Some BHG questions complete with pics.

[87supraturbo2]

Well I suspected that I had a BHG. The car was overheating and losing coolant, constant steam from the exhaust, although not much. So I parked the car and today I did a compression test and I was expecting to see a large difference in the compression #'s but the numbers came out like this
1 -- 160
2 -- 150
3 -- 150
4 -- 155
5 -- 140
6 -- 160

But when I took the oil cap off it was milky in the top of the cap and on the part of the cam that I could see.

Here is a pic of the cap. (sorry the pic is crap but you get the idea)

Here is one of the cam lobe.

But the thing I found strange was that it was milky when I took the oil cap off but it was fine when I check my oil with the dipstick? Is that normal. So my question which I'm pretty certain I know the answer to is do I have a blown headgasket or is there anything else that it could be?

-Thanks,

Matt

 

[Reign_Maker]

the numbers came out like this
1 -- 160

5 -- 140

That concerns me... Pull the head... Its time for an MHG and ARPs....

 

[87supraturbo2]

That concerns me... Pull the head... Its time for an MHG and ARPs....

If I do end up having to do the HG job, which is pretty clear that I will have to do it will have to be stock toyota gasket with ARP headstuds as I don't have the resources or the funds to pull the engine and get the block prepped properly for a MHG.

-Matt

 

[Tanya]

head gaskets blow in all sorts of ways. I never did a compression check on my #6 when it blew, but I know it still had to have been good, as the engine functioned with full power like nothing was wrong.

 

[edi]

to get the absolute best seal from your new head gasket you should resurface both the head and the block. however, i've see time and time again people only resurfacing the head and be just fine. i guess its kind of a gamble.

 

[Reign_Maker]

Get a cometic mhg, they are pretty forgiving... make sure the head is straight, clean the block surface, cometics will hold... And you can get one for a good price...

 

[dunnbeetle]

im kinda in the same situation....I just did my head gasket last spring(stock toyota with arps) but now it has already blown again, I dont have the time or money to pull the engine all the way out....and evene if i did there isnt a machine shop within 2 hrs of where i live that would do a good enough job on machining for a mhg

 

[Reign_Maker]

Machine the head, prep the block, slap on a Cometic...

You guys have to realize that stock composite head gaskets are completely worthless... If you look at the design of them you can see the ultimate flaw in them... You have these weak little copper rings RIGHT next to the compression chambers, and the only thing keeping that little copper ring in place is pressed cardboard... I dont care if you have a friend who had a friend who's cousin had a stocker on with ARPs and ran 15psi for ten years, its RARE, extremely rare... The odds are so stacked against you that the cost in the long run isnt worth the immediate cost of doing it RIGHT... I mean, how many times do you want to pull your head off and do this? Every Supra owner on this board, or any other Supra related forum, knows that the HG's are the weakest link to the 7M... Its not the motor's fault, its Toyota's... The motor is a fantastic, solid, beast of a motor, and a very fine platform to build on... It just needs the right stuff... So, give it what it needs, and enjoy many many years of fun boosting, instead a few months of fun, a few hours on the side of the road waiting for a tow truck, a head ache, more busted knickles, blood sweat and tears...

If you can pull and replace the head yourself, you can do a HG job in a weekend, and at a cost of about $300-$400 depending on what you go with... $125 for ARPs, $125 for your MHG, $100 for you head machined, and a few bucks for misc stuff... So now you have a motor that at least will hold the boost in the head...

Sorry for the long post, just sittin here sick...

 

[dunnbeetle]

lol thank you...well I already have the arps, have already done a hg job, just had the head machined last spring so im wondering if i will need to do it again? If not, then all i should have to do is check head and block for straightness, buy a cometic and slap it on?

 

[Reign_Maker]

And make sure the surfaces are CLEAN... And if they're straight, then yur good to go... The block isnt going to warp like a head... So the block should be OK... Just make sure the head is good... And BE HONEST with yurself, if the head is even the tiniest bit out, then have it machined...

 

[dunnbeetle]

alright, but the head has already been milled .020", how much more can be shaved off b4 its too much? and also what thickness would u reccomend getting the hg?

 

[Reign_Maker]

Your machinist should be able to tell you if and how much more you can take off... I dont have the exact number off the top of my head, and Im sick, so I dont wanna hunt it down, lol... *sorry... cough cough cough* You can make a determination of how thick you wanna go from there... I would say a 1.4mm or even as high as a 2mm... I put a 2mm in mine...

 

[mattjk]

How long have you been driving like that? I'd be worried about rod knock after you fix your head gasket.

 

[dunnbeetle]

the machinists around here know NUTHING about supras, anything foriegn around here, well, is bassically still foriegn...

I drove the car like that for a few months, I was told from numerous people around here that it would be ok...then i put it away for the winter. well it was nice out for about a month and the roads were clear so i was like why not....drove the car one day and poof, white smoke. so now im tryin to get it ready for spring again....why should i be worrying about rodknock though if i get a thicker mhg?

 

[Reign_Maker]

I think he was talking to the thread starter Dunn... The reason you dont drive with a bhg is, well, there are a few reasons you shouldnt... One is when you mix water with the oil, it looses its viscosity, thus lessening the lubrication to the bearings around the rods/crank... This creates the other problem: heat... Over heating and lack of lube are the two main causes for spun rod bearings, equalling rod knock... If you blow the hg and stop driving it, then the better chance your motor has of surviving...

 

[dunnbeetle]

oh ok yeah sry i kinda hi-jacked this and didnt realize it.....but yeah i understand what he's talking about now, I learned that the first time I blew my head gasket(knew nuthing about cars): kept driving it till i got a rod knock....now the engine is torn apart in my gaarage waiting for me to get money to rebuild it lol.

 

[87supraturbo2]

How long have you been driving like that? I'd be worried about rod knock after you fix your head gasket.

I haven't driven it at all since the oil turned milky like that. It started to overheat then I made it home and parked it. I've been checking it periodically but never driving it. The milky oil only started within the last week and the car has been parked for over a month. I haven't driven it at all with the oil looking like that.

- Matt

 

[trydrew]

I haven't driven it at all since the oil turned milky like that. It started to overheat then I made it home and parked it. I've been checking it periodically but never driving it. The milky oil only started within the last week and the car has been parked for over a month. I haven't driven it at all with the oil looking like that.

- Matt

Good. Don't.

I would definately remove the engine and tear it down.

Thats weird. It looks a lot like condinsation (sp?). I have an oil spill under my car right in the garage now that looks milky.
It was a very wet day today and I slide under my car to unbolt the engine mounts, and I noticed it all milky.
Anyway, that much water in your system is a pretty bad thing.

 

[canadianbacon]

Pay now, or pay later! I would do a complete rebuild with MHG. I would be worried if you got it back together and your bottom end blows. Where in N. Van are you? I might be able to give you some resources!

 

[87supraturbo2]

Pay now, or pay later! I would do a complete rebuild with MHG. I would be worried if you got it back together and your bottom end blows. Where in N. Van are you? I might be able to give you some resources!

Hey, I'm out towards Deep Cove. Reigns got me thinking about going with the cometic HG. But I really really just don't have the funds to pay for a full rebuild right now, as much as I would like to. I just want to get the car back on the road while a finish highschool. I grad in June so then I plan on getting a full time job for the summer to pay for the complete rebuild I have planned.

- Matt