Head skimming questions

[petert 588]

1.27 cam or crank degrees?

[ArthurH 7]

Sorry, should have been more explicit - cam degrees

[petert 588]

That's 2.6 crank, a significant amount.

[ArthurH 7]

I think I might return to plan A and install a offset dowel to cancel out that 'calculated' retardation, but then in parallel do as Tom suggests and get hold of a vernier pulley to do it 'properly', in slower time.

 

As an aside, we have also found, as is well documented on this forum, that the shimming we established with the head on the bench is now wrong following torquing the head down.  We were surprised by how much though - upto 0.15 mm.  This makes me wonder how critical the ambient temperature is.  We are working in a garage that is typically 4-5° C

[petert 588]

Yes, they move around heaps. Unlike a 16V, which you can finish on the bench.

[ArthurH 7]

Our local Peugeot dealer (Toomeys) can provide a vast range of shims (from 1.650 to 4.000 mostly in in 0.025 steps) but are not cheap and have a minimum order quantity of each size of 2 - so I am going to give this 2014 suggestion from Damir (thanks) a go later:

 

...so old shims can be reused and hand regrinded up to the required thickness for bringing the clearance back as specified .

 

I did this "hand shim regrind" a lot of time before and continue to use this method still today when ever i need to , after lapping the valves .. it's really easy and pretty quick too , all you need is a few sheets of 500grt and 800grt sanding papers , some 2 stroke oil (or any other oil will do ..) and of course an micrometer and feeler gauges , and some elbow grease !

Measure the clearances first , then calculate how much you need to take off the each shim to get the desired clearance . Then , before you start grinding the shims need to identify the top and bottom sides of the shim - top side has slightly chamfered edge and bottom side has sharp edge (can be distinguished visually , if not then by finger/nail pass round the shim edge you'll feel the difference between chamfered vs sharp shim edge) , when you figure out which side is which pick the side with the sharp edge cos you'll be doing the grinding on that side of the shim . The side with the sharp edge goes first ie. on the actual valve stem whilst the other side with chamfered edge must be on top faced opposite of the valve stem ie. it's the valve lifter contact side .

 

Tape a sheet of 500grt sanding paper on an nice flat board , lube the paper with some oil (not too much ! cos you'll be more "gliding" on the paper then removing metal from the shim surface) , pace the shim with the said side on the paper , grab it with fingers , press lightly and start grinding/turning the shim in circular motion .. do the grinding/turning for say 20sec. then stop , clean up the shim and measure it with micrometer and note how much you've taken off of it during that 20sec. , and perform as explained until you're almost up to the desired shim thickness then - switch the sanding paper for finer 800grt and do just a few seconds final grinding/turning in order to smooth up the surface . Clean up thoroughly free from any metal particles an fit on the head .. and check the clearances ... if needed repeat the process for fine clearance adjustment .

 

 

[DamirGTI 342]

It's the head bolt torque force .. which kinda "squashes" the head down the block an moves all of the valve clearances previously set on the bench off .. ambient temperature wont matter if it's in the cold range of 10-20C ie not measured with warm or hot engine .

 

If you need to thin the shim more than 0.05mm , can start with 80grt sanding paper to speed up the process , then switch to 180 and 500/800grt for finishing . Lube with WD-40 or 2 stroke oil .

 

0.15mm inlet , 0.30mm exhaust is how i set them up ... engine runs nicer an more quiet than set to the the OE spec (0.20 inlet , 0.40 exhaust)

 

Also , when i'm doing the valve clearances first i do the lifters "regrind" by hand same/similar as the shims - top lifter side press against the sanding 500grt paper , some WD-40 , and spin in spiral 8 motion till the lifter top turns kinda dull grey across the entire surface without dish in the middle or scratches . Afterwards measure and adjust valve clearances .

 

D

[ArthurH 7]

We ground down two shims yesterday - one of them by .15mm!  Very pleased with the result - turned out very parallel.  Can I assume what you refer to as the 'lifters' is what I call 'buckets'?  These were in an excellent condition with a very flat, mirror like finish - so I am leaving them alone.

 

We are getting close to starting the engine - so a couple of questions relating to that.  The Haynes manual says to retension the cam belt after the engine has been through a heat cycle.  Is that still the accepted wisdom?

 

Also, is it worth the trouble of pre-filling the oil cooler prior to initial start-up, or can that be achieved by spinning the engine with the plugs out?

[ArthurH 7]

Although I would still appreciate answers to my two questions above.  I think I have a more urgent issue that I would like your thoughts on.  Earlier in this thread I had written:

 

On 1/30/2019 at 3:26 PM, ArthurH said:

I think we will be OK applying the basic timing as we marked the crank pulley (couldn't find a hole in the block for a pin - but that's another story) and pinned the cam.

This evening we attempted to fit the cam belt (113 teeth - spring loaded tensioner).  We put the 10mm pin back into the cam pulley hole/head hole and lined up the marks I had made on the crank- so they were both exactly were they were when we took the old belt off.  The old belt had lost its printed timing marks - but nice and clear on the new belt.  Ensuring we had the rotation direction correct, we lined up the new belt line with the crank pulley mark.  To our horror, we found the line on the belt needing to align with the cam pulley mark was two complete teeth away!

 

Experimentally, we rotated the crank (clockwise) until the cam pulley belt line lined up with the cam pulley mark.  Once we had done that, we found that we could pin the crank pulley in this position (in to a gap between to cast 'lips'.

 

Unless we are missing the obvious, it would seem that for all of my son's ownership of the car - the whole 2018 race season, the cam had been advanced by two cam teeth (a crank angle of 360/21° ~17.1°)

 

What would be the symptoms of such an amount of timing error?  We wouldn't know if the ECU had been re-mapped following this error.

 

Edited February 7, 2019 by ArthurH

[ArthurH 7]

I guess the real question I'm asking, is there any chance we have misinterpreted this, and if not, does anyone think this could have been done deliberately?  The engine wasn't the most powerful of the 205s, but it didn't disgrace itself either...

[petert 588]

It may have ran but not very well. Two teeth? That's an awful lot of crankshaft degrees.

[ArthurH 7]

I thought continuing with this 'story' was the best way to post this next question.

 

We completed the engine build, had a track day at Brands, and took it to ATSpeed for a rolling road dyno set up.  Both of those went well.

 

First meeting of the 2019 season was also at Brands; a double header on the 13/14th April.  Disaster struck.

 

James outbraked himself in the damp going into Paddock and slid into the gravel trap.  The engine stopped, the marshals towed him out of the gravel - but the engine wouldn't fire.  They rolled him down Paddock Hill to attempt a bump start - but still nothing - so he was towed back into the paddock where we tried again to start it.  Had spark and fuel.  Took the timing belt cover off.  The belt was broken.   Gravel had got under the belt/lower pulley.

 

Bear in mind we had been spinning the crank on the starter motor.  I gently tried turning the camshaft from its bolt - it seemed to turn 'normally' - at that moment the pistons must have been appropriately clear of the valves.  Our logic was, what have we to lose if we fit a replacement belt and try it?  It took all day to get another belt (two motor factors lied about having one in stock) but we drove home and got one - took it back to Brands and fitted it.  To our considerable surprise, the engine ran - didn't sound rough.  James went to see the Clerk of the Course and got dispensation to start the second Sunday race from the back.  The race was good - James overtook many cars - but was a bit down on lap time from the test day a few weeks earlier.  The engine doesn't seem to spit or pop any more than before the breakage.

 

A long preamble - but my question is - how was the damage not far more severe?  Has this happened before?  Is it worth the effort and expense of stripping the engine (that is a lot of James' race budget) or to carry on? 

 

 

[Miles 331 1 Cars]

Do a leak down test, no leakage then it's good to go but your 1 in a million for a valve not to bend, Should of come over as I was at Brands on Sat with the Hot Hatch and Armed forces

Edited April 18, 2019 by Miles

[ArthurH 7]

It would have been great to have met you!  Could you expand on 'Leak down' test please?

[ArthurH 7]

The time between the Brands races and the next races at Mallory was too short for us to strip and inspect the engine - so James ran it again.  It continued to perform well, but James complained of a strange knocking from the bottom end, so we have now removed and stripped the engine.

 

We checked the shim gaps before removing the head, 7 were within a thou of where we had set them - one had increased by 4 thou. We removed the valves to check for straightness - there is no damage we can find to any of the valves (nor marks on any piston crowns).  It was as though the belt had never broken???

 

We don't plan to change the rings, so have clamped the tops of the liner to the block.  The shells, mains and BE, both +0.3, looked reasonable, but we will change them any way.

 

We have managed to buy original Peugeot BE shells at a decent price, but for the mains does anyone have experience of this manufacture/brand? https://www.ebay.co.uk/itm/Main-Shell-Bearings-0-3mm-for-PEUGEOT-205-I-205-II-305-II-309-I-309-II-405-I/113248931073

 

Looking on line, "Kings Bearings" seems to have a very good reputation in the US - but these are from Lithuania....

 

The knocking turned out to be a conrod BE nut touching the baffling in the sump, so very easy to fix.

 

I didn't pay any attention to which way the oil pump chain link was facing - does it matter?

 

 

 

Edited May 22, 2019 by ArthurH
Typo

[petert 588]

The best rod bearings are ACL 4B7700H, made here in sunny Australia. Available in STD or -0.25mm. Somebody in the UK bought a massive batch of them last year. Contact ACL to find out who, if you can't find any.

[ArthurH 7]

Thanks Peter, but we are at -0.30 already.  It is only the mains we are needing now.

[petert 588]

Then you want 4B7700P in -0.3mm for the rods next time. These are copper/lead/tin also. Mains are 5M7704A, but are a normal bearing. Thus you may as well use Kings etc.