1949 Dennis F1 Fire Truck Restoration

I'd prefer WD40 any Day. But it is not 1 of the more popular Smells with the Girls.

I dunno .. a dab of the old 90EP gear oil, behind the ears, gets the right "man scent" about ya, every time ..

It usually comes about, when ya need to swat an annoying insect, right after you've accidentally poured some 90EP, over your hands ..

A progress report on Dennis ...

I tried to remove the broken bolts from the block today, using the MIG tricks given by bigcam and loadstar. Firstly, building up with the MIG as bigcam suggested, all was going well until I tried to unscrew the bolt ... no way was it going to move. Tried a few times then changed bolts, but all that happened was the weld twisted off before the bolt turned.

OK, now to try loadstar's trick. Welded a nut on to the broken bolt and same same ... before the bolt turned, the nut twisted off. These bolts look like they have bonded well to the threaded hole!

Drilled another one and tried an ezyout. At about the time that I crossed my fingers, the ezyout snapped. Bugga - that's now hardened steel stuck in the hole! Luckily, the side-plate bolts go all the way through into the water jacket, so I sat a nut over the broken ezyout on the outside, and clamped a pair of vice grips through the access hole in the block and on to the ezyout on the inside. Bit of a twist clockwise, and with a "bang" the ezyout shot out.

So I decided that I'll drill the bolts out, and upsize the new bolts to 5/16" as onetrack suggested. I'll move away from the BSF tread to UNF, so I can use stainless steel bolts. At least I'm sticking to imperial!

Now to sort out the side cover plate. Apparently the existing plate can't be metal-sprayed, as it is mild steel and the heat will distort the plate, rendering it unusable. Looking at the pits, I would be reluctant to try and fill them with bronze, as I'll end up chasing the holes all over the place. And the other pits may very well hole through in a couple of years time. The two holes are showing in the photo at the top right and bottom centre



Time for some more lateral thinking methinks! I made up a new side cover plate out of 200 x 5 flat bar (190 x 160), and have drilled it to the bolt pattern of the original plate, to suit 5/16" bolts. When it all goes back together, I can sandwich the new plate between the block and the original plate, using 3/4" long bolts instead of 1/2" ones used originally. The new plate will be in contact with the coolant, and the original used just to look pretty from the outside. Both can have an anti-rust treatment before final fixing, and I can drill through the old plate and tap a thread into the new plate for a water temperature sensor.

So that's the plan. More to follow ...

Bugly, see if you can get some 2 pack epoxy paint and do the covers in that gear, no more problems after that.

Thanks bigcam, I'll do just that. I reckon that'll sort it out for the next 300 years!

Bugly- How deep is the dish in the plate, and is there any reason why it has the dish in it?
It seems a little odd for you to be able to fit up a flat plate, when the original was dished. Just makes me wonder, why it had the dish originally?

Cheers - Ron.

Gidday Ron -

The dish is stepped about 3mm on 2mm plate. All it does is cover the hole, so the only reason I can think of is that it is stepped to create some strength around the flange part. If it didn't have the extra strength given by the step, Mr Dennis and his brother may have had to increase the plate thickness to make it stronger.

I bolted the new plate up to the block this afternoon, and although it sits beautifully and is obviously much stronger, it doesn't look quite right compared to the original plate. That's when I decided to bolt the two plates on and use a slightly longer bolt. :

The earlier engines had a brass plate, which was flat.

Hi Bugly, if you are tapping a thread into cast iron you should make it UNC. If the threads go into the water you can coat them with a sealer used on holden head bolts.I can't remember what the stuffs called but it works well.

Hmmm ... thanks Paul (I think!)

My concern with UNC would be that the block is only perhaps 10mm through from outside to the inside water jacket. Would a course thread give enough 'bite' in 10mm? A 5/16" UNC bolt has 18TPI, as opposed to 24 TPI with 5/16" UNF. At 10mm, that's 7 threads of UNC or 9.5 of UNF. Might be enough (thinking out loud).

I'll have to throw this open to the forum for comment ...

Tonights question ... should I use 5/16" UNC or UNF bolts tapped into a cast iron block where there is only (say) 10mm between the outside of the block and the water jacket on the inside? Stainless steel bolts will be used either way.

All comments muchly appreciated!