In a bind

[kamikazemkiii]

Im seriously fuked at the moment i have a bhg and my other car is messed up in the shop. The supra is what im using to get back and fourth to school about 30 mins away. Stupid question but would it be okay to drive the supra and keep a close eye on the water temp? dont bite my ass for that one. If so it wont be for an extended time just a week? or long enough to have my other one on the road.

compression test yielded. is this common for a bhg?
#1 140
#2 140
#3 120
#4 110
#5 100
#6 115

thanks

 

[WesPatt]

Looks like something is messed up on #5 and the ones nearest it, from what I remember pressure of the cylinders should be within 15 psi of each other at max. Yours is all over the board from 140 to 100, I don't think your motor will do well like that.

If you keep driving on a BHG, you're only going to do more damage to the engine I suspect. probably not a good idea.

 

[A. Jay]

min pressure: 128 psi
max difference: 14 psi

Don't drive it.

 

[kamikazemkiii]

any idea if i could have another problem, if so what?

 

[thesupragod]

well, it could just be weak valve seals, or rings. Are you loosing coolant? Is your oil looking ok?

These are tell tale signs of BHG, low compression can be caused by many things.

If you are losing coolant, then dont drive it, unless you want to be stranded somewhere.

 

[WesPatt]

Just make sure the head isn't warped or damaged, and make sure all the remnant of the old gasket is gone, and you should be good. Then a MHG and proper torque.

Then another compression test.

Don't forget to re-torque after 3 or 4 heat ups and cool downs. and by heat up, I mean actually drive the car for 10 min or so, as long as everything is working right. Then you should be good.

 

[GrimJack]

There's a number of problems you could have. Could be fried rings. Could be dead pistons, or valves, or even the head or block itself failing.

Get a block test done, this tests for exhaust gasses in the coolant, and will let you narrow it down some. If there are exhaust gasses in the coolant, then you've got a large problem, and it's not so much the driving that's going to do more damage - although it's going to contribute in a bit way.

When you push exhaust through coolant, it chemically alters the coolant to make it corrosive. Then it starts to eat the engine from the inside out. In extreme cases, the head will fail catastrophically, loose all the coolant, overheat, and seize or warp. In less extreme cases the head is still often junked due to the corrosion from within.

Ideally, if you have exhaust showing up in the coolant, you need to stop driving it and drain the coolant.

If you don't, there are some other tests you *could* do, but chances are it won't really matter that much, because fixing anything that's causing compression numbers like that is going to require a teardown anyway, so why not just tear it down and figure out what's wrong at the same time?

 

[kamikazemkiii]

cmpression test was done when cold
will need to do when warm

 

[kamikazemkiii]

Just make sure the head isn't warped or damaged, and make sure all the remnant of the old gasket is gone, and you should be good. Then a MHG and proper torque.

Then another compression test.

Don't forget to re-torque after 3 or 4 heat ups and cool downs. and by heat up, I mean actually drive the car for 10 min or so, as long as everything is working right. Then you should be good.

Have the MHG and arp's didnt retorque tho.
oil looks clean but under the cap is milky

 

[kamikazemkiii]

and if i do drive it will be for 4 days,i forgot today was thursday
and i wouldnt boost

 

[mdr40z]

bet you didn't prep it right for MHG

 

[Bri7man]

cmpression test was done when cold
will need to do when warm

Yeah I learned the hard way, I had to do it twice.

Disconnect cps, ignition, efi fuse, and plug betw fuse box and strut tower and do test on a warm engine WOP for the 5 turns.

Ideally, if you have exhaust showing up in the coolant, you need to stop driving it and drain the coolant.

My overflow drains in a day of driving. I have a cometic + arp studs 1 month old from resurface. I forgot to do the fipg on the block when I put it back together. I'm not driving it now but should I drain coolant fill with water? The ratio right now is 80% water 20% coolant.

Absolutely no signs of overheating even under extreme conditions.

 

[kamikazemkiii]

bet you didn't prep it right for MHG

head was resurfaced but block wasnt

 

[CajunKenny]

Just make sure the head isn't warped or damaged, and make sure all the remnant of the old gasket is gone, and you should be good. Then a MHG and proper torque.

Then another compression test.

Don't forget to re-torque after 3 or 4 heat ups and cool downs. and by heat up, I mean actually drive the car for 10 min or so, as long as everything is working right. Then you should be good.

I don't meant to bust your chops here WesPatt; but, this isn't the best advice.

There's more to prepping for a MHG than making sure the head isn't warped/damaged and all the old gasket material is adequately removed.

Each manufacturer of MHG's has a minimum RA spec that must be met in order for proper function of their MHG. Both the head and block need to meet the required RA Spec. Not properly prepping gets folks in the position that he is in now.

The re-torq'ing advice is good. Jdub recommends 5 complete heat cycles. Then a re-torque.

 

[Suprapowaz!(2)]

How much could it be to rent a car for a couple of days? Probably cheaper than doing more damage to your Supra driving it with a BHG. You can chance it, but I'd rather bite the bullet and spend the money on a rental. Good luck though.

 

[WesPatt]

Umm... I know there is spec's to follow, but I assumed he knew of them and to check them.

Was just giving some basic advice I could think of, off the top of my head. I've been through the BHG. It's a long, tedious and complicated process... and a pain, I know.

Hopefully everything will be in tip top shape and all he needs a MHG.

 

[GrimJack]

Yeah I learned the hard way, I had to do it twice.

Disconnect cps, ignition, efi fuse, and plug betw fuse box and strut tower and do test on a warm engine WOP for the 5 turns.





My overflow drains in a day of driving. I have a cometic + arp studs 1 month old from resurface. I forgot to do the fipg on the block when I put it back together. I'm not driving it now but should I drain coolant fill with water? The ratio right now is 80% water 20% coolant.

Absolutely no signs of overheating even under extreme conditions.

Depends. If it fails a block test, you should drain it and leave it empty, IMO, until you can get the problem fixed.

 

[Toink]

Sounds real crappy man, hopefully you can have it fixed before the NC import meet this saturday.

 

[MA702Tone]

and if i do drive it will be for 4 days,i forgot today was thursday
and i wouldnt boost

If replacing the engine is not a concern when your financial issue clears up drive it, just have some cash on hand for the emergency tow, and a temporary resting point during the pinch.. Then when the dust settles get a replacement 7M refresh the seals, gaskets, bearing, oil pump, and the head gasket.. reuse the ARP hardware and you should be fine.. If cash flow is of concern then park it, and use possible public transportation, or call a friend, or carpool with some one from school. The easiest way to save some coin while in a pinch. Hope this may help you out

 

[CajunKenny]

Umm... I know there is spec's to follow, but I assumed he knew of them and to check them.

Was just giving some basic advice I could think of, off the top of my head. I've been through the BHG. It's a long, tedious and complicated process... and a pain, I know.

Hopefully everything will be in tip top shape and all he needs a MHG.

I didn't mean to offend WesPatt. I just wanted to make sure that any readers that don't know the proper process wouldn't be mis-informed.

The BHG subject has been WELL covered around these parts!