Billman250

I need to experiment with some parts I have here. I'd like to know how close the tolerances are held from cap to cap, or 1-5 capsets, or 5 capsets to cyl head.

I'm confident moving a complete set (5 lowers and 5 uppers) to another head is not a problem, I've done it a few times.

The question is are they line-bored, after they are attached to the head.
This would explain why you can only buy a cyl head with upper and lower caps.

Or are they held to their own individual tolerances, based on the positon of the dowel pins...

ChefJ

I understand that they are labeled 1-5 but they all appear to have the same shape and bolt pattern. They all have a bolt for the valve cover but IIRC it doesn't effect the caps at all its just the bolt.
I don't want to talk about wrong info but you may be able to use a different position in your case from a different car. #2 may fit your #1.

Anyone have insight??

Stratocaster

I am running a set of caps swapped from another head. All things are fine. I know I am not the only one either. As I have sold a set of caps (tops and bottoms) in the past. I think the tolerances are so close that they can be swapped. Honda makes a quality product.

jzz30

if anything a good machine shop can clean it up if you do find a replacement cap.

jimknapp

First question is, did you loosen all of the lash adjuster nuts all the way out before you tightened down the caps? I'll assume you did.

I run caps up and down, and on and off all the time while I'm doing degreeing in of camshafts and it doesn't seem to hurt anything. However, I am using a head with very light weight springs in it and a notch cut in the back so I can see the valves and how they clear the pistons. But I will run a head with only the intake side installed, or only the exhaust, or only the # 1 and # 4 cam towers installed. Point is I yank the caps on and off all the time with no problems, so your problem seems really weird

As to fixing it, yeah any good machine shop should be able to weld it back together and then align bore all five caps. But I'd be inclined to move the "wounded" cap to 2, 3, or 4 position just to be safe.

And just so you don't think it's all rosy out here for everyone but you, see my other post about a destroyed top end question.

All the best,

Jim

mxt_77

^ While I haven't done as much swapping as jimknapp, I've also swapped my cams 4 or 5 times and haven't had a problem. I'd definitely question whether the installation procedure was followed properly.

street_ruler

they are bored out with each head. like they put it on end and bore out the holes.

i dont know if the lower parts are removeable but if tehy are that may be a saving grace. if not, you;re boned.

jzz30

it broke at its weakest point. more than likely from installation error

street_ruler

oh that can be welded no problem.


its if they snap and the ridge/seat for the cam is affected. aslong as youare able to keep thetolerances good you are fine. just put it on the car, tack it well and then finish weld it. you will really only get one chance so do it right the first time. you will need to lay a small bead at a time cause if it expands and you weld that sucker shut it will push the cam seats (the part where the cam acrually rides on a think film of oil...the arch) outward and not be within tolerance...although at that point you may be albe to hone it out a bit to work but nothing is certan

street_ruler

personally after discovering that the cam tpower is replaceable (cap and seat) i would do that then take the head to a goooood machine shop and ahve them check the alignment with the other towers.


welding in my mind is a last resort with cam caps but it is doable.

also im from the world of b20a5 and b21a1 preludes....heads are about 120-150 for a complete with manifolds