MFranke

I noted an earlier discussion on these boards about a design change for 1988 that included better cam end plugs with metal pins inside. For 1987 the plugs were apparently just plastic, which failed, and the field fix was to install plain aluminum pins. The idea I got from reading about this was that backfitting plain aluminum pins may not be needed for 1988 and above, so maybe folks with 88s and above are leaving the original plugs there.

FWIW on inspection I noted some of the original plastic plugs in my 88 were gooey and they deformed when handled. These old plugs did however have metal pins in them. I replaced the plastic plugs with plain aluminum pins anyway so I wouldn't have to worry about the plastic plugs deteriorating further. Maybe this means I'll get more of a challenge to the end caps for leakage because the plastic plug is not there, but then again by not having the plastic there maybe the oil will drain more freely back to the cam housing and not sit at the end. Either way, its better than worrying about plastic pieces getting into the oil channels.

Mrmerlin

if you have the old style rubber plugs with the metal pins in them,
they should be swapped out for the aluminum dowels,

NOTE once a rubber plug type falls out you will lose oil pressure,
and possibly damage the bottom end as well as starve the valve train

GregBBRD

I'm not sure your information about when the "rubber" pieces were changed to the aluminum rods is correct. I think I first saw the aluminum rods in the GTS engines.

At any rate, the two pieces function exactly the same. The "rubber" plug style had a small "rod" sticking out of it, to block off the oil. The rubber didn't seal anything. It simply supported the small pin and kept it in the hole. The aluminum rod does the same amount of "pluging"....and can't fall out, because of the cam caps.

I'm sure that when whoever redesigned the rubber plug to a simple aluminum rod, there was a collective "duh" (in German) that went around the engineering table.

Vilhuer

Only GTS got alu pins from factory. Difference between '87 and '88 is that '87 heads have smaller holes and alu pins will not fit without modification. Can't recal when exacly change was done but in early '87 at least pin needs to be modified. Some earlier thread has more precise info about head change time.

Hilton

Must have been very early '87 -RoW #1022 didn't require modifying the pins to fit the journals.

17prospective buyer

Lol Hilton, so you're the one hogging all those desireable sunroof deletes!!

ROG100

Erkka - no mods needed to pins on early 87's here either.

Vilhuer

OK. So its only some of the first 2300 '87 engines made (5sp number started from 00501 and automatic from 05001), not all of them. In any case its good idea to at least mentally repair for pin modification if engine number is earlier than those two. I have seen two engines like that. Which is 100% of the sample of early '87 engines I have seen. Based on on your info it goes down to 50%?

jayc67

Thanks for the drawing, I was just trying to find the part numbers.

Vilhuer

GTS pin part number is 928 105 262 00. Its only one still available unless someone has old rubber stock from '91 or before. Five (5) pins needed contrary to what factory document says.

Hilton

That bulletin states "Some engines use 3mm diameter guide pins (the new size is 3.5mm diameter). On these engines new guide pins have to be reworked to 3mm diameter."

However, when it says "new" its talking about the new longer-pinned Rubber part - so it seems that even before then, there was a mix of journal sizes.

My engine is #00675 in Vin serial #1022, and has the 3.5mm diameter journals (the GTS metal pins fit with no modification).

0.5mm bigger is a lot of cross sectional area to be adding (37% more). Were they chasing oiling problems that early?

Vilhuer

There is early and late style rubber part. Early style had short 4mm visible metal part which goes inside head drilling. It was changed to 9mm long so that it stays on better. In early heads same 4mm rubber version was used in both 3mm and 3.5mm drilled heads. If they just had extended metal all the way to the top end of rubber piece it would have solved whole problem in February 1987. Though rubber part was too complex anyway as GTS all metal pin demonstrates.