Holley Sniper 2GC to 2F Install using Mosley Motors adapter

[charliemeyer007]

Cheap and effective is to do a dry then wet compression test on all cylinders. +1 for hearing valves is way better than burning them.

A crack in the dizzy cap can short out one jug, can be very hard to detect. Scrape the contacts inside the dizzy with a knife, small blade on swiss army knife is perfect for the task. Aluminium oxide build up on the post is an insulator. Pull the plug wires from the cap - clean and inspect the inside of the cap and the contact on the wire. Look at the boot end too.

 

[cruisermatt]

Do you hear the two “jumps” in the sound of the compression when it’s cranking? It sounds like you have two cylinders without compression, and a 2F can actually run ok on five cylinders. But four cylinders will be pretty poor. Would also explain by it’s been getting worse out of nowhere.

Hopefully just a blown head gasket between 4/5 or 5/6.

 

[desmocruiser]

Apologies for the dumbA$$ ness but, here is TDC? Correct?

And the clearance can now be checked on these valves? Correct?

 

[charliemeyer007]

If the valves on #1 are both loose its TDC. With dizzy cap off the rotor bug will be pointing towards #4 spark plug.

 

[desmocruiser]

Thanks.

Haven’t pulled the cap again, it is. DUI distributor and I assume the same orientation plus a PIA to get back on.

I stared to doubt myself when the tolerances are too tight for either the appropriate Intake or Exhaust gauges to fit any of the valves that are marked to be adjusted?!?!

 

[charliemeyer007]

I just pull all the plugs, set #1 to tdc - check/adjust. Grab metal fan and pull up watching threw the next in order spark plug hole with a flash light to see the piston come to the top - check and adjust. 1. 5. 3. 6. 2. 4.

 

[cruisermatt]

Thanks.

Haven’t pulled the cap again, it is. DUI distributor and I assume the same orientation plus a PIA to get back on.

I stared to doubt myself when the tolerances are too tight for either the appropriate Intake or Exhaust gauges to fit any of the valves that are marked to be adjusted?!?!

You can be at TDC #1 on either the compression or exhaust stroke. As Charlie said both rockers, and all the others pictured, should have lash (loose) when #1 is at TDC on the compression stroke.
Regardless, I think you're working a bit backkwards and should compression test before going further. Maybe I should have been more explicit in my previous comment about how it sounds during cranking.

 

[zerotreedelta]

Agree, there does seem to be a bit of a gallop while cranking. Curious what both a compression test and the lash show.

 

[desmocruiser]

You can be at TDC #1 on either the compression or exhaust stroke. As Charlie said both rockers, and all the others pictured, should have lash (loose) when #1 is at TDC on the compression stroke.
Regardless, I think you're working a bit backkwards and should compression test before going further. Maybe I should have been more explicit in my previous comment about how it sounds during cranking.

Thanks!

If I am correct and the mark I pictodenotes TDC ( that is where I thought Lash should be measured), there is none. The valves are so tight that a feeler gauge will not fit under the tip of the rocker.

I will test the compression next.

 

[Jdc1]

Thanks!

If I am correct and the mark I pictodenotes TDC ( that is where I thought Lash should be measured), there is none. The valves are so tight that a feeler gauge will not fit under the tip of the rocker.

I will test the compression next.

That might be exhaust TDC- you want to be on Compression stroke. Rotate 360* and see if the pushrods are loose.

 

[Augustiron]

Rotate the engine by hand and watch the number one intake valve open, and then close.
When it is closed, rotate the engine some more and the next TDC Mark will be TDC of number one on the compression stroke.

Yes the line you have shown in your photo is TDC, the BB is 7° BTC
But there is no way for us to know if it is TDC on the compression stroke or the exhaust from the photo

 

[jembourbe]

That might be exhaust TDC- you want to be on Compression stroke. Rotate 180* and see if the pushrods are loose.

Rotate the crank 360° till the line comes back to the window.

The crank rotates TWICE for every ONE rotation of the cam. So the crank can be at TDC, but the cam is only halfway there

 

[desmocruiser]

Here are the Compression test results, I am guessing that it is not going to yield positive news. The #1 and #2 that show zero pressure, is also accompanied by a different sound that sounds like air releasing from elsewhere. I will upload a video of 1-3 to compare.

1-6 respectively

0
0
130
120
120
130

 

[FJ60Cam]

This could be good news if you want it to be, likely the head gasket blew between the cyclinders. Best way to fail

With those compression numbers I’d pull the head, clean the decks really good, reinstall with a new gasket, peel out (ie, not spend $$$ on a head rebuild)

 

[desmocruiser]

#3 Cylinder - https://youtube.com/shorts/puU5Bsl-TXU?feature=shared

 

[desmocruiser]

This could be good news if you want it to be, likely the head gasket blew between the cyclinders. Best way to fail

With those compression numbers I’d pull the head, clean the decks really good, reinstall with a new gasket, peel out (ie, not spend $$$ on a head rebuild)

Thanks Cam! I think that is the best possible news!

 

[charliemeyer007]

Was that dry compression? Do it again wet. You have the valve lash set correctly?
Perhaps there is crud/deposits on valve seats. With engine running strike the rockers in line of action with a lead hammer - bumping open the valves in compression cycle can blow the crud off.

I would pull the head. You can use valve grinding and hand lap them for almost free. If your rings/bore is shot - this isn't going to fix that

 

[rlong]

Agreed.. 0, 0 adjacent very likely “just” head gasket! Good news!

 

[jembourbe]

I can't believe the engine ran so well on 4/6

 

[Augustiron]

Likely head gasket, but what about valve lash on 1&2?

If somehow the valve lash is extremely tight, and the valves aren't closing, you're not getting real numbers.

Valve lash, then compression test.

Looking at your screen name, don't worry the 2f valve adjustment is much easier than a desmo Ducati