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4.5 stoker question

9K views 28 replies 11 participants last post by  Mark Laczo 
#1 · (Edited)
I have a dove A block and wanting to build a 545 drag motor, I have questions after reading that a ford truck block should be used for its longer cly wall. should I be concerned or will a special piston skirt help or is there anything that can be done running a dove block. Has anyone had problems running this combo turning 7200 rpm
 
#4 ·
4.500 6.700 is really no problem at all in a DOVE block it'll work just fine. The differences in strength between a DOVE and any other production block are not a big factor.
 
#6 ·
4.500 6.700 is really no problem at all in a DOVE block it'll work just fine. The differences in strength between a DOVE and any other production block are not a big factor.
No,but the 4bolt main caps sure are easier on the thick webs.:)
 
#9 ·
I ran my 557 with a D1ve block with a 4.5 stroke and 6.7 rods for years with no problems. Never went with 4 bolt main caps because it was too expensive for machine work, AND the fact that the webs tend to crack where the splayed bolts go like 68xr7cat said. The set up had a tunnel with dual quads and a big cam, on the dyno made 836, and 718 at 7000. Just my thoughts......
 
#10 ·
Like dave said.... with a race only engine it aint a big deal. It would be if you were in your truck that was driven to work and back every day.

The D0VE mains are a better platform to install 4 bolt caps on...but... the 2 bolt blocks I've seen crack have not done so out by the pan rail where the D0VE are thicker. All have been from a main bolt hole to the cam bearing tunnel.....mostly at #2 main saddle.

Cap walk is cap walk and it is something most people can live with....untill.

Looks like the D0VE 2 bolt blocks were a design that offered Ford the option to install either main cap to the block....4 or 2 bolt.
 
#11 · (Edited)
Bull Crap

Thank you Dave McLain & Lem for the facts. It's way past time for there to be any more misinformation about this subject.
Paul Kane has posted the info on a very inexpensive and very proven way to 4 bolt a non DOVE block. It cost me just over $300 each to do them, this includes the caps, bolts, line bore and hone. Several others on this forum have used the info that Paul provided and are very happy with the results.
XR7 & Pro Pony PICS PLEASE
 
#13 · (Edited)
Thank you Dave McLain & Lem for the facts. It's way past time for there to be any more misinformation about this subject.
Paul Kane has posted the info on a very inexpensive and very proven way to 4 bolt a non DOVE block. It cost me just over $300 each to do them, this includes the caps, bolts, line bore and hone. Several others on this forum have used the info that Paul provided and are very happy with the results.
XR7 & Pro Pony PICS PLEASE
Bull Crap??? LOL here is your picture. As for your conversion method, was NOT what Dave McLain was talking about and BT caps are not cheap.

Regarding the outer bolt size anyone with common sense would understand drilling a hole in a web weakens it and when you look at the section width in that area any machinest worth anything would understand what I an talking about and why some prefer to use a smaller diameter bolt when converting a thin web block.

As for your method still more work than converting a D0VE-A just saves money on the caps and for a lot of guys, right or wrong when they see those little spacers it is a hard sell. They think it is something someone did in their basement. Not to mention you still have less material in that area.

Regardless seems to still be a good number of D0VE-A blocks around at reasonable prices (not everyone asks a premium...), so why bother with a thin web block unless you have a lot of money in it.
 

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#14 · (Edited)
XR7cat I never thought Dave McLain had ever seen the conversion I have done ? Second issue is I don't have a basement !! Third is I'm not selling anything to anyone !! It's just free info that might be of interest to anyone but you. I do not sell blocks 4 bolted or not and do not offer that service.
The pic is of a major explosion and not related in any way to a 4 bolt conversion, and is a far stretch from THEY CRACK
I think on the next block I 4 bolt I will use 1/2 " bolts in the outer holes as mine go far into the block well past the damage in the pic.
Does anyone have a pic of a cracked main web on a splayed 4 bolt conversion on a non DOVE block.
 
#16 ·
Vandy that picture was posted originally on this forum by Car by Carl and used to say a 4 bolt block can fail with no detail. You asked for a pic of a thin web block cracked at the outer bolt holes and you got it. Your request was an insult.

Now do I personally have a picture of a thin web block cracked NO, have I seen one yes. I also have seen a #2 main cap broke on SVO block too and NO I do not have a picture of that. I'm sure most builders and racers don't take a picture of everything to document on an internet forum. You don't believe my word well that is your problem.

Paul you dragged yourself into this thread and while you are at it drag yourself into this thread and correct Carl too...

http://www.460ford.com/forum/showthread.php?t=159690&highlight=4+bolt+main

Paul I do agree with you that in general ALL the OEM blocks are good and will easily hold 850hp no issue and should not say otherwise.


Vandy you just want a pissing match and say you are right. Paul you chimed in to help out your buddy. I'm tired of hearing about 2,000 hp nitro crap and all the rest of the BS. Guys have run that stuff since the 50's on all sorts of engines not just BBF and some pop and some live awhile. In fact most nitro stuff is SBC, BBC, and Mopar hemi. The magic to that is not yours.

I have no issue with using any OEM block and the statement that they all hold up about the same. What I do have an issue is saying no difference when converting to 4 bolt mains. The value of a D0VE-A block is in converting to a 4 bolt main. You want to be a smart a** and put 1/2" outer bolts in a thin web block be my guest. You prove nothing. I know of a late model stock 302 block that was raced for years at 800 hp and survived and was retired to truck use. No I do not have pictures of that either.

It all comes down to probability and common sense. Your prove it by show me a picture well I don't need your condescending prove it crap. You do things your way and other more knowledgeable guys will use a D0VE-A.

Steve
 

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#17 ·
4.5 stroker

I have been building this engine for over a year, rather saving up and buying parts when I could afford to, Engine venders and engine builders have given me some great advice and try and keep us who are not as experianced on track. This is priceless to us who ask for advice and know we are asking those who tried different avenues, things that worked for them and things they have tried that did not work. I am shooting for 850 hp with this build and purchased a dove a block from this site. I wanted to know if I should have purchased a truck block because of the longer cly. wall it has. Worried about piston rock at bdc with a 4.5 crank and 6.8 rod and if the dove block would be OK to use. Are there any mods that should be done. Thank you all for such a great site were everyone benifits from your knowledge.
 
#18 ·
block

On my build 557", (4.5" crank, 6.8" Alum rods) I followed Paul's oil mods for the block, I did a half fill cement job, and I installed the Milodon 4-bolt caps.

I also used the wider cam bearings from Randy Malik. I used a double pinned cam with a 7/16 bolt and nice thick washer.

My build is in the engine build section way back, I came out right at 850hp.

Just curious what heads are you going to use.

FWIW Mark
 
#23 · (Edited)
On my build 557", (4.5" crank, 6.8" Alum rods) I followed Paul's oil mods for the block, I did a half fill cement job, and I installed the Milodon 4-bolt caps.

I also used the wider cam bearings from Randy Malik. I used a double pinned cam with a 7/16 bolt and nice thick washer.

My build is in the engine build section way back, I came out right at 850hp.

Just curious what heads are you going to use.

FWIW Mark
Kassee P-51 your build sounds great. will be looking forward to reading it thanks, Bob
 
#19 · (Edited)
It may have already been stated, but if he uses the longest rod possible wouldn't that help negate piston rock by putting the wrist pin/piston farther up in the bore at BDC as compared to a shorter rod on the same stroke?
I have never built a stroker engine but imo I would rather have the meat in the saddles for the 4-bolt conversion than a few tenths deeper cylinders in a 850hp engine. It seems to be a compromise in any event.
Edit- I just read this entire thread over, and what a pissing match this has become. I have never seen a broken saddle in a BBF so I am very limited in what I can say BUT- I know people have had their experiences, some a lot more than others. But it makes structural and dimensional sense that 4-bolting a thunderjet block could increase the chances of breaking a saddle out from in between the pan rails. You are making the block more rigid by 4-bolting it so, of course it may break at the stress riser when it is trying to twist, right at the saddle/pan rail intersect where the added bolts are.
Like I said J-M-H-O!
 
#22 ·
Your structural sense conclusion sounds right to me if the 4 bolt conversion was done way wrong. The correct way to 4 bolt with splayed bolts is to use very strong and long outer bolts that go through the main web and deep into the large mass beyond. The outer bolt is used to strengthen the main web not weaken it. I have been installing and using 4 bolt splayed caps since my early hemi days. On the 392 the main webs there is even a large hole cast into the main web. Everyone that I know drilled the splayed bolt through into the water jacket because that was where the mass strength was (well past the main web). The block in the pic posted did break beyond the outer bolt at the point where the large mass begins. I do not know if there is a sheared off bolt remaining in that mass. I will not draw a conclusion that a properly done 4 bolt conversion weakens a non Dove block based on a pic of a catastrophic engine failure.
 
#21 ·
Steve,

Please go back to Post #15 and re-read it. The only matter I discussed is my disapproval of the use of an image to support a statement to which the image has absolutely no relevance.

If you want to discuss pushing OEM blocks to their limits--even the risks involved and higher chances of failure--then that's fine with me.

Paul
 
#25 ·
2 bolt caps on thin web blocks

I like to use 2 bolt billet caps for milder build's. My thought is the billet cap will flex less and not want to pinch in like a cast cap. Program Engineering has these.

For thin web 4 bolt conversions I don't care for the splayed caps as they seem to stress the web with their 7/16" and some 1/2" outer bolts. They eventually will crack.

I like CJ caps for the thin web conversions. The outer verticle 7/16" bolt will align with a tad bit more meaty area of the thin web vs the spalyed cap. Just mill the register completely off and use the 5/16 dowell for locating the cap. Started this about 25 years ago when we ran out of DOVE blocks for awhile. Was really suprised at how well it worked. Program has these as well.

I also think that filling the block can offer more stability for the main webbing.

Just a note: the Ford FR9 Cup engine uses verticle outer bolts on it's caps. I realise that is is pure race engine, just thought I would put it out there for info.
 
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