Distributor installation – is this right?!

[ESGWheel]

2005 5.0 GXi-E. This one has me confused and unsure if something is wrong. I had the original distributor out (for various reasons) but when reinstalling it with a new gasket I noticed the base of the distributor where it seats onto the block had a slight gap. About a 1/16”. The distributor was properly aligned and engaged with the oil pump. This was validated by first - it goes in - but if move it one tooth in either direction you can feel the shaft's tang hitting the oil pump and the distributor will not seat by about 3/4” or so. Everything about the original distributor is original (except cap and rotor).

As far as I know at the bottom end of the distributor there is not a ‘stop’ > the hollow distributor gear engages the cam and surrounds the slotted shaft fm the oil pump where the tang on the dist. shaft engages. I.e. the distributor shaft tang in the oil pump shaft’s slot does not ‘bottom out’ and the bottom face of the gear does not hit the top of the oil pump. That the only thing that stops the distributor from being inserted more is the flange on its housing checking against the block.

Thus, my surprise when it simply did not drop into place and fully seat against the block even when pushing it down. So, I pulled it out and installed a 2nd new gasket that took up most of the gap. And while perhaps not the smartest thing: I installed the clamp and noted the distributor firmly seating against the block. Started it up > ran great with expected oil pressures.

What am I not understanding?

 

[Fun Times]

In the following link by Don S, click the HVS pdf attachment file as it is a guide of how to install the Volvo Penta distributor.

Mecruiser 5.0L MPI distibutor proper clocking?

5.0L MPI Engine Serial OM618927. read a service bulletin on my issue of a miss fire at higher loads. It also stated to rotate the distibutor 1-2degrees if the issue persisted. I did this and the problem got so bad that at about 2500 RPM it misses so bad it sounds like the ECU is reducing...

forums.iboats.com

 

[ESGWheel]

FT,
Thanks for this, My clocking it 100% correct. My concern is the fact that the distributor did not fully seat on the block as expected. As if something was causing it to be slightly lifted off its flange. It did fully seat when clamped using the 2 gaskets but I am fearful that I am bottoming out some other component, like the bottom of the dist. gear against the top of the oil pump housing, which will rapidly cause metal shavings to happen.

It simply does not make sense to me and without being able to see what is causing it to be every so slightly lifted – since there should be nothing - has me scratching my head. In my mind its akin to putting on a tire on a car and the rim does not fully seat against the hub ‘by hand’ until you tighten the lug nuts – something must be between the rm and hub. And I did look inside at the pump / cam gear to see if anything got dropped in there > nada.

 

[stresspoint]

i would not run it like that , reason being is the distributor should drop all the way down without a gasket , so using 2 gaskets means ""as you stated "", something is going to bind up and grind away .
the dizzy could have some crud in the oil pump drive area ?? .

now that you have started the motor , it might pay to remove the dizzy and try again without a gasket , post back outcome .

there is not a lot that will cause the drive on the camshaft to not align so as the dizzy wont drop in , so i would concentrate on the oil pump to distributor mesh points.

 

[Bt Doctur]

why did you pull it and what work did you do on it?

 

[alldodge]

FT,
Thanks for this, My clocking it 100% correct. My concern is the fact that the distributor did not fully seat on the block as expected. As if something was causing it to be slightly lifted off its flange. It did fully seat when clamped using the 2 gaskets but I am fearful that I am bottoming out some other component, like the bottom of the dist. gear against the top of the oil pump housing, which will rapidly cause metal shavings to happen.

Guessing
The oil pump and shaft is connected together with a retainer (item 5). The retainer in most cases is nylon and both pieces sort of snap together. Maybe when Dist was removed it slipped up a tad. Could prove out the theory by taking something like a screw driver and tap the shaft down with a rubber mallet
https://www.mercruiserparts.com/bam/subassembly/31852/12840/140

 

[ESGWheel]

Some will remember that 70’s commercial where the guy slaps his head and says, “I could’ve had a V8!” A sort of ‘duh’ moment. In reading StressPoint’s post about ‘pull it out and have another look’ was a ‘duh’ moment for me. I’ll do that to see if anything shiny or curd. So, thanks Stress!

Doc: pulled it to replace the aftermarket one I put in last season. My original one had the classic stripped out thread for the cap hold down screw (due to plastic housing). While only one side and did work, was not right and made me nervous. Looking around for a fix I got enamored by the glitzy 'aluminum billet’ marine replacements out there and got one, installed last season and ran all season, no issues. But at same time was trying to understand about electrical boat components being J1171 compliant. Upon inspecting the OEM distributor I found small vents in the housing with a screen mesh over them and deduced this was want makes it J1171 compliant. See post: link. Did the aluminum billet have same? Thus, I decided to repair the original one and swap it back out and inspect the aluminum one and post my finding which is still to be done.

AllDodge: Thanks for the suggestion, I will use a scope to check this out along with anything else that may be interfering. I hope to be able to get to it this weekend as we are only a few weeks away from launching!

 

[stresspoint]

any outcome / solution yet ???.

 

[ESGWheel]

any outcome / solution yet ???.

Unfortunately, not yet.
While the weather has cooperated during the weekends, my body has not. I have had some issues with my knee the last few weeks and a recent MRI has revealed I have a crack in a critical weight bearing area – very painful! So now I have a boat with a suspect distributor install, the Risers and Manifolds off with new ones sitting in boxes along with a new radio to install as well. Target date for boat in water is 18 May but the season may be shot.
;-(

 

[ESGWheel]

Well, this is one of those cases where I must have been seeing things. I got back to this ‘issue’ and pulled the dist. and did a through inspection. No shinny areas where there should not be indicating something rubbing that should not be. A scope inspection of the hole showed all is as it should be. Confused I took off the gaskets and dropped back in the dist. It seated on the manifold as expected. So unsure what I was seeing before. Put it all back together and all is good. Thanks to all for your suggestions. I am chalking this one up to OMS (Old Man Syndrome).