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cam timing out



  F4R'd ITB'd '92 cup racer
right, when the cambelt was first done we checked it time and time again by turning it over by hand, checking the tensioner and checking the locking tools slotted in, which they did

it ran and idled without any problems in that car

since then i have moved the engine into another car, the engine hadn't been run for months. then last week we got it started again, now it was a little bit rough (like a very mild misfire) but we just put it down to the fact it hadn't been started for a while

then this weekend the rough idle has got worse, eventually leading to the car not wanting to idle at all, basically everytime i start it, it will run for 2 secs then die

i got a vid luckily of pretty much the precise moment the idle got worse, you can hear at first its just a bit lumpy, but then it struggles and cuts out, now it wont idle at all.

th_Video0020.jpg


i had a funny feeling it might be the timing, so using the long screwdriver down the spark hole method i found TDC, whipped the caps off and this is what i found

Photo0263.jpg

Photo0264.jpg


you can see that the exhaust cam lines up with the horizontal casing mark, but the inlet is visibly out of alignment, the more you move the crank either way the more out of alignment they go with each other

so in your opinions, what would cause the timing to go? had a few opinions already, dephaser pulley has play in it? tensioner problem (wouldnt both cams be out of alignment, not just the inlet) inlet cam bolt loose? (we definately torqued everything up as per the manual)

any other ideas?
 
  Lionel Richie
erm am i being daft here, or are they 180degrees out? i thought the grooves should be under the horizontal line or is it the otherway round, i can't remember off the top of my head, i always refer to the manual!

does the crank pin slot in with the cam tool?
 
  TVR Cerbera
the cams aren't at top dead center they are 180 out, so you have in fact got no4 at top dead center. What you have said has just about covered it, tensioner, cam bolts etc. That amount out shouldn't cause it not to idle it's not that far out
 
  F4R'd ITB'd '92 cup racer
Fred, did you get my email (your pm box is full) about the timing tools?

i did it at both the cylinder closest to flywheel (pictured) and cylinder closest to cambelt (not pictured) as i couldn't remember which was number 1

both times it showed they didnt line up perfectly with each other, whether the D's be facing up or down
 
  Lionel Richie
which e-mail address??

sod off doing the screwdriver down the hole thing

align the keyway on the crank with the webbing on the casting, whack the crank pin in, and the cam tool should slide in with a bit of a wobble
 
  F4R'd ITB'd '92 cup racer
btmperformance@gmail.com that one

so if its not the timing (will check it with the proper tools)

what else would cause it to run like that? btw the inlet smells of fuel, as do the spark plugs and the oil filler cap, could that be just due to attempting to start it a few times?

could headgasket problem cause poor compression and a very bad idle/cutting out?
 
  TVR Cerbera
no 1 is at flywheel end. Cams should be other way up. Do a comp test. Could also be coil pack or crank sensor too
 
  C63 AMG, F430 & 172
the Big D's should be facing up, although im not sure when there are that it would line up ?

TDC sensors are a common issue with no start
 
Would it matter if they were 180 out with a wasted spark system? I'm assuming it is wasted spark.

The cams turn once for 2 turns of the engine so just turn the engine through another full turn and they'll be offset downwards as should be for checking the timing. They definitely look out though.

1 and 4 are at TDC at the same time.

Daz, what was wrong with your engine in the end?
 
  C63 AMG, F430 & 172
Would it matter if they were 180 out with a wasted spark system? I'm assuming it is wasted spark.

The cams turn once for 2 turns of the engine so just turn the engine through another full turn and they'll be offset downwards as should be for checking the timing. They definitely look out though.

1 and 4 are at TDC at the same time.

Daz, what was wrong with your engine in the end?


Im pretty sure the F4R isnt wasted spark,

But all he needs to do is whack a 7mm drill bit in the front timing hole when the flywheel markers are inline then re check
 
  F4R'd ITB'd '92 cup racer
right got a few things to check there then

im just very very reluctant to adjust tdc and fire it up again as i dont think the timing is correct and the problems seem to have got worse the more i run it
 
  C63 AMG, F430 & 172
Roll it round to tdc then re check the cams first, do a good few turns of the engine to make sure it cranks by hand, if it's all good then I'm saying tdc
 
  TVR Cerbera
Would it matter if they were 180 out with a wasted spark system? I'm assuming it is wasted spark.

The cams turn once for 2 turns of the engine so just turn the engine through another full turn and they'll be offset downwards as should be for checking the timing. They definitely look out though.

1 and 4 are at TDC at the same time.

Daz, what was wrong with your engine in the end?

Ermm where do i start! cambelt had jumped, however valves were saved because the exhaust cam bolt wasn't tight and the pulley slipped too! also found the flywheel bolts were very loose, and btw i wasn't the last one to build the engine!
 


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