ok guys/Gals,

so, Scots engine is all together and we are starting to put on the intake and im working on getting the timing set, i go to put on the tensioner roller assembly and the little tensioner plunger, doesnt even fit close to the tensioner roller receiver. actually, its fits at about a 45 degree angle, so it doesnt fit correctly.
the blocks are the same (m28-11) and its the same tensioner we used on the other engine. also, the waterpump is the same as well. the water pump always had some funky shaft coming out of the waterpump that the tensioner idle roller fits on and then a little 10mm hex head bolt screws into it.

first of all, the entire assembly worked on the other engine! what could be different. were there differences on the blocks with the same M28-11 numbers? im wondering if we use the other type of main idle roller bolt , will the tensioner assembly sit farther in and then maybe it will line up?

the shop is kind of confused too. I think the waterpump is of the older year too, with the lower (non raised) shoulder for the idle roller bolt.

any ideas of why the roller assembly doesnt line up with the tensioner?

Thanks,

Mark (for scot)

 

Mark, I don't know the answer to your question. But I knew I had seen discussions of the differences. Maybe Garth will chime in.... meanwhile, check here and here.

HTH

 

wow, lots of info, but im still confused.

does scot have an early water pump with no raised boss area?

whats the long shaft with a threaded end to mount the entire tensioner roller structure? (the holbert uses the 84 style pump and tensioner i believe and it has a shoulder bolt)

and it looks like he has the early roller tensioner as the pivot hole is right on the centerline of the tensioner roller. this means the push rod is tilted toward the front of the car and also, doesnt even come close to being pushed in to be loose enough to fit the belt over the pulleys. this is what makes me think the block is different, but i know it cant be! (or can it) the thing is, it all worked on the other block, and why is it not working now!!!!!?????

so, will i (scot) need to buy or trade for an later tensioner, or get an earlier roller assembly?

confused,

MK (for scot)

ps as for reference, on the holbert car, i use the early water pump (84 style) shoulder bolt and the S4 tensioner with the bleeders. all of that lines up perfectly. should it???

thanks again!

 

Sorry, I don't know... I was hoping that seeing the pix of various parts would jog something. If the dimple in the arm is aligned with the center of the roller, then that is what garth is describing as a "later" unit. Your best bet is probably to call one of the big 3, email them the links so they can see the pics, email them pics of where you see the mismatch, and go from there. From what you're saying it seems that you have the wrong tensioner arm for your application. Pet shows part numbers 928.105.540.03 and 928.105.540.05 are both applicable for M28/11. Maybe there was a change mid-year, but you definitely need some expert help with this IMHO.

 

Hey Mark,
Could you snap some pics? - and clarify whether the water pump has a raised boss to contain an idler roller and shoulder bolt ... or is a S4 type pump with a threaded stud to pivot these parts.
The other critical dimension is to match the 'dimple' in the carrier arm to the centerline of the tensioner body: as you are aware, there are (too) many combinations! The key issue on tensioners is that slightly before the S4 ( '86 32v IIRC), the tensioner body centerline to block distance increased ~8mm .... so a match must be found in the position of the dimple in the carrier arm to allow the piston rod to line up.

 

Garth i think i understand now. All this came off the original euro engine we thought was built by greg brown, but we are not finding out, it may not have been.

the pump is S4, has no raised boss. it has the S4 style shaft that bolts to the pump, AND it has a tensioner roller assembly that has the pivot hole toward the outside (engine front) of the tensioner roller. the carrier part number is stamped with made in 04-86. part number ends in 489-18. so, its S4 as well. the tensioner is old. allen fill caps, etc. the pivot shaft angles toward the front to meet the carrier assembly. CLEARLY wrong, but it can work if someone didnt notice it. I didnt notice it, as the angle is not that clear when the piston is way back in the tensioner and you dont see much of that little shaft. anyway, it was a miss match. The only way out of this, is if we can find a S4 tensioner!!
RIGHT?? otherwise, we need to replace the pump, get the shoulder bolt and a new carrier arm with both rollers!!!!!!!

Hopefully, anderson will have one and be able to trade us for the stuff that came on the engine.

Thanks for the help.

any comments or suggestions if Mark A . doesnt have one?

Mark K. (again for scot)

 

Yeah, you're on track! The easy way out could be the correct carrier arm, as can be seen in the posts Dave referenced .. but there is not a clear p/n to identify the correct piece - so it's a question of digging up the right one.
The better option is the 'S4' tensioner: they are fitted with the brake bleed screws vs the allan cap type, and effectively line up the tensioner centerline, rod, dimple and TB centerline in the same vertical plane. This minimizes any twisting on the pivot pin, which the bushings prefer . You might also want to add the $10 cross brace from the pivot stud to the water pump - to further stabilize the carrier & roller.

 

It's going to suck, sorry to say, for you guys doing this work I've been through this. Euro engines and S4 tensioner parts do not like each other. I did it, but needed to modify a bunch of stuff including the belt covers.

 

Options are:

S4 tensioner, idler/arm and pump with screw/brace and S4 roller. And modified Euro driver's belt cover with S4 centre belt cover
or
Euro parts which have to be all euro or older style, including parts mentioned above.

 

Great!! Im worried now about the tensioner issue with the cover. so , the main cover wont fit right now? I sure would hate to have to go after a new water pump, shoulder bolt and entire tensioner roller assembly as well.

since we already have the S4 pump, with all components except the tensioner, can we just cut things or modify them to work?

MK

 

this car has run with the driver side cover and center cover. if all we change is the tensioner, wont that only effect the passenger side cover, if at all? as long as that little hole lines up with the tensioner, right??? however, i stripped mine with the Holbert S4 and the cover just sits against the tensioner and is held in place by the other 3 bolts in the center area ( that 13mm bolt is missing now and its not an issue)

mk

 

tensioner is bigger, so centre cover won't fit - pump different so centre cover will grind on the roller of the pump. this can heat (and did in my case) the pump and cause pump failure. now, the S4 centre cover won't fit the euro driver's side cover because it expects an S4 (with a distributor hole) unit, and that is made of aluminium and not plastic. So you have to cut the Euro's driver's cover to fit.

tensioner and roller arm must line up (same kind).
centre cover must be S4 for S4 pump and tens OR euro (both)
for S4 centre cover, must modify driver's cover.

I recommend you find a euro tensioner, pump and arm and call it good.

 

but this engine already has a center cover that worked with this pump and didnt rub (as far as we know, good point though)

we may have to grind down the center cover where mates near the tensioner. then, we can still use the PASSENGER( passenger right?) side cover!

I think we will give that ago, and see how it looks. the pump direction will be too expensive to change, plus, anderson is helping out to fix the mis matched parts that came on that doomed original euro engine! hey, just thought of something, since its euro already, maybe it will all fit!. (unless this was a set up that used a lot of the US stuff, which it sure looked like when it arrived!

mk

 

As long as you look carefully, you should be able to detect parts that rub/misalign.

 

Hmm ... well, there are differences in the pump exterior too. For instance I think the mechanical fan cannot mount to an S4 one. I may be wrong, but I assume you are using an electric fan anyway ...