Shaved head (Down to the Valves) Timing Problem

[fudde]

My car ran fine before I did any work to it (other than the white smoke coming out the tail pipe) so I decided to replace the head gasket. I took the head to a shop and they said it was warped and shaved it all the way to the valves and got a couple of valves while they were at it (they were still in it) . They also cleaned and pressure tested afterwards and said it was good to go.. (They shaved off 12 thousands and It appeared that it had work done to it before).. I spoke to my engine builder buddy and he told me that I might have higher compression and I might need adjustable cams( currently have stock) but it should still work.. So I put the car back together (I found a slightly thicker head gasket than stock) put the head back on and lined everything up (I had just done a timing belt job on my 92 eclipse (NT) and it fired up no problems).. I go to start the car, and it just it just floods (it acts like it wants to start but doesn't) I do a bit of reading (not wanting to believe I misaligned something - (I checked the timing marks again just to be sure and everthing in on) and find that my coolant temperature sensor may be the culprit.. So I check the voltages and resistance - everything ok.. I check the compression, everything not okay (90 - 70 - 90 - 120 - okay, maybe it's a timing problem- - Even though compression looks bad, the engine still wants to fire, so I decided to take a spare CTS, plug it in and heat it up with a heat gun... Car starts and runs, but runs pretty rough..

Just out of curiosity I hooked up the timing light to see how far off the timing is.. It's not even close (like 45 deg off) - I rotated the CAS (clockwise) and the engine starts to run a little better , but there's not enough adjustment to smooth it out.. (I Check the CAS too, it's lined up).

I guess my question is, if all the timing marks line up (crank shaft pully mark lines up with the 5 deg mark on the timing cover when the No. 1 cylinder is BTDC and the Cam Shaft marks line up ) - Is my shaved head causing my timing problem?? If so, how many How many degrees on the crankshaft pulley will one tooth of the Cam Shaft(s) make?? Can it be adjusted this way?? Thanks..

 

[GSX93DSM]

To me 12 thousands sounds a lilltle much, maybe that just me I'm not a machinist. You cut to far you will get into the water jackets and have serious problems. Also cause clearence problems. I would find out how far you can shave the head. Then go from there. Cause if that is your problem you don't want to end up with bent valves or something worse.

 

[fudde]

Well, actually it's about 12 thousands too much.. I believe 8 is the working limit but I measured what was left of the head and it turns out 8 or so was milled off the first time around and the shop took off another 12.. ugh.. But my engine builder buddy said not to worry.. Think I should worry??

If the No 1 cylinder is at TDC, should the craftshaft pulley be at 0 deg on the Timing Cover - Would the CamShaft Alignment marks line up or not line up (5 degrees off?)

And another noobie question, how do you get the picture of your ride to show up when you post (naturally mine would be a pic of a sh!t box pic)?? Not to get off topic though..

 

[91 Turbo Mitsu]

To me 12 thousands sounds a lilltle much, maybe that just me I'm not a machinist. You cut to far you will get into the water jackets and have serious problems. Also cause clearence problems. I would find out how far you can shave the head. Then go from there. Cause if that is your problem you don't want to end up with bent valves or something worse.

I have to agree. My concern would be the fact that they nicked valves when they shaved the head. WTF! I have done dozens of head gaskets on many different cars and I can tell you one thing for sure if they nicked valves when they shaved the head you will more than likely need a new head. As close as the valves are to the pistons I wouldnt be surprised if you tweaked some valves because to much material was removed. I have a head in my garage that I am going to check to see how much clearance there is from the valves because I would bet they took alot more than 12 thousands off. I'll let you know. Travis

 

[91 Turbo Mitsu]

Just went out and checked my spare head and there is about 14 thousands to the intake valves. If they took this much off I would say start looking for another head. Travis

 

[fudde]

Yeah, I've been looking on ebay just incase.. I also have a spare head from a 6 bolt (NT) and 2 heads from 7 bolt (NT) motors - will one of these work if I swap CAMS ? Also found a 90 turbo laser yesterday right down the road from where I work - lady dumped 1200 bucks into it just to have her car run like mine currently does... wonder what she'll take for it..

 

[92awddsm]

Your timing belt is installed wrong. Pull it off again, set the crank to tdc and make sure the notch on the backing plate lines up with the tic on the front case. Now, install the belt and make sure all marks line up properly after rotating the crank by hand a few revolutions. For every tooth off on the cam gears, it will equal about 7 degrees. By the sound of it, you are off 1 tooth on the crank which in turn puts both cams out of spec. This is probably why the compression is so low. And the dead giveaway that the in cam is out of time is the fact that you dont have enough adjustment on the cas to get ignition timing correct.

I personally would not worry with what was machined off of the head. Mine has been machined about .018", block was decked .012" and I have 2 pistons which are at zero deck and 2 that are .001-.002" positive deck. I am also running a cometic hp gasket and have never had any piston to valve clearance issues. As for compression, my cc'ed to 8.1:1 compression. And with the 1mm os valves in my head and comp 200 cams, I would have problems long before you.

And to clear up the misinformation on machining into water jackets, the deck thickness on almost every 4g63 head I have ever measured is usually around .350-450" thick. If .020" was to go into a water jacket, the head would have split open long ago from temp and cooling system pressure.

 

[telnut]

.008 is max for head shave, heads are the same, camshafts are different. Your other heads should work, just change cams. Exhaust cams are same for N/t and turbo A/T. Exhaust cam is different for turbo M/T
Intake Cams. are same for N/T and Turbo M/T. But different for A/T turbo. This is for 1g models.

Telnut
"Motor oil in my veins, nuts and bolts in my brain."

 

[DevilSperm]

Shaving that much off would almost require you to degree your cams. Even if the marks line up, your cams are still sitting closer to the block than designed for. I would say get some adjustable cam gears and dial them in right.

 

[fudde]

Thanks guys.. I'll pull it apart and give it another whirl.. 92awddsm are you running with adjustable cams??

 

[92awddsm]

Thanks guys.. I'll pull it apart and give it another whirl.. 92awddsm are you running with adjustable cams??

I ran it for 2 yrs without adjustable gears and stock cams, 1 yr with comp cams and stock gears, then I finally installed adjustable gears a little over a year ago.

 

[fudde]

So I pulled of the cover and checked the timing marks.. Everything looks okay.. I'm not sure where I should go from here.. Am I missing something??

 

[Turboeagletalon]

that pic looks right

 

[BUCK]

I know you said it was running well prior to this repair evolution but the FLOODING part of your Post sounds like CLASSIC dead/dying ECU - I'd check Caps immediately & watch your Oil level as Crankcase CAN Flood with Gas, been there done that - I would certainly try another ECU prior to Adjustable Cams - Hopefully those low Compression numbers are just an error of some sort & even if they aren't that's not gonna give you the Flooding problem - & Indeed those Timing marks look spot on to me provided the backing Plate isn't "flopped" - Making that a very RARE pic on these Boards... Good Luck

 

[drivemusicnow]

if you put a wrench on the oil pump sprocket, can you turn it at all?

Also, decking the head that much shouldn't really have any terrible effect. It certaintly wouldn't cause the timing to be THAT far off. seeing as how the sensor is attached to the camshaft, you shouldn't see any difference in timing at all.