Slow Blowthru engine build.

WarWagon

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Mar 10, 2007
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SLOW meaning build time. I'm in no hurry to slap some skill level model 1 tegether. The stock '85 140 casting engine I'm running now in blowthru configuration although old and tired (180K+) is still in good health and I'm going to continue to race and beat on it in the "Repeat procedure thread".

Originally I had two blocks to choose from for this build: '84 297 casting 4.1 block that I ran in factory drawthru mode. And what I thought was a'83 turbo block ends up being something else completely. A 397 casting block, weird 14 bolt FWD Turbo Riviera but it had '81 drawthru system on it. This was my MK 1 blowthru build engine before I hurt it and lost #2 cyl.
I was going to go with the 4.1 and build it for this project no doubt for sure then I started buying the rest of the parts and decided to change to a 109 casting block.
I bought a .030 bore 109 then a 20 bolt oil pan and timing cover with plans to go .040 with it and get forged Probe pistons with the nice narrow updated ring pack on stock rods and stock turbo crank.
Then found a local Built 109 .030 bore, O ringed grooved deck surfaces, #2 &#3 Billet main caps, front cam bore is grooved behind bearing, Stock turbo crank and stock 2 dot rods with Speedpro .030 Forged pistons. But it has one issue : #2 has a small section broke off the bottom inboard side facing the cam. Wasn't sure if it was going to be ok to run even though it was broke so low in the cyl. Going with a Comp 206/206 roller cam and what I believe are 885 lifters and a roller cam button. Iron heads is what this build uses, I have what some call Stage Jr's. No EGR or exhaust riser passages. Al (slamming6) has all credit for the bowl and port work. They have stainless exhaust valves and stock intake valves faced and 30* back cut. I sent them off to local head shop to have them surfaced and a three angle valve job, guide shortening and exhaust guide replacement. Going to use HD shafts with stock rocker arms, probably run Comp 6918 beehive or 941 valve springs. I have a set of Comp 6915 beehive springs with retainers and locators too. I'll reuse the intake and headers from the current engine, probably RJC shim head gaskets.
Pics of the built 109:






 

WarWagon

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Mar 10, 2007
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Stage Jr Iron heads, dirty from sitting:






Back and repaired from the local Head shop:



Comp 206/206 roller cam setup:
 

mikemcvaney

Active Member
Apr 20, 2009
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That thing should be stupid fast with all those goodies cant wait to see it together.
 

WarWagon

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If I consider using the o ringed block to build with the chipped cylinder. I do not want to use a o ring head gasket I 'd rather it be a fuse. What style of gasket could be used and seal on the o ring groove on this block?
 

dr_frankenstein

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Mar 17, 2008
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what we need to do is get the dimensions of the wire groove. then we can decide on wire thickness needed for the crush amount desired with the heads and pound it in.

but i wouldnt really see it being much of a fuse....

every head ive done with a wire groove goes one of 2 ways.... seals totally awesome and blows the bottom end out or it leaks like a sive and its a nightmare to get them to work right. Thats why so few around here do it... there like a bunch of variables that make the machining process the hard part.
 

fuzzyGN

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May 3, 2002
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I had a set of heads with the O-ring grooves in them that were going on a N/A 4.1L. I ended up milling the heads until flat. I sure didn't want to mess with them and I feel in 99.5% of the engine builds they are unnecessary. Mill them out and get a little more compression.
 

WarWagon

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I definitely don't want to use the o ring feature, the history I have on this block is the owner blew head gaskets twice and pulled the engine. I was told that it wasn't running o ringed gaskets both times they had blown, just a standard head gasket.
 

dr_frankenstein

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Mar 17, 2008
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Something sounds amiss, why didnt the original owner use the O-rings?

I think at this point, the o-ring grooves were probably done wrong and the original owner knew it...
 

dr_frankenstein

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Mar 17, 2008
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This is going to be hard to get past, filling the grooves will be marginal at best..... IMHO measuring the grooves to determine if there correctly machined would be the best case of action. if correct use an o-ring since the cuts are in the block.... if not another block would be a better choice. O-rings are so hard to get right simply because of the bore to head relationship has to be well established before the cuts are made, which entails tons of mock-up.

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fuzzyGN

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How deep are the grooves in the block? What is the deck height of the block? Basically, is there enough meat left to deck the block to rid yourself of the grooves? That would still be my first choice if all measurements come out acceptable.
 

WarWagon

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Lost a stock head gasket on the 140 block and Im not putting anymore $$ in it. Going to finish building the 109 and install it. Changing the block direction to my other +.030 109. Plan on cleaning up the used overbore and running the set of used .030 over TRW forged pistons I have, pulling a good crank, balancer, flexplate out of my old '83 block.
 

WarWagon

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I'll get another new double roller timing set and new stock oil pump gears to use in a spare 109 timing cover. Setting up new valve springs on these worked iron heads is about the only real thing left to figure out. Once the short block is together I have a set of Felpro 9441pt head gaskets to use along with new head bolts. I'll re use everything on the exhaust and induction side from my 140 block except the 60-1 turbo, keeping it for backup. I'll be stepping up to a 6265 built by Bison. Just untill next spring I'll have to keep the 10" PTC converter for now but it will be upgraded to 9.5
Will Comp 941 springs fit on a stock retainer? Will stock rocker arms be alright with Comp 206/206 roller cam for now?
 

charlief1

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Sep 20, 2007
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Shouldn't have a problem with the rockers but you might look at getting a set of HD shafts. The shafts are more prone to breakage under heavy pressure. If you feel like getting a set of rollers someone on evilbay is offering harland sharps for about $500 shipped.
 
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