Fading rings, switch back from synthetic?

[Jaguar_5]

Hello everyone, i've been lurking for awhile, thought i'd join in the fun, I have a White '87 Supra N/A daily driver, and a Red '87 turbo, targa, got it for cheap, barely drove home, tore it apart, bhg between 4 cylinders and a bunch of water jackets (pictures @ http://www.mkiiitech.com/forums/viewtopic.php?p=4147#4147 )

This is regarding the '87 with about 145k miles on it now (still running strong)
I've been running Royal Purple 5w30 for 2 oil changes now

I had some signs of a possible BHG, radiator overflowed once, waterfall sounds, occassionally abit of a spike in the thermostat... heater only blows warm at revs.

I replaced my radiator cap and burped the system (was unsure if the hill was steep enough, steep but not extreme), no more waterfall sound, heater still acts funny but alot better, and i saw abit of a spike on the thermometer on the freeway in stop and go traffic yesterday. Also the VSV works with the climate control just fine, goes all the way up and down. I noticed theres a leak sound coming from a white flush/purge cap on the radiater hose going from the VSV to the cyl head when i shut off the car and got out

I did a compression test, i didn't write down the results but this is real close:
Cyl 1: 165 psi
Cyl 2: 165
Cyl 3: 163
Cyl 4: 160
Cyl 5: 150 (shot up to 200 with abit of oil)
Cyl 6: 165

So it appears as though my rings are fading, the question is, could i still have a BHG? (i'm guessing yes) the other is, should i change back from synthetic or will that cause more problems (i lose about a qt. every 3,000) Should i just get something thicker?

 

[miggles]

i would have thought a 5w is a bit thin for a older motor.
I take it you had done the proper preps before the hg was replaced? (machining, checking for flatness etc)
Try getting a plastic bottle and cut the base off and wrap some cotton rag (clean) around the top so it will seal in the radiator.Fill it with coolant and run the car while the front end is jacked up.Any trapped bubbles will work their way out to the higher level in the bottle.
You can always try a thicker oil.As for loosing oil isit from oil leak or burning?

 

[Jaguar_5]

Sorry i lied, i'm running 10w30, not that theres a huge difference.

I've never had the headgasket replaced in this car, not sure if it has before, i'm guessing not

I'll try doing a more hardcore burp, after reading what you said a couple times i finally get what you mean, extend the height of the radiator cap basically

I don't have a visible leak, other than from the camshaft covers

 

[miggles]

Did you do all the cyl's wet too? what were the results.
The numbers are still reasonable for the amount of kms it has done.

 

[boost fiend]

when you burp it, make sure the heater is on full blast. might have air near the heater core. that will help get it all out.

 

[Jaguar_5]

I'm gonna burp it again tomorrow, the first time i did it, the heater was on, i think auto on 85, not max though

I didn't start with a cold engine, it cooled off for probably 30-40 mins on a pretty cold day

Cyl 5 was the only reading that made me nervous, its the only one i did a wet test on, it was pretty freezing outside so i just put everything back together

 

[Jaguar_5]

Couldnt really get the bottle trick to work, but i did it with a cold engine this time, heat on full blast, parked on a uphill AND raised the front 2 off the ground, got more air bubbles out, heater works better, but still occasionally goes cold (seems to only happen at low revs)

We'll see if i get temp spikes again

 

[NDBoost]

Couldnt really get the bottle trick to work, but i did it with a cold engine this time, heat on full blast, parked on a uphill AND raised the front 2 off the ground, got more air bubbles out, heater works better, but still occasionally goes cold (seems to only happen at low revs)

We'll see if i get temp spikes again

im getting cold spurts in my heater too but i dont overheat :icon_conf :nono:

 

[Jaguar_5]

It's weird, it rarely happens, but sometimes the heater is cold at revs, the thermostat spikes up, then drops right back to normal and i have heat...

I hope i don't have a BHG, though i'm not sure what else it could be at this point. I just need this car to run long enough to get my Turbo running! have pulled the engine and now just need to have it machined and then buy lots of parts, on that topic, how are the ebay gasket sets, for everything but the HG? (getting a MHG)