gtgt_bangbang
New member
head prep & installation comments
doing major rebuild , FSM at my side, want to make a couple points.
FSM instructs installing head WITH exhaust manifold torqued onto head (also install iron accessory brackets to head) before torquing head to block.
This is a great idea, to lessen tendency of deforming head after install, possibly unloading head gsk seal. Its a lot heavier & cumbersome of course but I'm convinced.
My iron manifolds were not quite flat from erosion/corrosion (manual spec = 005 max?), too off-flat to lap out manually ( flat glass and coarse wet dry SiC paper) , and since that heavy iron piece could easily deform the flat aluminum head at several points, I had my manifolds flat ground to restore planarity for mating to the spanky new head. Ask around for someone with a blanchard grinder to do the work.
Kind of spendy at $70 for pair in my one shop town but there is a lot of set up beforehand with this odd shaped part.
~~~~
The left and right exhaust manifold gaskets are different. The LONGER one goes on the passenger side to shield #5 plug from manifold. Seen more than a couple installed swapped L&R. Note #2 plug needs no shielding from manifold ( which is what you get if installed swapped) while swap also leaves #5 plug UNshielded from ex manifold.
~~~~
Ive seen /compared 3 diff mfgs head gaskets (have not seen the genuine Toy part new) and personally I wont stoop to put anything on but the latest felpro (vaguely blue , sticky one) until further developments warrant. I was tempted to spray some copper on it but Felpro says do it dry if they mention it at all.
~~~~~~~
I didnt need much gasket matching (making sure gaskets properly fit the castings ports, and casting mate to one antoher, with minimal steps and lips) for this motor, but make sure your ex.gasket does not intrude in the flow paths, those little lips and edges hanging out in the path are great ways to lose air flow thus performance. The best transition from part to part is smooth, but if the head ex port is a wee bit smaller than the manifold ex port, that exposed "corner" can help prevent ex.gas flowing backward toward valve. An exposed / intruding corner on the manifold side, I would remove as it hampers outward flow. Sure helps to have all the parts OFF engine to do this work.
I did a little bit of porting to head, mostly removing mold-core parting line flash. Damn if these heads dont 'look' very efficient, nice strait-ish round paths all the way from lower manifold on out. There is a little bit of path mismatch between intake ports on head and the lower intake manifold ports, but the manifold ports are so damn straight, its easy to look down in there to see the hang ups ( requires of course head ON block, loosely torqued on throw away head gaskets).
The object of porting without benefit of flow bench is NOT to enlarge anything, but to remove various casting flaws like mold parting lines, smooth turns sharp edges, and I take a little bit of the int valve guide off at the corner that faces into flow, and I used a snap bore gauge to check passage cross sections, relieving narrow zones without unduly enlarging already-wide parts. Again, nice round runners here made that relatively easy compared to some convoluted heads.
~~~~
if the head locator dowels were removed / galled up, fit fresh ones on block. They are available. The last thing you want is to hang up the head on some deformed dowels or scratch the head while installing. I have always worked those bad boys out of block with vice grips and curse words, at great risk to all exposed surfaces, but a shop just mentioned that they tap some thread inside the dowel to use a slide hammer. The tool up for that might be too $ for the occasional worker but sounds like a great idea.
~~~~~
toyota says dont re-use head bolts. GTGT agrees. Bolts are torqued to yield , meaning they done necked down (usually just above the threads engaged into block) and no longer clamp as well and could break. Reuse is unwise economy. In fact the crank girdle bolts are the same. I felt one juuuuust about to give way while doing a set up build, so I replaced the set. Another damn $70 into this motor but if that weakening bolt failed during final rebuild or worse out in use, I'd have been pished off about $1000 or more.
New head, rod and girdle bolts are good prevention.
~~~~~
I'll be doing a little shielding work to reduce the heat transfer from manifold to head but only at a couple nearest approaches, NOT an exh wrap per se.
Using bits of old / extra exhaust gasket and some header wrap held up by stainless wire (what, you dont have a roll of stainless bailing wire from Harborfeight? tsk tsk)
Air of course is the best insulator compared to any solid material (as long as it doesnt move) , but some extra radiation shields at key points is not a bad 2nd choice. Mainly where driver side exh manifold bulges toward head at #6, just at down spout. Hard to see unless engine on stand, then its forehead slapping obvious where the hottest point is.
doing major rebuild , FSM at my side, want to make a couple points.
FSM instructs installing head WITH exhaust manifold torqued onto head (also install iron accessory brackets to head) before torquing head to block.
This is a great idea, to lessen tendency of deforming head after install, possibly unloading head gsk seal. Its a lot heavier & cumbersome of course but I'm convinced.
My iron manifolds were not quite flat from erosion/corrosion (manual spec = 005 max?), too off-flat to lap out manually ( flat glass and coarse wet dry SiC paper) , and since that heavy iron piece could easily deform the flat aluminum head at several points, I had my manifolds flat ground to restore planarity for mating to the spanky new head. Ask around for someone with a blanchard grinder to do the work.
Kind of spendy at $70 for pair in my one shop town but there is a lot of set up beforehand with this odd shaped part.
~~~~
The left and right exhaust manifold gaskets are different. The LONGER one goes on the passenger side to shield #5 plug from manifold. Seen more than a couple installed swapped L&R. Note #2 plug needs no shielding from manifold ( which is what you get if installed swapped) while swap also leaves #5 plug UNshielded from ex manifold.
~~~~
Ive seen /compared 3 diff mfgs head gaskets (have not seen the genuine Toy part new) and personally I wont stoop to put anything on but the latest felpro (vaguely blue , sticky one) until further developments warrant. I was tempted to spray some copper on it but Felpro says do it dry if they mention it at all.
~~~~~~~
I didnt need much gasket matching (making sure gaskets properly fit the castings ports, and casting mate to one antoher, with minimal steps and lips) for this motor, but make sure your ex.gasket does not intrude in the flow paths, those little lips and edges hanging out in the path are great ways to lose air flow thus performance. The best transition from part to part is smooth, but if the head ex port is a wee bit smaller than the manifold ex port, that exposed "corner" can help prevent ex.gas flowing backward toward valve. An exposed / intruding corner on the manifold side, I would remove as it hampers outward flow. Sure helps to have all the parts OFF engine to do this work.
I did a little bit of porting to head, mostly removing mold-core parting line flash. Damn if these heads dont 'look' very efficient, nice strait-ish round paths all the way from lower manifold on out. There is a little bit of path mismatch between intake ports on head and the lower intake manifold ports, but the manifold ports are so damn straight, its easy to look down in there to see the hang ups ( requires of course head ON block, loosely torqued on throw away head gaskets).
The object of porting without benefit of flow bench is NOT to enlarge anything, but to remove various casting flaws like mold parting lines, smooth turns sharp edges, and I take a little bit of the int valve guide off at the corner that faces into flow, and I used a snap bore gauge to check passage cross sections, relieving narrow zones without unduly enlarging already-wide parts. Again, nice round runners here made that relatively easy compared to some convoluted heads.
~~~~
if the head locator dowels were removed / galled up, fit fresh ones on block. They are available. The last thing you want is to hang up the head on some deformed dowels or scratch the head while installing. I have always worked those bad boys out of block with vice grips and curse words, at great risk to all exposed surfaces, but a shop just mentioned that they tap some thread inside the dowel to use a slide hammer. The tool up for that might be too $ for the occasional worker but sounds like a great idea.
~~~~~
toyota says dont re-use head bolts. GTGT agrees. Bolts are torqued to yield , meaning they done necked down (usually just above the threads engaged into block) and no longer clamp as well and could break. Reuse is unwise economy. In fact the crank girdle bolts are the same. I felt one juuuuust about to give way while doing a set up build, so I replaced the set. Another damn $70 into this motor but if that weakening bolt failed during final rebuild or worse out in use, I'd have been pished off about $1000 or more.
New head, rod and girdle bolts are good prevention.
~~~~~
I'll be doing a little shielding work to reduce the heat transfer from manifold to head but only at a couple nearest approaches, NOT an exh wrap per se.
Using bits of old / extra exhaust gasket and some header wrap held up by stainless wire (what, you dont have a roll of stainless bailing wire from Harborfeight? tsk tsk)
Air of course is the best insulator compared to any solid material (as long as it doesnt move) , but some extra radiation shields at key points is not a bad 2nd choice. Mainly where driver side exh manifold bulges toward head at #6, just at down spout. Hard to see unless engine on stand, then its forehead slapping obvious where the hottest point is.
Last edited:
