castlesid Kevin Jackson Sidcup UK (361 posts) Registered: 11/18/2007 10:38AM Main British Car: 1975 MGB GT Rover V8 4.35L |
Buick 300 Crank.
Can anyone tell me, that if you use the 300 crank in the Rover 3.9 block, how you deal with the additional length of the crank at the flywheel end, in respect of mating to either the LT77 g/box or possibly the ZF autobox.
Kevin. |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Buick 300 Crank.
Kevin, Is your 3.9L set-up for 2.3" mains? If so , you going to bore to 300 size or grind journals to 2.3? I believe 300 crank is drilled deeper than Rover. Length difference is .5" max.? Most of these combo's will nest ok with 6" bell housing depth, except Ford manuals,(longer input). Seems like a 4.6 crank might be less work and you get a 1 pc. rear seal. They will off-set grind to a 3.3" stroke, with a 2.1" dia. rod journals,(stronger). Hope this helps, roverman.
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castlesid Kevin Jackson Sidcup UK (361 posts) Registered: 11/18/2007 10:38AM Main British Car: 1975 MGB GT Rover V8 4.35L |
Re: Buick 300 Crank.
Art,
Very helpful, I was asking as questions on how to stroke a Rover or Buick for that matter regularly come up and although you can buy a kit off the shelf they are somewhat expensive at £1500 - £2000 depending on piston and rod spec. i'm not planning to do it myself as I've only recently built a 4.35 using 77mm crank,5.85" chevy type rods and KB hypereutetic pistons, I am very happy with the way it runs, with the Crower 50232 cam and modded big valve Buick heads it really likes to rev. I'm guessing it has around 260 BHP but will get it measured once fully run in. Kevin |
NixVegaGT Nicolas Wiederhold Minneapolis, MN (659 posts) Registered: 10/16/2007 05:30AM Main British Car: '73 Vega GT 4.9L Rover/Buick Stroker |
Re: Buick 300 Crank.
[www.aluminumv8.com]
D&D fabrications sell a flywheel that takes up the difference in the length. Works great. The 2.5" mains are an issue. I guess you have to machine the crank and reharden the runs. The alternative is to line bore the block but I'd be nervous doing this with the old two bolt blocks. Let us know when you get it run in. It would be cool to know how much power it makes. Cheers. |
castlesid Kevin Jackson Sidcup UK (361 posts) Registered: 11/18/2007 10:38AM Main British Car: 1975 MGB GT Rover V8 4.35L |
Re: Buick 300 Crank.
Nick,
With a plentifull supply of 4.6 cranks it makes sense to have one offset ground to increase the stroke and for a cheap solution you could possibly machine a mm. off the top of the 4.6 pistons to maximise the stroke with all standard component although not for race use. When i get the new engine tested I'll post the results. Kevin. |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Buick 300 Crank.
Kevin, by the way, how did your 4.35L. Rover run-out at the drags? I would like to compare notes with anyone running roller cams in these engines. Anybody? Good Luck, roverman.
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castlesid Kevin Jackson Sidcup UK (361 posts) Registered: 11/18/2007 10:38AM Main British Car: 1975 MGB GT Rover V8 4.35L |
Re: Buick 300 Crank.
Art,
I didn't get there unfortunately as was a little unwell and I still have a cooling problem to solve. It seem I am getting an air lock just behind the thermostat and although I have cleared it a couple of times it keeps coming back! On start up the thrmostat does not open until you give the engine a quick blip of the throttle and you can then feel the header tank immediately heat up. I have been advised by other people using the performer manifold that it is quite common and that you need to drill one hole each side of the inner housing area through to the waterways that connect to the heads and that balances the system. I'm still not sure as I have run this manifold unmodified on my previous 3.5 engine and never had any cooling issues, any thoughts? Being paranoid about cylinder cracking behind the liner I had the coolant checked for hydrocarbons and it was fine so unlikel to be a liner or gasket problem. Kevin. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Buick 300 Crank.
Kevin, it's common to have a 1/8" hole through the thermostat plate itself which will let the air through. Position it as high as possible and if you find you prefer not to have it you can just change out the thermostat.
Jim |
Dan Jones Dan Jones St. Louis, Missouri (280 posts) Registered: 07/21/2008 03:32PM Main British Car: 1980 Triumph TR8 3.5L Rover V8 |
Re: Buick 300 Crank.
> I'm still not sure as I have run this manifold unmodified on my previous 3.5
> engine and never had any cooling issues, any thoughts? I drilled the holes on my Performer and ran a bleed nipple from the intake to the fill tank in my TR8. If you have an Offy Dual Port or Buick intake manifold, you'll see both have the holes cast in. IIRC, the Offy's were larger. I did the smaller ones like the Buick. You can see where the bleed is positioned (on the triangular pad right behind the thermostat housing) in this picture: [thewedgeshop.21.forumer.com] Woody sells the stainless fitting for $16: [www.thewedgeshop.com] I've had no cooling problems with these modifications. Dan Jones |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Buick 300 Crank.
Probably overkill, but anyone tried a choke cable controlled, butterfly, barrel or ball valve for themstat? roverman.
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castlesid Kevin Jackson Sidcup UK (361 posts) Registered: 11/18/2007 10:38AM Main British Car: 1975 MGB GT Rover V8 4.35L |
Re: Buick 300 Crank.
Dan.
Thanks for confirming that it's an effective mod, just don't understand why I didn't have any problems with my previous engine with the standard Performer manifold. Jim, Have the MGBV8 stat with the bleed valve at the top but doesn't have any effect as engine will warm up very quickly and the stat will not open until you give the throttle a good blip! Kevin. |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Buick 300 Crank.
It does sound like there is an air pocket behind the t-stat. The vent Dan described would remove that air to the surge tank. The port in the t-stat itself does the same thing only it will not get rid of the air at the very top of that chamber (which shouldn't really matter). I'd suggest maybe another hole or enlarge the existing one. If your t-stat housing is at or near the high point in your system, all of the air will go there when the engine is stopped. You have to purge that air before water can get to the thermostat and that could take a good while, what with the water pump recycling some of the air through the bypass hose (this provides water circulation around the thermostat during warmup). A 1/4" hole in the t-stat plate would not be too large under those conditions but 3/16 would probably work nearly as well. (1/4 will flow 4 times as much as 1/8"). If you get a quick warmup the opening is not too large.
But an important question, are your heads higher than your radiator top tank at any point? If they are you should be running a well designed surge tank to prevent steam pockets from forming in the heads and a vent line from the t-stat housing to that tank is a good idea. Jim |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Buick 300 Crank.
Well then it looks as if a larger bleed placed as high as possible should do the trick. Nice thing is, if it doesn't work out it's easily put back the way it was. For the vent line you need a place for it to go.
Jim |
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castlesid Kevin Jackson Sidcup UK (361 posts) Registered: 11/18/2007 10:38AM Main British Car: 1975 MGB GT Rover V8 4.35L |
Re: Buick 300 Crank.
Jim,
I'll do the holes in the manifold behind the stat first and if that doesn't completely cure the problem then fit the bleed at the top as Dan suggested. I suppose i could tee it into the hose between the header tank and the expansion tank as shown in the picture, basically the cooling system I have is standard MGBV8 ie a V8 rad with a standard MGB expansion tank. I still can' get my head round why the change of engine has caused a problem, although it's a common problem with rover V8 cooling systems getting airlocks. Regards, Kevin. |