[dbsupra]

auugh! a headgasket question. maybe i'll get some input

i have a new in shrink wrap toyota shortblock for my project going together. using a hks 1.2mm hg, should the deck be lapped? the factory toyota finish is really nice, but is it smooth enough for mhg sealing? id hate to screw with a perfectly good finish if i dont have to. the head surface was machined and it is a very nice finish as well. if you run your fingernail over the surface you can just barely feel the machine marks. not sure if this is good enough or not. so i just want to know a fresh from toyota block and a fresh from the machine shop head should be touched or leave well enough alone. i have yet to find any info on anyone using a mhg on NEW shortblock.
thanks for any input.
dave

 

[X-man]

Dave I checked clearances and torque spec's on everything last night and everything was perfect. Rod side clearance was .006(.006 to .011) on all six and the thrust clearance on the crank was .0025(.002 to .009 are spec's from the manual). The torque spec's on rod's and main were also dead on. I'm going to just go ahead and lap everything. I've run my block and head set up to 25 psi and never had an issue and I've got the stuff to do it, so I'm just going to go ahead and lap the two surfaces.

 

[dbsupra]

awesome!

if you want to go ahead and lap it thats ok. was just concerned bout taking more material off than necessary esp if it wasnt needed. better safe than sorry i spose. thanks for all your help.

dave

 

[X-man]

http://www.supras.com/~riemer/HKS/hksgaskets.html
Dave in this link Reg talked very highly of the machine finish from Toyota quoting it was suitable for use with a metal head gasket right out of the box. I might just do the head since the block is new.

 

[joliroger4]

Whats the deck look like? If I couldnt see or feel any milling marks, I would go ahead and just use it. I was thinking exactly like you Xman about how Reg said how good the factory finish is, but I wonder if that goes for replacement toyota shortblocks. What makes me say that is if you look in the MKIV section you can read a sticky about all the trouble those guys have had with the replacement factory shortblocks. One guy had a problem of sealing his HG. He tried both a Greddy and an HKS. I'm not trying to scare you into lapping, but its something I would keep in mind. If you cant see any milling marks with a magnifying glass and you cant feel anything, I would just lap the head and go for it.

 

[Faded87T]

Hey Dave, You can also give Joe a call at Bell's Motor Service (502-584-4853) downtown. Tell him I sent you. Joe took my block and head over to the diesel repair place he used to work at because they have a profilometer. Get the name of that place and maybe they would measure the surface smoothness for you.

Dale H
87T

 

[dbsupra]

joliroger-
i believe most of the problems the mkiv guys have had are due to the new blocks coming from mexico now. maybe we are talkin bout 2 diff issues.

dale-
hey! i wondered if you were still around. id like to check out your supra sometime. shoot me an email at [email protected]
as for the head/block- sean has them in VA, they arent here. for future i'll keep them in mind tho thanks.

dave

 

[amorak]

I would really suggest you at least measure the deck for flatness. Then search around here/SOGI list, as there are some pictures of what a 'good' RA is for a MHG :bigthumb:

I've never seen a new factory shortblock...Pics please!

 

[X-man]

Send me an email address at [email protected] and I'll send you some.

 

[Larry_A]

http://www.supras.com/~riemer/HKS/hksgaskets.html
Dave in this link Reg talked very highly of the machine finish from Toyota quoting it was suitable for use with a metal head gasket right out of the box. I might just do the head since the block is new.

I've talked to Reg R at great length ovr drinks & Italian food. Come to think of it, it's been awhile, & I miss him, LOL. Anyway, aftr speaking w/him, I wouldn't touch a new block deck. When you lay that virgin MHG on that virgin block deck, the feeling is magical...goosebumps will creep up your back. Oh what a feeling!