I am in the middle of getting an LQ9 ready to be swapped into my car and have run into a road block so to speak.

It is a stock 2005 Escalade shortblock with the flat top LQ9 pistons which have no valve relief and sit at zero deck or slightly above at TDC. It is getting stock 243 casting LS2 heads off a 2006 corvette.

Now I contacted Texas speed for a camshaft for this exact combo and subsequently bought their MS4 kit under their recommendation. I ended up with no piston to valve clearance (PTV) on both the intake and exhaust valves. I then contacted them and exchanged the cam for their TorquerV3 under their recommendation again and at my cost which resulted with .010 clearance on the intake valve and no clearance on the exhaust (checked in split overlap with low tension springs and a factory lifter modified to solid). This whole ordeal is getting to the 5 month mark and I can't get an answer as to what camshaft will fit my motor other than the stock (maybe not, haven't tried it yet).

I don't want to send camshafts back and forth with a supplier multiple times to find a solution to this issue. Anyone who has put an aftermarket camshaft into an LQ9 please chime in with what you used and the valve clearance you had in split overlap.

I myself am a certified auto technician with over 10 years experience in the trade and the engine is at a machine shop with over 30 years experience, I can provide any measurement or specification needed.

Thanks

 

So you are using solid lifters in this set up now?? Either one of them cams using the stock lifters will work with that set up..

 

just to check PTV, this is what I was told to do by the camshaft manufacturer to check PTV.

with the stock hyd lifter and light test spring I get the same PTV measurement/clearance.

 

well, I have no clearance, with the MS4 and turning the engine over by hand the valves hit hard enough to mark the pistons even with the light test springs and hyd lifter, with the torquer just the exhaust valve barely hits.

what valve clearance is typical to see with this setup/safe to run at? and what could I possibly be doing wrong?

I am using the factory timing set (only goes on one way) and the timing marks are aligned.

 

I have heard of ptv clearance using a l92 head before, flat tops. Not on the 243 heads.. I am sure you will find the answer here. Or even give TSP a call back to verify that they will work.. The piston does stick out of the bore 6-8k.. Are you sure the block has not been decked, the heads are def untoched??

 

I have been in contact with TSP and they can not offer an explanation as to why I am having this issue.

The heads are untouched and so is the block, the valve drop numbers are .200 on the intake and .235 on the exhaust. This is with the head on engine, piston at TDC with stock FelPro replacement gasket in place but head not torqued.

 

You have to torque the heaad for accurate valve drop #'s. I used the torquer 2 on my ex's LQ9 swapped camaro with ported 317 heads and no issues. Clearance was around 0.100-.130 on both valves. Were your cams degree'd in?

 

torquing the head would give me less clearance wouldn't it? when checking PTV the head was tight and yes both cams were degree'd in. I even sent the MS4 to someone with a cam doctor to confirm it was not a bad grind.

I have nowhere even close to that clearance in split overlap.

 

i had to cut reliefs to fit my 237/242 in my 6.0. you can rent the tools from a few guys on tech. it's not a bad job at all. just takes time and it's very repeditive.

 

I would rather not have to do that, but I guess it is an option, although, I would rather go to a smaller cam.

did you happen to measure the thickness of the top of the piston and how deep did you have to cut to get the clearance you needed?

I kind of figured that I was not the only person to have problems fitting these cams into an LQ9.