does my block need machining?

[Wilcox]

i recently bought a 7mge and a w58 from some people that didnt know what they had for 300. after doing a leakdown test and seeing suprisingly good results ( only 10psi loss ) i tore the head off and i can still see cross hatching in the cylinder walls. im going to replace the hg and some other odds and ends before i put it in my '87. i do not believe that this motor had a bhg, the hg was in good condition when i removed it, and i believe that it has less than 50k miles because the inside is rediculously clean. what do i do to test for block warpage? what else should i do before droping it in? i paln on using an oem hg and head studs to ensure she doesnt blow in the future.

thanks, wilcox

 

[BryanDyer]

i recently bought a 7mge and a w58 from some people that didnt know what they had for 300. after doing a leakdown test and seeing suprisingly good results ( only 10psi loss ) i tore the head off and i can still see cross hatching in the cylinder walls. im going to replace the hg and some other odds and ends before i put it in my '87. i do not believe that this motor had a bhg, the hg was in good condition when i removed it, and i believe that it has less than 50k miles because the inside is rediculously clean. what do i do to test for block warpage? what else should i do before droping it in? i paln on using an oem hg and head studs to ensure she doesnt blow in the future.

thanks, wilcox

The block wouldn't be the concern for war page as much as the head would since it is aluminum and is much softer than cast. If you take it to the machine shop they can tell you and if it is warped then leave it there for a resurface

 

[Wilcox]

i know that making sure both surfaces are level is a must. i already did a bhg job on my motor that i have now and it blew again because i didnt have the block decked and i didnt check to see if it needed it. what can i do to see if the block needs machining? feeler gauge and a straight edge?

 

[3p141592654]

It's all in the book...
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=74

 

[Wilcox]

thanks, i book marked it!

 

[Wilcox]

the TSRM calls for .10 warpage for the head otherwise rebuild it. i took a straing edge and feeler gauges and the majority of the block is closer to .05 and there is one corner that is .10 but its only a small portion. should i get it machined even if im using head studs instead of stock bolts?

 

[hvyman]

It's always a good idea to machine the head when it's off. Also good to have it check for cracks.

 

[Wilcox]

its a very new motor, you can still see the cross hatch in the cylinders and the bock is only warped .003 at the worst. if im using head studs will it make up for the difference? i guess i can always quit being a cheep ass and just get it machined if i have to.

 

[hvyman]

If you don't see the cross hatch your motor had problems. Had 1 engine with over 200k that still had it. That doesn't mean much.

If you want the best seal out of your hg the head should be machined. If you want a mhg the block should be machined as well. If you want to be cheap and not do anything that is up to you.

 

[IJ.]

It's a 20+ year old engine... of course it needs to be machined...

Just about every surface will be out of true.

 

[Wilcox]

It's a 20+ year old engine... of course it needs to be machined...

Just about every surface will be out of true.

this is true, i will have the head machined and ill have the machine shop install the new valve seals i have from the last BHG job i did [ and i didnt check the block for squarness and it blew again ]