Decking block and extrued honed cyl

[fasttrucker]

I was talking to rootys on the chat room last week.He asked me why i was/mech. was doing to the block in the machine shop.So i checked a little deeper into the reasons why.It seem you gain compression when you deck plane the block.I was told that you gain more compression then when you do the heads alone.The extruing honed cly-helps with the oil consumption,i was told that the engine cly are not true/round out of the factory and that by doing this the rings/oil bypass is improved.Anyway the machine shop says all will be ready monday.I hope. :rolleyes:

[Greg K]

I hope you mean trueing and not extruding. Never seen cylinders being extrude honed. Extrude honing is usually done on head ports and intakes.
Extrude honing is a process of moving an abrasive fluid like media to smooth out surface and sharp edges.
The cylinders should be align bored to the crank to true them up, then honed for finish and final tolerances.

[Rootsy]

This still doesn't make all that much sense Fast. As Greg said, ExtrudeHone is the process of forcing an abrasive putty back and forth through intake and exhaust ports in heads and manifolds in order to remove restrictions, it does not open the ports up, just removes restrictions.

Decking a block or head does improve compression ratio but honestly it is much cheaper to use a thinner head gasket and exactly what are they targeting for a static compression ratio? hopefully not more than the low 9's... you are probably burning premium as it is with your ECU modifications... They should be worrying more about quench distance than compression ratio really.

Did your motor use oil? did your mechanic measure the bores to verify that they were out of round and by how much? If so and they are honing it then i hope they are installing and gapping new rings and checking piston clearances. i have never run into serious roundness issues with bores in factory blocks... btu then again i am a small block guy... the BBC may in fact have an issue...

i tend to be skeptical when folks start doing all kinds of machine work on a motor with 150 hours on it... although you said you had 3 burnt valves... which is NOT a good thing... i'd be worried about that, this tells me you are running into a lean condition and it needs to be fixed. Did you end up scoring cylinders? this may be the reason they are honing cylinders.

[BigGrizzly]

Fast I don't want to tell you this. I heard of your situation from another board member. I have been doing engines for over 40 years and either your machanic is stroking you or you havn't a clue what he is doing. Big point he said YOU HAD 3 Burnt valves but you didn't notice it and your speed was acceptible for your boat. I question why the valves burnt or if they were truely bad. If they were burn't mabe that modified ECM did it! It is true some race shops actuall hone oversize rather than bore. It seems every time you turn around something else is wrong or there is a special thing(read that dollars) getting done. The old 454 did have a cylinder problem if over heated but that stopped in the early 1990's. I hope this guy is straigh, or just is using an excuse because your moter isn't done yet. any3way be carefull and good luck.

[Klingon]

3 burnt valves! You are diffently going to feel that in the performance of the motor. You are basically running a 5 cyl and besides the loss in power there will be a noticable roughness/vibration in the motor. If the valve are truly burnt then look to a lash problem, like the valves never really closed or an extreme mixture/timing issue. You might want to get the valves in your hand to see how they are burnt.
Anyway on a motor with only 150 hours I would question why doing any reboring of the cyliners unless a valve piece damaged the sidewall.

[MOP]

I am not up with the speed guys but was wondering about the decking issue. To my thinking when you cut heads, the chambers gets slightly smaller, but decking the chambers stay the same. So compression would be boosted more with cutting the heads than the block.

I to think you may be getting Hosed!

[Rootsy]

MOP,

cutting the chambers does reduce the volume yes. cutting the deck of the block reduces quench distance (distance from piston top to bottom of cylinder head). it is all a matter of how much volume you remove overall that determines how much compression gets boosted.

and i like the others are concerned and i would be asking serious questions. first and foremost when you took the boat to have stuff done was it running strong? and you just wanted more ooomph? i just HATE seeing hard working folks who may not be totally knowledgable on the subject get taken buy someone and it happens too often.

[MOP]

Rootsy as you can probably tell I try to help the shallow pocket guys, me being one of them. I can help out with the older stuff that I worked with but the new stuff I leave to the sharp new guys. I did a bunch of racing in the late 50's and quite early 60's. I was very lucky to be on the tech crew at field 5 down at Eglin AFB in the 50's. I got to meet some very good and some guys that went on to be famous that were nice enough to share some really good tips and some parts. I held the E gas record for awhile down there, it was a flat head and 6 cyl class. I ran a 292cu Chevys then went on to 302 GMC's with Giovanni cams, was a hard head. Most of my club members went to SB's which after awhile scorched my 6's. So I did finally give in and built Lula Bell a 37 Chev coupe 283 out to 301 Shaller 1/4 speed cam, dual quads and home made headers that depending on the day teetered between low 13's and high 12's. Then I was finally considered one of the boys. Early 60' I was heavily involved with the building of Bernie Shackers blown dragster boy was that slow by what I see running today. That was the last of the hot stuff, I went on to pay for muscle cars. The guy that from way back at field 5 that was my idol was The Don. He used to show up with a ratty Ford P/U and a dragster with a galvanized pipe frame in those days. We all know how he ended up, I ran into him at a diner about ten years later, it was after the drags at Westhampton on Long Island, I was floored when he recognized me from the old days on the tech crew. I again visited him at his museum in the 80's. He is still my Idol and a very fine gentleman.