Rocker arm falling off

[Vigo]

I've been messing with my tbi-piston van a bunch lately and it only seems to pick up knock counts ~2 psi earlier than stock turbo pistons on an otherwise stock setup. That's with a fairly serious compression ratio increase. With stock overboost in place I don't think it would ever even break. I don't think a shaved head is really worth worrying about unless you are trying to make serious power.

[turbovanman²]

The shim works fine, used one in my TIII with lots of boost, held just fine. Copper spray and bolt her down.

[135sohc]

Ok so 1 week in service and all hell broke loose this morning... Engine was bucking and breaking up, cut off twice. Hoping its just the hall effect deciding to be a POS.

[wheming]

I've used a copper shim on my spirit for 20 years. Never blew a headgasket on that car and used to run 25psi all the time racing, and have also on the street. The can be mounted above or below the headgasket, see it both ways. I had mine on the block side.
Or, if you are doing studs, you can just get one of those thicker Cometic gaskets, if it works out to be the correct thickness for the compression you want.

From your other update about the lower compresdion in one cylinder, i wonder if you have cracked one of your rings?

Sent from my SAMSUNG-SM-G870A using Tapatalk

[135sohc]

Not to count anything out yet but I am thinking #4 does have a broken top ring, its been suspect for awhile now and with the higher compression on 1-3 now its just that much more sensitive to the difference in cylinder pressures. They were expensive but those ARP studs are awesome.

[minigts]

What's happening with this? I missed the thread originally, but now curious as to what the issue is? Good luck with it though!

[135sohc]

The current issue ~I think~ is the now higher compression on 1-2-3 from the head getting resurfaced and the lower compression on 4 because of a suspected broken ring is causing an in-balance and the engine cannot compensate when placed under certain conditions like stop and go driving and extended idle time.

[cordes]

The current issue ~I think~ is the now higher compression on 1-2-3 from the head getting resurfaced and the lower compression on 4 because of a suspected broken ring is causing an in-balance and the engine cannot compensate when placed under certain conditions like stop and go driving and extended idle time.

At 313,00, are you thinking of a rebuild?

[135sohc]

It was already redone at 260. Then this little hiccup occurred and its just dragged out... Got a ball hone and a leakdown tester. Along with two sets of moly rings and 2 sets of rod bearings. Worst case I'll re-do all 4 pistons if the leakdown is bad, otherwise just #4 and keep on racking the miles up.