Turbo and Heating Questions from a Beginner

[wood]

hi men

couple of questions that i am hoping you old hands will be able to help me with concerning a 1990 uk supra

re the turbo : how can i tell if it is stock factory or aftermarket as there is some discrepancy on the paperwork ... any links to images ?

re heating : i have heard a lot about a design flaw on the early supras that led to engine overheating and blown head gaskets ... what are the tell-tale signs of this ? engine sounds great but interior heating will not heat maybe ???

any help appreciated over here ... thanks !

[87supra7mgte]

the stock turbo will say ct-26 on the compressor side, whether or not its been upgraded, idk, some of the other guys here will be able to tell you. a blown head gaskets will allow oil to mix with your coolant and vice versa. it will also show as white smoke coming from your exhaust. a way ive been told you can see if it is blown is to start it cold with the radiator cap off and let it warm up and see if bubbles appear where you can see, bubbles are bad. the reason behind the BHG is the torque specs for the head bolts, they were undertorqued from the factory and weren't corrected in the manuals for the cars. the book lists it as about 58 ft-lbs IIRC, we all recommend atleast 75-78 ft-lbs of torque.

link to pic of turbo(not installed) http://www.google.com/imgres?imgurl=...ch&um=1&itbs=1

[cre]

There are threads covering all three topics already. Start with the FAQ section.

The heater not working is unrelated to the blown head gasket issue. It's typically due to the VSV on the firewall dying (which connects to a bell shaped metal canister with a vacuum line running to it). Bypass the VSV so the vacuum line runs directly to the canister and see if that fixes it (I'm pretty sure this is covered in the MKIII FAQ section).

Testing for a blown HG which is not presenting significant symptoms is difficult. The two big tell-tale's are moisture in the oil (makes it look like chocolate pudding or presents beads of water in the oil when drained) and caustic coolant (you can get pH strips to test for this or a kit with a test tube device and some tablets you add to a sample).

The CT-26 may have been upgraded or it may be another rare version The only way to tell is to count the fins and measure everything. Look for a recent thread about the 7M-GTEU and the turbo-a.... someone posted dimensions in there.

NOTE: the thread states that the 7M-GTEU specifies a "A" group engine... this is inaccurate. The U merely signifies compliance with Unleaded fuel emissions regulations and the U was added as a designator to all Japanese 7M-GTE's (and I think possibly the European market vehicles). The meaning of every letter is available from Toyota.
7 = Generation
M=engine series
G = DOHC (F=SOHC)
T=Turbo (Z = Supercharged)
E = EFI
U = Emissions compliance (JDM and possibly Euro specific label)