29 replies to this topic

[BMGTZ]

Today I fired up the stroker I have been building for the past few months.

after getting oil pressure without ignition it fired up and purred like a kitten. The cams in it had been pretty lumpy in the 2 ltr that was in the car before. So at first, I was a bit surprised how smooth it was.

I had it running for a while to getting the thermostat to open and top up the rad. after about ten minutes the idle started to lump up. I thought nothing of that given how lumpy the idle was before in the 2 ltr. Little did I know that was the start of the exhaust cam gear slipping...it then suddenly stated to make a loud clacking noise. just like a really loud lifter that hasn't bled yet.

shut done and investigate....pulled the cam cover off and all looked normal. I popped a couple of lifters out on the inlet side because they because they looked a bit high. They were full of oil and fine.

disconnected the CAS and briefly cranked......loud clack emanating from front of engine. removed top cam cover....discover that three of the five adjusting nuts on the exhaust cam have disappeared and the cam has slipped to full retard.

yes my fault....should have checked the nuts were tight. NEVER assume because...blah blah blah.

so....Ive put the cam timing back to zero and it runs sweetly.

So .....what are the chances of bent valves guys? I think it went to 12 degrees retard. It had good piston to valve clearance , but that was when it was timed at the correctly.

I will put the bore cam in tomorrow to look for marks on the pistons.

fuck fidanza!! why would they leave them loose ???

[leadfoot]

a compression test would probably confirm / deny

[BMGTZ]

Too new to be accurate...rings wont be bedded in yet

[MDK87]

Too new to be accurate...rings wont be bedded in yet

I don't understand? If the valves are even slightly bent, shouldn't the compression be greatly reduced?
Just an idea...but what if you turn the crank to TDC, feed compressed air into cylinder 1 or 4 and listen for it coming out the exhaust or throw a balloon/glad wrap over the exhaust tip? You'd need a very well sealed exhaust system for that to work though... haha - what a dumb idea, I should go to bed
Omg, what a pain. I feel sorry for you man. I hope it all works out for you.

[Rockabilly]

Fingers crossed Brian xx Lucky you didn't rev it up. Yeah a comp test is your best test.
Yrs ago I put 2 sonata cam caps closest to the cam gears thinking they will be the same as the rest of the R4 caps.
They strangled the cams & sheared the pin off one cam gear & bingo, valves into the pistons. Spewed at myself grrrr.
Cheers !

[jack be nimble]

wanna borrow my leakdown tester?
or just pump some air in there and listen at exhaust pipe.

or,
pull exhaust off and put a little kero into each port (rotating engine to test the cylinder with valves shut). it will dissapear if there is any valves not sealed.
i think there would be enough of a downhill run to the valves to allow enough fluid to cover valve heads.

[bazeng]

Maybe with enough anti lag, the heat will soak into the valve and allow the valve to bend back into the original shape? Lol... Jk..

Sucks man... Fingers crossed for you...

[jack be nimble]

why kero?
The dynamic viscosity of water = 0.890 and of Kerosene = 0.00164....much thinner than water.

[Evo-00x]

Crap Brian, full retard on the exhaust cam eh? mega lumpy idle with nothing down low but an awesome top end lol
Thats some bad luck mate Hope its nothing too serious or nothing at all for that matter other than slight tippity taps.
Yeah my Fidanzas that I recently installed were also only a little more than finger tight when removed new from the box.
Torque specs I see are 40-45 inch/lbs.

[BMGTZ]

got angry...then Got drunk!

will shove the bore cam in to check for witness marks on the pistons. I think the clack noise was the cam gear going full advance then retard back and forth. the two last bolts have worn away the blue anodizing

[to4garret]

Thats fucking Shit Brian.

When i first got my Fidanza cam gears, i was amazed at how shitty the nuts and bolts (studs) looked. I did a quick hunt around for some replacements as i generally dilike imperial sizings on my car but i didnt find anything to replace them with.

In the end i just nipped them up with a blob on loc-tite to be sure.

Edited by to4garret, 08 October 2012 - 01:34 AM.

[BMGTZ]

Ok so pulled the plugs out and put the bore camera down the hole.....no marks on pistons

pulled off the front timing covers and all the nuts and washers fell out. reattached all the covers and belts. Ran the the engine....all quiet!! Did compression test. 175 0n all four. I was a happy man until the brand new cam belt tensioner started making noises like a stuffed ac tensioner.

even to it is a pain in the arse to have to change it...it is easier than taking the head off!!

[Evo-00x]

Thats much better thabn fukd internals any day mate
A stroke of luck at least... couldve been worse.

[ted]

Super stoked to hear theres no damage!!!

[milkandoj]

Just a random idea, i considered slotting a hole though the back next to one of the existing bolts, and installing another bolt (on say just 1/5 of the bolts), that way if it slips it hits the second bolt and reduced how far it can slide. It might only go say 6-8* rather than the full 12*.
Likely you only need to adjust the cams no more than say 6* retarded (unless the head or block is skimmed a lot) so this would lock it from going 12 degrees retarded if it slips.

[BMGTZ]

since it is unlikely that there would be need to adjust again after finding the "sweet point"..... We will drill and lock the whole gear with a single bolt that stops any slip when all is done

[EVL20T]

Arnt the gears balanced??

[Rockabilly]

You're a lucky young fella ;-) Get some good bolts & nuts to lockum as well.
Cheers !

[milkandoj]

The gears would be balanced, but do u think it would make much of a differnce, theres so many forces on the cam like the valve spring pressures varying as it rotates (for eg, moving the cams when doing a timing belt requires force at each increment of differnt valves opening).

Would a small bolt on each gear really matter? Or do two on each gear, opposing eachother so its more even.

[EVL20T]

I was reffering to the comment about "We will drill and lock the whole gear with a single bolt"

To me that soudns like 1 bolt on the whole gear, maybe i interpreted that incorrectly