View Full Version : New to the sc game, potential blown head gaskets

02-05-2017, 11:46 PM
Purchased my first sc a week ago, knowing it had a random missfire/ rough idle
Ending up pulling cel codes and they were reading lean on both sides, swapped one o2 sensor out with a old one I had laying around and now that side is reading good, however I noticed a little bit of smoke/ condinsation coming from the exhaust. Now it has been very cold and humid out, the car runs pretty good now also, no water in the oil or oil in the water, but I'm thinking there's a slight leak. Any good test to try? And if I do decided to do the gaskets, im going arp studs and would prefer mls gaskets, is the a complete kit that comes with mls head gaskets or do you have to buy them individually?

02-06-2017, 07:05 PM
If in doubt about head gaskets with one of these rigs, you probably need them :cool:

But seriously, if it's new to you, put good NEW o2's in it. Quit f-ing around with used ones... CRITICAL that they r good. I have had bad experiences with parts store replacements, and only use ford, one time I feel the extra $$$ r well spent at dealer. Also do plugs and wires. These cars r VERY sensitive to plug/wire problems and many misfire situations can b traced to them.

The MLS gaskets r a great piece, but my understanding of them is that the finish on both the head and block r critical, and smoother than factory is required. If you r not refinishing the block surface then the composite Fel-pros r the way to go. Dave at SCI, or Supercoupe Performance may have kits?


02-06-2017, 08:55 PM
Hello, from what you have said I would start with a compression test of all cylinders. May be time consuming but will pay off. If you have a rough idle it could be a burnt valve. Very possible with blown gaskets or the car thats been driven with a lean condition. Its best to know before pulling heads. Nothing worse then doing head gaskets to find it has a bad valve. Also do a leak down test afterword, this will help verify cylinder quality. Easy to do and a actual leak down tool dose not cost much. You can also make your own or use the hose from your compression gauge. Just remove schrader valve. However it is best to control air flow going in. This will allow you to find where air may be escaping. (Radiator Valves, Block) Ill be interested to hear how it goes. Dont give up. They are great to drive and do hold up well.

sam jones
02-07-2017, 12:49 AM
Good evening

Do the block test for escaped combustion gasses. See this link for example:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjqpf-Eiv3RAhUD92MKHRBjCG0QFghHMAA&url=https%3A%2F%2Fwww.napaonline.com%2Fnapa%2Fen%2 Fp%2FBK_7001006%2F&usg=AFQjCNHEaE1gpgjA0ijLSRdGfvHxra8kYg&sig2=Wo4VINs2fOkJu0VNV7ry0A

Your first goal is to make it reliable. Here is a portion of list I use for a new to me SC.

-Check for vacuum leaks. At idle the boost/vacuum gauge reading is @ 17-20.
-Pull codes and correct if any. Check and replace if necessary battery cables.
-Change spark plugs and inspect wires for damage.
-Cooling system. Have the radiator Professionally checked and cleaned. Replaced water pump, thermostat, and hoses.
-Check and if necessary service supercharger oil.
-Inspect and if necessary replace accessory, jackshaft and supercharger belts.
-Replace harmonic balancer washer and bolt. Replace harmonic/timing chain cover seal.
-Inspected and replace if necessary front suspension components (upper/lower control arms, tension strut bushing, anti-roll bar link, ect).
-Replace fuel filter
-Replace oil pump and filter
-Inspect and if necessary apply heat sink compound for the DIS.
-Replace ATF and filter.
-Inspect trunk area for signs of rust. Find and correct cause.
-Inspect and if necessary replace ignition switch.
-Replace power steering pump fluid.
-Inspect rack and pinion for leaks.
-Inspect and if necessary replace engine and transmission mounts.
-If equipped inspect manual transmission for signs of leak at the master cylinder line, reservoir, and tail shaft seal. Inspect the master cylinder rod and clutch peddle bushing for wear.
Replace if necessary
-If equipped check TEVES II anti-lock system for leaks (around the pump area) hard or intermittent trouble lights. Be prepared for a possible replacement ball accumulator.
-Check the rear hub assembly lock nuts for torque and brake hardware.
-Check the front hub assembly bearing for wear. Check front brake hardware. If your state has emission testing, get a pre test to see if emission system is working correctly and within state limits.

Welcome aboard and Good Luck.

02-07-2017, 02:44 AM
Congrats on your new SC. Great group here. Factory shop manuals and the search function are a huge help.

02-07-2017, 11:08 AM
Well after pressure testing the cooling system, found a leak at the thermostat housing, fixed it, drive the car, got a cel, pulled codes for maf circuit, and then did a koer test to find code 172 and 136 (both side o2 sensors reading lean) so I believe the maf is culprit. However I did also find the oil fill cap to be milky and a slight amount of white in the oil. Order arp head studs 233-4003 (2.8l Chevy) and felpro HS9642PT

Anything else I need to do the head gaskets? Would like to order everything today for the weekend

02-07-2017, 12:14 PM
If you have the heads off, you might as well do the motor mounts. And plugs and wires, of course. In addition to the head gaskets, you'll need a top end set. Anti-freeze, new oil & filter, etc.

02-09-2017, 02:29 AM
Got the passenger side head off, found a leak/messed up part in the head gasket, however the head gaskets say felpro on them. Looks as if they have already been done before. Am I goi g to have issues running the standered felpro gaskets with arp studs? Or should I go with the mls style ones?

sam jones
02-09-2017, 05:19 AM
Good morning

MLS style head gaskets would require the engine block cylinder surface to be machine with in the required RA finish.

The following are very brief steps to give the Fel-Pro gasket and you a successful cylinder head gasket replacement. Members of this forum might have more on this subject.

Have the heads checked and milled for flatness at your local machine shop.

Checked the block with a approved straight edge and feeler gauge for warping.

Clean the block of old gasket material. Cleaning is paramount.

Chase, tap or dye the following:

-Threaded engine block cylinder bolt holes.

-Cylinder head valve cover bolts and bore threads.

-Cylinder head to intake manifold bolts and threaded bore.

Clean or replace engine cylinder head alignment dowels.

Use ARP torque grease/lube only when installing studs, nuts and washers.

Double check all torque especially the intake manifold bolts.

Torque fasteners to spec. The subject of the intake manifold bolt torque is a matter of discussion. Use forum search.

Drain original oil fill. Serviced oil. Replace filter.

Good Luck.

Jimmy 2Coupes
02-09-2017, 06:23 PM
however I noticed a little bit of smoke/ condinsation coming from the exhaust. Now it has been very cold and humid out,

Sounds completely normal to me.

02-13-2017, 11:31 PM
I would fix the maf and take care of sensors/vacuum leaks before doing a head gasket replacement. The milky look on the oil cap is most likely from condensation from the cold/humid condition outside. Driving the car for 20-30 minutes should remedy that. These cars have lots of things that can cause wierd idle or running problems besides head gaskets. I'm personally troubleshooting my car at the moment. Just remember new parts don't necessarily mean it's good on these cars. I went through 4 alternators and 6 cam sensors before finding good ones.