auto2

I had the piston/sleeve pinched by OS rocket and now after a gallon plus of fuel it still has a serious pinch when cold.
If I use 2 fingers on the flywheel I can turn it past TDC but it is not easy.
If starts right up and idles great has fair power but wont rev up.
1/2 way down the straight it sounds too rich and boggy.

problem is it is temping out at 260-270 and I don't think I should lean it out any more.

I would say it has 2/3 the power of when it was new.

you think it just isn't broken in yet?

I did install a new rod and I'm wondering if I should change it after this kind of a break in.

BTW I did preheat it to 200 degrees for the first 1/2 gallon.
also run 30 percent with the extra head shim.


I'm starting to think getting a sleeve pinched is not as cheap as it sounds.
25 bucks for the pinch .then 30 bucks for fuel to break it in- plus wear and tear on the buggy plus my time>..hummm.

redheat8

well purchasing a new sleeve would have been the key, but you didnt , how many shims are you using one should be plenty as you already no I'm sure the more you add the more conpression you get and by doing that you change everything , I wouldnt spend to much time messing with it and instead purchase a new sleeve , or even engine , RED

auto2

no wrong. more shims = less compression.

my other engine is an RB and i'm thinking to keep everything the sameI'm going to sell the OS on ebay and get another RB.

anyone want to but this VZbp??:-)

I justthink it's not quite broke in yet and need a little more running. because I always preheat it it is just taking a long time to run itself in.

other opinions?

redheat8

You are so right and for my mistake I apoligize, more shims less compression, and less== more thanks for bring that to my attention, RED

auto2

just wanted to give you guys a little update here.
I run blue thunder race 30 and was adding klotz 7 OZ to a gallon to bring up the oil content to OS recommendations.




well I got tired of this engine just not runing right and put in stock fuel( no extra oil) the other day and after 4 tanks it is now running like new!! pinch 90 percent gone.
so what do you think? the klotz was preventing it from wearing in?
now that it is broke in should I go back to the recommended oil percentage? Hummm.....

Frost_

My Feedback: (1)

Sounds like it was over-pinched.... that would also be what's wasting that 1/3 you are missing of power..., the force needed to constantly overcome the pinch at TDC.

auto2

yes your right. the point here I was making is the klotz is such a good lube that the piston couldn't break itself in even with too much pinch until I ran it without the klotz. Unless it was just a coincidence.

Frost_

My Feedback: (1)

you may well be right....

Some friends of mine in high-school were building a sweet stroked-small-block.... They used the slick50 additive right off the bat....

200 miles later they had to TEAR IT BACK DOWN, replace the rings and RE-HONE the cylinders!!! The rings just wouldn't seat. The back of the slick50 can tells you not to use it on a new engine; I guess that's why....