7M-GTE and head gasket

[kuchie]

Hi

I have a MS-112 Crown which i fitted the 7M-GTE and a R154 gearbox in.

Apart from all the hassles and little things to get it on the street, and other ongoing problem and bad advice, i had finally got things sorted out and drove mostly rather well.

Now not haing driven this car more than 6,000Ks i finally see the head gasket is giving way. I am losing water out of the expansion tank and a rather high build up of pressure and air bubbles in the radiator. Oil is fine though

Since this has happened what are my options to have it built stronger, possibly to handle up to 18-20psi ? And who can be trusted to do this as i think its a job just a little out of my range of skills. I dont know really where to begin. I dont have an endless budget but while the motor is being pulled to bits might as well get a few things done..

Things like:-

Steel Head gasket? or any other choices
ARP head bolts/studs
Forged or semi forged pistons?


Michael

[whatthe?]

If you are pulling the engine apart and want it to last, MHG and forgies would be my recommendation. You will need the head and block to be machined ultra smooth and flat, so make sure you take it to a shop that has experience with this sort of thing (or these engines preferably). ARP head studs are worth their weight in gold for a properly sealed 7M, as they wont stretch anywhere near what the factory jobs will. Studs also won't twist as much when you torque them up as bolts do. Forgies are nice to have but the standard jobs should cope with 18psi. Of course, if youre going to the expense of a proper engine rebuild and, once again, want it to last, I'd certainly consider them (in fact I did). What turbo are you planning to run BTW? A CT26 is never going to see 20psi

[EldarO]

Metal head gasket and ARP studs BARE MINIMUM!

youd also want to get the block and head machined dead flat to provide the best clamping force to give the HG the best chance of survival.

7MPower.com list the 7M as being able to handle 400rwhp on stock internals, which further sets in the image that the M series engine provided, a bulletproof motor capable of producing quite insane amounts of power.

the whole HG fuckup at the factory tarnised the M series reputation, and now, when anyone thinks 7M, they atuomatically think BHG!

this just isnt true, prepare it properly, and it will provide you with ample power to satisy that little bug inside you.

the site is there to look at, but there is also a guide to build up your engine to certain levels.

the link is here: http://7mpower.com/7m_buildup.shtml

have fun, and, one bit of advise, you'll be hearing quite often on toymods.

Do it right, Do it once, Or dont complain!

spend that little bit extra now, and save yourself a headache or seven

Eldar.O.

[ed]

why does everyone say studs?? bolts are 99% as good for 99% of users

[whatthe?]

for an extra $10, why not get the studs? Besides, ARP bolts for a 7M are a lot harder to get than studs (unless you ebay them)

[BlackSupra]

Metal
7MPower.com list the 7M as being able to handle 400rwhp on stock internals, which further sets in the image that the M series engine provided, a bulletproof motor capable of producing quite insane amounts of power.

the link is here: http://7mpower.com/7m_buildup.shtml

Eldar.O.

Dead set the yanks have nothing.

700rwhp on stock cams from a 7m........riiiiiiiight.

If you don't do it right the first time, it's only going to come back and haunt you in a few months. Ask around and find out where people have had their 7M's built that havent broken and take it there.

[Stomps]

hey man, i have done this twice.. first time used HKS 1.2 mm steel gasket and ARP head studs.. had no problems, sold the motor.. that job was professionally done, cost me $1300 ish, for the work, $800 for the gasket.. (about 3 years ago) done by Steve DelCaro, he has built drag car motors, he knows his shit.

recently did it again got a COMETIC 1.2mm Steel gasket for $200, ARP head studs $256
got the head machined for a carton of piss, (Usually about $80) once you take it off.. cleaned and decked the block myself.. (lucky the cometic gaskets come with a "glue" on either side, so my block didnt have to be mirror finished..

since then car has made >300rwhp at 17psi, and has been run at 20psi (not dynoed)
have not had any issues so far after a year of driving..\

I would highly recomend Steel gasket and ARP head studs,

but seriously if you have the motor apart and have some money to spend, do it once, do it right.. it will save you a lot of stress in the future..

Stomps

[1200det]

To further on everyones wonderful feedback dont forget the SEARCH feature as this has been covered many times in the past months

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[Shifty]

It's a time consuming but easy job. I did it myself with no experience, armed only with a bodgy toolkit and a workshop manual which listed the first step of head gasket replacement as "remove cylinder head" which I found very helpful.

I meticulously cleaned the block surface with a series of sharp chisels, rags and thinners to clean all the oil off - being careful not to fill the cylinders and galleries with scrapings.

The head I took to Southside Cylinder Heads in Macgregor - they disassembled, cleaned, inspected, machined and reassembled it for $100+GST and had it back to me the next day. A replacement Toyota head gasket was about $160 (these have been updated from the original item) and on top of that there was a few hundred in miscellaneous expenses for thinners, chisels, new oil, oil filter, coolant and a radiator flush. Shouldn't cost you much more than $500 DIY.

From memory they are TTY bolts so I'd suggest that you replace them with ARP items, though in most cases the standard ones will be fine as long as they have not been overtightened in the past. I used the standard bolts, and while I sold the car a number of years ago I believe it is still going strong with no money spent on it, and has been running a higher boost level that whole time.

A lot of people blow engines (of all types, not just 7Ms) and run crying that they aren't strong, but 95% of the time this is because something else was wrong such as a dodgy tune, fuel issue or high inlet temperatures. With an appropriate tune I have no doubts that a basic replacement such as the above should be plenty strong enough to handle 400hp, though if you have the money/time then I strongly suggest a full engine rebuild if you are looking at serious modifications in future.

Forged pistons are a must and beyond that a new set of bearings, seals, belts, water pump and recored (or at least flushed) cooling system will be necessary. Don't expect much change from $4000 if doing it this way.

[cambelt]

Who knows where to buy the cometic head gaskets for a 7m,
cheers

[kuchie]

Thanks for the advice everyone !

Ok Well i want to do it properly so i am shopping around.. Not too interested in upgrading theturbo yet but want the motor ready for it when i do get that far

I dont plan to pull out the motor any time soon after putting it back in so i do want it right first time.

mentioning getting a new water pump and thermostat...etc etc well ive only done all this through the last 3 months, timing belt and all that is new.!

Cometic head gaskets.. found them at a place called rocket industries think they are in huntingwood

Michael

[EldarO]

had mine done for around $2.4k

this included a full head reco, full radiator reco, full flush, new head gasket (toyota genuine) and new studlies.

i havent had any problems so far, although i think my radiaotr cap is a bit dodge, so ive been losing a bit of water.

Eldar.O.