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Cranked motor out of timing..
by
Kameron
on 22 Aug, 2017 19:06
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So I was swapping in a different IP after testing it out and during the process I must of slipped some teeth and thrown the cam out of timing. While the the crank is at TDC the cam lock was pointing straight up and down, not good.. Well to my demise I did not realize the motor was out of time until I gave it a quick crank and knew immediately that it did not sound too well
In a resort to try and fix the issue and asses any damage I removed the belt from the cam pulley and tried to reset the timing by hand, but the cam would not budge in the slightest in either direction. Very frustrating turn of events; How do I go about this and what are the odds that I didn't just bend every valve in my engine? Anyone out there have a motor with an IP attached they are willing to sell?
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#1
by
vanbcguy
on 22 Aug, 2017 19:20
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You almost certainly have trashed valves unfortunately. You may have trashed some followers too. Check for spiderweb cracks in the tops of the cam followers.
The valves on these engines project straight down towards the flat piston top. As a result they don't "bend" per se, they instead get squashed and the stems get shorter. This can lead people to believing their engine is fine after an event like yours as the valve will still seal once you get things unstuck. The problem is the head tends to drop off the valve 5-10k miles later completely destroying the piston and head.
You definitely are going to be pulling the head. You probably are only replacing a couple of valves, but it's a good time to be doing a head rebuild.
Valve marks on the pistons are not a big deal, you shouldn't need to replace pistons. They will however identify which valves you need to do.
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#2
by
Kameron
on 22 Aug, 2017 19:33
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Thanks for a hasty response. I will be pulling the head soon the see the damage. Definitely looking into a rebuild since the head is coming off, considering one of those rebuild kits off partsplace. Also still in the market for a new injection pump, If you know of anyone selling for a decent price i'd be interested.
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#3
by
Kameron
on 05 Sep, 2017 18:00
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I've got the head off after taking a look over the valves and turning the cam a bit they all appear to be in working condition, but considering what was said above they still might be smashed but be able to seal
Although when I took a look at the pistons they all appeared to have feint outlines of the valves just as if they kissed the pistons. Other then the light outline, the pistons were all unscathed and showed no scuffing or damage, same on the face of the valves. I suppose that I should disassemble the head further to inspect the components?
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#4
by
air-cooled or diesel
on 05 Sep, 2017 19:26
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it may be just slight kisses you may be ok, however there is no way to know. if on the one you put it back together and get it right, you ll find out in about 20 mins of run time. thats about the time it ll take for a valve or more to go(can be less). disassembling head doesnt prove too much. for one your getting no problems turning cam, and a visual its conclusive unless you can really see it. it (a problem/or defect) can be waay less than a visual and can lead to catastrophic failure. it may be an expense but i think the easiest way to tell is get the head(assembled) pressure tested. or 2-take note of all valves that kissed and change all, the associated lifters are suspects also.
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#5
by
vanbcguy
on 05 Sep, 2017 19:30
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Bad valves can easily go a few thousand miles before dropping a head too...
You want to look at the valve stems, they will be mushroomed if they are damaged.
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#6
by
air-cooled or diesel
on 05 Sep, 2017 22:18
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ive damaged a few valves thru the years, all mine have bent, this can just be the 'starting of a bend' just a fraction is enough. mushrooming the stem isnt different, its damaged in a different area, -way. i suppose in that case just taking valve out may be an indicator enough. (valve should come out of guide w/o much resistance) then perhaps take all suspect valves to a (good) shop and get them verified.? probably the simplest solution. otherwise its a chance game your playing, what if it doesnt go your way? no answer necessary.
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#7
by
libbydiesel
on 06 Sep, 2017 15:17
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Seriously, don't mess around. The only inspection necessary is to look at the piston crowns to see which valves left an imprint in the carbon. Replace every valve that touched a piston while cranking. Doing anything else at this point is just silly.
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#8
by
air-cooled or diesel
on 06 Sep, 2017 15:39
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dont forget the involved lifters.
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#9
by
air-cooled or diesel
on 07 Sep, 2017 13:10
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then perhaps take all suspect valves to a (good) shop and get them verified.?
on the other hand, an intake valve costs $22, exh $28, good ones, then again that may be an old price, still. if a shop testing one valve price comes close, you havent lost anything buying new valves.
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#10
by
Kameron
on 07 Sep, 2017 16:39
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Since this motor is new to me I am in no rush to get it back together. I want to see what is good and what is not and replace components accordingly.
Now this is a noob question, since I am looking at removing the valves, is the special spring compressor, "VW541", a necessity? The bentley obviously uses this tool but I know that there is usually some work around when it comes to "special" tools.
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#11
by
fatmobile
on 11 Sep, 2017 14:53
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I use my drill press to compress the springs.