Webber Carburetors

[dat240z71]

I'm an issues with the # six cylinder. My carbs were work good before I pulled them of to replace a bad head gasket. After installing the crabs. I notice the car was missing on the #6 cylinder. Pulled the plugs and 1-5 was nice and " brown" but plug on # 6 was wet and fouled. I bought a new plug and replaced it car idle and ran great until # 6 plug fouled and gain in a few miles. I puled the plug out of #6 and grounded it on the shock tower bolts and confirmed that there was spark at the plug. I replaced the wire on #6 just in case. The plug still fouled out. I then lean out the carb on # 6 still the plug still fouled out. I stitched out the plug from #3 and #6. . Drove the car  same result run good until the plug in #6 foul out. I turned the mixture screw all the way in and the plug ids still fouling out. Any ideas what I can check next. No issues befor the headgasket blew. I have had the car three years, this is my second driving season with the new engine

N42 block with flat top pistons. .020 over

Port and polish N42 head

Webber 45's " Carbs were new at the time of the build Two years ago

Robello 3'0 tight lash  street cam. I don't have any spec. on the cam. Robello won't  tell me

MSA six into two header.2.5" exhaust.

3k miles on rebuild.

Just did a compression test. 120 PSI on 1-4 and 100 psi on #5 &6

 

Edited May 19, 2019 by dat240z71

[Patcon]

What weber carbs? What are their history? You didn't have this issue before the head gasket? How long have you had the car?

[Mark Maras]

Those compression #s should be 165 or above. Are you sure the valves are adjusted correctly? Just reread your first post. No specs on the cam? As in no lash adjustment specs?

[dat240z71]

.007 is the adjustment for the lash both intake and exhaust is what Rebello told me.  He also said to  adjust at the lash not the traditional way at the bottom of the lobe and the rocker are surface.  What I ment Robello wouldn't tell me anything about the Duration/Lift. Just that this is one of the cams he use in some of his 3.0 engines. 

Edited May 19, 2019 by dat240z71

[jonbill]

Maybe there's nothing wrong with the carbs and the new HG is leaking coolant into #6

[dat240z71]

Just got done adjusting the valves,  all the clearance were too tight, couldn't get the .007 gauge bottom of the lobes and the rockers. Set both intake and exhaust valves at .007 now the compression has gone up to 150 psl on all cylinders. Tomorrow I will go for a test drive 

Edited May 19, 2019 by dat240z71

[dat240z71]

Hey guys what's the correct procedure to perform a compression test. I may have doing this wrong. The way I been doing test is removing one plug at a time and depressing the acellarator peddle then crank the engine, but this was on a cold engine.  I read the engine has to been up to operation temp and all plus out.   Is that the correct procedure?

[Mark Maras]

 150 psi is better but it should be a little higher. Is there any valve noise (clatter or clicking) after the last valve adjustment? If not, I suspect the valve adj. is still too tight.

 I pull all the plugs during a compression test and hold the throttle wide open. After checking all the cylinders, recheck the first two again. They will usually be higher the second time around due to oil circulation.

[dat240z71]

Well do,  report back 

[dat240z71]

Well Im afraid things have gotten worse.  Took the car out to get the engine up the temp to perform the compression test,  after a couple of miles started to hear a rattling sound from the engine.  Got home pulled the valves cover and found one on the lash pad felling out of thr retainer.  Tried to put the lash pad back but the opening in the retainer is damaged cant get the lash pad bach in. Is it possible to replace the retainer with the head on and the camshaft still in place, or do i have to pull the head yet Again 

Edited May 19, 2019 by dat240z71

[Mark Maras]

The retainer can be replaced without removing the head.  Same procedure as changing valve seals without removing the head. One of the members will report on the brand and model # of the valve spring compressor that is used. I've got brain fade.

[dat240z71]

After fixing the retainer, I did a compression test the result was 

1. 150

2. 150

3. 165

4 165

5 145

6. 145

Installed the plugs started the car and ran worse. Missing and popping out the intake.  Check the carburetors with the "snail "1-5 pulling the same amount of air, #6 was a little off at 4 . I thought the poor   was due to the fact the valves were now set correctly and the compression has risen, I should retuned the carburetors . Now the backfireing louder, at times flames would pop out the front two crabs and backfires out the exhaust, a few times it sounds like gun shot.  After all I still have the original problem #6 plug is still wet.