28 replies to this topic

[Ferg]

Hi guys having trouble finding a 202 block to bore 30thou for a turbo rebuild. So the question is what's the differance between blocks, can i bore a 173 block and fit the 202 black crank rods etc. Blocks i've tried so far are all 40 - 60 thou already and there's plenty of 173 blocks around
Thanks Ferg

[Ferg]

Thanks Jeff pretty obvious now ..........red motor - red motor crank.
Blue/Black motor - Blue/Black crank.
I want to use the black crank so will have to keep looking for a good block
Thanks ferg

[debkar]

Thanks Jeff pretty obvious now ..........red motor - red motor crank.
Blue/Black motor - Blue/Black crank.
I want to use the black crank so will have to keep looking for a good block
Thanks ferg

Hi Ferg

I gave black 3.3 crank and rods in my 186 block, nice combination. Block says 186,

Regards Simon

[debkar]

Yep just get the mains journals turned down, could do the same thing to fit the crank/rods into a red 173 block, providing its a rope rear seal one.

On that note, i didnt think they made rope rear seal 186's? How did you do it debkar?

Cheers.

Gday Bomber,

The machine shop ground crank to 186 size for me , and I use a neoprene rear main seal. I'm not sure if 186 had rope seals either.

Also need to be aware that black crank has dowel to locate flywheel, (good idea anyway) but you either need to remove dowel, a black flywheel, or flywheel machined to dowel.

I used a blue flywheel as I think from memory, they are around same weight as XU1 red flywheel. I use red pressure plate and clutch, so had to get the flywheel drilled to suit the smaller pressure plate,

Regards Simon

[debkar]

Ok cool, i thought the cranks were different rope to neoprene as well, must be able to machine it to suit neo.

And yes, the dowel is a very good idea....keep it.

Cheers.

Yes, will do, added another as well, running two dowels on the motor,

[FastEHHolden]

And there is a neo seal to fit rope blocks...contact Rodomo

[yel327]

I don't believe that for a minute. 202 and 186 "sleeves" are definitely larger diameter than a 173 or 179, by how much I don't know. As Bomber says you can see it when you look at them. I certainly wouldn't be comfortable with a 173 at +0.185". I can't believe you guys can't find 202 or 186 blocks either. The damn things are everywhere. I'll see if I can find you one around here. Greg at ClassicOzWreck would have at least half a dozen of each in the yard, but as above they may all have to go at least +0.040. Does it have to be a red block or are you happy with blue or black blocks?I'm pretty sure there is even half a dozen of them up at my mate's place. We normally throw them away as no-one ever wants to even pay what they are worth in scrap! I used to see 202's still in cars at the scrap yard even a year ago (i've only ever pulled them out when they have had JP or NP numbers on them, even let a few lesser examples get scrapped like 2600S, JL and 186K).

Edited by yel327, 09 January 2010 - 06:57 PM.

[Heath]

I'm pretty sure the 'sleeve' of a 179 is the same as a 186, but I didn't think that 173s were the same...

[Stinga]

wasnt one fella on here with the hb taking a 149 block out to cop a 202 crank and pistons? could have possibly been a 161 i cant remember.

[greens nice]

wasnt one fella on here with the hb taking a 149 block out to cop a 202 crank and pistons? could have possibly been a 161 i cant remember.

yehp, dont know what sleeves he was using tho, whether it was bored past the cylinder walls and new ones sleeved in or not. Maybe uppo44 can shed some light? . there was a bloke from gympie that raced a grey motor in speedway, he reckons he could get 186 cubes out of a grey by using sleeves from some tractor, but then again its all just what one can lead another to beleive, whether its true or not, dont think it would apply to reds..
enough dribble.
ive always been told and beleived that the o/d of a 173 bore was unique like 149

bomber, if youve still got that 173 can u post up the measurements.

[Heath]

ive always been told and beleived that the o/d of a 173 bore was unique like 149

Yes, that was my understanding too, but I'm happy to be wrong!

[yel327]

Ok fella's i agree the bores do get thin but if you do a search on here this has all been run through before and all 173-202 blocks where cast with the same thickness and 161's down had there own.I have been playing with reds for over 20yrs and have already done all of this and am currently doing it now with a red 173 with 202 crank,rods and out 40" although the bore is getting thin i still have a few mill to play with after it was sonic tested after boring plus hopefully the grout fill will hold it or just resleeve the whole block and have thicker bores to start with.The blue 173(2.8) and blue 202(3.3) where cast in the same fashion and from what i have been told the early 2.8 has 186 size journals and some of the later ones had the 3.3 size journals.I will try and get some pics up once the block comes back from the engine builder and get the measurements of how much thickness is left for some info.Think about it though the HP(179) EH blocks where able to bored to 192 or 194 if you went 80" and these became the 179 from HD onwards.When holden started with the HQ they offered a 173 or 202 and from what i have been told and as mention in a previous thread these were cast with the same moulds and just bored to suit and had the main tunnels bored to suit the crank as the early reds had a 3 1/4in bolt spacing and the red 173/202 has 3 1/2in bolt spacing on the main cap so you can't use these caps on any early red as they don't fit.Anyway each to there ownopinion and i will agree to disagree but just trying to help out from my own personal experience.

Jeff

Jeff I may be wrong but I believe that no 173 ever got 202 main bearing journals. You may also be correct about the same moulds for 173 and 202 but I find that very hard to believe. It's certainly not consistent with most other GMH or GM engines of the era (like 253-308). Some of the Engineering changes would be applied to both (like cap bolt spacing) and this is certainly consistent with most running changes in GMH engines along the way ie whatever 308 got 253 got. Many of the external castings would be common too which makes sense.
You'll also find similarites with early SBC's - in the early days the blocks had thicker walls, so pre 1968 engines like the old 265 and 283 will both often take a 0.125" overbore, as does the McKinnon 307 used in HK-HT. However later blocks like the 302/327/350 and the 400 don't really like much more than +0.040, or max or +0.060 if you are lucky.
Also remember that GMH developed a new casting plant after mid 1967 and you'll find that blocks cast before this time are different, and I think one of those differences is thicker bores hence th old early EH HP blocks and later EH and HD 179 blocks being able to take big overbores.
It will be interesting to see the results of sonic testing. I'm certainly happy to be proven wrong.

[yel327]

Interesting. I will do some investigating this week...

[VitcLJ]

Group NC relaxed rules to allow the use of the 3.3 blocks (3.3 cast in side of block) due to the 202 blocks getting difficult to find in good condition. They are certainly (202's) getting a lot scarcer now, will soon be like the old greys and basically unobtainable from wreckers. Only old hoarders and enthusiasts will have them. Dont forget the last of the 3.3 blocks were cast in 1985 and the 202 were a few years prior to that so they are getting long in the tooth.

[yel327]

Not all 173s are the same. The later 2850 engines definitely had the bigger main journals. Bomber measured up smaller cylinder ODs on his red 173s but I always thought the late 2850s shared the same coring as the 202. And I seem to remember someone mentioning the regulations being relaxed (not sure if it was HQ or group NC or what now) to allow the use of late 2850 blocks because of the growing scarcity of useable 202s. Unfortunately I don't have one handy at the moment to measure..

Just found some specs. Johnno you are right, VH 2.85 blocks use 202 main bearings. Easy way to build yourself a 186 (ie 202 block, blue 173 crank) if you wanted to for some obscure reason! Looks like Starfires (at least VH series examples) use the same bearings too.