Bent Valves, AGAIN?

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wikd69
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Re: Bent Valves, AGAIN?

#31 Post by wikd69 » Tue Oct 11, 2011 12:21 pm

Ls7camaro wrote:Guys, thanks for all the input.

Here is what I found / did. First, Disassembled everything to the short block. Sent the heads back to PA with my dad to a machine shop his friends use. The Valve to Guide Clearance needed to be "Opened" up a bit on the exhaust valves. Once that was done, heads have been re-assembled, and then the shop checked the amount each valve was in proportion to each other in the heads. I re-assembled everything, but in doing so, used "Silly Putty" to measure the Piston to Valve Clearance, when I cut the putty and the lowest level it was .051 thick, so with the head gasket, .039 compressed, gave me .090 and then the valve lash was .028. So I am good there.

I just took the car to Dragway 42 on Sunday Oct 9, the car ran really good 11.66 @ 115mph, the car does pull to the drivers side and launches really well, right now there are drum brakes on the front and rear, and the sloppy steering, any suggestions on how to fix that would be GREAT. Now, if we put Disk brakes on the car, do you put them on the front or rear(bigger tires, more stopping power?) The car needs some tweaks and some prettying up, but with some fine tuning all the way around, I am thinking this car should be in the 11.30 to 11.40 range.

THANKS Everyone for all your Advice and Help.
Wow, you've been busy !!!! So did you determine the guides were too tight ? Is that was the problem was ?
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

Ls7camaro
Posts: 113
Joined: Tue Mar 25, 2008 11:31 am
Location: Medina, OH

Re: Bent Valves, AGAIN?

#32 Post by Ls7camaro » Tue Oct 11, 2011 8:42 pm

I think that valve to guide clearance was part of the problem, the lash was wrong, the guy that built the engine gave my dad a set of lash #'s .012 and .014 and it was supposed to be .028 and .030, so that could have been part of the problem, I also put the cam straight up, it was advanced. Also switched from an HEI distributor to a MSD distributor, I know that didn't do anything, but the car ran way stronger. This was the fastest the car has ever run. I really do think there is another couple tenths shaved off by tuning. I ran the slicks at 12lbs of air, using multi leafs with a extra ply and South Side Machine bars.
I can't wait for race season, this has got to be the year.

Ls7camaro
Posts: 113
Joined: Tue Mar 25, 2008 11:31 am
Location: Medina, OH

Re: Bent Valves, AGAIN?

#33 Post by Ls7camaro » Thu Oct 13, 2011 12:05 pm

The Problem? I know the engine shop said the valve to guide clearance was too tight, so that very well could have been the problem, it binding the valve that bit of time and then the piston making contact. I think the head gasket now is just .009 thicker compressed. Just think there where too many cooks in the kitchen.
I can't wait for race season, this has got to be the year.

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