Started the Velocity up today and I have an exhaust leak. The first cylinder on the port side. I can hear and feel the leak. Headers are CMI e top/sport, 502 No tails just rubber coupling.

I understand I will need new gaskets. What type are best and where can I get them?

Secondly, how difficult a job is replacing the gaskets and what do I need to know to do the job correctly?

Thanks,

Padraig

You need a torque wrench, 25-30 lb/ft.

Difficulty is relative to your workspace.

Cometic makes a nice MLS exhaust gasket.

check all sealing sides for warpage with a very good straight edge to and then clean them up real well. Brake cleaner works well for final clean up plus leaves no residue. .

we have had good luck Ultra seals Mr. Gaskets and always recheck torque specs thru out the year. I like also that they have the outside hangers on the gasket to just drop in after you bolted the 2 outsides of the exhaust manifold.

Thanks Bup, where do you get them? Are all exhaust gaskets for a 502 the same or are they specific to the header? What are they torqued to and is there a tightening pattern?

Padraig

All should be the same, 25-30# tq, work inside to out.

O Reilly's but before that Mallory Marine in which was all made by Mr Gasket in Ohio USA in which all owned at that time by the same companies. I was dealer for Mallory Marine but Sierra bought them out about 2 years ago to get rid of the comp.


Like above said inside out but tighten in a 3 pass each bolt with torque wrench. run engine to full warm up then recheck torque specs. The a couple times per year check again.

Why I like these Mr gasket Ultra Seals - here is why.

Mercruiser OEm stock dry joint exhaust manifolds would blow the gasket in short order even within 30 hours of run time plus after replacing with OEM gaskets in about 2 or 3 years later would blow again. .

The Mercruiser OEM Dry joint exhaust maniflolds and risers are very heavy cast iron in which did not help either plus some not torqued correctly from factory when new shipments.

Anyways the 100s I have changed out in the past 7 or 8 years from blown OEM Mercruiser Dry joint manifold gaskets to Mr gaskets ultra seals - they have had no problems since - still going strong. I stick with what works for me and the many that I changed out. No bull at least well over 100 pairs I have changed over the years.

Second that on the Mr. Gasket Ultra Seals! I had a header loosen and the exhaust leak destroyed 2 spark plug boots and damn near caught my engine cover on fire! I did replace the gasket but the one that was on there showed absolutely no signs that it had been leaking. I expected to see it burnt away somewhat. Nope!! I have O-O-O-OReilly"s order them for me. Always have them in one day!.

Thanks everyone. I was in panic mode as I have the Seneca Lake Poker Run this coming Saturday.

I talked to Eddie Young and he recommends and is sending out a set of SS multi layer gaskets. He says they last forever and won't fail like my existing ones even if the header becomes lose. More expensive but sounds worth it in the long run.

I will likely have more questions as I get into this so thanks in advance!

Padraig

Yesterday was my lucky day. Only one bolt was a pain. Had to use open end, one quarter turn at a time. Gasket came off intact. Gasket at front cylinder eaten away, back cylinder not far behind! Bolts were not tight, me bad, should have checked at beginning of season. Will check stbd side.

Gaskets are scheduled to be delivered today.....Now if it only stops raining!

Padraig