whatever it falls back to at idle is ok...is that correct? If i then connect the vac line and rev to 3k plus no load i should see 38 degrees or so.....?

 

Forget the 009 , just make sure the dizzy is moving freely , the vac can is working , the mechanical side is working freely and timing is spot on WHEN FULLY ADVANCED as this is where the damage happens . There's a decent window between safe running and over advanced detonation , err on the safe side at around 28 degrees fully advanced rather than 30-32 , just for now .

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Will do the clean tomorrow guys. Both one of the intact pists and the infamous cracked one. Thanks all.

 

Correct , 7.5 degrees to set the tickover and you'll see 40 ish in places with everything connected up .

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Was i right on how i ser the timing by the way...and should i be worried if i see 35 plus degrees with the vac line on?

 

Sorry replies crossed... thanks lasty.

 

Yes. 7.5 static to get it started, then make sure it doesn’t advance more than 30 (28 better IMO). It’ll likely drop back to about 10 at idle, but that doesn’t really mean anything. With vac connected, it’s hard to test.

 

With vacuum line on at part throttle I believe the maximum advance may be as much as 46 degrees.

But at wide open throttle or vacuum line off and plugged this should be really no more than 30 degrees.

 

For those who were interested in the pistons... these have been rubbed with a bit of wd40 and a rag.

 

I am close now on getting ready to do a first start. Static time done, oil in and fuel lines on. Oil light went out quick after turn over with no ignition so no disasters yet. I put a fuel pressure gauge in and have 3 psi via the elec pump and the malpasi - think this is ok...?