ReBuild in Progress, Questions arise....

[SupraDreamPDR]

Okay, i blew my stock HG at the drag strip a month ago (have 165K on the odo). so i pulled the motor (thanks to the 49 steps author), removed the tranny and put it on an engine stand. started to tear it apart, got everything off, the head removed and down to the bear block. now, my questions are, i still have the camshafts, valves, etc in the head, could i take that to my machine/engine shop (to have it decked/planned) with all that stuff still on there or should i remove everything? also, when removing the exhaust manifold, some of the studs came out and looks like they stripped the threads on the head... how can i fix this? my block still has the crank pully, crank, pistons and oil pump still on it (i can NOT get the crank pulley free for the life of me!), so can i just take that to my shop like this too? And, when installing a MHG, you need to have both the head and the block planned?

 

[fiyota]

And, when installing a MHG, you need to have both the head and the block planned?

Yes.

 

[jdub]

Take it to the shop with it all on there...you're getting a valve job done, right? They need to replace the valve seals and clean up the seats with a 3 angle. The cams need to be on there to check shim clearances...go for the middle of TRSM spec.

If you stripped the exhaust studs (very common BTW)...they will need to be helicoiled. I'd have them all done and use new studs. Also, replace the banjo fitting and bolt at the back of the head...these get in pretty bad shape on a hi-mile motor.

What is the plan for the bottom end? Hone & re-ring or new forged pistons and a re-bore? Since you have the head off, I'd take it to the shop...they probably got a big impact wrench that will take the crank bolt right off. If you plan to assemble the bottom end yourself, make sure you keep the crank bearing retainers, rods, etc. all in the proper order....same for the cam retainers.

The block will need to be decked to prep for a MHG...both the block and head must have the decking done to the RA spec (or less) for the MHG used. You will need to have the rods dressed and new bearings for the crank...if you use Toyota bearings, you will be able to get to the tight side of the clearance spec. Have the crank bearing surfaces checked and micro-polished...balancing the crank is a good idea too Consider balancing the rods & pistons.

Replace the oil pump, crank & cam seals, etc...might as well get a complete Toyota gasket kit. It will have everything you need.

 

[MDCmotorsports]

^Exactly what he said.

Make sure the machine ship is capable of getting the surface smoothness correct on the head and block.

 

[SupraDreamPDR]

ok. i am probably going to try and reuse the stock rods and maybe get some stock sized pistons, if the stock ones are no good (Like Nippon racing or new stock Toyota pistons). dont really want forged, cause i heard it causes piston slap on warm up and idle. i am probably just going to have the shop rebuild the head and block, also have them balance the crank and rods and pistons. then i will reassemble the rest of the motor, everything not internal. so need to get a full gasket set, can i just get the ones off of Ebay? What RA spec for a GReddy 1.5mm MHG?

 

[jdub]

ok. i am probably going to try and reuse the stock rods and maybe get some stock sized pistons, if the stock ones are no good (Like Nippon racing or new stock Toyota pistons). dont really want forged, cause i heard it causes piston slap on warm up and idle. i am probably just going to have the shop rebuild the head and block, also have them balance the crank and rods and pistons. then i will reassemble the rest of the motor, everything not internal. so need to get a full gasket set, can i just get the ones off of Ebay? What RA spec for a GReddy 1.5mm MHG?

I've got Ross pistons and they don't slap at all. The manufacturers have tightened up the spec on piston clearances...slap is not the issue it once was. The only way you will be able to use your current pistons is if the cylinders are still in spec...i.e. not out-of-round w/ min wear on the walls (good cross hatch still there). Then a hone with oversize rings will work and save some $$$. If a bore to oversize is required, you will need new pistons.

Don't have experience with Nippon, but I've seen the Wisco forged pistons and they are nice with out killing your wallet. Forged pistons give you more of a safety factor...if the price is close for either, go forged. The stock rods are very strong and will work up to pretty high HP numbers. Consider using ARP crank and rod bolts.

Get a Toyota OEM gasket set from Jeff at Champion Toyota.

The RA spec for the Greddy is in the 20-30 range. I'm a fan of the Cometic MHG...it's cheaper and more forgiving on the RA...it's spec is 50 or less and it works well. You want to remove the rivet on a Cometic before you install. In any case, get the machine shop to deck to the lowest RA their machine is capable of doing. Check this out (stolen from IJ ):
http://www.babcox.com/editorial/ar/eb70228.htm

Also, the thickness of the MHG will be determined by how much material is removed from the head & block...the stock gasket is 1.0mm; take the amount removed from both and add to 1.0mm for the correct thickness.

Make sure the machine shop understands a couple of things:
- The RA on the head and block must be at spec or below
- Crank bearing clearances are critical...the tight side of spec is preferred. Toyota makes different oversize bearings to make this happen.
- The valve shim clearances need to be mid-range...too tight can cause a bent valve. The valves will likely need to be re-shimmed after break-in at some point.
- Check the shim clearances and cam retainer torque yourself.
- When you're putting it all together, torque spec for the ARP hardware should be used following the pattern in the TRSM. Don't over torque!

As you go...do a search here for your question first, read up on it. Ask a question if you can't find the answer and somebody will help ya out