Possible Mi16 Hydraulic Lifter Problem?

[geoffmslater 0]

Hoping someones experience will guide me here,

 

I recently forgot to tighten up crank nut after cambelt tension check, to cut a long story short I noticed my oil pressure on zero, I knew straight away my problem, so i tightened nut up, car went for another day and then threw a conrod out side of block, I am an idiot for not tightening that nut up.

 

I have rebuilt a new block and placed my original head on it (the head that would have suffered lack of oil).

 

Problem is I have started the car but is is running bad from idle right up in revs and sounds loud, i am fairly sure everything has been hooked up properly.

 

I suspect I have damaged one or more hydraulic lifters, is this most likely?, valves looked fine, and damaged piston did not go near valves. I know i should have checked the lifters when head was out of car but I needed to get it as much back togeter as I could.

 

I intend to compression check then my options as I see it are as follows

 

1. buy complete set of new lifters - very expensive especially getting them to NZ and takes time

 

2. check for damaged lifters and replace them only with new

 

3. replace with used lifters from a spare head I have, preferred option if they are likely to be able to bed in because of them being used. My knowledge is that lifters must be used in same position, this makes me think used lifters inserted in new location is a no no.

 

can anyone advise if i am on the right track?

 

Thanks Geoff

[Green Machine 3]

if the hydrolic lifters have been drained of oil, it can take a while for them to refill and work properly.

[geoffmslater 0]

Thanks, but I have had it up and down street so doubt that is problem as normally would be ok by now.

[petert 601]

Hold it at 2000 rpm for 10 mins. before jumping to conclusions.

[geoffmslater 0]

thanks Peter, I think you are right, although I have brand new rings which I really want to be bedding in immediately, in this case do you think I had better go for more of a drive trying to load rings a bit? to avoid glazing

[petert 601]

You won't glaze it up it 10 mins. Any new cam has to be run in for that long anyway.

[geoffmslater 0]

Thanks I will try tomorrow, if nothing comes of that, what do you think my order of checks should be. I will take spark plugs out again and throughly clean, as they were quite oily

[petert 601]

If they're still noisey after 10 mins. I'd take them out and service them. By that, I mean completely stripping them, cleaning to new condition, then re-assembling. One may be stuck by varnish deposits.

[PumaRacing 2]

It's quite likely that a head that has been on a wrecked bottom end will have camshaft bearings and camshaft journals ruined from the swarf that came up with the oil and lifters that are also full of it. The head on the Mi16 I mention on my website that suffered the same fate was scrap by the time the bottom end failed.

 

There is however no problem with swapping lifters around or fitting new ones on this type of OHC engine. Only lifters in pushrod engines or OHC engines with rockers need to stay on the same camlobe they started life off on.

[petert 601]

It's quite likely that a head that has been on a wrecked bottom end will have camshaft bearings and camshaft journals ruined from the swarf that came up with the oil and lifters that are also full of it.

 

But how would it get through the filter/screen? Assuming it's in position.

[PumaRacing 2]

The filter only screens out rocks. Anything smaller than the mesh size goes straight through and kills the top end. Proper oil and air filters screen down to the micron level. The little nylon filter only screens down to about 0.3mm. That's an ideal size particle to ruin bearings and lifters. Why they put it in there I've no idea because no other engines have it that I'm aware of.

 

Are you telling me that with all the engines you mention building or being involved with you've never seen a ruined top end after a blown up bottom end?

[petert 601]

Are you telling me that with all the engines you mention building or being involved with you've never seen a ruined top end after a blown up bottom end?

 

Nah. The one that really got me was a 16V that had thrown a rod, spitting bits back through the head and into the inlet manifold. The owner maticulously built a new one then bolted back on the old inlet manifold. It had this strange rattle, there sometimes, sometimes not. When it finally blew I discoved two small fragments of ring embedded in two piston crowns. Just enough to give zero clearance! Sometimes.

 

I also have a set of 16 lifters from a head that rebuilt after bead blasting. Neadless to say they're carnage.